Can split-belt treadmill training improve dual-task turning performance in patients with Parkinson’s disease with Freezing of gait

Abstract

BACKGROUND AND AIM: Motor-cognitive dual tasks (DT) pose several difficulties for patients with Parkinson’s disease with Freezing of gait (PD+FOG) as it requires continuous adaptation and switching of attention. Targeted motor-cognitive DT training has been shown to improve DT performance in PD+FOG with limited retention and transfer effects. Split-belt treadmill training (SBT) implicitly requires online monitoring and adaptation of gait, however the potential to induce learning and influence DT performance is unknown. Therefore in this study, we investigated whether motor adaptation training by means of SBT could improve motor-cognitive DT performance in PD+FOG. METHODS: To date, thirty-nine PD patients with FOG and twenty-seven age-matched healthy controls (HC) participated in a single training session at two centers (KU Leuven, Belgium and CAU of Kiel, Germany). They were randomized to four 30-minutes (6x5min) intervention groups: A) SBT belts’ speed ratio 1:2; B) SBT belts’ speed ratio 3:4; C) SBT changing belts’ speed ratios; D) Tied-Belt. For the SBT conditions (A-C) the belt's speed was reduced of the leg with the longer step length measured during overground gait analysis. A one-minute 360° turning at the spot test with alternating directions and while simultaneously performing an auditory stroop task was performed pre- and post-training as well as at 24h retention. A linear mixed models analysis was applied to investigate the effect of training condition over time. RESULTS: Preliminary analysis showed that PD+FOG and HC both improved in DT Turning from Pre-training to 24h Retention (DT Peak Turning Speed: Main effect of Time F=6.07; p>0.01; Relative change from baseline to Retention: PD+FOG 6.1%; HC 7.9%). Although PD+FOG showed deterioration from Pre- to Post-training, likely due to fatigue and dopamine exhaustion, offline consolidation was preserved (DT Peak Turning Speed: Post-training to Retention – relative change: PD+FOG 8.1% vs HC 2.6%). Performance on the auditory Stroop task also showed improvements from Pre-training to retention, trending towards greater improvements for SBT vs Tied Belt training in the whole group (Faster Response Time – Training*Time effect F=1.59; p=0.22; relative change from Baseline to retention 3.3%) and for PD+FOG subgroup (Lower Response Time variability – Training*Time effect F=2.09; p=0.16 ; relative change from Baseline to retention 7.6%) CONCLUSIONS: A single SBT session was seen to induce learning in HC as well as PD+FOG, with motor adaptation effects showing trends of transfer and automaticity to DT turning situation. This improved automaticity possibly frees up attentional resources as improvements were found in the cognitive task as well. Future work should investigate these mechanisms as well as the longer term effects of SBT on motor-cognitive DT performance.status: publishe