title: Somatosensory shift of postural control in dizzy patients.
abstract: CONCLUSIONS
  Postural control is dependent on the visual system in normal conditions. Shift from visual to somatosensory dependence in dizzy patients suggests that utilizing the stable visual references is recommended for the rehabilitation of dizzy patients.
  
  
  OBJECTIVE
  To investigate which of the visual or somatosensory system is mainly used for substitution of the impaired spatial orientation in dizzy patients.
  
  
  METHODS
  We recruited 189 consecutive patients with or without dizziness and vestibular dysfunction. Dizzy patients were divided into three groups: acute, episodic, and chronic dizziness. Vestibular function was assessed by caloric test, traditional head impulse test, and head shaking nystagmus. Visual or somatosensory dependence of spatial orientation was assessed by posturography on a solid surface or on foam in eyes open or closed condition. The foam ratio (posturography with/without foam) when eyes were closed was indicative of somatosensory dependence of postural control, whereas the Romberg ratio on foam showed visual dependence. (Romberg ratio on foam)/(foam ratio with eyes closed) was calculated and used as an index of the visual/somatosensory dependence of postural control.
  
  
  RESULTS
  The visual/somatosensory ratio of postural control was significantly lower in dizzy patients as well as patients with vestibular dysfunction, however, no differences were found between acute, episodic, and chronic dizziness.
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, Osaka University Graduate School of Medicine , Suita, Osaka , Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Okumura
authors.forename: Arata
authors.initials: A
authors.lastname: Horii
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kitahara
authors.forename: Takao
authors.initials: T
authors.lastname: Imai
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Uno
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Osaki
authors.forename: Hidenori
authors.initials: H
authors.lastname: Inohara
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002908:Chronic Disease; D004244:Dizziness / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D003639:Hearing Loss, Sudden / Q000150:complications / Q000503:physiopathology; D006801:Humans; D008297:Male; D008575:Meniere Disease / Q000150:complications / Q000503:physiopathology; D008875:Middle Aged; D009949:Orientation / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D011446:Prospective Studies; D013003:Somatosensory Cortex / Q000503:physiopathology*; D065855:Spatial Processing / Q000502:physiology*; D015837:Vestibular Diseases / Q000150:complications / Q000503:physiopathology; D055815:Young Adult
keywords: Spatial orientation; dizziness; posturography; vertigo; vestibular; visual