Poster F36, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
Effect of deep brain stimulaton of the subthalamic nucleus in Parkinson’s disease on verbal fluency
Friederike Leimbach1, Socorro Pieters1, Catherine Cheung1, Leonora Wilkinson1, Donna Page1, Catherine Jones1, Ludwig Zinzro1, Marwan Hariz1, Tom Foltynie1, Patricia Limousin1, Marjan Jahanshahi1; 1UCL Institute of Neurology
Verbal fluency involves a set of executive processes and rerieval of information from memory. Studies investigating the cognitive effects of subthalamic nucleus (STN) deep brain stimulation (DBS) have consistently revealed a decline of patients’ verbal fluency after surgery (Combs et al., 2015). However, the exact mechanisms of these deficits remain to be investigated. The aim of this study was to investigate the effects of STN DBS on different aspects of verbal fluency. 19 patients with Parkinson’s disease (PD) were assessed within a month prior to STN DBS surgery and 12-24 months after surgery with STN-DBS on and on medication on both occasions. Three verbal fluency tasks were completed: phonemic, semantic and alternating category. In addition to the number of words correctly generated, the size of the phonemic and semantic clusters and the number of phonemic and semantic switches were recorded. The results indicated significant post-surgical decline in phonemic, semantic and alternating category fluency. The number of phonemic switches was significantly reduced after surgery for both phonemic and semantic fluency tasks. This finding is consistent with previous observations of a positive correlation between the number of words generated and the measure of switching with increased gamma band activity in the local field potentials recorded from the implanted electrodes in the STN in PD patients while they performed phonemic and semantic fluency tasks (Anzak et al, 2011). The significant reduction of switching following surgery suggests that STN DBS alters functioning of fronto-striatal circuits involved in executive functions.
Topic Area: EXECUTIVE PROCESSES: Other