Vocal Cord Abductor Paralysis Evaluated by Laryngoscopy in Multiple System Atrophy

Objectives: Multiple system atrophy (MSA) is a chronic neurological disorder characterized by atypical parkinsonism and autonomic dysfunction. Sudden death during sleep is common among MSA patients. Sleep laryngoscopy demonstrates the restriction of abduction of vocal cords with a markedly reduced size of the glottic chink. Vocal cord abductor paralysis (VCAP) is considered to be an important predisposing factor of sudden death in MSA. The aim of this study was to elucidate the effects of VCAP on sleep and the utility of awake and sleep laryngoscopy in MSA. Methods: We recruited 14 patients with MSA presenting with snoring (4 men and 10 women; mean age, 54.6 years; disease duration, 4.2 years; International Cooperative Ataxia Rating Scale [ICARS], 46.9). After performing arterial blood gas analysis, spirometry, and polysomnography (PSG), awake and sleep laryngoscopy were performed. Results: Sleep laryngoscopy revealed that 7 patients exhibited VCAP and 7 patients did not. Between these 2 groups, there were no significant difference in the following findings: sex, disease duration, ICARS, findings of daytime blood gas analysis and PSG findings (mean SpO2 during sleep, AI, AHI and arousal index). Five of 7 patients who exhibited VCAP also showed bilateral arytenoidal tremor on awake laryngoscopy. Conclusion: These findings suggest that MSA should be followed by sleep laryngoscopy, however, it is difficult to perform sleep laryngoscopy as a routine evaluation. Since early diagnosis of VCAP is difficult to make on awake laryngoscopy, arytenoidal tremor may be useful as a sign to predict VCAP.