Utilizing Sensor-based Motion Analytics to Objectively Assess Normal Pressure Hydrocephalus-associated Gait and Balance Patterns

Introduction: Normal Pressure Hydrocephalus (NPH) is a potentially reversible syndrome characterized by ventriculomegaly, urinary incontinence, gait apraxia, and cognitive dysfunction. The diagnosis of NPH typically relies on clinician observation and patient self-reporting, with symptom severity ranked according to the Japanese Normal Pressure Hydrocephalus Grading Scale (JGS). The purpose of this study was to compare sensor-derived measurements of gait and balance with clinical assessment of NPH severity to develop an objective functional gait index (FGI) to aid in clinical decision making.

Methods: The gait of 30 patients diagnosed with NPH was assessed using the JGS (0: normal gait; 1: unstable but independent gait; 2: walks with one cane; 3: walks with 2 canes/walker frame; 4: unable to walk) according to clinician observations prior to lumbar tap, post-lumbar tap, and post-shunt placement. A sensor-based motion analytics platform (BioMech Lab), was used to assess quantitative functional gait and balance at these timepoints. Functional gait parameters including cadence, single-support symmetry and normality, double-support normality, impact symmetry, pelvic deviation, and toe-off symmetry were averaged to obtain a FGI score at each timepoint. Subjects also performed a series of balance tasks, during which cranial (vestibular) deviation from midline was measured.

Results: The subjects demonstrated an average of 2.3% and 3.5% overall improvement in FGI and balance metrics respectively after shunting. Comparison between the JGS gait scoring system and the objective FGI revealed significant agreement (p = 0.05; 90-100 FGI: 0 JGS; 80-89.9 FGI: 1 JGS; 50-79.9 FGI: 2 JGS; 0-49.9 FGI: 3 JGS)

Conclusion : This study demonstrates that patients diagnosed with NPH who received a shunt had measurable changes in functional gait and balance metrics which corresponded to clinical observations. Such analyses may be used to develop an objective categorization system of gait and balance for NPH patients.