Laryngeal electromyography: a useful technique for the investigation of vocal cord palsy

Percutaneous needle laryngeal electromyography was used in 22 patients with an established vocal cord palsy of non-laryngological cause. Recordings of action potentials from both vocalis and cricothyroid muscles produced expected results in 8 patients with skull base lesions. In 6 patients with known lesions below the clavicles, ipsilateral cricothyroid activity was found to be normal despite the vocal cord lying in the lateral (or cadaveric) position. In 2 patients electromyography helped establish the site of the lesion. Eight patients with idiopathic cord palsies showed varying cricothyroid function but in all vocalis activity was absent.