title: Early diagnosis and stage classification of vocal cord abductor paralysis in patients with multiple system atrophy.
abstract: OBJECTIVE
  Vocal cord abductor paralysis (VCAP) is a life threatening complication which may cause nocturnal sudden death in patients with multiple system atrophy. However, the early diagnosis of VCAP is often difficult to make on routine laryngoscopy performed during wakefulness, as stridor, which is the sole symptom of VCAP in the early stage, develops only during sleep. The aim was to investigate laryngeal dysfunction in patients with multiple system atrophy while awake and asleep.
  
  
  METHODS
  Seven patients with multiple system atrophy with nocturnal stridor and five control patients were studied. Vocal cord movement was analysed by laryngoscopy while the patients were awake and also during sleep induced by intravenous diazepam.
  
  
  RESULTS
  When awake, for the seven patients with multiple system atrophy normal movement of the vocal cords occurred in three, mild abduction restriction in three, and paradoxical movement in one. When asleep, however, all showed obvious paradoxical movement with high pitched inspiratory stridor. In controls, there were no differences in the vocal cord movement between wakefulness and sleep. From these findings, VCAP could be divided into four stages: stage 0 (normal) with normal vocal cord movement during both wakefulness and sleep, stage 1 (mild VCAP) with normal movement during wakefulness and paradoxical movement during sleep, stage 2 (moderately severe VCAP) with abduction restriction during wakefulness and paradoxical movement during sleep, and stage 3 (severe VCAP) with an almost midline position for the vocal cords during both wakefulness and sleep.
  
  
  CONCLUSIONS
  Laryngoscopy during sleep can disclose subclinical VCAP, making an early diagnosis of VCAP in patients with multiple system atrophy. Stage 2 of VCAP seems to be a suitable stage for tracheostomy in patients with multiple system atrophy.
authors.affiliation: Department of Neurology, Tokyo Metropolitan Neurological Hospital, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Isozaki
authors.forename: A
authors.initials: A
authors.lastname: Naito
authors.forename: S
authors.initials: S
authors.lastname: Horiguchi
authors.forename: R
authors.initials: R
authors.lastname: Kawamura
authors.forename: T
authors.initials: T
authors.lastname: Hayashida
authors.forename: H
authors.initials: H
authors.lastname: Tanabe
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003645:Death, Sudden / Q000209:etiology; D005260:Female; D006801:Humans; D007828:Laryngoscopy; D008297:Male; D008875:Middle Aged; D009849:Olivopontocerebellar Atrophies / Q000150:complications*; D010300:Parkinson Disease / Q000150:complications*; D012720:Severity of Illness Index; D012791:Shy-Drager Syndrome / Q000150:complications*; D012890:Sleep; D014826:Vocal Cord Paralysis / Q000145:classification / Q000175:diagnosis* / Q000209:etiology* / Q000628:therapy; D014851:Wakefulness