DUGNO : TE F A. Vila, M.D.', F. Reymond, M.D.', V. Rialle, Ph.D.2 dElsuomyographie, Cenllc Hospitalicr el Universilaue'. DCpartemenl de mtMmafiqmsmtistiqnes . el mfmnatique rn6dicales. Fxulle de MedSins2, Gnmblc. France) ( Lpboralcuc

S.F'ientka1, J.Willamowski1, D.Ziebelin.Ph.D.1, A.VilaM.D.2. F.Reymond,M.D.Z. L.Abaoub,M.D.2 (UNwnie & Savorc,LabomtoLC dlntclligenccAruTiielle.Chamb5y'. Lzboraroired'Elecuomyographie.C u m Hospitalierel UnivCrPilak, Grenoble 2, F m )

Computuized methods of automatic quantitative elcmomyography &MG) had been widely studied, and resulted in differentEMG signal analysis profedures. Their clinical value in routine practice may now he estimated owing to the new EMG integrated systems. We have used various automatic quantitative EMG methods as a routine since 1986: integrated surface EMG; specrral analysis; interference pattern analysis; mcasuremcnt of single motor unit potentials during weak contraction. We compared the parametas provided by those methods: mean rectified voltage, rout mean square and N m s per second of the integrated EMG mean and median frequency from the spectral analysis; turns per second, amplitude per turn and the ratio between these two parameters of the interference pattern analysis; the number of polyphasic. the mean duration and the amplitude of motor unit potentials. We compared the results statistically from Tibialis Anterior, Biceps Brachii and Abductor Pollicis Brevis in muscles with definitely normal, neurogenic or myogenic patterns, as well as unspecified ones. The results are discussed to define the interest of such automatic quantitative EMG methods as routine diagnostic tools.




IYkJMEL SchoReld IS. M.B. B.S. Fawall P.R.W FRCP KennBtt R.P M.D. (Regional Neuroloplcal Center Newcaslleupon-lyne England). Conventional nerve conduction techniques estimate the near- maximum amdudion velocily and can be normal 1 oniy a portion of the nerve is wmpmmised. This study of the

application of wndudlon velocity distribution (CVD) analysis has

tm, aims:-

1. TO improve the single response CVD method of Kovacs el. a1.(1879)for routine studles. 2.

To determine lhe wndudion velocity dlstribution m patients wilh a mild carpal tunnel syndrome.

A good eslimate of a single nerve fibre adion potential (SFAP) is essential in each


for the sing* response

CVD method.

A prcgrammable stimulator has been

designed to perform sequential recruitment sludies allowing the divkion of lhe compound nerve adion potential (CAP) into a number of subpopulatiins. from which a 'best' estimate of the SFAP can ba obtained. The PCAP CCV method


Cummins el. al. (1978)was used

for wmparath purposes wilh modMcalions. Gaod estimates of a SFAP were obtained from a wnlrol group but inRial studies of a

patient group indicated that inadequate responses may be found when lhe compression

was signficanl. A 3cm. platinum strip electrode has been used to reduce the effects of rewrdlng geOmetW allowing a 'standard SFAP to be used in all cases.


Abstracts: Computerized and Quantitative EMG

The specialized environment approach enables the newphysiologist to m a t e his own expert system through introductionof his own knowledge. This approach falls between an almost inflexibleexpm system and a shell system that is not really appropriate for the needs of the neurophysiologist. It was chosen as a result of much experience whilst developing expert systems at the EMG laboratory of CHU Grenoble: including MYOSYS (1982-86) which aid to represent the entire EMG knowledge in PROLOG and NEUROP (1987-90)in which a shell was used to represent knowledge only about neuropathies. These projects revealed certain problems. In MYOSYS t h m were maintenance and validation problems and in NEUROP general problems inherent to a shell. i.e. resmctive knowledge representation and no flexible user interface The discussed environment is based on a deep model that explicitly represents the expert's knowledge. This suppons coherence of the knowledge base, the generation of adequate explanations and an user adapted howledge acquisition interface. The EMG examination is an interactive process that analyses clinical symptoms, suggests and evaluates hypotheses of dysfunctions, proposes suitable protocols and makes conclusionsat different levels of absuaction. This reasoning process may be expressed in different smtegies which have to be adapted to the state of the patient's examination and to general circumstances such as limiting factors e.g. medical tnamxnts. To achieve the required flexibility for our system we chose a blackbaard architecmrc for the internal representation. This architecture provides a problem solving mechanism for reasoning simultaneously on several levels of abstraction.

ANALYSIS OF MOTOR UNIT POTENTIAL ACTIVITY USING FOUR-CHANNEL I N T W S C U L A R RECORDING Tapani Salmi, M.D and Markku I( Nieminen, M.D. (Lab Clin Neurophysiology, Helsinki University Hospital, Helsinki, Finland) We have constructed a recording system with four simultaneous intramuacular recording sites to analyze the location of the motor unit potential (MUP) activity within the muscle. The recarding system consists of two needle electrodes located 5 mm from each other and supplied with two recording sites situated 5 mm from each other. Thus recording sites are situated in the corners of a tetrahedron. The signals f r m the four electrodes are digitized by an IBM PC computer and the peaks of the MUPs are identified. In our model the decay of the MUP amplitude is presumed to be exponential and equal to both X and Y directions. Using this exponential model and the area of the simultaneous peaks of MUPs on the four channels, the relative distances of the generators from each corner and thereafter the location of Mups are calculated on the recording plane. Because both the distance and the amplitude of MUP is now known, the relative size (correlating to the nunbar of fibers) of the generator can be calculated. The generators of equal size appearing repeatedly in same location are presented graphically as a map of activated MUPs. This graph simulates the common muscle biopsy. The quantitative parameters calculated are independent on the diatance between the electrode and MUP. In the recording of normal subjects (tibialis anterior muscle) using the present method we are capable to analyze an area of 10 x 15 nun of muscle tissue.


October 1990



H Modarres-Sadeghi MD. RJ Guiloff MD (Westminster Hospital, London. UK).

W Guiloff HD, H Modarres-Sadeghi MU (Westminster Hospital, London, UK)

The distribution of conduction velocities (CVs) of 1692 Fw.recorded over

Each of 22 faaeiculatians (FUe) had a Macro EMG (MAC) potential of similar

the adductor digiti minimi of 33 normal subjects, with 60 supramaximal stimuli

amplitude, area and shape to that of a voluntarily activated motor unit (W).

at the wrist. was shifted towards faster values than expected from the

These homologous paire

distribution of CVs in single peripheral nerves.

The dietribution Of CVS of

81 single unit F, recorded with a bipolar needle electrode (BNE) and threshold

sampled in 10 patients. All pus, and PUS not activated voluntarily (n-189), had e higher mean

stimulation, in 8 subjects. was similarly shifted. F frequency during 200 stimuli correlated with the CV of these units ( ~ 0 . 3 5 ,p-0.002).


(VFUs) were always recorded at the same electrode sites

and muscle penetrations. in 9/10 brachial biceps, out of 200 W s and 211 FUs

number o f s p i k e s in their triggering single fibre (SF) potential# (p



On t h e b a s i s o f Discrete H i l b e r t T r a n s f o r m a t i o n (DHT) s p e c t r a l p a r a m e t e r s f o r d y n a m i c EMG a n a l y s i s c a n b e i n t r o d u c e d . Within a n a l y s i s i n t e r v a l s w h i c h are u s e d i n t h e same m a n n e r a s i n S p e c t r a l a n a l y s i s , t h e i n s t a n t a n e o u s p o w e r of EMG f r e q u e n c y b a n d s c a n b e c o m p u t e d as tyrne series of t h e same i n t e r v a l d u r a t i o n . A c l o s e c o n n e c t i o n e x i s t s between i n s t a n t a n e o u s power and t h e c u r r e n t phenomenalogy o f power s p e c t r a l a n a l y s i s b e c a u s e t h e i n s t a n t a n e o u s power o f a d e f i n e d f r e q u e n c y b a n d c a n b e s e e n a s t h e e x a c t d y n a m i c e q u i v a l e n t of t h e c o r r e s p o n d i n g mean p o w e r v a l u e d e d u c e d f r o m t h e power s p e c t r u m . A multichannel EMG recording [I6 channels) makes t h e r e p r e s e n t a t i o n o f t h e t o p o g r a p h i c a l d i s t r i b u t i o n of t h e s p e c t r a l p a r a m e t e r b y a c o l o u r e d map p o s s i b l e . Additionally, t h e i n s t a n t a n e o u s power c a n b e u s e d t o c a l c u l a t e map s e q u e n c e s . I n t h i s w a y , m o v e m e n t - r e l a t e d c h a n g e s o f EMG a c t i v i t y c a n b e q u a n t i f i e d by map s e q u e n c e s of a n a r b i t r a r y t i m e resolution. By c a l c u l a t i o n o f i n s t a n t a n e o u s f r e q u e n c y v i a DHT an a r t e f a c t d e t e c t i o n s c h e m e f o r ECG i n t e r f e r e n c e c a n b e s u g g e s t e d . U s i n g t h i s c o n c e p t of EMG p r o c e s s i n g , a new a n d common m e t h o d i c a l b a s i s o f EMG power s p e c t r a l a n a l y s i s c a n b e i n t r o d u c e d . T h e p r o g r a m p a c k a g e MYOMAP w h i c h c o n t a i n s t h e s e f u n c t i o n s was d e v e l o p e d f o r NORAXON OY ( F i n l a n d ) . I t s c l i n i c a l u t i l i t y c a n b e shown , e . g . i n r e h a b i I i t a t i o n , o r t h o p a e d i c s , p h y s i c a l t h e r a p y a s w e l l as s p o r t s m e d i c i n e .


Mamoli B. M . D .

( N e u r o l o g i s c h e s K r a n k e n h a u s R o s e n h U g e l , A-1130

Wien. V i e n n a )

1-T Middletiin. M.D., C.S. Pattichis, M.Sc.. C.N. Schms, Ph.D., K. h z a r o u . and M. Christophidnu, M.D. (MDRTC Neuromusculor Unit, Mukrriio.~Hospitul, ivicusru, Cyprw),

I n t e r f e r e n c e p a t t e r n s f r o m t w e n t y d i f f e r e n t s i t e s of t h e r i g h t (BIC) and t h e r i g h t q u a d r i c e p s f e m o r i s (QUA) a t 20, i t s maximum f o r c e were r e c o r d e d w i t h C N - e l e c t r o d e s f r o m 1 4 h e a l t h y women ICO, age 26-39), 10 p o s s i b l e DMD-carriers (PC, age 26-36] a n d 4 o b l i g a t e DMD-carriers IOC. a g e 30-39). T h e y

biceps brachii 4 0 a n d 60% of

w e r e a u t o m a t i c a l l y a n a l y s e d u s i n g t h e m e t h o d of W i l l i s o n 1964 ( T I A - a n a l y s i s ) . I n both m u s c l e s t h e t u r n s per s e c o n d I T / S l increased c o n t i n o u s l y f r o m CO t o OC [KO PC OCI w l t h o u t a s i g n i f i c a n t d i f f e r e n c e of its m e a n s i e x c e p t KOIOC). T h e same t e n d e n c y c o u l d b e s e e n w i t h t h e a m p l i t u d e s p e r t u r n LAIT) o f t h e B I C a n d p a r t l y t h e QUA. T h e T I S a n d t h e A/T w e r e h i g h e r i n t h e BIC t h a n

i n t h e QUA ( e x c e p t AlT KO). T h e r a t l o A / T : T / S w a s i n a l l t h e g r o u p s a n d b o t h m u s c l e s l o w e s t a t 40% ( e x c e p t KO QUA) a n d h i g h e s t a t 20% ( e x c e p t PC a n d OC BIC) of its maximum f o r c e . T h e e q u i v a l e n t v a l u e s o f t h e r a t i o were h i g h e r i n t h e QUA t h a n i n t h e BIC. T h e m e a n s o f t h e r a t i o a t 2 0 % of t h e maximum f o r c e of b o t h m u s c l e s Were s i g n i f i c a n t l y h i g h e r i n CO t h a n i n PC a n d OC (except COIOC B I C I . U s i n g S t a l b e r g ' s m e t h o d t o e v a l u a t e t h e l i m i t s of n o r m a l v a l u e s f o r T I S a n d AlT n o n e of t h e DMD-cariiers s h o w e d p a t h o l o g i c a l v a l u e s . E x c e p t t h e r a t i o A/T:TIS a t low l e v e l s of maximum f o r c e T I A - a n a l y s i s seems t o b e of l i t t l e h e l p t o d e t e c t DMDcarriers.

Abstracts: Computerized and Quantitative EMG

Motor Unit Action Potentials (MUAPs) were recorded from the biceps brachii muscle of normal subjects a n d patients suffering of motor neuron d i s e a s e (MND) and myopathies

T h e latter g r o u p included patients with m u s c u l a r dystrophy

polymyositis a n d mitochondria1 disease T h e numerical panern recognition (NPR) algorlthm b a s e d on the MUAP features h a s b e e n used to identihi a n d SeleCI MUAPs

The parameters measured were

amplitude p h a s e s duration area spike duration a n d spike area T h e s e parameters have b e e n applied to Aflificial Neural Net (ANN) models trained to diagnose normals MND


myopathic patients

were utilised to train the

Supervised a n d unsupervised learning algorithms

neural net models


Analysis of the data w a s carried out using 12 input models where the mean value and t h e standard deviation of the 6 parameters of all MUAPs collected from each subject formed t h e input vector, and 120 input models, where t h e values of t h e individual parameters for e a c h MUAP formed the input vector In born tha 12 a n d t h e 120 input models

a maximum diagnostic yield of 80% w a s obtained

T h e hndings of this study a n d individual borderline


cases will b e discussed

October 1990






L. Kasatkina, 8 . Gacht, MD (Institute of General Pathology and Pathophysiology of the Hedical Academy,Moscm,USSR).


C.Otte, M.D.', G.Sieben, M.D.0, L.Vercauteren, Ir.*, M.Praet, M.D., L.Boullart, Ir.*, J.Brouns, M.D.', J.D.Guieu, M.D.**

(*Ghent State University-Belgium


Universite de Lille -France)

The study demonstrates the value of results obtained with different methods of motor

unit investigation and to es-

timate their significance for the diagnosis of peripheral neurogenic disorders. Tibia1 muscles of 145 patients were ex-

dried with various EHG methods, including fiber density (PD) and jitter. The results demonstrate that there is a correlation between MUP durations and Macro peak-to-peak amplitudes (R-0.48). M a c r o - m s and FD (R=0.37). There is no correlation between MUPs duration and FD. The difference between maximal sizes of w p s and M a c r o - m s is more pronounced in neuronopathy than in neuropathy. The mean M~cM-MUP amplitude value is increased 2-5 times depending on typs of the disease, degree of involvement and muscle strength. The highest values of jitter (with blockings) were seen in neuronopathic muscles with low strength and atrophies. The combination of all techniques contributes information on the capacity of motor neurone to form compensatory innerva-

Many E.M.G. Expert systems are inference machines that desi with uncertainty in a probabilistic or categorical way. Recently, b t i f i c i a i Neural Networks (A") have been successfully employed In several expert systems. The Topological Mapplng technique (Kohonen) Is an ANNparadigm (modeled after the laminate and columnar architecture of the sensory neocortex) that in its unsupervised learning mode adeptlveiy self-organires and "maps" the inherent perceptual reiationshlp of the pattern data and its statistlcei texture es a ZD-projection from the signal space to the feature space. Thls important dimensionality reduction property of the mapping process is further enhanced by application of a ilnear vector quantification algorithm. In its learning phase (implemented in Occam I1 on INMOS T-800 transputers) the E.M.G. patterns were presented to the system as a set of multidimensional vectors. The neuron- and parametermaps were ported to the appllcatlon platform (a '386 PC Turbo-Pascal envlronment) in a user-friendly expert system configuratlon. The results on E.M.G.- signsis are reported and experience with this paradigm is commented.

tion and to create neuromuscular contacts


Abstracts: Computerized and Quantitative EMG


October 1990

Abstracts of poster and platform presentations: Fourth International Conference on Computerized and Quantitative EMG. Mainz, Germany, September 13-15, 1990.

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