Clinical and Electromyographic Characteristics of Unilateral Vocal Fold Paralysis With Lower Cranial Nerve Injury

The aim was to investigate the clinical and electromyographic characteristics of patients with unilateral vocal fold paralysis (UVFP) combined with lower cranial nerve injury.

This is a case series with chart review.

Among 368 patients with idiopathic UVFP, 31 patients (8.4%) were eventually diagnosed with lower cranial nerve palsy after examinations of the head and neck, radiology, and electromyogram (EMG). The clinical and electromyographic characteristics of these patients were analyzed.

Of the 31 patients, 27 patients exhibited obvious abnormal lower cranial nerve injury physical signs, and 4 patients showed atypical physical signs, identified by EMG. Ultimately, 41.9% (13/31) were diagnosed with idiopathic causes, 38.7% (12/31) with intracranial or skull-base lesions on radiology, 12.9% (4/31) with lower cranial neuritis, and 6.4% (2/31) with radiation-induced lower cranial nerve palsy. Among the cranial lesions, lesions of the jugular foramen region were the most common (50%, 6/12). All 26 patients who underwent EMG tests were confirmed to have vagus nerve impairments (11 complete and 15 incomplete) and accessory nerve impairments (16 complete and 10 incomplete), whereas only 13 patients (50%) exhibited hypoglossal nerve injuries (5 complete and 8 incomplete).

For patients with clinically "idiopathic" UVFP, physical examinations of the lower cranial nerves are essential screening procedures. For patients with abnormal or suspicious physical signs, radiology should be performed to detect possible cranial or cervical lesions. EMG tests were strongly recommended to identify suspicious lower cranial nerve injury and its severity, and may help to predict the prognosis.