| Deep brain stimulation (DBS) has seen an emergence as a surgical technique to alleviate the symptoms of those with Parkinson's disease (PD). Surgical intervention in the treatment of PD declined after the introduction of levodopa in 1968. Although levodopa was effective in treating many of the symptoms of PD, by the early 1980s the limitations of pharmacotherapy coupled with technological advances in imaging techniques had led to a renewed interest in surgical treatments.; This study examined 30 subjects from the University of California-San Francisco (UCSF) and San Francisco Veterans Administration Hospital (SFVAMC) before and after unilateral DBS of the globus pallidus internus (GPi) or subthalamic nucleus (STN). Twenty-four males and 6 females acted as their own controls, and raw scores were examined for each patient pre- and postoperatively on measures of cognition and mood. Patients were compared on 4 measures; 2 verbal memory measures, Rey Auditory Verbal Learning Test, 1–5 total trials and immediate recall (Rey, 1964); 1 verbal fluency measure, Controlled Oral Word Association Test, total score (Benton & Hamsher, 1976, 1983); and 1 measure of mood, the Beck Depression Inventory, total score (Beck, Ward, Mendelson, Mock, & Erbaugh, 1961). All subjects were controlled for age at the time of surgery, stage of disease, dementia, intelligence, severe depression, and anxiety.; The results from the primary analysis found that patients in either the STN or GPi groups did not demonstrate any cognitive or affective decline relative to preoperative baseline following surgical DBS. Although there were no group effects of the surgery itself, examination of individual raw change scores suggested patients are equally likely to decline or improve on at least one dependent measure. These results are consistent with the few studies which have been conducted that have examined unilateral stimulation of the STN or GPi.; Overall, DBS promises to be a relatively safe alternative to ablative surgery for the alleviation of Parkinsonian symptoms. It was further recommended that future research employ methods that improve power of the research design and consider use of reliable methods of comparing patients' performance so as to establish clinical validity of research findings. |
