title: Correlation of midbrain diameter and gait disturbance in patients with idiopathic normal pressure hydrocephalus.
abstract: OBJECTIVE
  Although gait disturbance is an important feature of idiopathic normal pressure hydrocephalus (NPH), only tentative theories have been offered to explain its pathophysiology. It has been suggested that the mesencephalic locomotor region is the anatomical substrate for the development of the hypokinetic NPH gait. To investigate this possibility, we evaluated the correlation between gait disturbance and midbrain diameter.
  
  
  METHODS
  We enrolled 21 patients with NPH and 20 age-matched control subjects for the study. The maximal diameter of the midbrain and pons, and the width of the lateral and third ventricles were measured using midsagittal T1-weighted MRI and axial T2-weighted MRI, respectively. Gait disturbance, cognitive dysfunction, and incontinence were semiquantified.
  
  
  RESULTS
  The maximal midbrain diameter was significantly smaller in the NPH group than in the controls (14.8 +/- 0.9 vs. 17.1 +/- 0.7 mm, p < 0.001). There were inverse correlations between the midbrain diameter and the widths of the two ventricles (r = -0.562, p = 0.008 for the third ventricle, and r = -0.510, p = 0.018 for the lateral ventricle). The severity of gait disturbance was negatively correlated with the midbrain diameter (r = -0.598, p = 0.004), but the degree of cognitive dysfunction and incontinence showed no significant correlation with midbrain diameter or ventricular width.
  
  
  CONCLUSIONS
  This study suggests that midbrain atrophy is significantly associated with gait disturbance in NPH.
authors.affiliation: Dept. of Neurology, College of Medicine Ajou University, Woncheon-dong San 5, Paldal-ku Suwon, Kyungki-do, 442-749, South Korea. phisland@chol.com
authors.forename: Phil Hyu
authors.initials: PH
authors.lastname: Lee
authors.forename: Suk Woo
authors.initials: SW
authors.lastname: Yong
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Ahn
authors.forename: Kyoon
authors.initials: K
authors.lastname: Huh
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D020233:Gait Disorders, Neurologic / Q000150:complications / Q000473:pathology*; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000209:etiology / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008636:Mesencephalon / Q000473:pathology*; D008875:Middle Aged; D012189:Retrospective Studies; D013223:Statistics as Topic; D018709:Statistics, Nonparametric