Multiple system atrophy (MSA) is a chronic neurologic disorder characterized by atypical Parkinsonism and autonomic dysfunction. Sudden death during sleep is common among MSA patients. Sleep laryngoscopy demonstrates the restriction of vocal cord abduction 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 is to elucidate the effects of VCAP on sleep and the utility of awake and sleep laryngoscopy in understanding MSA.
We recruited 34 patients with MSA presenting with snoring (12 men and 22 women; with the following statistical means: age, 60.2 years; disease duration, 4.3 years; International Cooperative Ataxia Rating Scale [ICARS], 51.3). After performing arterial blood gas analysis, spirometry and polysomnography (PSG), awake and sleep laryngoscopy were performed.
Sleep laryngoscopy revealed that eighteen patients exhibited VCAP, whereas the remaining patients didn’t. Between these two groups, there were no significant differences in the following findings; sex, disease duration, ICARS, daytime blood gas analysis results and PSG findings (mean SpO2 during sleep, AI, AHI and arousal index). Seventeen of the eighteen patients who presented with VCAP exhibited bilateral arytenoidal tremor with awake laryngoscopy, while another group didn’t have an identifiable arytenoidal tremor.
These findings suggest that MSA should be assessed by sleep laryngoscopy. It is difficult, however, to routinely perform sleep laryngoscopy. While an early diagnosis of VCAP is difficult to make utilizing awake laryngoscopy, the presence of an arytenoidal tremor may be a guide towards predicting VCAP.