ABSTRACT
Laryngeal electromyography [EMG] was carried out for twenty patients with vocal fold immobility [VCI], diagnosed with indirect laryngoscopy. They were followed up for six months. A control group often subjects was included. The specificity of EMG in detecting VFI was 100%, and sensitivity 80%. Thirteen patients [65%] with abnormal EMG had a lesion of recurrent and superior laryngeal nerves and 3 [15%] had recurrent laryngeal nerve lesion alone. A significant statistical difference was found between EMG of patients and controls regarding all parameters. In cricothyroid, EMG was normal in 7 [35%], signs of reinnervation in 1 [5%], chronic neuropathy in 8 [40%] and denervation in 4 [20%]. EMG of thyroarytenoid was normal in 4 [20%], reinnervation in 3 [15%], chronic neuropathy in 9 [45%] and denervation in 4 [20%]. After six months 4 patients [20%] had full recovery, while 16 patients [80%] had persistent VFI. EMG of thyroarytenoid and cricothyroid showed no significant statistical difference between resolved cases and controls. There was a significant statistical difference between patients with resolved and those with persistent VFI as regards spontaneous activity, recruitment and interference patterns, but no significant statistical difference between the two groups regards MUAPs morphology. The positive predictive value of laryngeal EMG was 93.7%, and negative predictive value was 75%. The sensitivity of EMG in predicting recovery was 93.7%, and specificity 75%. Laryngeal electromyography is a useful adjunct to the diagnosis and prognosis of VFI. It provides information about the site and duration of lesion and differentiates fixation from paralysis. It is helpful in predicting recovery of vocal fold motion after laryngeal nerve injury