Effects of Subthalamic Nucleus Deep Brain Stimulation and Levodopa on Balance in People with Parkinson's Disease: A Cross Sectional Study.

Subthalamic nucleus deep brain stimulation (STN-DBS) and levodopa are common treatment strategies for Parkinson's disease (PD). However, the specific effects of these treatment strategies on balance and its components remain unclear. This cross-sectional study of people with PD and STN-DBS compared balance in the treated state (ON-medication/ON-stimulation) and untreated state (OFF-medication/OFF-stimulation) using the Balance Evaluation Systems Test (BESTest). Total BESTest scores from the treated and untreated states were compared to assess overall balance. Scores for the six sections of the BESTest were further compared to assess differences in specific components of balance between treatment conditions. Twenty-nine participants were included (Male: 21, Female: 8, Mean Age ± SD: 65.0 ± 6.9). Total BESTest scores showed improved balance in the treated state compared to the untreated state (Treated: 67.56 ± 10.92; Untreated: 59.23 ± 16.51, p < 0.001). Four sections (Stability Limits/Verticality, Anticipatory Postural Reactions, Sensory Orientation, Stability in Gait) of the BESTest significantly improved in the treated state relative to the untreated state, after correcting for multiple comparisons (p < 0.05). These results demonstrate that STN-DBS and levodopa improve overall balance and provide a first step toward understanding the effects of these treatment strategies on specific components of balance.