[Neurophysiological investigations in amyotrophic lateral sclerosis]

Amyotrophic lateral sclerosis (ALS) is a degenerative disease which prognosis is poor. Early diagnosis permits to set up immediately adapted treatment and cares. Available diagnostic criteria are based on the detection of both the central and peripheral motor neuron injury in bulbar, cervical, thoracic and lumbar regions. Electromyographic study is the key tool to identify peripheral motor neuron involvement. Conduction velocities are systematically performed to rule out differential diagnosis. Needle examination records abnormal activities at rest and looks for neurogenic pattern during muscle contraction. Motor unit potentials morphology is modified primary to recruitment. Motor evoked potentials remain the test of choice to identify impairment of central motor neurons. For the monitoring of ALS patients, the MUNE technique (motor unit number estimation) seems the most interesting.