Article abstractTwenty-three patients with hemifacial spasm were studied clinically and electrodiagnostically. Seven patients had mild facial weakness. All patients had clinical evidence of synkinesis, which often varied considerably. Facial nerve conduction and blink reflex latencies were normal. Facial synkinesis could be measured objectivelyon the involved side in all patients by simultaneouslyrecording from the orbicularis oculi and orbicularis oris muscles at the time of supraorbital nerve stimulation. Using this procedure, synkinesis was also observed in association with aberrant regeneration after Bell palsy but was not seen in other movement disorders involving the face. The demonstration of synkinesis and its variability in hemifacial spasm can be of value in differentiating hemifacial spasm from other movement disorders affecting the face and provides further insight into its pathogenesis. NEUROLOGY 29: 1261-1272, September 1979
Hedacial spasm: Clinical and electrophysiologic observations Raymond G. Auger, M.D. Hemifacial spasm is characterized clinically by habit spasm, tardive dyskinesia, and aberrant reparoxysmal bursts of involuntary tonic or clonic generation after facial nerve injury. If one of these activity occurring in muscles innervated by the conditions presents in an atypical manner, the facial nerve on one side of the face. The spasm diagnosis may be difficult. rarely occurs bilaterally.’ We studied patients with hemifacial spasm clinAlthough many early accounts of facial move- ically and electrophysiologically to establish ment disorders probably included hemifacial criteria that would aid in differentiating hemifaspasm, the authors tended to group these disorders cia1 spasm from other movement disorders of the into the single entity “tic non-douloureux.” It was face. The study was also undertaken to measure Gowers2 who clearly distinguished hemifacial objectively the phenomenon of synkinesis, present spasm from other movement disorders of the face. to some degree in all patients with hemifacial Brissaud3 established criteria t o differentiate spasm. habit spasm from hemifacial spasm, and since then, several articles have described the clinical Methods. Twenty-three patients with clinically features of the latter.4-6Although most cases of diagnosed “cryptogenic” hemifacial spasm were hemifacial spasm are “cryptogenic,” the condition seen during the 24 months from December 1976 to has been attributed to compression of the facial November 1978. Special attention was given to the n e r ~ e . ~Gardner -l~ and Sava13 and Jannetta and presence of weakness and associated movements associates14suggested that vascular compression in muscles of the face after blinking and grimacing of the facial nerve is frequently the cause, with (facial synkinesis). None of the patients had a hisremission following vascular decompression. tory of Bell palsy or other evident facial-nerve Although hemifacial spasm differs from facial trauma. All patients had roentgenograms of the myokymia clinically and electromyographically, head, including views of the internal auditory the two terms are often used s y n o n y m ~ u s l y . ~ canals, ~ and all findings were normal. Eleven paHowever, facial myokymia presents clinically as a tients had computed tomographic (CT) scans; two fine, continuous, undulating movement involving patients had brainstem auditory evoked responses, and one patient had a vertebral angiomuscles of the face, usually unilaterally, and there is commonly little or no difficulty in differentiat- gram. Results of all of these studies were normal. ing this type of movement from the clonic and tonic Patients with disorders that mimic hemifacial spasms of hemifacial spasm. Moreover, the elec- spasm were also studied: seven patients with estromyographic patterns differ.l 6 sential blepharospasm, one patient with frequent Other conditions that can be mistaken clinically focal seizures of cortical origin involving the musfor hemifacial spasm are essential blepharospasm, cles on one side of the face, one patient with severe focal cortical seizures involving the facial muscles, tardive dyskinesia resembling hemifacial spasm From the Department of Neurology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota. Accepted for publication February 28, 1979. Dr. Auger’s address is Department of Neurology, Mayo Clinic, Rochester, MN 55901.
September 1979 NEUROLOGY 29 1261
Hemifacial spasm in some respects, and two patients with facial myokymia. In addition, we studied four patients with aberrant regeneration after Bell palsy. Electrodiagnostic studies were carried out with the patient lying supine in bed in a warm room using an electromyograph (TECATE4). The facial nerves were stimulated directly with a two-prong stimulator with the cathode behind the earlobe and the anode over the mastoid process. Squarewave stimuli of 50 to 150 V and 0.1 to 0.5 msec were used to produce a maximal response to nerve stimulation. Recording electrodes consisted of 6-mm tin disk electrodes held in place by tape (BlendermB) over the quadratus labii superioris muscle group beside the nose or over the inferior portion of the orbicularis oculi muscle. The ground electrode, consisting of a 2.0-cm-squarelead plate, was placed over the chin. Recordings were made on a cathode-ray oscillograph using an amplifier with a frequency response from 1.6 Hz b 8 kHz (3 dE3 attenuation). The sensitivity was 0.5 or 1.0 mV per centimeter, and the sweep speed was 2.0 msec per centimeter. Permanent tracings were made on direct-print photorecording paper. The latency of the initial response of the muscle was recorded, and the amplitude was measured from t h e baseline to the maximal negative deflection. For blink-reflex studies, the supraorbital nerves were stimulated percutaneously with a two-prong stimulator with the cathode over the supraorbital notch and the anode on the forehead. Square-wave stimuli of 0.05 to 0.2 msec duration at 50 to 200 V were delivered. Six-mm tin disk recording electrodes were placed 2 t o 3 cm apart, one over the inferior aspect of the orbicularis oculi muscle laterally and the other at the lateral angle of the orbit. The stimuli were of such intensity that both the early and late responses were just maximum and nearly stable upon repeated trials. Shocks of the same intensity were delivered to each side in each subject. The ground electrode was placed over the chin. Cathode-ray oscillograph recordings were made from the right and left orbicularis oculi muscles simultaneously by means of two amplifiers with frequency responses from 32 Hz to 3.2 kHz (3 dB attenuation). The gain was set at 200 pV per centimeter, with sweep speeds of 5 to 10 msec per centimeter. A minimum of five superimposed responses to stimuli given at irregular intervals a t least 5 seconds apart were recorded for the right and left supraorbital nerve. Permanent tracings were made on direct-print photorecording paper. The latencies of the initial deflections of the ipsilateral early and bilateral late responses were measured. The amplitude of the early response was measured from the negative to the positive peak. To measure the presence or absence of synkinesis involving the facial muscles, the supraorbital nerve was stimulated on both the involved
1262 NEUROLOGY 29 September 1979
and the uninvolved sides in a similar manner, and recordings were made simultaneously from the orbicularis oculi and another muscle innervated by the facial nerve, usually the orbicularis oris, using a concentric needle electrode (DISA 13L50) inserted into the muscle. Spontaneous and voluntary muscle activity were studied with a concentric needle electrode in the orbicularis oris muscle on the involved side in all patients and in the orbicularis oculi muscle in most patients. To measure the pattern of motor-unit discharge during tonic and clonic spasms, units were isolated by means of a bipolar concentric needle electrode (DISA 13K13). Recordings were made on a cathode-ray oscillograph by means of an amplifier with a frequency response from 32 Hz to 16 kHz (3 dB attenuation). The sensitivities used were 50, 100, and 200 pV per centimeter and the sweep speed was 10 msec per Centimeter. At the same time, recordings were made on an FM tape recorder (Ampex Model 306-1, one-channel FM tape recorder). The tape was subsequently played back, and selected portions of the electromyograph were photographed on direct-print photorecording paper at paper speeds of 10, 50, and 100 cm per second. When playing back the recordings, a high-pass filter was used to reduce artifact from background muscle movement and distant motorunit activity. This filter had a lower cutoff frequency of approximately 500 Hz.
Results. Clinical data. The ages of the 23 patients with hemifacial spasm (11 men and 12 women) ranged from 38 to 76 years, with a mean of 57 years. The duration of symptoms before examination was 1 to 25 years, with a mean of 5.6 years. Eleven patients had involvement of the left side, and 12 had involvement of the right side. No patient had bilateral hemifacial spasm. One patient had trigeminal neuralgia involving the maxillary division of the trigeminal nerve on the contralatera1 side. Three patients reported past temporary remissions. In one patient, the remission lasted 4 months and seemed to occur after a head injury from an automobile accident. In another patient, a spontaneous remission lasted approximately 2 years. In a third, a spontaneous remission lasted 3 months. In each patient, the spasm recurred. Seven patients had minimal weakness of the orbicularis oculi or orbicularis oris muscles on the involved side. All patients had synkinesis on the involved side, most prominent during and for several minutes after a spasm. In many patients, the associated movements could be seen only on close observation and consisted of simultaneous contraction of the orbicularis oris, mentalis, or platysma muscle when blinking or simultaneous contraction of the orbicularis oculi muscle when grimacing. However, when patients were observed
during quiescent periods, free of hemifacial spasm for several minutes, persistent synkinesis was not nearly as severe. In fact, in some patients, no clinically evident synkinesis was seen if the patient had been free of spasm for several minutes. Aside from the Endings relative to facial-nerve function, results of the neurologic examination were essentially normal in all patients. Electrodiagnostic observations. No statistically significant difference was noted between the involved and the uninvolved sides in the latencies or amplitudes of the responses obtained on direct facial nerve stimulation or on supraorbital nerve stimulation. With direct facial-nerve stimulation, the mean latency was 3.3k0.5 msec on the involved side compared with 3.3 ? 0.5 msec on the uninvolved side. The mean amplitude was 1.9 2 0.8 mV on the involved side compared with 2.0 0.9 mV on the uninvolved side. With supraorbital nerve stimulation, the mean values of early and late responses were within the normal range on both the involved and uninvolved sidesI7(table). The reflex latencies were not significantly different on the two sides. No individual patient had more than a 0.7-msec difference on the involved side compared with the uninvolved side when the latency of the early response was measured. Only one patient had a late-response latency that was 8 msec greater on the involved side than on the uninvolved side; this difference was probably within the limits of normal variation. The most interesting observation pertained to
*
contraction of other muscles innervated by the facial nerve on the affected side when the supraorbital nerve was stimulated. The normal response after supraorbital nerve stimulation is contraction of the orbicularis oculi muscle alone, without associated contraction of any other muscle innervated by the facial nerve (figure 1);this was also true on the uninvolved (normal) side in patients with hemifacial spasm. On the involved side, however, supraorbital nerve stimulation produced a synkinetic contraction of other facial-nerveinnervated muscles on the ipsilateral side (figure 2). Although this phenomenon was demonstrated in all of the patients by recording from the orbicularis oris muscle during supraorbital nerve stimulation, a similar response could be obtained by simultaneously recording from other muscles innervated by the facial nerve (figure 3). Successive responses varied in some patients in terms of presence or absence of the early and late responses and their latencies when measured from the orbicularis oris muscle during supraorbital nerve stimulation. On occasion, either the early or the late response or, sometimes, both responses, did not occur. This was particularly true when the spasms had been quiescent for several minutes (figure 4). In all 23 patients with hemifacial spasm, synkinesis could be detected by this method. An early response from the orbicularis oris muscle coinciding with the early (Ri)component of the blink reflex was seen in all 23 patients on the involved side at some time during the period of observation.
Late response Early response __--Latency (msec) Amplitude (mV)
Ipsilateral latency (mew)
Contralateral latency ( m e )
Involved side 23
23
0.3
36.0
37.0
0.9
0.2
4.6
5.6
9.0-12.5
0.1-0.7
28-48
27-50
Sample size
23
Mean
10.9
SD Range
23
Uninvolved side 23
23
0.35
35.0
35.2
1.0
0.29
3.4
3.9
9.6-14.0
0.06-1.2
28-40
26-41
Sample size
22
Mean
11.2
SD hnge
22
* There w a ~no statistically significant difference between the involved side and the uninvolved side for any of the parameters tested (t test for paired data).
September 1979 NEUROLOGY 29 1263
Hemifacial spasm
fl
a*
Orbic oculi
I
4
R1
t
Or
.
J200
O r is VV
1 O’ms A less consistent response, coinciding with the late (R3)component of the blink reflex, was present in 20 patients on the involved side and was not detected in 3 patients. The mean latency of the earliest response from the orbicularis oris muscle was 12.42 1.6 msec. This latency was significantly longer than the mean latency of the earliest response of the orbicularis oculi muscle (10.9 msec). The difference
Figure 1. Response to supraorbital nerve stimulation in normal person. Simultaneous recording from orbicularis oculi and orbicularis oris muscles. Orbicularis oculi contracts without associated contraction of orbicularis oris. R I = early response; R2 = late response.
was the result of a longer conduction time in the peripheral nerve to the orbicularis oris muscle rather than in other parts of the reflex circuit. Seven facial nerves were stimulated at the stylomastoid foramen in five control subjects while we recorded from the orbicularis oculi and orbicularis oris muscles with the electrode positions used in the reflex test. The latency when recording from the orbicularis oculi muscle was 3.0 2 0.6
*4 p ;
L. orbic oculi
R. orbic oculi
L
R. orbic o r i s
J200
pv
10 ms B
1
Figure 2. Responses to supraorbital nerve stimulation in patient with left hemifacial spasm. Simultaneous recording from orbicularis oculi and orbicularis oris muscles. With left supraorbital nerve stimulation (A), the orbicularis oris contracts simultaneously with the orbicularis oculi (that is, synkinesis is present). With right supraorbital nerve stimulation (B), synkinesis is absent.
1264 NEUROLOGY 29 September 1979
msec, compared with 4.2 t 1.3 msec when recording from the orbicularis oris. The difference was significant ( p < 0.05) and was essentially the same as the difference in reflex latencies, thus accounting for the difference in total reflex time. On the uninvolved side, synkinesis was not present in any patient during supraorbital nerve stimulation. No response of the orbicularis oris occurred while we recorded simultaneously from the orbicularis oculi and orbicularis oris muscles. With the exception of the associated movements that follow Bell palsy or other facial nerve injury, conditions that may mimic hemifacial spasm showed no evidence of synkinesis on supraorbital nerve stimulation. These conditions included essential blepharospasm, focal cortical seizures, facial myokymia, and tardive dyskinesia. The four patients with aberrant regeneration after facial paralysis, however, showed facial synkinesis on supraorbital nerve stimulation, as reported by
other^.^^,^^ However, in contrast to the variable synkinetic response in patients with hemifacial spasm, the response after facial paralysis was stereotyped and did not vary in occurrence in either clinical or electromyographic examinations (figure 5). In hemifacial spasm, the needle electrode examination did not demonstrate abnormal insertional activity or fibrillation potentials. In the absence of a spasm, motor-unit potentials were normal. During the spasm, the abnormalities were similar to those described by others.16,zw23 Brief clonic jerks merged into a tonic spasm lasting several seconds (figure 6). The clonic jerks were of variable duration, lasting from 10 to 200 msec. The interval between bursts also varied considerably, from 20 to 225 msec. The firing rate of individual motor-unit potentials varied form one clonic burst to the next and also varied within a burst. This is demonstrated in
R. orbic oculi R. orbic oris A
R. orbic oculi 4 ' -
v
B
R. mentalis
*
'$
Ne-L
F
p
R . or b ic o c u Ii
R, platysma JZOO 10 ms
C
pv
Figure 3. Responses to supraorbital nerve stimulation inpatient with right hemifacial spasm. (A) Simultaneous recording - ,from orbicularis oculi and orbicularis oris muscles. (Bj Simultaneous recording from orbicularis oculi and mentalis. ( C ) Simultaneous recording from orbicularis oculi and platysma muscles. There is synchronous contraction (synkinesis) of all muscles innervated by the facial nerve after supraorbital nerve stimulation on the involved side.
September 1979 NEUROLOGY 29
1265
Hemifacial spasm
Orbic oculi
A
L---
Orbic oris
Orbic oculi
C
I ,
1,
Orbic oris
-
V
T200rv 10 ms
.
figure 7, a continuous record of the activity of two different motor-unit potentials during three brief twitches. In the lowermost sweep (sweep l),a short burst lasted approximately 10 msec. During this burst, motor-unit potential A and motor unit potential B both fired only once. There was then an interval of 25 msec before the next burst, which lasted 20 msec. During this burst, motor unit potential A and motor unit potential B each fired twice, at rates of approximately 150 Hz. There was then an interval of about 60 msec before the next burst, which lasted 60 msec (beginning in sweep 3 and continuing through sweep 4). During this burst, motor unit potential B discharged seven times, at first firing rapidly (approximately 230 Hz); but toward the end of the burst, the firing rate slowed to approximately 75 Hz. Motor unit potential A, however, discharged four times at an irregular but rapid rate. During a tonic spasm, individual motor unit potentials could not be identified and, therefore, firing rates could not be determined. The electromyographic tracings during a tonic spasm were similar to those of a full interference pattern seen during voluntary contraction.
1286
NEUROLOGY 29 September 1979
Figure 4 . Responses to right supraorbital nerue stimulation. Simultaneous recording from the right orbicularis oculi and orbicularis oris muscles in a patient with right hemifacial spasm. (A) Five superimposed responses obtained when the patient was free of spasm for several minutes. (B) Single response obtained as spasm is beginning. (C)Fiue superimposed responses obtained after sustained spasm. Note variability of response of the orbicularis oris muscle.
Discussion. Caraceni and Negri,24 using a mechanical stimulus t o the supraorbital nerve, studied four patients with hemifacial spasm; they concluded that the latency of the blink reflex was prolonged on the involved side. We found no such difference in latency when an electrical stimulus was used to initiate the reflex. Also, our study did not confirm the observations of Smorto and Basmajian,25who reported the constant presence of an early reflex response on the involved side when the contralateral supraorbital nerve was stimulated. This was not seen in any of our patients. Our results were similar to those of Bohnert and Stohr,26who studied 20 patients, using techniques similar to ours. They also found normal latencies in response t o stimulation of the facial and supraorbital nerves. In only one of their patients was the early response 1.2 msec longer on the involved side than on the uninvolved side. Synkinesis was demonstrated in the seven patients evaluated while recording from the orbicularis oris muscle during supraorbital nerve stimulation. Clinically, synkinesis in hemifacial spasm has been noted by other a ~ t h o r s . 6 , ~ ,Synkinesis ~ 6 * ~ ~ in our patients was well demonstrated by recording
Orbic oculi Orbic oris
Orbic oculi Orbic oris
Orbic oculi Orbic oris 7
J200 pv 10 ms
Figure 5. Responses to supraorbital nerve stimulation. Simultaneous recording from orbicularis oculi and orbicularis oris muscles in patient with facial synkinesis after recovery from Bell palsy. (B) Response obtained 5 minutes after A. (C) Response obtained 15 minutes after A. Note consistency of response of orbicularis oris muscle.
Jzoo
pv
100 ms
Figure 6.Recording obtained with bipolar concentric needle electrode i n orbicularis oris muscle during hemifacial spasm. Several brief clonic spasms occur at irregular intervals (upper tracing), culminating in sustained tonic spasm (lower tracing).
September 1979 NEUROLOGY 29 1267
Hemifacial spasm
simultaneously from the orbicularis oculi and orbicularis oris muscles or from other facial muscles while stimulating the supraorbital nerve. This technique provided an objective method of studying synkinesis, particularly when it was difficult to detect clinically. In patients with hemifacial spasm, the orbicularis oculi muscle contracts simultaneously with other facial-nerve-innervated muscles ipsilaterally, but not on the asymptomatic side. Lambert, Love, and MulderZ8commented on this phenomenon in hemifacial spasm and noted its absence in facial myokymia. Others also used this technique to study aberrant regeneration after facial nerve paralysis, noting a similar response.1 8 ~ 1 9 This observation may be helpful in differentiating atypical hemifacial spasm from other conditions that may mimic this disorder, such as essential blepharospasm, facial myokymia, focal epilepsy, orofacial dyskinesia, or habit spasm. In these conditions, as demonstrated in this study and as previously demonstrated by Lambert, Love, and MulderZ8 in facial myokymia, facial synkinesis is absent on supraorbital nerve stimula-
tion. It is present, however, in aberrant regeneration after facial nerve paralysis; therefore, a history of facial paralysis must be excluded before the presence of synkinesis can be accepted as evidence of hemifacial spasm in a patient with an abnormal movement involving the face. However, a variable response recorded from the orbicularis oris muscle during supraorbital nerve stimulation suggests hemifacial spasm rather than postparalysis synkinesis. Additionally, this observation raises questions about the cause of hemifacial spasm. Synkinetic movements involving one side of the face could be explained by one or more of the following mechanisms: (1)aberrant regeneration after nerve injury; (2) abnormal nuclear firing owing to a hyperexcitable facial-nerve nucleus; (3) transaxonal or ephaptic spread of the nerve impulse, resulting from an artifical synapse after nerve injury. In hemifacial spasm, aberrant regeneration is unlikely because none of our patients had a history of facial weakness or facial nerve injury. Moreover, the synkinesis observed clinically is often variable, more prominent during the spasm
4
3
2 1
,
I 100 pv
T
5 ms
1288 NEUROLOGY 29 September 1979
Figure 7. Continuous recording at fast sweep velocity during three brief clonic spasms recorded with bipolar concentric needle electrode in the orbicularis oris muscle. (See text.)
and for some time after the spasm. This variation is often also evident electromyographically. If aberrant regeneration were the cause, the synkinesis should not vary clinically or electrically, as in aberrant regeneration after Bell palsy. The second possibility-abnormal nuclear firing owing to a hyperactive facial nerve nucleus-was advanced by Wartenberg6 and has received further support by F e r g u ~ o n One . ~ ~ observation tending to contradict this theory is that spaceoccupying lesions associated with hemifacial spasm almost invariably involve the extraaxial portion of the facial nerve rather than the intraaxial portion. Moreover, intraaxial brainstem lesions have rarely been reported as causes of hemifacial spasm but have been reported frequently as
causes of facial myokymia, a disorder quite different both clinically and electromyographically from hemifacial spasm. Another observation tending to militate against the theory of a hyperactive facial-nerve nucleus in hemifacial spasm was provided by a patient with acute tetanus and risus sardonicus. In this patient, in whom hyperactivity of the facial nerve nucleus is clearly implied, no synkinesis was evident on supraorbital nerve stimulation during simultaneous recording from the orbicularis oculi and orbicularis oris muscles (figure 8). The third possibility that may explain synkinetic movement of one side of the face is transaxona1 spread of the nerve impulse (ephaptic transmission) resulting from nerve compression or
R. orbic oculi R. orbic o r i s A
1. orbic oculi -
f i L. orbic
oris
1200 pv
10 ms B Figure 8. Response to supraorbital nerue stimulation. Simultaneous recording from orbicularis oculi and orbicularis oris muscles in a patient with acute tetanus associated with intermittent episodes of risus sardonicus. (A) Response to right supraorbital nerue stimulation. (Bi Response to left supraorbital nerue stimulation. No synkinesis is present.
September 1979 NEUROLOGY 29 1269
Hemifacial spasm
nerve injury. In this hypothesis, the fibers directed toward one muscle group excite adjacent nerve fibers directed to another muscle group. In hemifacial spasm, one would postulate that a t the site of injury the nerve fibers directed toward the orbicularis oculi muscle excite adjacent nerve fibers directed toward other muscles innervated by the
facial nerve, and vice versa. This theory has attracted many proponents, who favor compression of the facial nerve by vascular structures. In this hypothesis, increased irritability of the nerve would result from compressive injury, and ephaptic transmission would account for the synkinetic activity.
n
, I
R. orbic oris
\
B
R. orbic oris 7
J200 pv C Figure 9. Responses to right supraorbital nerve stimulation. Simultaneous recording from orbicularis oculi and orbicularis oris muscles in a patient with hemifacial spasm, before and after vascular decompression. (A) Before surgery. (B) One week after surgery. (C) Three months after surgery. Synkinesis, present before surgery (A), is also present 1 week after surgery (B),but can no Longer be detected 3 months after surgery ( C ) .
1270 NEUROLOGY 29 September 1979
Vascular compression of the facial nerve at o r facial weakness at any time. This observation suggests a causal relationship near the brainstem may be a contributing factor in many patients with cryptogenic hemifacial spasm. between vascular compression and hemifacial spasm, at least in this patient, although this must This is supported by the observations of remission of hemifacial spasm after vascular decompres- be interpreted with caution because spontaneous of com- remissions O C C U ~ .In ~ i ~ n In . ~some ~ patients, , ~ ~ *the~ source ~ ~ the present series of 23 papression may be other than vascular. Woltman, tients, for example, 3 patients reported temporary Williams, and Lambert' reported benefit from de- remissions. Nevertheless, the impressive results of vascular decompression recorded by Jannetta compression of the facial nerve within the facial and associates14and others 1 3 s 3 0 support the role of canal in patients with hemifacial spasm, but this procedure was subsequently abandoned when it vascular compression and ephaptic transmission in the pathogenesis of this disorder. was found that only 2 of 10 patients had lasting benefit. l 3 However, Fabinyi and Adams3'j questioned whether the benefits obtained from the decomHemifacial spasm has also been reported as a manifestation of space-occupying lesions compres- pressive procedures resulted from the actual separation of the offending vessel from the nerve or sing the facial nerve, including aneurysm^,^^-'^ arteriovenous malforrnations,l3 and tumors in the whether they were due to a nonspecific effect resulting from minor trauma and fibrosis of the cerebellopontine angle."1° However, as pointed out by WartenbergG and demonstrated in the large nerve.36In their study, six patients had no abnormal vessels surrounding the nerve. Nevertheless, surgical series of Jannetta and associates,14 the a nonabsorbable sponge was introduced between occurrence of hemifacial spasm with spacethe seventh and eighth nerves and then wrapped occupying lesions of this nature is extremely rare. around the seventh nerve. The patients obtained Experimentally, transaxonal spread of nerve lasting relief from the spasm and improved as impulses has been demonstrated in areas of nerve injured by cutting or compression. Granit, Leksell, much as three patients in whom an offending vessel was decompressed. Fabinyi and Adams example, demonstrated in the and S k ~ g l u n dfor ,~~ suggested that where compression was of doubtful injured sciatic nerve of the frog that the nerve significance, the relief of spasm was brought about impulses traveling in motor fibers could spread to adjacent sensory fibers. Moreover, transaxonal or by the fibrotic effect of the nonabsorbable sponge electrotonic transmission has been demonstrated on the nerve at its exit from the brainstem. to occur naturaly in some species, such as in the Therefore, although current thinking by most workers favors the concept of localized nerve inseptate giant axons of the earthworm and crayfish and in the ciliary ganglion of the Ephaptic jury related t o compression as the underlying excitation between dorsal and ventral roots of bare cause of hemifacial spasm, the accumulated evidence does not allow a definite conclusion. lumbosacral spinal-root axons was demonstrated in dystrophic mice.33 Further evidence supporting the concept of localized nerve injury or compression was provided Acknowledgments by needle-electrode examination of the muscles The author wishes to thank Drs. Jasper R. Daube and Edward involved in hemifacial spasm. The clonic spasms H. Lambert for their assistance in the preparation of this manwere usually associated with irregular bursts of uscript. motor-unit discharges at frequencies of 150 to 250 Hz. Electric discharges of this frequency are seen in irritant lesions of nerve trunks produced exReferences perimentally by compression or i ~ c h e m i a . ~ ~ , ~ ~ We studied one patient with socially incapaci1. Sicard A, Bloch M: Bi-spasme facial: Alcoolisation des branches de division du nerf facial. Rev Neurol (Paris) tating right-sided hemifacial spasm (figure 9). At 20:119-121, 1910 surgery, a small loop of the anteroinferior cerebel2. Gowers WR: A Manual of Diseases of the Nervous System. lar artery impinged on the inferior aspect of the Philadelphia, P Blakiston & Company, 1888, pp 660-669 seventh nerve. The seventh nerve was mobilized, 3. Brissaud E: Tics e t spasmes cloniques de la face. J Med Chir Pract 6549-64, 1894 and an Ivalon@sponge was placed between it and 4. Babinski J: Hemispasme facial peripherique. Rev Neurol the loop of the anteroinferior cerebellar artery. (Paris) 13:443-450, 1905 One week after surgery, the patient still had hemi5. Ehni G, Woltman HW: Hemifacial spasm: Review of one facial spasm, less severe than before surgery. Synhundred and six cases. Arch Neurol Psychiatry 53:205-211, kinesis was still present, as evidenced by simul1945 6. Wartenberg R: Hemifacial Spasm: A Clinical and Pathotaneous contraction of the orbicularis oculi and physiological Study. New York, Oxford University Press, orbicularis oris muscles on supraorbital nerve 1952 stimulation (figure 9B). However, 3 months later, 7. Woltman HW, Williams HL, Lambert EH: An attempt to the spasm had disappeared and no synkinesis was relieve hemifacial spasm by neurolysis of the facial nerves: A report oftwo cases of hemifacial spasm with reflections on present (figure 9 0 . Postoperatively, there was no
September 1979 NEUROLOGY 29 1271
Hemifacial spasm the nature of the spasm, the contracture and mass movement. Proc Staff Meet Mayo Clin 26236-240, 1951 8. Cushing HW: Tumors of the Nervus Acusticus and the Syndrome of the Cerebellopontile Angle. Philadelphia, WB Saunders Company, 1917, p 166 9. Revilla AG: Neurinomas of the cerebellopontile recess: A clinical study of one hundred and sixty cases including operative mortality and end results. Bull Johns Hopkins Hosp 80254-296, 1947 10. Revilla AG: Differential diagnosis of tumors a t the cerebellopontile recess. Bull Johns Hopkins Hosp 83:187-212,1948 11. Campbell E, Keedy C: Hemifacial spasm: A note on the etiology in two cases. J Neurosurg 4:342-347, 1947 12. Maroon JC, Lunsford LD, Deeb ZL: Hemifacial spasm due to aneurysmal compression of the facial nerve. Arch Neurol 351545-546, 1978 13. Gardner WJ, Sava GA: Hemifacial spasm: A reversible pathophysiologic state. J Neurosurg 19:240-247, 1962 14. Jannetta PJ, Abbasy M, Maroon JC, et al: Etiology and definitive microsurgical treatment of hemifacial spasm: Operative techniques and results i n 47 patients. J Neurosurg 47:321-328, 1977 15. Maroon JC: Hemifacial spasm: A vascular cause. Arch Neurol 35:481-483, 1978 16. Hjorth RJ, Willison RG: The electromyogram i n facial myokymia and hemifacial spasm. J Neurol Sci 20:117-126, 1973 17. Kimura J: Electrically elicited blink reflex in diagnosis of multiple sclerosis: Review of 260 patients over a seven-year period. Brain 98:413-426, 1975 18. Kimura J , Rodnitzky RL, Okawara S-H: Electrophysiologic analysis of aberrant regeneration after facial nerve paralysis. Neurology (Minneap) 25:989-993, 1975 19. Stohr M: Der Orbicularis oculi-Reflex bei der Beurteilung defektgeheilter peripherer Facialisparesen. J Neurol 212:85-89, 1976 20. Thiebaut F, Isch F, Isch-Treussard C, et al: Ehude electromyographique de quelques cas d’hemispasme facial. Rev Neurol (Paris) 90:291-296, 1954 21. Magun R, Esslen E: Electromyographic study of reinnervated muscle and of hemifacial spasm. Am J Phys Med 38:79-86, 1959
1272 NEUROLOGY 29 September 1979
22. Jesel M, Isch F.: gemispasme facial peripherique primitif: gtude EMG. Rev Neurol (Paris) 110:181-188, 1964 23. Bratzlavsky M, Vander Eecken H: Hemispasme facial primitif: Correlations cliniques et electromyographiques. Acta Neurol Belg 71:365-382, 1971 24. Caraceni T, Negri S: Le reflexe de clignement dans l’hemispasme facial primitif Considerations electromyograhiques. Electromyogr Clin Neurophysiol12:85-89,1972 25. Smorto MP, Basmajian JV: Electrodiagnosis: A Handbook for Neurologists. Hagerstown, MD, Harper & Row, Publishers, 1977, pp 138-142 26. Bohnert B, Stohr M: Beitrag zum Spasmus facialis. Arch Psychiatr Nervenkr 224:ll-21, 1977 27. Sadjadpour K: Postfacial palsy phenomena: Faulty nerve regeneration or ephaptic transmission? Brain Res 95:403406, 1975 28. Lambert EH, Love JG, Mulder DW: Facial myokymia and brain tumor: Electromyographic studies. (Abstr)News1 Am Assoc Electromyogr Electrodiag 8:8,1961 29. Ferguson JH: Hemifacial spasm and the facial nucleus. Ann Neurol497-103, 1978 30. Neagoy DR, Dohn DF: Hemifacial spasm secondary to vascular compression of the facial nerve. Cleve Clin Q 41:205214,1974 31. Granit R, Leksell L, Skoglund C R Fibre interaction in injured or compressed region of nerve. Brain 67:125-140, 1944 32. Grundfest H: Synaptic and ephaptic transmission. In Quarton GC, Melnechuk T, Schmitt FO (Editors): The Neurosciences: A Study Program. New York, Rockefeller University Press, 1967, pp 353-372 33. Rasminsky M: Ectopic generation of impulses and crosstalk in spinal nerve roots of “dystrophic” mice. Ann Neurol 3:351-357, 1978 34. Adrian ED: The effects of injury on mammalian nerve fibres. Proc R SOC Lond [Biol] 106:596-618, 1930 35. Kugelberg E: “Injury activity” and “trigger zones” in human nerves. Brain 69:310-324, 1946 36. Fabinyi GCA, Adams CBT: Hemifacial spasm: Treatment by posterior fossa surgery. J Neurol Neurosurg Psychiatry 41:829-833, 1978
Hemifacial spasm: Clinical and electrophysiologic observations Raymond G. Auger Neurology 1979;29;1261 DOI 10.1212/WNL.29.9_Part_1.1261 This information is current as of September 1, 1979 Updated Information & Services
including high resolution figures, can be found at: http://n.neurology.org/content/29/9_Part_1/1261.full.html
Citations
This article has been cited by 4 HighWire-hosted articles: http://n.neurology.org/content/29/9_Part_1/1261.full.html ##otherarticles
Permissions & Licensing
Information about reproducing this article in parts (figures,tables) or in its entirety can be found online at: http://n.neurology.org/misc/about.xhtml#permissions
Reprints
Information about ordering reprints can be found online: http://n.neurology.org/misc/addir.xhtml#reprintsus
Neurology ® is the official journal of the American Academy of Neurology. Published continuously since 1951, it is now a weekly with 48 issues per year. Copyright © 1979 by the American Academy of Neurology. All rights reserved. Print ISSN: 0028-3878. Online ISSN: 1526-632X.
Hedacial spasm: Clinical and electrophysiologic observations Raymond G. Auger, M.D. Hemifacial spasm is characterized clinically by habit spasm, tardive dyskinesia, and aberrant reparoxysmal bursts of involuntary tonic or clonic generation after facial nerve injury. If one of these activity occurring in muscles innervated by the conditions presents in an atypical manner, the facial nerve on one side of the face. The spasm diagnosis may be difficult. rarely occurs bilaterally.’ We studied patients with hemifacial spasm clinAlthough many early accounts of facial move- ically and electrophysiologically to establish ment disorders probably included hemifacial criteria that would aid in differentiating hemifaspasm, the authors tended to group these disorders cia1 spasm from other movement disorders of the into the single entity “tic non-douloureux.” It was face. The study was also undertaken to measure Gowers2 who clearly distinguished hemifacial objectively the phenomenon of synkinesis, present spasm from other movement disorders of the face. to some degree in all patients with hemifacial Brissaud3 established criteria t o differentiate spasm. habit spasm from hemifacial spasm, and since then, several articles have described the clinical Methods. Twenty-three patients with clinically features of the latter.4-6Although most cases of diagnosed “cryptogenic” hemifacial spasm were hemifacial spasm are “cryptogenic,” the condition seen during the 24 months from December 1976 to has been attributed to compression of the facial November 1978. Special attention was given to the n e r ~ e . ~Gardner -l~ and Sava13 and Jannetta and presence of weakness and associated movements associates14suggested that vascular compression in muscles of the face after blinking and grimacing of the facial nerve is frequently the cause, with (facial synkinesis). None of the patients had a hisremission following vascular decompression. tory of Bell palsy or other evident facial-nerve Although hemifacial spasm differs from facial trauma. All patients had roentgenograms of the myokymia clinically and electromyographically, head, including views of the internal auditory the two terms are often used s y n o n y m ~ u s l y . ~ canals, ~ and all findings were normal. Eleven paHowever, facial myokymia presents clinically as a tients had computed tomographic (CT) scans; two fine, continuous, undulating movement involving patients had brainstem auditory evoked responses, and one patient had a vertebral angiomuscles of the face, usually unilaterally, and there is commonly little or no difficulty in differentiat- gram. Results of all of these studies were normal. ing this type of movement from the clonic and tonic Patients with disorders that mimic hemifacial spasms of hemifacial spasm. Moreover, the elec- spasm were also studied: seven patients with estromyographic patterns differ.l 6 sential blepharospasm, one patient with frequent Other conditions that can be mistaken clinically focal seizures of cortical origin involving the musfor hemifacial spasm are essential blepharospasm, cles on one side of the face, one patient with severe focal cortical seizures involving the facial muscles, tardive dyskinesia resembling hemifacial spasm From the Department of Neurology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota. Accepted for publication February 28, 1979. Dr. Auger’s address is Department of Neurology, Mayo Clinic, Rochester, MN 55901.
September 1979 NEUROLOGY 29 1261
Hemifacial spasm in some respects, and two patients with facial myokymia. In addition, we studied four patients with aberrant regeneration after Bell palsy. Electrodiagnostic studies were carried out with the patient lying supine in bed in a warm room using an electromyograph (TECATE4). The facial nerves were stimulated directly with a two-prong stimulator with the cathode behind the earlobe and the anode over the mastoid process. Squarewave stimuli of 50 to 150 V and 0.1 to 0.5 msec were used to produce a maximal response to nerve stimulation. Recording electrodes consisted of 6-mm tin disk electrodes held in place by tape (BlendermB) over the quadratus labii superioris muscle group beside the nose or over the inferior portion of the orbicularis oculi muscle. The ground electrode, consisting of a 2.0-cm-squarelead plate, was placed over the chin. Recordings were made on a cathode-ray oscillograph using an amplifier with a frequency response from 1.6 Hz b 8 kHz (3 dE3 attenuation). The sensitivity was 0.5 or 1.0 mV per centimeter, and the sweep speed was 2.0 msec per centimeter. Permanent tracings were made on direct-print photorecording paper. The latency of the initial response of the muscle was recorded, and the amplitude was measured from t h e baseline to the maximal negative deflection. For blink-reflex studies, the supraorbital nerves were stimulated percutaneously with a two-prong stimulator with the cathode over the supraorbital notch and the anode on the forehead. Square-wave stimuli of 0.05 to 0.2 msec duration at 50 to 200 V were delivered. Six-mm tin disk recording electrodes were placed 2 t o 3 cm apart, one over the inferior aspect of the orbicularis oculi muscle laterally and the other at the lateral angle of the orbit. The stimuli were of such intensity that both the early and late responses were just maximum and nearly stable upon repeated trials. Shocks of the same intensity were delivered to each side in each subject. The ground electrode was placed over the chin. Cathode-ray oscillograph recordings were made from the right and left orbicularis oculi muscles simultaneously by means of two amplifiers with frequency responses from 32 Hz to 3.2 kHz (3 dB attenuation). The gain was set at 200 pV per centimeter, with sweep speeds of 5 to 10 msec per centimeter. A minimum of five superimposed responses to stimuli given at irregular intervals a t least 5 seconds apart were recorded for the right and left supraorbital nerve. Permanent tracings were made on direct-print photorecording paper. The latencies of the initial deflections of the ipsilateral early and bilateral late responses were measured. The amplitude of the early response was measured from the negative to the positive peak. To measure the presence or absence of synkinesis involving the facial muscles, the supraorbital nerve was stimulated on both the involved
1262 NEUROLOGY 29 September 1979
and the uninvolved sides in a similar manner, and recordings were made simultaneously from the orbicularis oculi and another muscle innervated by the facial nerve, usually the orbicularis oris, using a concentric needle electrode (DISA 13L50) inserted into the muscle. Spontaneous and voluntary muscle activity were studied with a concentric needle electrode in the orbicularis oris muscle on the involved side in all patients and in the orbicularis oculi muscle in most patients. To measure the pattern of motor-unit discharge during tonic and clonic spasms, units were isolated by means of a bipolar concentric needle electrode (DISA 13K13). Recordings were made on a cathode-ray oscillograph by means of an amplifier with a frequency response from 32 Hz to 16 kHz (3 dB attenuation). The sensitivities used were 50, 100, and 200 pV per centimeter and the sweep speed was 10 msec per Centimeter. At the same time, recordings were made on an FM tape recorder (Ampex Model 306-1, one-channel FM tape recorder). The tape was subsequently played back, and selected portions of the electromyograph were photographed on direct-print photorecording paper at paper speeds of 10, 50, and 100 cm per second. When playing back the recordings, a high-pass filter was used to reduce artifact from background muscle movement and distant motorunit activity. This filter had a lower cutoff frequency of approximately 500 Hz.
Results. Clinical data. The ages of the 23 patients with hemifacial spasm (11 men and 12 women) ranged from 38 to 76 years, with a mean of 57 years. The duration of symptoms before examination was 1 to 25 years, with a mean of 5.6 years. Eleven patients had involvement of the left side, and 12 had involvement of the right side. No patient had bilateral hemifacial spasm. One patient had trigeminal neuralgia involving the maxillary division of the trigeminal nerve on the contralatera1 side. Three patients reported past temporary remissions. In one patient, the remission lasted 4 months and seemed to occur after a head injury from an automobile accident. In another patient, a spontaneous remission lasted approximately 2 years. In a third, a spontaneous remission lasted 3 months. In each patient, the spasm recurred. Seven patients had minimal weakness of the orbicularis oculi or orbicularis oris muscles on the involved side. All patients had synkinesis on the involved side, most prominent during and for several minutes after a spasm. In many patients, the associated movements could be seen only on close observation and consisted of simultaneous contraction of the orbicularis oris, mentalis, or platysma muscle when blinking or simultaneous contraction of the orbicularis oculi muscle when grimacing. However, when patients were observed
during quiescent periods, free of hemifacial spasm for several minutes, persistent synkinesis was not nearly as severe. In fact, in some patients, no clinically evident synkinesis was seen if the patient had been free of spasm for several minutes. Aside from the Endings relative to facial-nerve function, results of the neurologic examination were essentially normal in all patients. Electrodiagnostic observations. No statistically significant difference was noted between the involved and the uninvolved sides in the latencies or amplitudes of the responses obtained on direct facial nerve stimulation or on supraorbital nerve stimulation. With direct facial-nerve stimulation, the mean latency was 3.3k0.5 msec on the involved side compared with 3.3 ? 0.5 msec on the uninvolved side. The mean amplitude was 1.9 2 0.8 mV on the involved side compared with 2.0 0.9 mV on the uninvolved side. With supraorbital nerve stimulation, the mean values of early and late responses were within the normal range on both the involved and uninvolved sidesI7(table). The reflex latencies were not significantly different on the two sides. No individual patient had more than a 0.7-msec difference on the involved side compared with the uninvolved side when the latency of the early response was measured. Only one patient had a late-response latency that was 8 msec greater on the involved side than on the uninvolved side; this difference was probably within the limits of normal variation. The most interesting observation pertained to
*
contraction of other muscles innervated by the facial nerve on the affected side when the supraorbital nerve was stimulated. The normal response after supraorbital nerve stimulation is contraction of the orbicularis oculi muscle alone, without associated contraction of any other muscle innervated by the facial nerve (figure 1);this was also true on the uninvolved (normal) side in patients with hemifacial spasm. On the involved side, however, supraorbital nerve stimulation produced a synkinetic contraction of other facial-nerveinnervated muscles on the ipsilateral side (figure 2). Although this phenomenon was demonstrated in all of the patients by recording from the orbicularis oris muscle during supraorbital nerve stimulation, a similar response could be obtained by simultaneously recording from other muscles innervated by the facial nerve (figure 3). Successive responses varied in some patients in terms of presence or absence of the early and late responses and their latencies when measured from the orbicularis oris muscle during supraorbital nerve stimulation. On occasion, either the early or the late response or, sometimes, both responses, did not occur. This was particularly true when the spasms had been quiescent for several minutes (figure 4). In all 23 patients with hemifacial spasm, synkinesis could be detected by this method. An early response from the orbicularis oris muscle coinciding with the early (Ri)component of the blink reflex was seen in all 23 patients on the involved side at some time during the period of observation.
Late response Early response __--Latency (msec) Amplitude (mV)
Ipsilateral latency (mew)
Contralateral latency ( m e )
Involved side 23
23
0.3
36.0
37.0
0.9
0.2
4.6
5.6
9.0-12.5
0.1-0.7
28-48
27-50
Sample size
23
Mean
10.9
SD Range
23
Uninvolved side 23
23
0.35
35.0
35.2
1.0
0.29
3.4
3.9
9.6-14.0
0.06-1.2
28-40
26-41
Sample size
22
Mean
11.2
SD hnge
22
* There w a ~no statistically significant difference between the involved side and the uninvolved side for any of the parameters tested (t test for paired data).
September 1979 NEUROLOGY 29 1263
Hemifacial spasm
fl
a*
Orbic oculi
I
4
R1
t
Or
.
J200
O r is VV
1 O’ms A less consistent response, coinciding with the late (R3)component of the blink reflex, was present in 20 patients on the involved side and was not detected in 3 patients. The mean latency of the earliest response from the orbicularis oris muscle was 12.42 1.6 msec. This latency was significantly longer than the mean latency of the earliest response of the orbicularis oculi muscle (10.9 msec). The difference
Figure 1. Response to supraorbital nerve stimulation in normal person. Simultaneous recording from orbicularis oculi and orbicularis oris muscles. Orbicularis oculi contracts without associated contraction of orbicularis oris. R I = early response; R2 = late response.
was the result of a longer conduction time in the peripheral nerve to the orbicularis oris muscle rather than in other parts of the reflex circuit. Seven facial nerves were stimulated at the stylomastoid foramen in five control subjects while we recorded from the orbicularis oculi and orbicularis oris muscles with the electrode positions used in the reflex test. The latency when recording from the orbicularis oculi muscle was 3.0 2 0.6
*4 p ;
L. orbic oculi
R. orbic oculi
L
R. orbic o r i s
J200
pv
10 ms B
1
Figure 2. Responses to supraorbital nerve stimulation in patient with left hemifacial spasm. Simultaneous recording from orbicularis oculi and orbicularis oris muscles. With left supraorbital nerve stimulation (A), the orbicularis oris contracts simultaneously with the orbicularis oculi (that is, synkinesis is present). With right supraorbital nerve stimulation (B), synkinesis is absent.
1264 NEUROLOGY 29 September 1979
msec, compared with 4.2 t 1.3 msec when recording from the orbicularis oris. The difference was significant ( p < 0.05) and was essentially the same as the difference in reflex latencies, thus accounting for the difference in total reflex time. On the uninvolved side, synkinesis was not present in any patient during supraorbital nerve stimulation. No response of the orbicularis oris occurred while we recorded simultaneously from the orbicularis oculi and orbicularis oris muscles. With the exception of the associated movements that follow Bell palsy or other facial nerve injury, conditions that may mimic hemifacial spasm showed no evidence of synkinesis on supraorbital nerve stimulation. These conditions included essential blepharospasm, focal cortical seizures, facial myokymia, and tardive dyskinesia. The four patients with aberrant regeneration after facial paralysis, however, showed facial synkinesis on supraorbital nerve stimulation, as reported by
other^.^^,^^ However, in contrast to the variable synkinetic response in patients with hemifacial spasm, the response after facial paralysis was stereotyped and did not vary in occurrence in either clinical or electromyographic examinations (figure 5). In hemifacial spasm, the needle electrode examination did not demonstrate abnormal insertional activity or fibrillation potentials. In the absence of a spasm, motor-unit potentials were normal. During the spasm, the abnormalities were similar to those described by others.16,zw23 Brief clonic jerks merged into a tonic spasm lasting several seconds (figure 6). The clonic jerks were of variable duration, lasting from 10 to 200 msec. The interval between bursts also varied considerably, from 20 to 225 msec. The firing rate of individual motor-unit potentials varied form one clonic burst to the next and also varied within a burst. This is demonstrated in
R. orbic oculi R. orbic oris A
R. orbic oculi 4 ' -
v
B
R. mentalis
*
'$
Ne-L
F
p
R . or b ic o c u Ii
R, platysma JZOO 10 ms
C
pv
Figure 3. Responses to supraorbital nerve stimulation inpatient with right hemifacial spasm. (A) Simultaneous recording - ,from orbicularis oculi and orbicularis oris muscles. (Bj Simultaneous recording from orbicularis oculi and mentalis. ( C ) Simultaneous recording from orbicularis oculi and platysma muscles. There is synchronous contraction (synkinesis) of all muscles innervated by the facial nerve after supraorbital nerve stimulation on the involved side.
September 1979 NEUROLOGY 29
1265
Hemifacial spasm
Orbic oculi
A
L---
Orbic oris
Orbic oculi
C
I ,
1,
Orbic oris
-
V
T200rv 10 ms
.
figure 7, a continuous record of the activity of two different motor-unit potentials during three brief twitches. In the lowermost sweep (sweep l),a short burst lasted approximately 10 msec. During this burst, motor-unit potential A and motor unit potential B both fired only once. There was then an interval of 25 msec before the next burst, which lasted 20 msec. During this burst, motor unit potential A and motor unit potential B each fired twice, at rates of approximately 150 Hz. There was then an interval of about 60 msec before the next burst, which lasted 60 msec (beginning in sweep 3 and continuing through sweep 4). During this burst, motor unit potential B discharged seven times, at first firing rapidly (approximately 230 Hz); but toward the end of the burst, the firing rate slowed to approximately 75 Hz. Motor unit potential A, however, discharged four times at an irregular but rapid rate. During a tonic spasm, individual motor unit potentials could not be identified and, therefore, firing rates could not be determined. The electromyographic tracings during a tonic spasm were similar to those of a full interference pattern seen during voluntary contraction.
1286
NEUROLOGY 29 September 1979
Figure 4 . Responses to right supraorbital nerue stimulation. Simultaneous recording from the right orbicularis oculi and orbicularis oris muscles in a patient with right hemifacial spasm. (A) Five superimposed responses obtained when the patient was free of spasm for several minutes. (B) Single response obtained as spasm is beginning. (C)Fiue superimposed responses obtained after sustained spasm. Note variability of response of the orbicularis oris muscle.
Discussion. Caraceni and Negri,24 using a mechanical stimulus t o the supraorbital nerve, studied four patients with hemifacial spasm; they concluded that the latency of the blink reflex was prolonged on the involved side. We found no such difference in latency when an electrical stimulus was used to initiate the reflex. Also, our study did not confirm the observations of Smorto and Basmajian,25who reported the constant presence of an early reflex response on the involved side when the contralateral supraorbital nerve was stimulated. This was not seen in any of our patients. Our results were similar to those of Bohnert and Stohr,26who studied 20 patients, using techniques similar to ours. They also found normal latencies in response t o stimulation of the facial and supraorbital nerves. In only one of their patients was the early response 1.2 msec longer on the involved side than on the uninvolved side. Synkinesis was demonstrated in the seven patients evaluated while recording from the orbicularis oris muscle during supraorbital nerve stimulation. Clinically, synkinesis in hemifacial spasm has been noted by other a ~ t h o r s . 6 , ~ ,Synkinesis ~ 6 * ~ ~ in our patients was well demonstrated by recording
Orbic oculi Orbic oris
Orbic oculi Orbic oris
Orbic oculi Orbic oris 7
J200 pv 10 ms
Figure 5. Responses to supraorbital nerve stimulation. Simultaneous recording from orbicularis oculi and orbicularis oris muscles in patient with facial synkinesis after recovery from Bell palsy. (B) Response obtained 5 minutes after A. (C) Response obtained 15 minutes after A. Note consistency of response of orbicularis oris muscle.
Jzoo
pv
100 ms
Figure 6.Recording obtained with bipolar concentric needle electrode i n orbicularis oris muscle during hemifacial spasm. Several brief clonic spasms occur at irregular intervals (upper tracing), culminating in sustained tonic spasm (lower tracing).
September 1979 NEUROLOGY 29 1267
Hemifacial spasm
simultaneously from the orbicularis oculi and orbicularis oris muscles or from other facial muscles while stimulating the supraorbital nerve. This technique provided an objective method of studying synkinesis, particularly when it was difficult to detect clinically. In patients with hemifacial spasm, the orbicularis oculi muscle contracts simultaneously with other facial-nerve-innervated muscles ipsilaterally, but not on the asymptomatic side. Lambert, Love, and MulderZ8commented on this phenomenon in hemifacial spasm and noted its absence in facial myokymia. Others also used this technique to study aberrant regeneration after facial nerve paralysis, noting a similar response.1 8 ~ 1 9 This observation may be helpful in differentiating atypical hemifacial spasm from other conditions that may mimic this disorder, such as essential blepharospasm, facial myokymia, focal epilepsy, orofacial dyskinesia, or habit spasm. In these conditions, as demonstrated in this study and as previously demonstrated by Lambert, Love, and MulderZ8 in facial myokymia, facial synkinesis is absent on supraorbital nerve stimula-
tion. It is present, however, in aberrant regeneration after facial nerve paralysis; therefore, a history of facial paralysis must be excluded before the presence of synkinesis can be accepted as evidence of hemifacial spasm in a patient with an abnormal movement involving the face. However, a variable response recorded from the orbicularis oris muscle during supraorbital nerve stimulation suggests hemifacial spasm rather than postparalysis synkinesis. Additionally, this observation raises questions about the cause of hemifacial spasm. Synkinetic movements involving one side of the face could be explained by one or more of the following mechanisms: (1)aberrant regeneration after nerve injury; (2) abnormal nuclear firing owing to a hyperexcitable facial-nerve nucleus; (3) transaxonal or ephaptic spread of the nerve impulse, resulting from an artifical synapse after nerve injury. In hemifacial spasm, aberrant regeneration is unlikely because none of our patients had a history of facial weakness or facial nerve injury. Moreover, the synkinesis observed clinically is often variable, more prominent during the spasm
4
3
2 1
,
I 100 pv
T
5 ms
1288 NEUROLOGY 29 September 1979
Figure 7. Continuous recording at fast sweep velocity during three brief clonic spasms recorded with bipolar concentric needle electrode in the orbicularis oris muscle. (See text.)
and for some time after the spasm. This variation is often also evident electromyographically. If aberrant regeneration were the cause, the synkinesis should not vary clinically or electrically, as in aberrant regeneration after Bell palsy. The second possibility-abnormal nuclear firing owing to a hyperactive facial nerve nucleus-was advanced by Wartenberg6 and has received further support by F e r g u ~ o n One . ~ ~ observation tending to contradict this theory is that spaceoccupying lesions associated with hemifacial spasm almost invariably involve the extraaxial portion of the facial nerve rather than the intraaxial portion. Moreover, intraaxial brainstem lesions have rarely been reported as causes of hemifacial spasm but have been reported frequently as
causes of facial myokymia, a disorder quite different both clinically and electromyographically from hemifacial spasm. Another observation tending to militate against the theory of a hyperactive facial-nerve nucleus in hemifacial spasm was provided by a patient with acute tetanus and risus sardonicus. In this patient, in whom hyperactivity of the facial nerve nucleus is clearly implied, no synkinesis was evident on supraorbital nerve stimulation during simultaneous recording from the orbicularis oculi and orbicularis oris muscles (figure 8). The third possibility that may explain synkinetic movement of one side of the face is transaxona1 spread of the nerve impulse (ephaptic transmission) resulting from nerve compression or
R. orbic oculi R. orbic o r i s A
1. orbic oculi -
f i L. orbic
oris
1200 pv
10 ms B Figure 8. Response to supraorbital nerue stimulation. Simultaneous recording from orbicularis oculi and orbicularis oris muscles in a patient with acute tetanus associated with intermittent episodes of risus sardonicus. (A) Response to right supraorbital nerue stimulation. (Bi Response to left supraorbital nerue stimulation. No synkinesis is present.
September 1979 NEUROLOGY 29 1269
Hemifacial spasm
nerve injury. In this hypothesis, the fibers directed toward one muscle group excite adjacent nerve fibers directed to another muscle group. In hemifacial spasm, one would postulate that a t the site of injury the nerve fibers directed toward the orbicularis oculi muscle excite adjacent nerve fibers directed toward other muscles innervated by the
facial nerve, and vice versa. This theory has attracted many proponents, who favor compression of the facial nerve by vascular structures. In this hypothesis, increased irritability of the nerve would result from compressive injury, and ephaptic transmission would account for the synkinetic activity.
n
, I
R. orbic oris
\
B
R. orbic oris 7
J200 pv C Figure 9. Responses to right supraorbital nerve stimulation. Simultaneous recording from orbicularis oculi and orbicularis oris muscles in a patient with hemifacial spasm, before and after vascular decompression. (A) Before surgery. (B) One week after surgery. (C) Three months after surgery. Synkinesis, present before surgery (A), is also present 1 week after surgery (B),but can no Longer be detected 3 months after surgery ( C ) .
1270 NEUROLOGY 29 September 1979
Vascular compression of the facial nerve at o r facial weakness at any time. This observation suggests a causal relationship near the brainstem may be a contributing factor in many patients with cryptogenic hemifacial spasm. between vascular compression and hemifacial spasm, at least in this patient, although this must This is supported by the observations of remission of hemifacial spasm after vascular decompres- be interpreted with caution because spontaneous of com- remissions O C C U ~ .In ~ i ~ n In . ~some ~ patients, , ~ ~ *the~ source ~ ~ the present series of 23 papression may be other than vascular. Woltman, tients, for example, 3 patients reported temporary Williams, and Lambert' reported benefit from de- remissions. Nevertheless, the impressive results of vascular decompression recorded by Jannetta compression of the facial nerve within the facial and associates14and others 1 3 s 3 0 support the role of canal in patients with hemifacial spasm, but this procedure was subsequently abandoned when it vascular compression and ephaptic transmission in the pathogenesis of this disorder. was found that only 2 of 10 patients had lasting benefit. l 3 However, Fabinyi and Adams3'j questioned whether the benefits obtained from the decomHemifacial spasm has also been reported as a manifestation of space-occupying lesions compres- pressive procedures resulted from the actual separation of the offending vessel from the nerve or sing the facial nerve, including aneurysm^,^^-'^ arteriovenous malforrnations,l3 and tumors in the whether they were due to a nonspecific effect resulting from minor trauma and fibrosis of the cerebellopontine angle."1° However, as pointed out by WartenbergG and demonstrated in the large nerve.36In their study, six patients had no abnormal vessels surrounding the nerve. Nevertheless, surgical series of Jannetta and associates,14 the a nonabsorbable sponge was introduced between occurrence of hemifacial spasm with spacethe seventh and eighth nerves and then wrapped occupying lesions of this nature is extremely rare. around the seventh nerve. The patients obtained Experimentally, transaxonal spread of nerve lasting relief from the spasm and improved as impulses has been demonstrated in areas of nerve injured by cutting or compression. Granit, Leksell, much as three patients in whom an offending vessel was decompressed. Fabinyi and Adams example, demonstrated in the and S k ~ g l u n dfor ,~~ suggested that where compression was of doubtful injured sciatic nerve of the frog that the nerve significance, the relief of spasm was brought about impulses traveling in motor fibers could spread to adjacent sensory fibers. Moreover, transaxonal or by the fibrotic effect of the nonabsorbable sponge electrotonic transmission has been demonstrated on the nerve at its exit from the brainstem. to occur naturaly in some species, such as in the Therefore, although current thinking by most workers favors the concept of localized nerve inseptate giant axons of the earthworm and crayfish and in the ciliary ganglion of the Ephaptic jury related t o compression as the underlying excitation between dorsal and ventral roots of bare cause of hemifacial spasm, the accumulated evidence does not allow a definite conclusion. lumbosacral spinal-root axons was demonstrated in dystrophic mice.33 Further evidence supporting the concept of localized nerve injury or compression was provided Acknowledgments by needle-electrode examination of the muscles The author wishes to thank Drs. Jasper R. Daube and Edward involved in hemifacial spasm. The clonic spasms H. Lambert for their assistance in the preparation of this manwere usually associated with irregular bursts of uscript. motor-unit discharges at frequencies of 150 to 250 Hz. Electric discharges of this frequency are seen in irritant lesions of nerve trunks produced exReferences perimentally by compression or i ~ c h e m i a . ~ ~ , ~ ~ We studied one patient with socially incapaci1. Sicard A, Bloch M: Bi-spasme facial: Alcoolisation des branches de division du nerf facial. Rev Neurol (Paris) tating right-sided hemifacial spasm (figure 9). At 20:119-121, 1910 surgery, a small loop of the anteroinferior cerebel2. Gowers WR: A Manual of Diseases of the Nervous System. lar artery impinged on the inferior aspect of the Philadelphia, P Blakiston & Company, 1888, pp 660-669 seventh nerve. The seventh nerve was mobilized, 3. Brissaud E: Tics e t spasmes cloniques de la face. J Med Chir Pract 6549-64, 1894 and an Ivalon@sponge was placed between it and 4. Babinski J: Hemispasme facial peripherique. Rev Neurol the loop of the anteroinferior cerebellar artery. (Paris) 13:443-450, 1905 One week after surgery, the patient still had hemi5. Ehni G, Woltman HW: Hemifacial spasm: Review of one facial spasm, less severe than before surgery. Synhundred and six cases. Arch Neurol Psychiatry 53:205-211, kinesis was still present, as evidenced by simul1945 6. Wartenberg R: Hemifacial Spasm: A Clinical and Pathotaneous contraction of the orbicularis oculi and physiological Study. New York, Oxford University Press, orbicularis oris muscles on supraorbital nerve 1952 stimulation (figure 9B). However, 3 months later, 7. Woltman HW, Williams HL, Lambert EH: An attempt to the spasm had disappeared and no synkinesis was relieve hemifacial spasm by neurolysis of the facial nerves: A report oftwo cases of hemifacial spasm with reflections on present (figure 9 0 . Postoperatively, there was no
September 1979 NEUROLOGY 29 1271
Hemifacial spasm the nature of the spasm, the contracture and mass movement. Proc Staff Meet Mayo Clin 26236-240, 1951 8. Cushing HW: Tumors of the Nervus Acusticus and the Syndrome of the Cerebellopontile Angle. Philadelphia, WB Saunders Company, 1917, p 166 9. Revilla AG: Neurinomas of the cerebellopontile recess: A clinical study of one hundred and sixty cases including operative mortality and end results. Bull Johns Hopkins Hosp 80254-296, 1947 10. Revilla AG: Differential diagnosis of tumors a t the cerebellopontile recess. Bull Johns Hopkins Hosp 83:187-212,1948 11. Campbell E, Keedy C: Hemifacial spasm: A note on the etiology in two cases. J Neurosurg 4:342-347, 1947 12. Maroon JC, Lunsford LD, Deeb ZL: Hemifacial spasm due to aneurysmal compression of the facial nerve. Arch Neurol 351545-546, 1978 13. Gardner WJ, Sava GA: Hemifacial spasm: A reversible pathophysiologic state. J Neurosurg 19:240-247, 1962 14. Jannetta PJ, Abbasy M, Maroon JC, et al: Etiology and definitive microsurgical treatment of hemifacial spasm: Operative techniques and results i n 47 patients. J Neurosurg 47:321-328, 1977 15. Maroon JC: Hemifacial spasm: A vascular cause. Arch Neurol 35:481-483, 1978 16. Hjorth RJ, Willison RG: The electromyogram i n facial myokymia and hemifacial spasm. J Neurol Sci 20:117-126, 1973 17. Kimura J: Electrically elicited blink reflex in diagnosis of multiple sclerosis: Review of 260 patients over a seven-year period. Brain 98:413-426, 1975 18. Kimura J , Rodnitzky RL, Okawara S-H: Electrophysiologic analysis of aberrant regeneration after facial nerve paralysis. Neurology (Minneap) 25:989-993, 1975 19. Stohr M: Der Orbicularis oculi-Reflex bei der Beurteilung defektgeheilter peripherer Facialisparesen. J Neurol 212:85-89, 1976 20. Thiebaut F, Isch F, Isch-Treussard C, et al: Ehude electromyographique de quelques cas d’hemispasme facial. Rev Neurol (Paris) 90:291-296, 1954 21. Magun R, Esslen E: Electromyographic study of reinnervated muscle and of hemifacial spasm. Am J Phys Med 38:79-86, 1959
1272 NEUROLOGY 29 September 1979
22. Jesel M, Isch F.: gemispasme facial peripherique primitif: gtude EMG. Rev Neurol (Paris) 110:181-188, 1964 23. Bratzlavsky M, Vander Eecken H: Hemispasme facial primitif: Correlations cliniques et electromyographiques. Acta Neurol Belg 71:365-382, 1971 24. Caraceni T, Negri S: Le reflexe de clignement dans l’hemispasme facial primitif Considerations electromyograhiques. Electromyogr Clin Neurophysiol12:85-89,1972 25. Smorto MP, Basmajian JV: Electrodiagnosis: A Handbook for Neurologists. Hagerstown, MD, Harper & Row, Publishers, 1977, pp 138-142 26. Bohnert B, Stohr M: Beitrag zum Spasmus facialis. Arch Psychiatr Nervenkr 224:ll-21, 1977 27. Sadjadpour K: Postfacial palsy phenomena: Faulty nerve regeneration or ephaptic transmission? Brain Res 95:403406, 1975 28. Lambert EH, Love JG, Mulder DW: Facial myokymia and brain tumor: Electromyographic studies. (Abstr)News1 Am Assoc Electromyogr Electrodiag 8:8,1961 29. Ferguson JH: Hemifacial spasm and the facial nucleus. Ann Neurol497-103, 1978 30. Neagoy DR, Dohn DF: Hemifacial spasm secondary to vascular compression of the facial nerve. Cleve Clin Q 41:205214,1974 31. Granit R, Leksell L, Skoglund C R Fibre interaction in injured or compressed region of nerve. Brain 67:125-140, 1944 32. Grundfest H: Synaptic and ephaptic transmission. In Quarton GC, Melnechuk T, Schmitt FO (Editors): The Neurosciences: A Study Program. New York, Rockefeller University Press, 1967, pp 353-372 33. Rasminsky M: Ectopic generation of impulses and crosstalk in spinal nerve roots of “dystrophic” mice. Ann Neurol 3:351-357, 1978 34. Adrian ED: The effects of injury on mammalian nerve fibres. Proc R SOC Lond [Biol] 106:596-618, 1930 35. Kugelberg E: “Injury activity” and “trigger zones” in human nerves. Brain 69:310-324, 1946 36. Fabinyi GCA, Adams CBT: Hemifacial spasm: Treatment by posterior fossa surgery. J Neurol Neurosurg Psychiatry 41:829-833, 1978
Hemifacial spasm: Clinical and electrophysiologic observations Raymond G. Auger Neurology 1979;29;1261 DOI 10.1212/WNL.29.9_Part_1.1261 This information is current as of September 1, 1979 Updated Information & Services
including high resolution figures, can be found at: http://n.neurology.org/content/29/9_Part_1/1261.full.html
Citations
This article has been cited by 4 HighWire-hosted articles: http://n.neurology.org/content/29/9_Part_1/1261.full.html ##otherarticles
Permissions & Licensing
Information about reproducing this article in parts (figures,tables) or in its entirety can be found online at: http://n.neurology.org/misc/about.xhtml#permissions
Reprints
Information about ordering reprints can be found online: http://n.neurology.org/misc/addir.xhtml#reprintsus
Neurology ® is the official journal of the American Academy of Neurology. Published continuously since 1951, it is now a weekly with 48 issues per year. Copyright © 1979 by the American Academy of Neurology. All rights reserved. Print ISSN: 0028-3878. Online ISSN: 1526-632X.
