Head Rotation Impairs Balance and Walking in People With Mild to Moderate Multiple Sclerosis: A Pilot Study

Background: People with multiple sclerosis (MS) have an increased risk of falls, which are often associated with changes in movement direction and preceded by head rotation (HR). We aimed to investigate the effects of HR on postural control and gait temporal parameters in people with MS compared with controls (Cs) and to quantify the number of strides required to correct gait after HR. Methods: Eighteen people with MS (44.4 ± 9.9 years; 3.1 ± 1.5 Expanded Disability Scale Score) and 10 Cs (43.6 ± 10.3 years) participated. Postural control during a standing task on a force plate was assessed and quantified by center of pressure displacement. Gait was assessed by 2D sagittal video analysis and analyzed with Kinovea. After30 seconds of unperturbed walking on a treadmill, participants were instructed to turn their head to the left and walk on, followed by a right HR. The 10 strides after the HR were compared with the mean of normal walking strides. Inter- and intragroup comparisons were performed using a mixed model for repeated measurements. Hierarchical testing was used for stride analysis. Results: While standing, people with MS performed worse in all conditions and increased center of pressure displacement after HR in comparison with Cs (P ≤ .05). While walking, both groups increased the relative stance phase after HR (P ≤ .05); however, people with MS reduced stride times (P ≤ .05), and Cs maintained them. After HR, people with MS needed 3 strides to normalize stride times back to baseline, versus 1 to none for Cs. Conclusions: People with MS have higher transient imbalance while walking and standing after an HR compared with Cs.