FROM T H E INSTITUTE O F NEOROPHYSIOLOGY, UNIVERSITY O F COPENHAGEN,

COPENHAGEN, DENMARK.

ELECTROMYOGRAPHY IN RELATIVES O F PATIENTS WITH PROGRESSIVE MUSCULAR DYSTROPHY

A Summaryl)

Giuseppe Caruso and Fritz Buchthal

Excitability (refractory period of small muscle fibre bundles), electromy- ographic and enzymatic studies were made in most of nineteen patients with progressive muscular dystrophy and in all of forty-three clinically asymptomatic siblings and parents.

Excitability studies gave the most consistent finding in that the absolutely refractory period of muscle was shorter than normal, as short as in patients, in eleven of the fourteen female relatives of twelve patients with the clinically severe type of dystrophy (Duchenne). In twelve of the fourteen male relatives the refractory periods were normal. These differences indicate that the procedure is useful in identifying carriers of the disease. Findings in the relatives of patients with the restricted types of dystrophy were consistent with this conclusion.

The electromyographic parameters were within the range of normal in most relatives and they cannot be used to identify the individual carrier. The average findings deviated from normal: the duration of motor unit potentials was diminished in the female relatives and normal in the males; the amplitude of motor unit potentials was diminished and the incidence of polyphasic potentials was increased in both female and male relatives. The average deviations from normal were slight but were statistically significant.

Lactic acid dehydrogenase serum levels were increased in half the female and male relatives of the patients with the Duchenne type of the disease. The individual values of GOT and GPT were within the normal range, the average level of glutamic oxalacetic transaminase being slightly above normal in female and male relatives and the glutamic pyruvic transaminase levels being normal.

Giuseppe Caruso, M.D., Fritz Buchthal, Professor, Universitetets neurofysiol. institut, Juliane Maries Vej 36, K~benhavn 0, Deninark.

l) A more detailed publication is in press in ,,Brain”.

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OPEN DISCUSSION

ERNA CHRISTENSEN: Professor Buchthal asks for measuring of inusclc fiber diameter in each histological specimen. From a histopathological point of view it is not necessary for an exact diagnosis. Neurophysiologists always ask for figures. Neuropathologists make the diagnosis from the impression of the general picture.

Other discussion participants: K. G . Henriksson.

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NERVE CONDUCTION INVESTIGATION

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