Is the midbrain involved in the manifestation of gait disturbance in idiopathic normal-pressure hydrocephalus?
Gait disturbance is the most common symptom in idiopathic normal-pressure hydrocephalus (iNPH). However, its pathophysiology in iNPH has not been clarified. Some researchers have hypothesized that the mesencephalic locomotor region, which is a functionally defined area in the brainstem playing an important role in locomotion, is involved in the development of gait disturbance in iNPH. The purpose of the study was to investigate whether the midbrain is involved in the manifestation of gait disturbance in iNPH. Twenty-one iNPH patients who showed clinical improvements after shunt surgery were studied. Brain magnetic resonance imaging (MRI) was performed and clinical symptoms were assessed before and 1 year after surgery. Gait disturbance was assessed by the Timed Up and Go test and gait subcategory of the iNPH Grading Scale, a validated assessment tool for iNPH symptoms. Anteroposterior, left-to-right diameter and cross-sectional areas of the midbrain were measured at the inferior collicular level of axial images in MRI. The diameters and cross-sectional area of the midbrain at baseline did not show significant correlation with gait assessments at baseline (Spearman's correlation). The midbrain measurement did not show significant difference between the baseline and postoperative values (paired t test), and its change rates did not show significant correlation with the change (rates) of the gait assessments. In this study there were no findings to suggest involvement of the midbrain in the manifestation of gait disturbance in iNPH. The hypothesis that the mesencephalic locomotor region is involved in the manifestation of gait disturbance in iNPH needs to be reconsidered.
Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, 980-8575, Japan. khiraoka@cyric.tohoku.ac.jp
Kotaro
K
Hiraoka
Hiroshi
H
Yamasaki
Masahito
M
Takagi
Makoto
M
Saito
Yoshiyuki
Y
Nishio
Osamu
O
Iizuka
Shigenori
S
Kanno
Hirokazu
H
Kikuchi
Etsuro
E
Mori
D000368:Aged; D002557:Cerebrospinal Fluid Shunts; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008636:Mesencephalon / Q000473:pathology* / Q000503:physiopathology