Introduction : Bilateral vestibulopathy (BV) has a severe impct in quality of life life [1]. Symptoms, particularly imbalance, during the performance of daily living tasks (DLT) remains poorly understood. To our knowledge, existing research has focused mainly on the analysis of patient movements in controlled laboratory settings, leaving movements associated with DLT largely unexplored [2]. Inertial measurement units (IMUs) offer promising potential to fill this gap by enabling objective assessment of patient movements in daily life settings. They could facilitate screening and clinical follow-up on a larger scale, without the need for a specialized laboratory environment.
Research Question : This study investigates the potential of IMU-derived parameters to highlight dynamic instability in BV patients during DLT.
Methods : A cohort of 60 participants was examined, comprising 20 BV patients (11 females; 61.0±11.6 years), 20 unilateral vestibulopathy patients (UV) (10 females; 59.5±5.3 years) and 20 healthy subjects (HS) (10 females; 57.9±5.2 years). Nine IMUs were placed on anatomical segments (Figure 1) and participants performed 15 DLT in a semi-standardized environment. Parameters indicative of dynamic stability such as jerk [3], root mean square (RMS) of angular velocity [4], and mean of quantity of activity (QoA) [5] were calculated. Non-parametric ANOVA tests were used to evaluate the discriminating capacity of these parameters across groups and tasks.
Results : Preliminary analyses identified 3 tasks as the most discriminative when analyzing trunk IMU data (walking on an inclined plane, walking on a beam and walking in darkness; Figure 1). The BV group showed significantly lower jerk values for the walking in darkness (BV/HS p<0.01, BV/UV p<0.01) and for the walking on an inclined plane (BV/HS p<0.01, BV/UV p<0.001) tasks. Conversely, jerk values were significantly higher for the walking on a beam task for the BV group (BV/HS p<0.05). Finally, significant differences were observed during the inclined plane task for RMS of angular velocity and mean of QoA (BV/HS p<0.01, UV/HS p<0.05; BV/HS p<0.05, UV/HS p<0.01 respectively).
Discussion : While low jerk values typically indicate smoother movements, in BV patients they may reflect motor compensatory strategies aimed at minimizing abrupt movements due to vestibular deficits [6]. Conversely, healthy subjects can perform more rapid motor adjustments, resulting in increased jerking without loss of stability. This study reveals restricted movement patterns in BV patients, suggesting that rehabilitation efforts should focus on restoring movement fluidity and range of motion to mirror those of healthy individuals. Identifying and analyzing dynamic stability holds promise for advancing our understanding of vestibulopathy and monitoring the effectiveness of rehabilitation therapies.
