The effect of subthalamic nucleus deep brain stimulation and dopaminergic treatment on dual-task manual dexterity in Parkinson's disease

Background and purpose Dual-task manual dexterity is required to perform activities of daily living and is affected by cognitive functions. This study aimed to investigate the effects of two main treatment options, subthalamic nucleus deep brain stimulation (STN-DBS) and dopaminergic treatment (DT), on dual-task manual dexterity and cognitive functions of people with Parkinson's disease (PwPD). Methods Twenty-one PwPD were assessed in four different conditions as medication on-off and STN-DBS on-off in random order. Motor symptoms were measured with the Movement Disorder Society-Unified Parkinson Disease Rating Scale, motor section (MDS-UPDRS-III). Single and dual-task manual dexterity was assessed with the Nine-Hole Peg Test (NHPT) and cognitive functions were assessed with the Stroop Test (ST) and the Trail Making Test (TMT). Results Both DT and STN-DBS enhanced MDS-UPDRS-III, and the combination of DT and STN-DBS provided further improvement. Only STN-DBS enhanced dominant hand single-task NHPT scores. Non-dominant single-task NHPT scores and dual-task NHPT scores improved with both treatments alone; however, STN-DBS resulted in more improvement than DT. Dual-task interference, ST, and TMT scores improved with both treatments alone; however, combining DT and STNDBS did not provide more improvement. Conclusion DT, STN-DBS, and combining both treatments have different effects on motor symptoms, single and dual-task manual dexterity, dual-task interference, and cognitive functions. These results indicate that DT and STN-DBS may affect motor and cognitive functions via different mechanisms. Effects of DT and STN-DBS on manual dexterity may depend on the degree of cognitive involvement in manual dexterity tasks.

Automated summary

This study investigated the effects of subthalamic nucleus deep brain stimulation (STN-DBS) and dopaminergic treatment (DT) on dual-task manual dexterity and cognitive functions in people with Parkinson's disease. The results showed that DT, STN-DBS, and the combination of both treatments had different effects on motor symptoms, single and dual-task manual dexterity, dual-task interference, and cognitive functions. DT and STN-DBS may impact motor and cognitive functions through different mechanisms, and the degree of cognitive involvement in manual dexterity tasks may influence the effects of these treatments.