Instrumental assessment of stair ascent in people with multiple sclerosis, stroke, and Parkinson's disease : a wearable-sensor-based approach

Stair ascent is a challenging daily-life activity highly related to independence. This task is usually assessed with clinical scales suffering from partial subjectivity and limited detail in evaluating different task aspects. In this paper, we instrumented the assessment of stair ascent in people with multiple sclerosis (MS), stroke (ST), and Parkinson's disease (PD) to analyze the validity of the proposed quantitative indexes and characterize subjects' performances. Participants climbed 10 steps wearing a magneto-inertial sensor [magneto-inertial measurement unit (MIMU)] at sternum level. Gait pattern features (step frequency, symmetry, regularity, and harmonic ratios), and upper trunk sway were computed from MIMU signals. Clinical modified dynamic gait index (mDGI) and mDGI-Item 8 “Up stairs” were administered. Significant correlations with clinical scores were found for gait pattern features (r s ≥ 0.536) and trunk pitch sway (r s ≤ -0.367) demonstrating their validity. Instrumental indexes showed alterations in the three pathological groups compared to healthy subjects and significant differences, not clinically detected, among MS, ST, and PD. MS showed the worst performance, with alterations of all gait pattern aspects and larger trunk pitch sway. ST showed worsening in gait pattern features but not in trunk motion. PD showed fewer alterations consisting in reduced step frequency and trunk yaw sway. These results suggest that the use of an MIMU provided valid objective indexes revealing between-group differences in stair ascent not detected by clinical scales. Importantly, the indexes include uppertrunk measures, usually not present in clinical tests, and provide relevant hints for tailored rehabilitation.