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The following 4 article abstracts report on effects of Deep Brain Stimulation on functions such as working memory, speed of mental processing, bimanual motor speed and coordination, speech. The first study found some negative results, especially in patients over age 69. Does anyone have more information about this or know of similar studies? I will see if I can obtain the full article. --------- Forwarded message ---------- From: WE MOVE <[log in to unmask]> To: <[log in to unmask]> Date: Fri, 8 Dec 2000 17:09:52 -0600 Subject: Effects of DBS in Parkinson's disease Message-ID: <[log in to unmask]> 1. Neuropsychological consequences of chronic bilateral stimulation of the subthalamic nucleus in Parkinson's disease JA Saint-Cyr, LL Trepanier, R Kumar, AM Lozano, AE Lang Brain 2000;123:2091-2108 Deep brain stimulation of the subthalamic nucleus can lead to long term declines in neuropsychological measures, especially in older patients, according to this study. Eleven PD patients, including 6 older than age 69, received bilateral DBS to the STN. In both younger and older patients at 12 months post-operation, UPDRS motor scores had improved and levodopa daily doses had declined, with greater changes in younger patients for both measures (Kumar 1998). Neuropsychological evaluations were performed at baseline and postoperatively both at early (3-6 months) and late (9-12 months) time points. At the early time point, results showed significant declines in working memory, speed of mental processing, bimanual motor speed and coordination, and other areas, with more consistent decline in older patients. By the late time point, only learning based on multiple trials had recovered to baseline values. The authors state, "Tasks reliant on the integrity of frontal striatal circuitry either did not recover or gradually worsened." 2. An investigation of the effects of subthalamic stimulation on acoustic measures of voice C Dromey, R Kumar, AE Lang, AM Lozano Movement Disorders 2000;15:1132-1138 DBS to the STN produces little significant improvement in speech variables, according to this report. A variety of speech-related variables were measured both on and off medication in 7 PD patients before and 6 months after bilateral STN electrode implantation. At 6 months for the group as a whole, no significant change was seen in any of the measures of speech production in the off-med on-stim state. In the on-med on-stim state, there were small increases in sound pressure level and fundamental frequency variability. The authors state, "These findings are consistent with several other studies that have reported disparity between limb and speech improvements after neurosurgical intervention for Parkinson's disease." 3. Effect of bilateral deep-brain stimulation on oral control of patients with parkinsonism M Gentil, P Garcia-Ruiz, P Pollak, AL Benabid European Neurology 2000;44:147-152 Deep brain stimulation of the STN improves force and control of the articulatory organs, while stimulation of the ventral intermediate nucleus (VIM) does not, according to this study. Force generation and control in the tongue, upper lip, and lower lip were measured in 10 STN patients and 4 VIM patients on and off stimulation after at least 10 hours off medication. STN stimulation significantly improved maximal voluntary force in all three organs by at least 50% over no stimulation, while VIM stimulation had no significant effect. STN stimulation improved target force precision as well, while VIM stimulation either had no effect or worsened it (in the tongue). STN stimulation improved speech as measured by UPDRS Item 18, while VIM stimulation worsened it. 4. No tissue damage by chronic deep brain stimulation in Parkinson's disease C Haberler, F Alesch, PR Mazal, P Pilz, K Jellinger, MM Pinter, JA Hainfellner, H Budka Ann Neurol 2000;48:372-376 Brains were examined from 8 patients who had received DBS to either the STN (2) or the VIM (6), and who had died of unrelated causes. Patients had received stimulation for 3-69 months prior to death, except for 1 patient who died 2 days after implantation of myocardial infarction. In all but this last patient, a thin inner capsule of connective tissue was found around the lead track, whose thickness was not correlated with duration of stimulation. No difference was seen in tissue changes surrounding active contacts versus those surrounding insulated parts of the lead. Other changes noted in some patients included slight microglial activation around the lead track. The authors state, "We conclude that chronic DBS does not cause damage to adjacent brain parenchyma." 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