Objective assessment of gait in normal-pressure hydrocephalus

OBJECTIVES: Gait abnormalities are an early clinical symptom in normal pressure hydrocephalus (NPH), and subjective improvement in gait after temporary removal of CSF is often used to decide to perform shunt surgery. We investigated objective measures to compare gait before and after CSF drainage and shunt surgery. DESIGN: Twenty patients and nine controls were studied. Quantitative gait measures were obtained at baseline, after 3 days of controlled CSF drainage, and after shunt surgery. Decision to perform surgery was based on response to drainage, and patients were assigned to shunted or unshunted groups for comparison. RESULTS: There was no improvement after CSF drainage in the unshunted group (n = 4). In the shunted group (n = 15) velocity, double-support time, and cadence improved significantly after drainage, and improved further after shunt surgery. The degree of improvement after drainage significantly correlated to the degree of improvement postshunt for velocity, double-support time, cadence, and stride length. CONCLUSIONS: There are significant, quantifiable changes in gait after CSF drainage that correspond to improvement after shunt surgery for patients with NPH. Use of objective gait assessment may improve the process of identifying these candidates when response to CSF removal is used as a supplemental prognostic test for shunt surgery.