[Clinical neurophysiology for estimation of progression and prognosis in ALS]

The role of clinical neurophysiology in the evaluation of disease progression in ALS has to be precised. To be included in the methodology of therapeutic trials, neurophysiological methods have to be quantitative, sensitive and reproducible. Their goal is to assess peripheral and central motor neuron loss but also compensatory processes such as reinnervation. The peripheral motor neuron loss can be evaluated by compound muscle action potential amplitude and mainly by motor unit number estimate (MUNE). Peripheral reinnervation can be evaluated by fiber density and macro-MUP amplitude. Functional aspects of reinnervation can be assessed by jitter measurement or the occurrence of decrement when using repetitive stimulation. Central motor neuron loss can be evaluated by transcranial magnetic stimulation and the triple collision technique (TST). Among the various electrophysiological approaches, MUNE and TST seem to be the most appropriate to evaluate peripheral and central motor neuron loss over time in ALS.