Peak Turning Velocity As a Marker of Balance Confidence and Walking Limitation in Persons with MS

Background: Straight-line gait parameters have been used extensively in persons with multiple sclerosis (pwMS) to assess balance and walking limitations. Turn parameters have not yet been used and may add additional information towards these assessments.

Objectives: Determine whether peak turning velocity (PTV) during the Six Minute Walk Test (6MWT) and Timed Up and Go (TUG) adds predictive power to straight-line stride velocity (SV) in the modeling of self-perceived balance confidence and walking limitation in pwMS.

Methods: 91 subjects (EDSS 0 – 6.5) performed the TUG and 6MWT. Spatiotemporal gait analysis was conducted using APDM Opal wireless body-worn sensors, which include a gyroscope, accelerometer, and magnetometer. Six sensors were placed on the subject: 2 on the ankles, 2 on the wrists, 1 on the lumbar spine region, and 1 on the thorax. Step-wise regression analyses were conducted independently for the TUG and 6MWT to determine addition of PTV to SV in the prediction of balance confidence (Activities-Specific Balance Confidence Scale (ABC)) and walking limitation (12-item Multiple Sclerosis Walking Scale (MSWS-12)).

Results: 6MWT SV and 6MWT PTV were moderately correlated (r = 0.527; p < 0.0001). TUG SV and TUG PTV were moderately correlated (r = 0.576; p < 0.0001). Whereas SV during the 6MWT predicted 20.2% of ABC, the addition of 6MWT PTV increased the predictability of the model to 32.8% (p < 0.0001). SV during the TUG predicted 18.5% of ABC, but the addition of TUG PTV increased the model’s predictability to 28.1% (p < 0.001). Similar results were found for the MSWS-12, as SV during the 6MWT predicted 27.9% of ABC, but increased to 40.5% with the addition of 6MWT PTV (p < 0.0001). SV during the TUG predicted 26.9% of MSWS-12, but the addition of TUG PTV increased the model to 35.9% (p < 0.001).

Conclusions: Turning velocity appears to improve modeling of self-perceived balance confidence and walking limitations when added to a straight-line gait parameter. Consistent results were found whether using a test consisting of a single turn (TUG) or multiple turns (6MWT). This emphasizes that turn speed and stability should be assessed clinically, and quantitative measures of turning may have potential as an outcome measure for clinical trials.