Dysphagia in X-linked bulbospinal muscular atrophy (Kennedy disease).

Dysphagia in X-linked bulbospinal muscular atrophy (Kennedy disease) has never been characterized in detail by objective swallowing studies. We assessed the nature of swallowing impairment in Kennedy disease by undertaking fiberoptic endoscopic evaluation of swallowing examinations of 10 genetically confirmed patients with Kennedy disease who were scored according to an ordinal rating scale including 25 different items. The results were compared to an age-matched control group of 10 healthy volunteers. Swallowing dysfunction was found in 80% of patients with Kennedy disease. The main pattern of dysphagia was an incomplete food bolus clearance through the pharynx with residues left in the valleculae overflowing into the laryngeal vestibule after the swallow. Total duration of the pharyngeal swallow was significantly shorter in patients with Kennedy disease compared to the control group. These findings suggest that dysphagia in Kennedy disease is predominantly characterized by an impairment of the pharyngeal phase of swallowing resulting from reduced base-of-tongue movement and bilateral paresis of pharyngeal and laryngeal muscles.