Neuropsychological effects of pallidotomy in patients with Parkinson's disease

Functional surgery for Parkinson's disease treatment: a structured analysis of a decade of published literature

The aim of this study was to analyse and compare published data during the last decade on the different approaches to Parkinson's disease surgery. Eighty-eight papers published between 1990 and 2001 fulfilled the inclusion criteria. Full-text and prospective papers on lesion and stimulation of GPi or STN were assessed. Descriptive analysis of surgery procedure and population under study was performed, as well as a meta-analysis of the most consistently reported variables. A total of 1702 patients underwent surgery with a mean age of 58.75 years (range 46.5 - 72.5), mean duration of illness 13.6 years (8.1 - 18.1) and a male:female ratio 1.5:1. Mean postoperative follow-up was 9 months (1 - 52). Single blind assessment was performed in two papers, while double blind evaluation was used in 6. In the GPi group, no difference was found between the pre- and postoperative levodopa equivalent daily dose (960.39 v. 943.13; p > 0.05), while the STN group showed a marked reduction (1104.8 v. 483.04; p < 0.05) of this dosage. Meta-analysis of the most consistently reported variables (UPDRS total score, UPDRS motor score, UPDRS ADL score and Schwab & England score showed that Nucleus, Bilaterality of Approach and Surgical Procedure were the best moderators for defining outcome. Bilateral DBS STN procedures proved to be associated with better outcome. Microelectrode recording was not found to be a moderator that influenced outcome. Although there was a significant improvement of dyskinesias among the different approaches described in the papers, the heterogeneity of data makes it impossible to perform a structured analysis on this item.

Neurosurgical management of abnormal muscle tone in childhood

No longer are only a limited number of treatments available to help children and their families deal with childhood hypertonia. It is now possible to provide a child with a treatment specific to his or her muscle tone problems and consequently meet the family's functional goals. The prospects can only improve over the next few years, given the level of interest exhibited by pediatric neuro- and orthopedic surgeons supported by pediatricians, pediatric physical and occupational therapists, pediatric neurologists, and pediatric physiatrists.

Verbal fluency declines after pallidotomy: an interaction between task and lesion laterality

Verbal fluency declines are commonly reported after pallidotomy in patients with Parkinson's disease. However, it is not clear whether there is an interaction between side of surgery and task format (lexical vs. semantic) or whether error rates (perseverations, intrusions, rule violations) increase after surgery. This study examined verbal fluency before and approximately 4 months after unilateral pallidotomy. The left and right pallidotomy groups were matched on key demographic, cognitive, and disease variables. Pallidotomy resulted in a decline in lexical but not semantic verbal fluency, and this decline was most evident in the left-sided surgery group. Error rates (perseverations, intrusions, and rule violations) were not affected by pallidotomy. Findings support the role of left frontal-basal ganglionic circuits in word retrieval processes and/or lexical search and access.