Computer-aided analysis of muscle fibre conduction velocity in neuromuscular diseases

The objective was to measure muscle fibre conduction velocity (MFCV) in the biceps brachii of normal subjects, and patients with mild myopathies and anterior horn cell diseases. Unisolated steel needles served as stimulation and recording electrodes. By aid of a computer program for data acquisition and analysis, up to 1,400 single fibre potentials could be recorded from a single muscle and analysed within 30-45 min. Normal values for mean, minimum, maximum CV and 5%, 25%, 75% and 95% percentiles were established. Females have slower mean and minimal CV than men but maximal MFCV were similar for the two groups. Age has no statistical influence. Myopathic patients showed a MFCV decrease of the already slow muscle fibre population. In neurogenetic diseases the distribution was biphasic with the conduction of the formerly fast conducting fibres either enhanced or reduced. Using different statistical parameters to describe the spectrum of muscle fibre conduction properties provides a sensitive tool to evaluate functional impairment in mild myopathies and to separate them from mild neuropathies.