RESEARCH: Different mechanism of vocal cord paralysis between spinocerebellar ataxia and multiple system atrophy

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J Neurol Sci 2002 May 15;197(1-2):37-43

Different mechanism of vocal cord paralysis between spinocerebellar ataxia

(SCA

1 and SCA 3) and multiple system atrophy.

Isozaki E, Naito R, Kanda T, Mizutani T, Hirai S.

Department of Neurology, Tokyo Metropolitan Neurological Hospital, 2-6-1,

Musashidai, Tokyo 183-0042, Fuchu, Japan

While multiple system atrophy (MSA) is frequently associated with vocal cord

paralysis (VCP) causing severe respiratory failure, it is still unknown

whether

hereditary types of spinocerebellar degeneration develop similar laryngeal

paralysis. We analyzed the laryngeal function from the viewpoints of

fiberoptic

laryngoscopy and laryngeal myopathology and then attempted to clarify the

difference of the mechanism of VCP among the patients with spinocerebellar

ataxia type 1 (SCA 1), type 3 (SCA 3), and MSA. Seven patients with SCA 1,

nineteen with SCA 3, and eleven with MSA were studied. Vocal cord movement

was

analyzed by fiberoptic laryngoscopy during wakefulness and diazepam-induced

sleep (sleep load test). Paraffin-embedded sections or cryosections of the

intrinsic laryngeal muscles from five autopsied cases (one with SCA 1 and

four

with SCA 3) were histologically examined. VCP was found in two of the seven

SCA

1 patients (29%), three of the nineteen SCA 3 patients (16%), and in nine of

the

eleven MSA patients (82%). VCP observed in SCA 1 and SCA 3 was various in

the

severity and showed no exacerbation on sleep load test in all of the eight

patients but one SCA 3 patient. In this patient, the findings of fiberoptic

laryngoscopy were quite similar to those found in MSA. All the intrinsic

laryngeal muscles including cricothyroid (CT), interarytenoid (IA), and

posterior cricoarytenoid (PCA) muscles showed neurogenic atrophy in one

autopsied SCA 1 and four SCA 3 patients. Our conclusion is that VCP in SCA 1

and

SCA 3 contrasts with that in MSA in its occurrence, response to the sleep

load

test, and the distribution of the neurogenic abnormalities among the

intrinsic

laryngeal muscles.

PMID: 11997064 [PubMed - in process]