Perioperative real-life mobility assessment using wearable step counts in idiopathic normal pressure hydrocephalus after ventriculoperitoneal shunt surgery: a prospective pilot study.

Idiopathic normal pressure hydrocephalus (iNPH) is commonly treated with ventriculoperitoneal shunt (VPS) implantation, yet accurate patient selection remains challenging because conventional diagnostic tests are variably standardized and partly subjective. We evaluated whether wearable step-count monitoring may provide an objective assessment of real-life mobility and help identify patterns of postoperative mobility improvement. In this prospective pilot study, perioperative mobility was recorded using a wrist-worn wearable tracker (Garmin Vivofit 4). The primary endpoint was change in mean daily step count after VPS implantation. Secondary analyses included comparison between objective responders and non-responders, characterization of the postoperative time course of mobility change, association between objective and subjective clinical response, and exploratory receiver operating characteristic (ROC) analysis to identify a preoperative step-count threshold associated with postoperative mobility improvement. Clinical trial number: not applicable. Twelve patients completed the study protocol. In the overall cohort, postoperative step count increased numerically but did not differ significantly from baseline. Objective responders (n = 8) showed a significant increase in daily step count from 1656 ± 356 to 2311 ± 373 steps/day (p < 0.05), whereas non-responders (n = 4) showed no improvement. Responders had significantly lower preoperative daily step counts than non-responders (median 1118 [IQR 563-1869.5] vs. 5148 [IQR 4202.25-5796.5] steps/day; p = 0.049). In responders, mobility gains became significant from postoperative week 9 onward (F(12,84) = 9.75, p < 0.001), peaking at approximately 2.5-fold baseline by week 11. Objective mobility response was associated with subjective clinical improvement: 7 of 8 objective responders (87.5%) reported postoperative benefit, with a significant linear-by-linear association between objective and subjective outcome (p = 0.033). Exploratory ROC analysis identified a preoperative step-count threshold of 1881 steps/day (AUC = 0.875). Wearable step-count monitoring may enable objective assessment of real-life mobility in iNPH and could complement perioperative evaluation after VPS implantation. Larger prospective studies are needed to validate its role in patient selection and postoperative monitoring.