Dynamic gait stability in patients with idiopathic normal pressure hydrocephalus with high and low fall-risk.

BACKGROUND

This study aimed to investigate whether dynamic gait stability differs between idiopathic normal-pressure hydrocephalus with high- and low-fall-risk.

METHODS

Participants comprised 40 idiopathic normal-pressure hydrocephalus patients and 23 healthy-controls. Idiopathic normal-pressure hydrocephalus patients were divided into those with high-fall-risk (n = 20) and low-fall-risk (n = 20) groups using the cut-off score of ≤14/30 for fall-risk on the Functional Gait Assessment. Dynamic stability during gait was assessed by three-dimensional motion analysis. Dynamic stability was defined as the ability to maintain an extrapolated center of mass within the base of support at heel contact, with the distance between the two defined as the margin of stability. Conscious motor control was assessed by the Movement-Specific Reinvestment Scale.

FINDINGS: Anteroposterior and mediolateral margin of stabilities were significantly larger in both idiopathic normal-pressure hydrocephalus groups than in healthy-controls. The mediolateral margin of stability was significantly higher in the high-fall-risk group than in the low-fall-risk group; whereas, the anteroposterior margin of stability did not differ between idiopathic normal-pressure hydrocephalus groups. The Movement-Specific Reinvestment Scale was significantly higher in the high-fall-risk group than in the low-fall-risk group.

INTERPRETATION: Idiopathic normal-pressure hydrocephalus patients with have high forward and lateral dynamic stability during gait regardless of their fall-risk. In particular, idiopathic normal-pressure hydrocephalus patients with high-fall-risk may consciously maintain lateral dynamic stability to a greater extent than those with low-fall-risk. These findings highlight a conscious motor control component in the pathological gait of idiopathic normal-pressure hydrocephalus, and provide clues for rehabilitation and fall prevention strategies in idiopathic normal-pressure hydrocephalus patients.