title: Gait analysis in idiopathic normal pressure hydrocephalus--which parameters respond to the CSF tap test?
abstract: OBJECTIVE
  Normal pressure hydrocephalus (NPH) is an often underestimated cause of hypokinetic gait disorders in the elderly. Diagnosing NPH is a complex problem, since many symptoms overlap with other neurological diseases. The purpose of the present study was to characterize the gait pattern in NPH quantitatively. Additionally, we analyzed the improvement of gait parameters following tapping of cerebrospinal fluid (CSF).
  
  
  METHODS
  Gait analysis was performed in 10 patients and 12 age-matched healthy controls during overground and treadmill locomotion.
  
  
  RESULTS
  Compared to healthy controls, patients with NPH walked significantly slower, with shorter and more variable strides and a somewhat lower cadence. The feet were not lifted to a normal height and the dorsal extension of the forefoot prior to heel-strike was insufficient. Balance-related gait parameters such as step width and the foot rotation angles were significantly increased in NPH, while their variability was lower. Only some gait parameters improved after tapping 30 ml CSF. Gait velocity increased by about 23% due to an increased stride length, while the cadence remained unchanged. Balance-related gait parameters and the foot-to-floor clearance during swing were not affected by the treatment.
  
  
  CONCLUSIONS
  In conclusion, we found a triad of decreased stride length, decreased foot-to-floor clearance and a broad-based gait to be the typical features of the gait abnormality in NPH. Only the stride length improved following a diagnostic spinal tap. These results may help to more reliably diagnose the condition of NPH in a routine clinical setting.
authors.affiliation: Department of Neurology, Christian-Albrechts-Universität zu Kiel, Niemannsweg 147, D-24105, Kiel, Germany. h.stolze@neurologie.uni-kiel.de
authors.forename: H
authors.initials: H
authors.lastname: Stolze
authors.forename: J P
authors.initials: JP
authors.lastname: Kuhtz-Buschbeck
authors.forename: H
authors.initials: H
authors.lastname: Drücke
authors.forename: K
authors.initials: K
authors.lastname: Jöhnk
authors.forename: C
authors.initials: C
authors.lastname: Diercks
authors.forename: S
authors.initials: S
authors.lastname: Palmié
authors.forename: H M
authors.initials: HM
authors.lastname: Mehdorn
authors.forename: M
authors.initials: M
authors.lastname: Illert
authors.forename: G
authors.initials: G
authors.lastname: Deuschl
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002557:Cerebrospinal Fluid Shunts; D005260:Female; D005684:Gait / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000150:complications / Q000503:physiopathology* / Q000601:surgery; D008297:Male