@incollection{seemann2024context,
author = "Jens Seemann and Martin A. Giese and Matthis Synofzik and Winfried Ilg",
abstract = "Objectives: In this observational study, we aim to unravel performance markers of ataxic gait for upcoming therapy trials using wearable sensors. We hypothesize that in short, trial-like time-frames gait measures captured in complex real-life settings of patients are more sensitive to natural disease progression compared to lab-based gait assessments and clinical rating scales.
Methods: We assessed longitudinal gait changes of 24 subjects with spinocerebellar ataxia (SCA types: 1, 2, 3, 6) at baseline (SARA:9.4±4.1), 1-year and 2-years follow-up assessment by three body-worn inertial sensors in two conditions: (1) laboratory-based walking; (2) real-life walking in everyday environment. In the real-life walking condition, a context-sensitive analysis was performed by selecting comparable walking bouts according to bout length and number of performed turns. Movement analysis focussed on measures of spatio-temporal variability, in particular lateral step deviation (LSD) and a compound measure of spatial variability (SPcmp).
Results: Cross-sectional analyses revealed high correlation to ataxia severity (SARA) and patients subjective balance confidence (ABC-Scale) in both conditions (r>0.7). While clinical ataxia score and gait measure in lab-based gait assessments identified changes after two years only (SARA: rprb=0.71; LSD: rprb=0.67), real life assessment of lateral step deviation and a compound measure of spatial step variability identified changes already after one year, with high effect sizes (LSD: rprb=0.66; SPcmp: rprb=0.68) and additionally increased effect sizes after two years (LSD: rprb=0.77; SPcmp: rprb=0.82).
Discussion: Utilizing a context-sensitive matching procedure with high robustness to disease-independent changes of environment, real-life gait measures capture longitudinal change within one year with high effect size. In contrast, clinical scores like the SARA or lab-based gait measures show longitudinal change only after two years.
Conclusions: Features of real-life gait constitute promising performance markers for upcoming therapy trials, yielding ecologically validity, earlier sensitivity and increased effect sizes in comparison with clinical scores and lab-based gait assessment.",
booktitle = "2024 International Congress for Ataxia Research (ICAR) London",
title = "{C}ontext matters: {G}ait analysis in real-life—but not in-lab or {SARA}—reveals disease progression in spinocerebellar ataxias already after 1 ",
year = "2024",
}