Degree of Cortical Atrophy affects Neuropsychological Outcome Following Bilateral
Title: Subthalamic (STN) Deep Brain Stimulation (DBS) in Patients with Parkinson
Hooman Azmi, MD, Hackensack University Medical Center, Hackensack, NJ; Cynthia
Kubu, Phd, Cleveland Clinic, OH; Andre Machado, MD, PhD, Cleveland Clinic, OH;
Milind Deogaonkar, MD, Cleveland Clinic, OH; Thomas Frazier, Phd, Cleveland Clinic,
OH; Ali Rezai, MD, Cleveland Clinic, OH;
Mild declines on word fluency tests are among the most common neuropsychological
changes following STN DBS for the treatment of PD. Although declines on word fluency
measures have been well demonstrated in the research literature, there is no clear
consensus if this effect holds true for all patients or if there are specific patient factors that
confer increased risk of decline. The goal of the current study was to examine the role of
cortical atrophy on changes in word fluency following placement of bilateral STN DBS
electrodes in patients with PD.
38 patients completed a common measure of word fluency (Controlled Oral Word
Association Test) prior to and following surgery. Degree of cortical atrophy was inferred
by calculating whole brain volume corrected for total intracranial volume (WB/TIV).
Based on WB/TIV score, patients were divided into those whose score fell < 25th
Abstract percentile for the entire sample (Low Volume Group; n=9) and those whose score fell >
25th percentile (High Volume Group, n=29). A repeated measures ANOVA was used to
compare the groups’ word fluency scores prior to and following surgery.
The repeated measures ANOVA revealed a significant interaction between Low versus
High WB/TIV groups and time such that patients with lower WB/TIV volumes declined
significantly more on the word fluency measure following surgery than those with higher
WB/TIV volumes (p<0.05).
These data demonstrate that whole brain volume affects neuropsychological outcome
following placement of bilateral STN/DBS electrodes in patients with PD. Patients with
lower whole brain volumes, presumably reflecting increased cortical atrophy,
demonstrated greater declines on a word fluency measure than those with higher whole
brain volumes. Neuroimaging variables may provide additional information regarding
potential risk to cognitive function in PD patients undergoing STN DBS.
This information can be used for patient selection and surgical decision making.
H. Azmi, None; C. Kubu, None; A. Machado, Intel Medical 4, 5; Medtronic 1; M.
Deogaonkar, None; T. Frazier, None; A. Rezai, Intelect Medical 1, 2, 3, 4, 5; Medtronic
1, 2, 3, 5.