title: Postural function in idiopathic normal pressure hydrocephalus before and after shunt surgery: a controlled study using computerized dynamic posturography (EquiTest).
abstract: BACKGROUND
  Postural dysfunction is one of the major features of idiopathic normal pressure hydrocephalus (iNPH). With computerized dynamic posturography (CDP) balance can be assessed objectively. The primary aim of this study was to describe the postural function in iNPH patients pre- and post-operatively in comparison with healthy individuals (HI) using CDP.
  
  
  METHODS
  Thirty-five patients (16 M, 19 F) with a mean age of 73 (range 49-81) with iNPH, and sixteen HI (7 M, 9 F) aged 73 (62-89) were included. iNPH patients were operated on with a ventriculo-peritoneal shunt. Patients and HI were tested regarding motor function, balance and cognition. CDP, EquiTest (NeuroCom International, Clackamas, OR), was performed before and three months after shunt surgery and twice in HI, with a three-month interval.
  
  
  RESULTS
  Pre-operatively, the 35 patients had poorer balance measured with the Sensory Organizing Test (SOT) score in every condition (p=0.01 in SOT 1 and p<0.001 in SOT 2-6) compared to the HI. The greatest difference was in test conditions measuring mainly vestibular function, where loss of balance (LOB) was frequent. Twenty patients were evaluated three months after shunt surgery and 18/20 (90%) of them were considered shunt responders, with a mean improvement of motor score of 26% (range 5-67%). There was an improvement post-operatively in the weighted composite SOT score (p<0.05) but no significant change in any of the SOT conditions. LOB was not significantly reduced in any of the test conditions.
  
  
  CONCLUSIONS
  CDP showed that the patients had a poorer balance than the HI. The greatest difference was in SOT 5-6, indicating that the postural disturbance is of primarily central vestibular origin. There was a slight improvement of balance post-operatively.
authors.affiliation: Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Sweden. Fredrik.Lundin@lio.se
authors.forename: F
authors.initials: F
authors.lastname: Lundin
authors.forename: T
authors.initials: T
authors.lastname: Ledin
authors.forename: C
authors.initials: C
authors.lastname: Wikkelsø
authors.forename: G
authors.initials: G
authors.lastname: Leijon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001696:Biomechanical Phenomena; D002557:Cerebrospinal Fluid Shunts; D003071:Cognition / Q000502:physiology; D003627:Data Interpretation, Statistical; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000134:cerebrospinal fluid / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology; D012677:Sensation / Q000502:physiology; D059409:Stroke, Lacunar / Q000473:pathology
keywords: Computerized dynamic posturography; Idiopathic normal pressure hydrocephalus; Postural function; Shunt surgery