Mobile brain-body imaging markers of treatment-related responses in a man with Parkinson's disease

Lateralized Subthalamic Stimulation for Axial Dysfunction in Parkinson's Disease: Exploratory Outcomes and Open-Label Extension

BACKGROUND

A randomized trial suggested that reducing left-sided subthalamic stimulation amplitude could improve axial dysfunction.

OBJECTIVES

To explore open-label tolerability and associations between trial outcomes and asymmetry data.

METHODS

We collected adverse events in trial participants treated with open-label lateralized settings for ≥3 months. We explored associations between trial outcomes, location of stimulation and motor asymmetry.

RESULTS

14/17 participants tolerated unilateral amplitude reduction (left-sided = 10, right-sided = 4). Two hundred eighty-four left-sided and 1113 right-sided stimulated voxels were associated with faster gait velocity, 81 left-sided and 22 right-sided stimulated voxels were associated with slower gait velocity. Amplitude reduction contralateral to shorter step length was associated with 2.4-point reduction in axial MDS-UPDRS. Reduction contralateral to longer step length was associated with 10-point increase in MDS-UPDRS.

CONCLUSIONS

Left-sided amplitude reduction is potentially more tolerable than right-sided amplitude reduction. Right-sided more than left-sided stimulation could be associated with faster gait velocity. Shortened step length might reflect contralateral overstimulation.

Reduced Proactive and Reactive Cognitive Flexibility in Older Adults Underlies Performance Costs During Dual-Task Walking: A Mobile Brain/Body Imaging (MoBI) Study

Age-related reductions in cognitive flexibility may limit modulation of control processes during systematic increases to cognitive-motor demands, exacerbating dual-task costs. In this study, behavioral and neurophysiologic changes to proactive and reactive control during progressive cognitive-motor demands were compared across older and younger adults to explore the basis for age-differences in cognitive-motor interference (CMI). 19 younger (19 - 29 years old, mean age = 22.84 +/- 2.75 years, 6 male, 13 female) and 18 older (60 - 77 years old, mean age = 67.89 +/- 4.60 years, 9 male, 9 female) healthy adults completed cued task-switching while alternating between sitting and walking on a treadmill. Gait kinematics, task performance measures, and brain activity were recorded using electroencephalography (EEG) based Mobile Brain/Body Imaging (MoBI). Response accuracy on easier trial types improved in younger, but not older adults when they walked while performing the cognitive task. As difficulty increased, walking provoked accuracy costs in older, but not younger adults. Both groups registered faster responses and reduced gait variability during dual-task walking. Older adults exhibited lower amplitude modulations of proactive and reactive neural activity as cognitive-motor demands systematically increased, which may reflect reduced flexibility for progressive preparatory and reactive adjustments over behavioral control.