Below is the abstract of another study on neuropsychological effects of DBS, that found opposite results from the Un. of Toronto study. This one found no adverse effects in a study of about 60 patients, 12 months after surgery. BUT a critical sentence about the subjects which was not included in this abstract, but was found in the full article is: "No other neurologic impairment was found and brain MRI was normal.Patients were relatively young and had no significant cognitive or mood impairment before surgery. " Again, let me know if you wish to read the full article (about 14pages). Also below is a report on DBS from "Highlights From the Sixth International Congress of Parkinson's Disease and Movement Disorders" (the full reports is available on Medscape (www.medscape.com) -- requires free registration) As you'll read there is some difference of opinion among the experts on many of the questions about dbs and other surgery. However the benefits and risks of surgery over the long term are being studied, and it seems the research is starting to give some clues about which people might be at a higher risk for negative results. Any comments, opinions? How can people considering surgery best make an informed decision? Linda ABSTRACT: National Library of Medicine: IGM Full Record Screen TITLE: Neuropsychological changes between "off" and "on" STN or GPi stimulation in Parkinson's disease. AUTHORS: Pillon B; Ardouin C; Damier P; Krack P; Houeto JL; Klinger H; Bonnet AM; Pollak P; Benabid AL; Agid Y AUTHOR INSERM EPI 007 and U 289, Federation de Neurologie AFFILIATION: and Centre d'Investigation Clinique, Hopital de la Salpetriere, Paris, France. [log in to unmask] SOURCE: Neurology 2000 Aug 8;55(3):411-8 CITATION IDS: PMID: 10932277 UI: 20392490 ABSTRACT: BACKGROUND: In a previous study on a consecutive series of 62 patients with PD, the authors showed that bilateral subthalamic or pallidal continuous high-frequency deep brain stimulation (DBS) affects neither memory nor executive functions 3 to 6 months after surgery. OBJECTIVE: To investigate the specific effects of DBS by comparing the performance of patients with the stimulator turned "on" and off." METHODS: The performance of 56 patients on clinical tests of executive function was compared after 3 and 12 months of DBS of the subthalamic nucleus (STN; n = 48) or the internal globus pallidus (GPi; n = 8) with the stimulator "on" or offf." Global intellectual efficiency, verbal learning, and mood were also evaluated with the stimulator "on." The performance of another group of 20 patients was compared after 6 months of DBS of the STN (n = 15) or the GPi (n = 5) with the stimulator "on" or "off" on more experimental tests recently shown to be more sensitive to l-dopa therapy. RESULTS: When the stimulator was "on," STN patients showed a mild but significant improvement in psychomotor speed and working memory. In comparison with the presurgical state, STN patients had no cognitive deficit at 12 months, except for lexical fluency. There was no differential effect of STN or GPi stimulation. CONCLUSIONS: 1) The specific effect of DBS seems to mimic the action of l-dopa treatment in the cognitive as in the motor domain; 2) the surgery associated with DBS does not appear to affect the cognitive performance of patients with PD 12 months later, except for a mild deficit in lexical fluency. MAIN MESH Cognition/*physiology HEADINGS: *Electric Stimulation Therapy Parkinson Disease/*drug therapy Parkinson Disease/*physiopathology PUBLICATION TYPES: CLINICAL TRIAL JOURNAL ARTICLE ------------------------------------------------------------------------ Conference Highlights From the Sixth International Congress of Parkinson's Disease and Movement Disorders www.medscape.com/ Deep Brain Stimulation Dr. Pierre Pollak of the University of Grenoble, France reviewed the merits and disadvantages of placing deep brain stimulators in the globus pallidum pars interna (GPi) vs the subthalamic nucleus (STN).[20] DBS has several advantages over permanent lesions in the treatment of PD. GPi was the site of choice until recently, when studies suggested that placement of the stimulators in the STN is followed by improvement in a greater variety of symptoms than with GPi placement. Dr. Pollak's main point was that because there have not yet been any studies directly comparing the 2 procedures in a prospective fashion, no firm general conclusion can be reached. However, based on the experience so far reported, the following is likely true: 1. STN placement allows greater reduction in the dose of levodopa still required after surgery; 2. Dyskinesias are relieved by the 2 procedures to a similar degree, but require less energy consumption for the STN; 3. the risk of neurologic sequelae seems similar when each procedure is performed unilaterally, whereas it may be lower for the STN when a bilateral procedure is required. The second advantage may seem trivial, but it may imply a significant difference in how often the subcutaneous battery powering the stimulator needs to be replaced. Thus, STN may indeed turn out to be the site of choice for DBS placement in PD treatment. However, new applications of GPi DBS placement are also currently being evaluated, and in some cases are very promising (as for generalized dystonia). Thus, GPi may turn out to be the site of choice for DBS in the treatment of other movement disorders. Panel Discussion: Surgery for PD At the end of the session on surgical treatments, a panel of speakers addressed several questions in a forum format. The panel was chaired by Dr.Andres Lozano of the Toronto Western Hospital, (Toronto, Canada) and included Dr. Fahn, Dr. Pollak, Dr. José Obeso (Clinica Universitaria, Pamplona, Spain, and Dr. Mahlon Delong (Emory University, Atlanta, Georgia). The following questions were addressed: How many patients with PD should undergo surgical treatment? The range of responses was 10% to 30%. Dr. Delong added that he expects this number to grow with continued progress in the surgical approach. Dr. Fahn commented that surgery should be saved for later stages of the disease, given its risk of irreversible complications. Dr. Pollak, on the other hand, added that a younger age is the critical factor for a good outcome, adding difficulty to the choice of the ideal stage at which to consider surgery. At what point in the illness should surgery be offered? Dr. DeLong suggested not waiting too long. Even early in the course of PD, patients may lose employability, confidence, and social contacts, which may never be regained. Thus, surgery should be offered before irreversible changes in quality of life. Dr. Obeso felt it is too early to decide; now is the time to focus on obtaining more data to answer this question adequately. Dr. Pollak recommended not too early but not too late: 6 to 7 years after the diagnosis is made seems like a good compromise between the ever-present risk of surgical complications and the time when PD-related complications become serious. Dr. Fahn recommended maximizing medical treatment before considering surgery but also avoiding waiting for too advanced an age because of the higher risk of surgical complications at later ages. How do you select a target for the surgical procedure? Dr. Obeso acknowledged a bias in favor of the STN but also pointed out that comparative studies are needed before we really know the answer. Dr. Pollak, on the other hand, questioned the worth of a large-scale randomized study for this question. He argued that we already know from smaller studies that STN placement of DBS allows a greater reduction of levodopa. A randomized study may require more than 200 patients to detect this advantage, and he expressed doubt that such a study would be worthwhile. Which is preferable, surgical lesion or DBS? Dr. Fahn acknowledged that stimulators are very expensive, both in equipment cost and amount of time required for adjustment of parameters after the procedure. However, he said he has so far found the improvement more impressive with DBS than with lesions and that the possibility of removal of the current or even the hardware is very attractive in case of adverse effects. Thus, he favored DBS. Dr. Obeso pointed out that lesions may need to remain part of our armamentarium simply because many centers may never be able to develop the resources needed to follow a large number of patients with stimulators. Along the same lines, Dr. Delong mentioned that lesions may be the only option for many years in poor countries. Finally, Dr. Pollak suggested an option for the future, which might resolve the differences between the techniques: progressive formation of lesions through increased stimulation via a DBS electrode. How concerned should patients be about the neurocognitive adverse effects of surgery, such as visual hallucinations, cognitive deficits, and depression? Dr. Pollak said these are relatively rare, except for apathy. The latter seems to occur in about one fourth of patients and often improves by resuming treatment with dopamine agonists. Hypomania is rare, usually occurring transiently just after surgery and responding to short-term treatment with clozapine. END