Rapid assessment of gait and speech after subthalamic deep brain stimulation.

Background: Describe a rapid assessment for patients with idiopathic Parkinson's disease (PD) and deep brain stimulation of the subthalamic nucleus reporting worsening speech and/or gait problems.

Methods: We retrospectively reviewed 29 patients that had improvement in gait and/or speech within 30 min after turning stimulation off. Clinical data analyzed include unified PD rating scale motor scores and stimulation parameters before and after adjusting stimulation. All patients received electrode efficacy and side effect threshold testing. Stimulation parameters were adjusted to maximize efficacy, avoid side effects, and maximize battery longevity.

Results: Turning stimulation off revealed reversible speech and/or gait stimulation side effects within 30 min. Focusing on six factors revealed stimulation modifications that improved motor symptoms, eliminated stimulation side effects, and reduced battery drain. Primary stimulation parameters modified were cathode selection and pulse width reduction.

Conclusions: Stimulation-induced side effects impacting gait and speech can be identified within 30 min. A systematic evaluation can distinguish disease progression from reversible stimulation side effects and improve motor outcomes over the long term.