Motor unit hyperactivity states (a correlative clinico-electromyographical study).

Abstract

The systematic overview of spontaneous motor unit or muscle fiber activity is presented. In Part 1 the precise clinical description of fasciculations, myokymia and cramps/spasms was made using a dynamic holistic approach. The differences are often a matter of excitation quantity. Correlations with electrophysiological findings were elaborated on the grounds of literature data and personal experience. Electrophysiological correlations with clinically visible fasciculations resulted in the finding that the same clinical phenomenon may have many entirely different electrophysiological correlates. The special forms of repetitive discharges were described additionally: positive giant potentials of quadriceps muscles appearing in healthy muscular individuals and grouped potential discharges of very chronic nerve ending involvement. The electrophysiological features and genesis of many motor unit hyperexcitability signs were discussed, while topic differentiation possibilities and symptomatic treatment were recommended for some. The spontaneous activity in different nosological entities was presented in Part 2. Again the literature data on diseases with conspicuous fasciculations, myokymia and cramps with additional personal experiences (pesticide intoxication, Isaacs syndrome, hereditary autosomal cramp disease, chronic syndrome due to parathyroid insufficiency, chronic tetanus and others) were presented. A description was also given of personal observations in strictly localized forms: single nerve or root lesions and in M. Romberg patient. Symptomatic and causal treatment was suggested for some of them. Clinically similar signs may have entirely different causes responding specifically to carbamazepine, D3, PAM, or surgical decompression. The electromyographic finding may remain clinically silent even in myotonia.