Paroxysmal ataxic dysarthria.

PAROXYSMAL

ATAXIC

DYSARTHRIA

Ronald Netsell and Raymond D. Kent University of Wisconsin, Madison

This report reviews 13 cases in which a dysarthria appeared, remitted, and reappeared within seconds. The speech pattern of each case was characteristic of ataxic dysarthria. A cinefluorographic film for one of the subjects provided a rare opportunity to study the articulatory dynamics of this disorder. Multiple sclerosis either was given as a diagnosis or was strongly suspected in each case, and carbamazepine has been an effective treatment. Speculations concerning the origin of the paroxysmal and ataxic character of the dysarthria are presented along with a preliminary checklist for identifying the disorder.

A relatively recent literature has evolved concerning a form of dysarthria that signals with high probability the presence of multiple sclerosis (Parker, 1946; A n d e r m a n n et al., 1959; Espir, Watkins, and Smith, 1966; DeCastro and Campbell, 1967; Harrison and McGill, 1969; Espir and Millac, 1970; Miley and Forster, I974). T h i s dysarthria (I) appears to have the perceptual characteristics of ataxic dysarthria as described by Darley, Aronson, and Brown (1969); (2) usually occurs with other neurologic disturbances associated with cerebellar disorder; and (3) is episodic in presenting for a few seconds, remitting for a few minutes, and r e a p p e a r i n g for a few seconds. For these reasons and for the purposes of this article, this speech disorder is referred to as

paroxysmal ataxic dysarthria. REVIEW

O F 13 C A S E S

T h e reported incidence of this paroxysmal movement disorder in multiple sclerosis is small (eight in a series of 600 consecutive patients with multiple sclerosis, or 1.3%) although the true incidence might be higher if more persons were alerted to the symptomatology (Espir and Walker, 1969). T h e dysarthric component of these episodes may appear with other ataxic symptoms or in addition to neurologic disturbances implicating systems outside the cerebellum and its interconnections ( A n d e r m a n n et al., 1969; Espir et al., 1966; Miley and Forster, 1974). However, as the review of cases presented below will reveal, the mere presence of the paroxysmal ataxic dysarthria is strong evidence to suspect multiple sclerosis. 93

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NETSELL, KENT: Paroxysmal Ataxic Dysarthria 95

According to Parker (1946), the earliest report of paroxysmal dysarthria with multiple sclerosis (MS) appeared in 1926. Parker reviewed 10 cases of "periodic ataxia" with associated speech problems encountered at Mayo Clinic between 1924 and 1943. Six of these cases were diagnosed as MS while the remaining four presented "an undetermined form of familial cerebellar ataxia." T h e description of speech and other motor problems in the cases of MS was limited to the statement that "speech may be reduced during the attack to a mumble, the gait is staggering to the point of falling and performance of all finer movements of the fingers and hands becomes impossible" (p. 643). T h e speech and equilibrium of the four familial cases was described as "essentially the same" as that of the MS cases. However, the familial cases differed from the MS cases in that the symptoms of the former "were more violent and bitterly complained of . . . . . tended to occur in the morning," and "attempted relief with various drugs met with consistent failure" (p. 644). Table 1 summarizes the signs and symptoms listed for 10 cases of paroxysmal ataxic dysarthria with MS that appeared in four reports subsequent to Parker (Andermann et al., 1959; Espir et al., 1966; DeCastro and Campbell, 1967; Harrison and McGill, 1969) and three cases seen by the present authors. Two of these latter cases have been reported by Miley and Forster (1974) whereas the third case (RT) was seen by one of us (RN) in 1965 and is the subject of the cinefluorographic analysis that appears in a later section of this report. Since only the broad description quoted above was used in the Parker report, his cases of paroxysmal ataxic dysarthria with MS are omitted from the table. It should be pointed out that the absence of an X in a given column of Table 1 means only that the neurologic sign or symptom was not mentioned by the author(s). Therefore, particular signs and symptoms may have been more prevalent than shown in the table. For example, in five cases the paroxysms could be precipitated through overbreathing, which is a rapid and forced exchange of air volume. T h e other authors did not report asking their cases to overbreathe. Communication Status

As indicated in Table 1, each case was reported to exhibit dysarthria during the episodes. No authors mentioned a single instance of aphasia, apraxia, or hearing loss. Each author reported that the communication problem during the paroxysms was limited to dysarthric speech, and at least one of the descriptors slurring, scanning, or drunken was applied to 12 of the 13 cases reviewed here. These terms typically are used in the description of ataxic dysarthria (Darley et al., 1969; Brown, Darley, and Aronson, 1970). It is speculated that the paroxysmal dysarthria presented by these cases is of the ataxic type because of the (1) prevalence of these descriptors in the literature reviewed here, (2) use of the word ataxia with respect to limb motor problems during paroxysms of all 13 cases, and (3) assessment of ataxic dysarthria in each of the three cases we observed personally.


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Associated Motor and Sensory Problems Each of the 13 cases presented ataxia in the limbs as well as some problem with vision during the paroxysms. T h e patients described their gait or armhand-finger movements as "drunken, incoordinated" and "clumsy" d u r i n g the episodes. T w o instances of "spasticity" and "weakness" were reported during nonparoxysmal periods. For the most part, the subjects were free of motor disability except during the paroxysms or as MS progressed considerably. T h e first hint of neurologic disorder usually a p p e a r e d as a sensory disturbance. Blurred vision, diplopia, and numbness or paresthesia in the hands often were noted in retrospect to have occurred two months or so prior to the first paroxysmal attack. T h e authors of the reports stated that the 15-30 second d u r a t i o n of the paroxysms was too brief to allow formal neurologic testing. Consequently, description of neurologic disturbance during the paroxysms was limited to the presence of dysarthria and ataxia of limb movements. D u r i n g the nonparoxysmal periods, 10 cases experienced nystagmus, eight presented abnormal reflexes of u p p e r motor neuron systems, and three showed an "intention tremor." In all five cases where carbamazepine (Tegretol) was given, the paroxysms remitted although the more static symptoms associated with advanced MS did not. T h e r e was not strong EEG evidence for cortical seizures reported for these patients. Of the seven cases with EEG data, only two had abnormal recordings, and neither EEG was regarded as support of cortical seizures. No case reported a loss of consciousness during these episodes. Of course, seizure p h e n o m e n a at lower levels of the neuraxis are a possibility.

Speculations Concerning Pathophysiology Miley and Forster speculate that the origin of the paroxysmal symptoms is in excessive neuronal discharge or of impaired transmission of impulses. These authors suggest that brain stem nuclei are hyperexcitable due to demyelination and subject to epileptic discharge. T h e ataxic components of the paroxysms are attributed to "functional i n t e r r u p t i o n of cerebellar or brain stem tracts." Although Miley and Forster frame an either-or question with respect to excessive neuronal discharge at the brain stem level versus impaired transmission of impulses at the cerebellar level, it seems possible that these conditions could coexist. It is of interest that the paroxysms could be triggered by overbreathing or some form of emotional stress. In all cases where overbreathing was performed, an episode could be evoked (Espir et al., 1966; Miley and Forster, 1974). Espir et al. hypothesized that paroxysmal periods occurred only when new plaques were being formed, that is, when the disease was in an active or e x p a n d i n g stage. Paroxysms could not be elicited by overbreathing when their patients were in a stage of remission or reduction of the MS signs. Espir et al. suggested that overbreathing and emotional stress resulted in a transient



hypoxia to the partially denuded neurons which, in turn, yielded the transient sensorimotor dysfunctions observed during the episodes. Summing up to this point, we suggest the following possibilities. During an active stage of MS, the neurons are especially sensitive to changes in oxygen supply and paroxysms are triggered by disturbances in this supply. T h e presenting symptoms are determined by the extent of demyelination in the various sensorimotor systems. Brain stem involvement might result in excessive neuronal discharge whereas cerebellar involvement is responsible for the ataxic symptoms. Ataxic dysarthria is always present and need not implicate demyelination in the cerebellum per se if the disease has damaged the cerebellar peduncles to a significant extent. We are not aware of any autopsy material in cases of paroxysmal problems and, therefore, anatomic support for the above speculation is lacking. A CASE STUDY

T o our knowledge, there is no published account that allows for a quantitative comparison of the articulatory movements during normal and abnormal episodes in paroxysmal dysarthria. This condition offers a rare opportunity to study both normal and dysarthric patterns within the same speaker during a single examination period. As mentioned earlier, one of us (RN) had the opportunity to examine an individual with paroxysmal ataxic dysarthria in 1965. Cinefluorography was used to obtain detailed records of articulatory movements during normal and dysarthric samples of speech. This case study is based on the cinefluorographic film, supplemented by spectrographic analyses of the simultaneously recorded acoustic signal. T h e analyses of the film and spectrograms were guided by several questions concerning possible differences between the normal and dysarthric utterances. In particular, we wanted to determine if there were differences in (1) articulatory placements for consonants and vowels, (2) rates of articulatory movement, (3) coordinations of articulatory movements, and (4) ranges of articulatory movement. The Subject

T h e patient was a 33-year-old male with no previous neurologic history. Approximately two months before he was seen in the Department of Neurology at the University of Iowa Medical School, he began experiencing the paroxysms, which consisted of a loss of balance, blurring of vision, and ataxic dysarthria. T h e subject reported that he felt "drunk" during these episodes and that he was embarrassed because he felt that others would think that he had been drinking on the job. T h e paroxysms occurred regularly every four to five minutes and lasted for 15-30 seconds. In this regard, our subject appears similar to Subjects 5 and 6 in the reports of Espir et al. and subject JE in the report of A n d e r m a n n et al. T h e patient was given a provisional diagnosis of multiple sclerosis and was lost to follow-up.


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Proced u res

Perceptually normal and perceptually dysarthric recitations of the speech sample were filmed at the rate of 24 frames per second, hence affording a 40msec sampling interval. T h e subject was able to anticipate the episodes by a matter of a few seconds and therefore could signal the examiners to activate the cinefluorographic equipment at appropriate times. T h e speech sample included six VCV utterances constructed with the stops /ptkbdg/ embedded in a symmetric vowel /o/ frame, the digits 1-10 (counting), and the sentences Please buy me that cute little dog and It's easy to see fish if they swim slowly. T h e film was analyzed by means of rear projection with a Lafayette analyst. T h a t is, the X-ray image was projected through one side of a transparent tracing platform, and the operator traced the image from the opposite (front) side. Measurements were derived from the tracings with the aid of a transparent template bearing reference lines and the outlines of several bony structures (Figure 1). A reference point C was defined as the approximate center of the curved portion of the vocal tract, so that the reference lines CA, CP, CVa, CV2, and CR served as radii for the specification of tongue position. These radii were chosen because they corresponded to important directions of tongue movement: for example, line CA corresponded to the typical vector of tongue motion for apical stop production, line CV2 corresponded to the typical vector of tongue motion for dorsal stop production, and line CR corresponded to the vector of anterior-posterior motion of the tongue root. The measurements were made by overlaying the template on each tracing and recording the values with a Hewlett-Packard 9864A digitizer coupled to a Hewlett-Packard

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9810A p r o g r a m m a b l e calculator. T h e values were r e c o r d e d by the digitizer to the nearest t e n t h of a m i l l i m e t e r a n d s u b s e q u e n t l y were p r i n t e d out by the calculator. I n d i v i d u a l m e a s u r e m e n t s were as follows: LO, or lip opening, is the minimum distance between the upper and lower lips. IO, or incisal opening, is the distance between the lower central incisor and the maxillary outline, as measured along a line that represents the average path of motion of the lower incisor. CA, or tongue position along the center to alveolus line, is the distance between reference point C and the intersection of reference line CA with the tongue outline. CP, or tongue position along the center to prepalate line, is the distance between point C and the intersection of reference line CP with the tongue outline. CV1 and CV2, which record tongue position along the center to velum lines, are the distances from point C to the intersections of reference lines CV1 and CV2 with tile tongue outline. VE, or position of the velar eminence, is the location of the eminence on a line that represents the average path of velar motion. The location was specified as the distance between an arbitrary point on the motion path and the position of the eminence on that path. CR, or position of the tongue root along the center to root line, is the distance between point C and the intersection of reference line CR with the tongue outline. LH, or larynx height, is the distance between reference line C R and the aryepiglottic fold, as measured along a perpendicular from CR. (This measurement is rather an indirect indication of the position of the larynx, but it probably reflects most superior-inferior movements of the laryngeal mass.) T h e acoustic signal recorded on the s o u n d track of the film was analyzed with a Kay Electric 6061A S o n a - G r a p h e q u i p p e d with a plug-in scale magnifier (6076C). S p e c t r o g r a m s were o b t a i n e d for a full-scale w i d e - b a n d analysis a n d an expanded-scale n a r r o w - b a n d analysis. T h e w i d e - b a n d s p e c t r o g r a m s were used to e x a m i n e features of frication a n d resonance, a n d the n a r r o w - b a n d spectrograms were used to estimate f u n d a m e n t a l frequency contours from the harmonic i)atterns. Results

Cinefluorographic Analyses. T h e VCV utterances allow t h e inspection of three types of oral c o n s o n a n t m o v e m e n t s in the s y m m e t r i c vowel frame. Results for the three types of oral constrictive a n d release gestures are presented in F i g u r e 2. T h e bilabial gestures for / b / are r e p r e s e n t e d by m e a s u r e m e n t L O ; the t o n g u e tip gestures [ o r / d / , by m e a s u r e m e n t CA; a n d the tongue dorsum gestures f o r / 9 / , by m e a s u r e m e n t CV2. For each VCV u t t e r a n c e , the g r a p h on the left applies to the dysarthric p a t t e r n , a n d the g r a p h on the r i g h t applies to the n o r m a l p a t t e r n . T h e longer d u r a t i o n s of the d y s a r t h r i c utterances are i m m e d i a t e l y a p p a r e n t , with a m a r k e d l e n g t h e n i n g of the VC transitions, which are easily twice as long for the d y s a r t h r i c as for the n o r m a l recitations. T h e differences in slope between the d y s a r t h r i c a n d n o r m a l transitions are taken to m e a n t h a t t h e a r t i c u l a t o r y velocities were r e d u c e d i n the d y s a r t h r i c state.


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Figure 2. Oral constrictive and release gestures for dysarthric (left) and normal (right) productions of three VCV utterances. The ordinates are scaled in millimeters, and the data points are plotted at intervals of 40 msec. Bilabial movements are represented by measure LO; tongue tip movements, by measure CA; and tongue dorsum movements, by measure CV2.

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Figure 3. Variations in jaw opening, expressed as measurement I0, during dysarthric (unfilled circles) and normal (filled circles) recitations of five VCV utterances. The ordinate is scaled in millimeters, and the data points are plotted at intervals of 40 msec. The vertical lines indicate the approximate midpoints of consonantal closure.

Similar results were obtained for the voiceless cognates produced in the symmetric vowel frame. Temporal variations of measurement IO (incisal opening) are portrayed in Figure 3. These plots illustrate jaw movements during dysarthric (unfilled circles) and normal (filled circles) productions of VCV utterances. T h e approximate midpoint of consonant closure is indicated by the vertical line in each graph. The dysarthric and normal recitations frequently differed with respect to (1) the average position of the jaw during the vowel, with the mandible being held in a lower position during dysarthric utterances; and (2) the participation of the jaw in consonant articulation, with the jaw exhibiting larger movements in the dysarthric productions. The second of these differences would seem to be a consequence of the first, since the jaw usually closed some-


NETSELL, KENT: Paroxysmal Ataxic Dysarthria

101

what for consonant production. Usually, the position of the jaw at the midpoint of consonant closure tended to be about the same for dysarthric and normal productions. Dysarthric and normal articulatory patterns are illustrated for the sentence CA

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Figure 4. Top: Measurements LO and IO, in millimeters, recorded at 40 msec intervals during a dysarthric recitation of the sentence, Please buy me that cute little dog. Bottom: Same measurements made during a normal recitation of the test sentence.

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Figure 5. Measurement CA, in millimeters, recorded at 40 msec intervals during dysarthric (top) and normal (bottom) recitations of the sentence, Please buy me that cute little dog.

Please buy me that cute little d o g in Figures 4, 5, 6, and 7. Figure 4 allows

comparison of lip opening (LO) and incisal opening (IO) during dysarthric recitation (top curves) and normal recitation (bottom curves). Some differences between the dysarthric and normal patterns are as follows. 1. The dysarthric recitation had a longer duration. 2. During the dysarthric state, the subject failed to make the third bilabial closure for the/rn/ in me (confirmed by spectrographic analysis). 3. The mandible was almost constantly lower (more open) for the dysarthric recitation. 41 The range of jaw movement was greater for the dysarthric state. Data for measurement CA, which was are displayed in Figure 5. T h e dysarthric respect to the range of movements and along line CA. An overall impression of

designed to record apical movements, and normal curves are dissimilar with the number of movements occurring these differences is that the pattern of


102 JOURNALOF SPEECHAND HEARING DISORDERS

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tongue tip articulation was much simplified for the dysarthric recitation, with omission of m a n y gestures that could be observed in the normal recitation. Contacts for apical consonants were occasionally missed for this sentence and also for the counting sequence (1-10). In view of the conspicuous abnormalities in articulations of the tongue tip, other dimensions of tongue movement were examined to determine if the dys-

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Figure 6. Top: Measurements CP and CR, in millimeters, recorded at 40 msec intervals during a dysarthric recitation of the sentence, Please buy me that cute little dog. Bottom: Same measurements made during a normal recitation of the test sentence.

Figure 7. Measurement VE, in millimeters, recorded at 40 msec intervals during dysarthric and normal recitations of (top) the sentence, Please buy me that cute little dog, and (bottom) counting one, two, three.

arthric i m p a i r m e n t affected the tongue as a whole. Data for measurements CP and C R are presented in Figure 6 for the sentence Please buy me that cute little dog. Measurement C P represents tongue movements in the vicinity of the palate, and measurement C R represents tongue movements in the vicinity of the lower pharynx. Reductions in the range of movement are evident for both of these measurements in the dysarthric recitation. These data are interpreted to mean that in the dysarthric state, the tongue body assumed a relatively central position in the oral cavity and deviated from that position only slightly for the production of various speech sounds. Data for measurement VE, or position of the velar eminence, are shown in Figure 7. T h e top two curves apply to dysarthric and normal productions of Please buy me that cute little dog. These two curves reveal differences in the rates of velar motion, with reduced velocities of both elevating and lowering



103

gestures in the dysarthric state. It is noteworthy that in the dysarthric recitation, the velum lowers for t h e / m / e v e n though the bilabial closure for this segment was not accomplished (see Figure 4). T h e bottom curves in this illustration portray data for measurement VE during dysarthric and normal counting from I-3. Although the dysarthric utterance is only slightly longer in duration than the normal utterance, differences in the velocities of elevating gestures are nonetheless apparent. Both the first and second ascents of the velum are slower in the dysarthric than in the normal state.

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Figure 8. Vocal tract profiles corresponding to the point in time at which the lingual constriction for / z / in please is released and the bilabial closure for / b / in buy is accomplished (test sentence: Please buy me that cute little dog.) The dysarthrlc and normal profiles differ especially in the positions of the laryngeal-hyold structures.

Finally, the cinefluorographic analyses revealed differences between dysarthric and normal utterances in the elevation of the hyoid bone and the larynx. During the dysarthric utterances, the hyoid bone and the larynx frequently assumed more superior positions than during the normal utterances. Hence, measurement LH tended to be smaller for the dysarthric production of a given speech item. Figure 8 provides a comparison of vocal tract profiles during dysarthric and normal speech to illustrate these differences. Each profile was traced from a frame that corresponded to the release of the lingual constriction for /z/ in please and the beginning of bilabial closure for /b/ in buy, the test sentence being Please buy me that cute little dog. It is significant that such a comparison could be made, since the identification of this articulatory time point implies that the coordination of movements was quite similar for the dysarthric and normal recitations. Figure 8 reveals that the dysarthric and normal vocal tract profiles differed in the (1) positions of the jaw, hyoid bone, and aryepiglottic fold, and (2) shape of the anterior portion of the tongue. Similar differences were noted in other comparisons of selected frames and have been mentioned in conjunction with previous figures. Hence, it appears that the dysarthric speech pattern was characterized by a greater open-


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ing of the jaw, an elevation of the laryngeal-hyoid structures, and a loss of fine control in the articulation of the blade and tip of the tongue. Three ataxic episodes were recorded on the cinefluorographic film and the articulatory abnormalities described above were similar in each of the episodes even though the speech material (VCV syllables, counting, sentences) differed in each episode. Replications of particular speech tasks were not obtained in order to minimize radiation to the subject. .....

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Spectrographic Analyses. Because of the rather small number of utterances involved, no effort was made to derive detailed measurements from the spectrograms. However, the spectrograms were an additional source of information and served to confirm the interpretations of the cinefluorographic data. A spectrographic comparison of dysarthric and normal speech (counting: one, two, three) is presented in Figure 9. Some of the more obvious contrasts in the spectrograms have been labeled with the numbers 1-4. T h e number 1 points to a difference in the rate of formant movements for the g l i d e / w [ in one. T h e dysarthric production of the syllable had a longer duration than the normal production, and the rate of formant-frequency change was much slower for the dysarthric production. T h e number 2 marks a contrast in the production of the stop-plosive ]t/ in the word two. Whereas the normal production was characterized by a prominent noise burst, the dysarthric production was virtually



devoid of such a feature (possibly, the noise burst was so weak as to be obscured by the noise floor of the cinefluorography laboratory). T h e number 3 indicates a difference between dysarthric and normal formant patterns in the word two. In this case, the dysarthric formant patterns were closer to the ideal target frequencies f o r / u / : note in particular the lower (hence more extreme) frequency value of the second formant in the dysarthric production. Apparently, the normal production was subject to undershoot or vowel reduction. Finally, the number 4 points to differences in the formant pattern for t h e / r / a n d / i / c o m b i n a t i o n in the word three. T h e normal production is characterized by more prominent resonances and by larger shifts in formant frequencies. Estimates of fundamental frequency were obtained from the harmonic patterns displayed on scale-expanded, narrow-band spectrograms. Comparisons were made between dysarthric and normal utterances for the approximate midpoints of vowel segments. In the following comparisons, the description of the vowel sample is followed by two numbers, the first representing the fundamental frequency for the normal recitation and the second, the fundamental frequency for the dysarthric recitation. T h e difference between the two values (dysarthric value minus normal value) is indicated in parentheses. 1. 2. 3. 4. 5. 6.

First vowel in /aka/--125 Hz, 148 Hz (23). Second vowel in/aba/--125 Hz, 137 Hz (12). Second vowel in /apa/--145 Hz, 194 Hz (49). Vowel /A/ in one--132 Hz, 150 Hz (18). Vowel/i/ in three--122 Hz, 130 Hz (8). Vowel/x/in six--125 Hz, 135 Hz (10).

T h e values cited above demonstrate that the subject's fundamental frequency tended to be higher for the dysarthric than for the normal recitations. In fact, when a difference in fundamental frequency between dysarthric and normal productions was observed, the higher value almost always was associated with the dysarthric production. Sometimes the difference was quite l a r g e almost 50 Hz in Example 3 above. Possibly, these differences in fundamental frequency were associated with the differences in hyoid-larynx position portrayed in Figure 8. T h e increased frequency of vocal fold vibration is consistent with a tensing and lengthening of the folds that might result from laryngeal elevation (Sonninen, 1968). Discussion

Because the abnormal speech patterns observed in cases of paroxysmal dysarthria have been described as ataxic in nature, it is of interest to compare the articulatory disturbances of the present speaker with those of an ataxic dysarthric described by Kent and Netsell (1975). The speech patterns of the latter subject were characterized by reductions of articulatory velocities, prolongations of vowel postures and consonant constrictions, errors in the rate,


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range, and direction of articulatory movements, and a variety of abnormalities in laryngeal control. T h e speaker studied here exhibited many of the same disturbances, especially with regard to the rate, range, and direction of movements. Thus, the speech deviations of the present subject and those of the ataxic subject studied by Kent and Netsell are at least grossly similar. T h e resemblance of the dysarthric patterns lends physiological support to the notion that the salient speech disturbances of paroxysmal dysarthria are ataxic in character. Kent and Netsell suggested that many of the speech abnormalities of ataxic dysarthria could be explained by a generalized hypotonia of the speech musculature. They proposed that the hypotonia "results in a delay in the generation of muscular forces (hence producing the speech abnormality of prolongation), a reduced rate of muscular contraction (hence producing slowness of movement), and reduced range of some movements (hence producing the phenomenon of telescoping)" (p. 130). Hypotonia also seems to be a likely explanation for many, but not all, of the articulatory abnormalities recorded for the present subject. T h e larynx-hyoid elevation and the increased fundamental frequency do not seem compatible with a hypotonic musculature. In fact, these latter characteristics are reasons to suspect that the suprahyoidal muscles have a greater degree of contraction in the dysarthric than in the normal speech patterns. Moreover, heightened activity of the extrinsic musculature of the larynx could explain in part the lowering of the mandible observed during the dysarthric recitations, since it is conceivable that a strong contraction of the hyomandibular musculature would have the dual effects of laryngeal-hyoid elevation and mandibular lowering. One important similarity between the paroxysmal dysarthric reported here and the ataxic dysarthric studied by Kent and Netsell is that both speakers exhibited essentially normal patterns of succession for articulatory gestures; that is, the ordering of articulatory movements was not disturbed. Although the general successional pattern was intact, individual movements were abnormal and the overall movement patterns were prolonged. T h e preservation of the desired successional patterns in the face of conspicuous abnormalities in individual structural movements and speaking rate might be explained by assuming that the successional pattern for speech movements is programmed at the cortical level and that cerebellar dysfunction results in the delayed and inaccurate execution of the required submovements. In short, the coordination of articulatory movements is not destroyed, even though the overall movement pattern is slowed and individual movements may be misdirected. This principle is consistent with the fact that an error in the execution of one submovement did not cause a complete breakdown of the articulatory program. For example, whereas the paroxysmal dysarthric completely missed the target of bilabial closure for / m / in Please buy me that cute little dog (as shown by the curve for LO in Figure 4), he nonetheless accomplished the velar lowering needed to realize the nasality feature for this segment (as shown in Figure 7). Moreover, after the error in labial articulation occurred, he appeared to continue without


NETSELL, KENT: Paroxysmal Ataxic Dysarthria 107 interruption the articulatory program for the remainder of the utterance. This dysarthric p a t t e r n cannot be described as discoordination, because discoordination usually implies errors in the synchrony or tinting of two or more movements. A surprising feature of the data for the present subject and the data for the ataxic subject of Kent and Netsell is that discoordination was rare, so that essentially normal coarticulatory patterns were observed. For example, in both the normal and dysarthric recitations of the sentence Please buy me that cute little dog, the present subject initiated the gesture of velar lowering for t h e / m / in me almost simultaneously with the release of the bilabial closure f o r / b / in buy. Since labial and velar movements are as independent as any two articulatory movements can be, the accurate timing of these articulations in the normal and dysarthric patterns is a striking example of coordinated control. Furthermore, the ataxic subject of Kent and Netsell exhibited this same coordination of labial and velar movements in this sentence, even though the utterance as a whole was perceived as being grossly abnormal. Another i l l u s t r a t i o n of coordination is seen in Figure 8, which demonstrates that the relative patterning of lingual and labial movements was similar for the normal and dysarthric recitations, even though individual lingual and labial gestures were seriously disturbed in the dysarthric production. In view of these observations, it appears that dysarthria of the ataxic variety may not be so much a problem in the coordination of c o m p o n e n t articulatory gestures as a problem in the controlled execution of individual movements, the seriation of which is essentially normal. Given this interpretation of the motoric abnormalities resulting from cerebellar lesion, the role of the cerebellum in speech would seem to be to m o n i t o r the positions of the speech organs and generate appropriate motor instructions to realize the articulatory targets implied by a cortically generated motor program. Thus, the cerebellum may serve to supplement and revise as necessary the basic p r o g r a m supplied by the motor cortex. Such a view is compatible with the notions of cerebellar function in motor control expressed by Eccles (1969, 1973), l t o (1970), and Brooks (1972). For a discussion of some of these notions applied to speech, see Kent and Netsell (1975).

IMPLICATIONS

F OR E V A L U A T I O N

AND TREATMENT

A Preliminary Checklist Each of the 13 individuals reviewed in this report is presumed to have presented a paroxysmal ataxic dysarthria and was given a definite or provisional diagnosis of m u l t i p l e sclerosis. Although the case studies reported to date are relatively few, it is possible to list a few items that have characterized this group. As such, this checklist should be regarded as highly preliminary and


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s u b j e c t to r e v i s i o n w i t h t h e a d d i t i o n of n e w cases of this disorder. F i v e i t e m s c o n s t i t u t e this i n i t i a l list: 1. A few to several h u n d r e d paroxysms occur per day with each episode lasting approximately five to 30 seconds. 2. T h e speech pattern d u r i n g the paroxysms is perceived as ataxic dysarthria. Other speech patterns may be present, but ataxic dysarthria must be perceived. 3. T h e paroxysmal behavior may remit and reappear much later in time with the exaggeration of the previous set of symptoms or the addition of new ones or both. 4. T h e r e is no clinical or laboratory evidence of cortical seizures. 5. Overbreathing tends to evoke the paroxysms.

Response to Treatment As m e n t i o n e d e a r l i e r , t h e p a r o x y s m a l d i s t u r b a n c e s h a v e r e m i t t e d i n e a c h case i n w h i c h c a r b a m a z e p i n e ( T e g r e t o l ) was a d m i n i s t e r e d . A l t h o u g h t h e m a j o r i t y of l o n g - t e r m MS p a t i e n t s w i t h s p e e c h p r o b l e m s h a v e b e e n s h o w n to i m p r o v e w i t h s p e e c h t h e r a p y ( F a r m a k i d e s a n d B o o n e , 1960), t h e p a r o x y s m s of t h e p a t i e n t s i n t h e p r e s e n t r e p o r t p r o b a b l y are too b r i e f for t h e a p p l i c a t i o n of c o n v e n t i o n a l s p e e c h r e h a b i l i t a t i o n measures. ACKNOWLEDGMENT

This research was supported by Research Grants NS 09627, NS 11022, and NB 02662 front the National Institute of Neurological Diseases and Stroke. The authors are grateful to James C. Hardy, Department of Speech Pathology and Audiology, University of Iowa, for permission to analyze the cinefluorographic film. Requests for reprints should be addressed to Ronald Netsell, Department of Communicative Disorders, 1975 Willow Drive, University of Wisconsin, Madison, Wisconsin 53706. REFERENCES

ANDERMANN, F., COSGROVE,J. B. R., LLOYD-SMITH, D., and WALTERS, A. M., Paroxysmal dysarthria and ataxia in multiple sclerosis. Neurology, Minneap., 9, 211-215 (1959). BROOKS, V., Some new experiments on cerebellar motor control. In J. Cordeau and P. Gloor (Eds.), EEG supplement No. 31, Recent Contributions to Neurophysiology. Amsterdam: Elsevier (1972). BROWN, j., DARLEY, F., and ARONSON, A., Ataxic dysarthria. Int. ]. Neurol., 7, 302-318 (1970). DARLEY, F., ARONSON, A., and BROWN, j., Differential diagnostic patterns of dysarthria. ]. Speech Hearing Res., 12, 246-269 (1969). DECASTRO, W., and CAMPBELL,j., Periodic ataxia. I. Am. reed. Ass., 200, 892-895 (1967). ECCLES, j., The dynamic loop hypothesis of movement control. In K. N. Leibovic (Ed.), Information Processing in the Nervous System. New York: Springer-Verlag (1969). ECCLES, j., A re-evaluation of cerebellar function in man. In J. Desmedt (Ed.), New Developments in Etectromyography and Clinical Neurophysiology, Vol. 3. Basel: Karger (1973). ESPIR, M. L. E., and MmLAC, P., Treatment of paroxysmal disorders in multiple sclerosis with carbamazepine. ]. Neurol. Neurosurg. Psychiat., 33, 528-531 (1970). ESPIR, M. L. E., and WALKER, M. E., Carbamazepine in multiple sclerosis. Lancet, 1, 280 (1969). ESPIR, M. L. E., WATKINS, S. M., and SMITH, H. V., Paroxysmal dysarthria and other transient neurological disturbances in disseminated sclerosis. J. Neurol. Neurosurg. Psychiat., 29, 323330 (1966). FARMAKIDES, M. N., and BOONE, D. R., Speech problems in patients with multiple sclerosis. J. Speech Hearing Dis., 25, 385-390 (1960).



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HARRISON, M., and MCGILL, J. I., Transient neurological disturbances in disseminated sclerosis: A case report. J. Neurol. Neurosurg. Psychiat., 32, 230-232 (1969). ITO, M., Neurophysiological aspects of the cerebellar motor control system. Int. J. Neurol., 7, 162-176 (1970). KENT, R., and NETSELL, R., A case study of an ataxic dysarthric: Cineradiographic and spectrographic observations. J. Speech Hearing Dis., 40, 52-71 (1975). MILEY, C. E., and FOmTER, R. M., Paroxysmal signs and symptoms in multiple sclerosis. Neurology, Minneap., 24, 458-461 (1974). PARKER, H. L., Periodic ataxia. Coil. Pap. Mayo Clin. Mayo Fdn., 38, 642-645 (1946). SONNINEN, A., T h e external frame function in the control of pitch in the h u m a n voice. In A. Bouhuys (Ed.), Sound Production in Man, Ann. N.Y. Acad. Sci., 155, 68-90 (1968). Received February 18, 1975. Accepted March 25, 1975.


Ataxic dysarthria revealing Fahr's syndrome and hypoparathyroidism.

The dysarthria-clumsy hand syndrome: ataxic or bradykinetic hand?

Paroxysmal dysarthria ataxia syndrome responds to lacosamide.

Isolated paroxysmal dysarthria caused by a single demyelinating midbrain lesion.

Paroxysmal dysarthria-ataxia in remitting-relapsing Bickerstaff's-like encephalitis.

The Effects of Topic Knowledge on Intelligibility and Lexical Segmentation in Hypokinetic and Ataxic Dysarthria.

Phonological markers of sentence stress in ataxic dysarthria and their relationship to perceptual cues.

Speech serial control in healthy speakers and speakers with hypokinetic or ataxic dysarthria: effects of sequence length and practice.

Dysarthria with tricyclic antidepressants.

ataxic diplegia with immunodeficiency.

or corona radiata infarction.

Ataxic quadriparesis due to bilateral capsular infarcts.

Implementing two treatment approaches to childhood dysarthria.

[Cerebellar dysarthria--a review of the literature].

Maternal reproductive histories in ataxic cerebral palsy.

Pseudochoreoathetosis in sensory ataxic variant of Guillain-Barré syndrome.

Vowel acoustics in dysarthria: mapping to perception.

An Early Sign of Wilson's Disease: Dysarthria.

Paravermal infarct and isolated cerebellar dysarthria.

Clinical anatomic study of pure dysarthria.

Raynaud phenomenon causing lingual pallor and dysarthria.

Automated Speech Rate Measurement in Dysarthria.

Paroxysmal Tachycardia.

[Paroxysmal choreoathetosis].