Deep brain stimulation effects on verbal fluency dissociated by target and active contact location

Area of Science:

• Neurology
• Neurosurgery
• Speech Pathology

Background:

• Deep brain stimulation (DBS) is effective for Parkinson's disease (PD) motor symptoms.
• DBS can negatively affect verbal fluency, impacting quality of life.

Purpose of the Study:

• Investigate how electrode coordinates in the subthalamic nucleus (STN) or globus pallidus interna (GPi) influence verbal fluency changes after DBS.
• Determine if left hemisphere electrode location predicts verbal fluency alterations.

Main Methods:

• Analyzed verbal fluency in 40 PD patients before and after DBS targeting STN or GPi.
• Correlated active electrode positions (superior/inferior, anterior/posterior, lateral/medial axes) with postoperative fluency changes.

Main Results:

• Verbal fluency declined significantly post-surgery in both STN and GPi DBS groups.
• In STN-DBS, superior left active electrode placement predicted greater fluency declines.
• Electrode position in the right STN or GPi did not predict fluency changes.

Conclusions:

• Left STN electrode location is a critical factor in DBS-induced verbal fluency changes in PD.
• Findings may inform surgical targeting to mitigate cognitive side effects of DBS.