Subjects with Parkinson's Disease (PD) and freezing of gait (FOG) may experience plantar sensory losses and decrease of brain connectivity in brain areas related to sensory-motor integration. Automated Mechanical Peripheral Stimulation (AMPS) is a technique used to deliver plantar stimulus and that is able to induce immediate positive effects on brain connectivity and functional mobility. Thus, in this study, we investigated the long-term effects of AMPS on resting state brain connectivity (rsfMRI) and gait velocity of subjects with PD and FOG.

Twenty-five subjects with PD and FOG were randomly assigned to receive real AMPS (AMPS group) or placebo stimulation (AMPS SHAM group) in two target areas of both feet along four weeks (total of eight sessions). Primary and secondary outcomes included changes in rsfMRI and gait velocity, respectively. The single-subject functional connectivity maps were created using five Regions of Interest (ROI): left, right and mid sensory-motor regions, and left and right basal ganglia.

Nineteen patients were included in the rsfMRI analysis. The connectivity of the left basal ganglia increased with other four brain regions after real AMPS stimulation. AMPS group also showed increased connectivity between the right primary sensory-motor area and left prefrontal cortex and presented a higher increase in gait velocity. Additionally, brain connectivity between Medium Primary Sensory Motor Area and Right Primary Motor Cortex and between Right Primary Sensory Motor Area and Left Supplementary Motor Cortex were positively correlated with gait velocity (r=0.78 and r=0.77, respectively) (Table 1).

Our results showed that AMPS is able to promote long-term changes on rsfMRI, mainly in those areas related to sensory processing and sensorimotor integration. AMPS could ameliorate reduced plantar sensory abnormalities and facilitate brain compensatory pathways, and this could be the rationale behind the gait performance improvement after AMPS.