Carpal tunnel syndrome is the most frequent entrapment neuropathy. Ner
ve conduction studies and electromyography are useful to appreciate th
e localization and the degree of nerve involvement, and help to the th
erapeutic management. Various electrophysiological procedures may be u
sed and are reviewed. For each of them positive (sensitivity and speci
ficity) and negative points (technical difficulties, errors and false
positive) are reported. A guideline is proposed.