Medication and subthalamic nucleus deep brain stimulation similarly improve balance and complex gait in Parkinson disease

Abstract

Background: Dopaminergic medications and subthalamic nucleus deep brain stimulation (STN-DBS) alleviate motor symptoms in Parkinson disease, but balance and gait are more variably affected. Balance reports are particularly inconsistent. Further, despite their prevalence in daily life, complex gait situations including backward and dual task gait are rarely studied. We aimed to assess how medications, STN-DBS, and both therapies combined affect balance and complex gait.

Methods: Twelve people with Parkinson disease were evaluated OFF medication with STN-DBS OFF and ON as well as ON medication with STN-DBS OFF and ON. Motor impairment was measured with the Movement Disorder Society Unified Parkinson Disease Rating Scale motor section (MDS-UPDRS-III). The Mini-Balance Evaluations Systems Test, timed-up-and-go, and dual task timed-up-and-go measured balance and mobility. Preferred-pace forward, fast as possible forward, backward, dual task forward, and dual task backward gait were also analyzed.

Results: Medication improved MDS-UPDRS-III scores, dual task timed-up-and-go, and stride length across all gait tasks. STN-DBS improved MDS-UPDRS-III scores, balance scores, dual task timed-up-and-go, and stride length and velocity across all gait tasks. Medication and STN-DBS combined did not provide additional benefits over either therapy alone.

Conclusions: Overall, dopaminergic medications and STN-DBS provided similar improvements in balance and gait tasks, although the effects of STN-DBS were stronger, potentially due to reductions in medication doses after surgery. Lack of synergistic effect of treatments may suggest both therapies improve balance and gait by influencing similar neural pathways.

Figure 1

Total MDS-UPDRS-III (A), as well as tremor (B), rigidity (C), bradykinesia (D), and PIGD (E) subsections across STN-DBS and medication conditions. Medication improved total MDS-UPDRS-III and rigidity scores. STN-DBS improved total MDS-UPDRS-III and all subsection scores. Values are means+SDs.

Figure 2

Balance was quantified using the mini-BESTest (A), as well as timed-up-and-go (TUG, B) and dual task timed-up-and-go tests (DT-TUG, C) across STN-DBS and medication conditions. Mini-BESTest score improved with STN-DBS. DT-TUG improved with medication and STN-DBS. Values are means+SDs.

Figure 3

Velocity (A), stride length (B), and cadence (C) were assessed across conditions during Fwd, Fast, Bkd, DT-Fwd, and DT-Bkd gait. Velocity improved with STN-DBS. Stride length improved with medication or STN-DBS. Improvements were similar across gait tasks. Values are means+SDs.