Instrument-supported gait analysis characterizes gait domain changes in patients with suspected normal pressure hydrocephalus

AbstractBackground: Idiopathic Normal Pressure Hydrocephalus (iNPH) is a potentially reversible cause of cognitive impairment, urinary incontinence, and gait disturbances, which typically present with a characteristic slow, shuffling, and wide-based gait. Gait velocity, which is reduced relative to healthy controls, improves in iNPH patients following a spinal tap test. This study aimed at evaluating the criterion of a 20% gait velocity improvement in the 10 m walk test to identify responders and non-responders in a cohort of patients with probable iNPH receiving a spinal tap test as well as the added value of instrument-supported gait analysis.Methods: We assessed pace, rhythm, variability, postural control, and force in 59 patients with clinically suspected iNPH undergoing a spinal tap test, applying the 10 m walk test and an instrument-supported gait analysis. The change in gait velocity assessed in the 10 m walk test was used to differentiate patients with a positive response to the spinal tap (> 20% improvement, responders) from those with no relevant response (< 20% improvement, non-responders). Group differences were analyzed using chi-square tests, independent sample t-tests, Mann-Whitney-U tests and repeated measure ANOVAs.Results: Unlike non-responders (n = 39), responders (n = 20) showed significant changes in the gait domain pace in the 10 m walk test. Moreover, instrument-supported gait analyses revealed additional improvements in the gait domains variability, rhythm, postural control and force in responders only.Interpretation: This study confirmed the clinical utility of the 20% gait velocity improvement criterion for differentiating responders and non-responders in a cohort of patients with mostly probable iNPH, in whom clinical parameters alone were insufficient for classification. Notably, instrument-supported gait analysis validated this criterion by providing a more comprehensive characterization of gait disturbances compared to the 10 m walk test. However, further-especially longitudinal-studies are needed to reveal the full potential of the instrument-supported gait analysis in patients with (early/probable) iNPH.Keywords: Center of force; Center of pressure; Ground reaction force; Kinetics; iNPH.