@incollection{bohn01_understanding_2025,
author = "Kristina Bohn and Jens Seemann and Matthis Synofzik and Winfried Ilg",
abstract = "BACKGROUND AND AIM: Ataxic gait is typically characterized by an unstable, stumbling gait, increased step width, and high gait variability. The characteristic high variability is thought to result from the complex interaction between cerebellar-induced deficits in balance control and multi-joint coordination, the compensatory strategies used, and inaccurate postural adjustments to the apparent loss of balance. The interplay and relative importance of these individual factors and their development over the course of the disease are not fully understood. Clarifying their relationship during disease progression would allow both efficient neurorehabilitation and the development of disease-phase sensitive performance markers for clinical trials. Here, we aimed to investigate the role of ataxia-specific balance dysfunction in static (stance) and dynamic (gait) conditions, particularly in very early and pre-symptomatic disease stages (i.e., mutation carriers without clinical manifestation). METHODS: We assessed static and dynamic balance of subjects with degenerative cerebellar ataxia at baseline and 1-year follow-up using three body-worn inertial sensors. Stance conditions included natural stance and feet together stance with eyes opened and eyes closed. As a measure of static balance performance we used the sway path length (SPL) based on the hip sensor. Walking was performed in laboratory settings, i.e., supervised straight walking of a 60m corridor at preferred speed, and unsupervised in real life. The compound measure of spatial step variability (SPcmp), which integrates step length variability and lateral step deviation, served as a measure of ataxia-specific gait variability. RESULTS: Cross-sectional analysis of symptomatic ataxia patients (n = 44, SARA = 10.1) revealed correlations between SPL during natural stance and SPcmp during walking, with increasing effects moving from laboratory (r = 0.36, p {\textless} 0.0001) to real-life conditions (r = 0.51, p {\textless} 0.0001). For the group of pre-ataxic mutations carriers (n = 33, SARA = 0.7) we saw a strong trend for the relation of gait variability and sway in a stance task with increased complexity (i.e., feet together, eyes closed) (r = 0.25, p = 0.06). The relation was particularly evident longitudinally when 1-year changes in stance sway and gait variability were correlated (r = 0.44, p = 0.01). CONCLUSIONS: We were able to identify specific influences of the static balance mechanism on gait in pre-symptomatic mutation carriers, suggesting that alterations in balance control mechanisms already play a verifiable role in pre-symptomatic and very early disease stages, whereas cerebellar-induced deficits in balance control and multi-joint coordination and compensatory strategies such as slowing down may have a greater influence in later disease stages. This highlights the importance of static stance testing and related balance exercises in rehabilitation, particularly in pre-symptomatic and early disease stages.",
booktitle = "International Society of Posture and Gait Research (ISPGR) Maastricht",
title = "{U}nderstanding the relationship of static and dynamic balance measures in ataxic stance and gait at different disease stages",
year = "2025",
}