Imposed faster and slower walking speeds influence gait stability differently in Parkinson fallers

Objective - This cross-sectional study sought to evaluate the effect of imposed faster and slower walking speeds on postural stability in people with Parkinson’s disease (PD).

Design - Cross-sectional cohort study.

Setting - General community.

Participants - 84 PD patients (51 with a falls history; 33 without) and 82 age-matched controls were invited to participate via neurology clinics and pre-existing databases. Of those contacted, 99 did not respond (PD=36; controls=63) and 27 were not interested (PD=18; controls=9). Following screening, a further 10 patients were excluded; 5 had deep brain stimulation surgery and 5 could not accommodate to the treadmill. The remaining 30 patients completed all assessments and were sub-divided in PD fallers (n=10), PD Non-Fallers (n=10) and age-matched controls (n=10) based on falls history.

Protocol - Symptom severity, balance confidence and medical history were established prior to participants walking on a treadmill at 70%, 100% and 130% of their preferred speed.

Main Outcomes - Three-dimensional accelerometers assessed head and trunk accelerations and allowed calculation of harmonic ratios (HRs) and root mean square (RMS) accelerations to assess segment control and movement amplitude.

Results - Head and trunk control was lower for PD Fallers than PD Non-Fallers and Older Adults. Significant interactions indicated head and trunk control increased with speed for PD Non-Fallers and Older Adults, but did not improve at faster speeds for PD Fallers. Vertical head and trunk accelerations increased with walking speed for PD Non-Fallers and Older Adults, while the PD Fallers demonstrated greater anteroposterior RMS accelerations compared with both other groups.

Conclusion - The results suggest that improved gait dynamics do not necessarily represent improved walking stability and this must be respected when rehabilitating gait in PD patients.