what are the "behavioral effects of stimulation"

tks


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From: "rayilynlee" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, January 10, 2009 2:25 PM
Subject: DBS for advanced PD


> Deep Brain Stimulation Treatment For Advanced Parkinson's Disease Patients 
> Provides Benefits, Risks
> ScienceDaily (Jan. 9, 2009) - Patients with advanced Parkinson disease 
> (PD) who received deep brain stimulation treatment had more improvement in 
> movement skills and quality of life after six months than patients who 
> received other medical therapy, but also had a higher risk of a serious 
> adverse events, according to a new study.
> Deep brain stimulation is a surgical treatment involving the implantation 
> of electrodes that send electrical stimulation to specific parts of the 
> brain to reduce involuntary movements and tremors. It is the surgical 
> intervention of choice when PD motor (movement) complications are 
> inadequately managed with medications, according to background information 
> in the article. "However, recent reports highlighting unexpected 
> behavioral effects of stimulation suggest that deep brain stimulation, 
> while improving motor function, may have other less desirable 
> consequences," the authors write. They add that there are few randomized 
> trials comparing treatments, and most studies exclude older patients.
> Frances M. Weaver, Ph.D., of Hines VA Hospital, Hines, Ill., and 
> colleagues conducted a randomized trial to compare the benefits and risks 
> of deep brain stimulation with those of best medical therapy for patients, 
> of a wide age range, with PD. A total of 255 patients with PD were 
> enrolled; 25 percent were age 70 years or older. The participants were 
> randomized to receive bilateral deep brain stimulation with leads of the 
> stimulation device implanted in the following locations of the brain: 
> subthalamic nucleus (n = 60) or globus pallidus (n = 61); or received best 
> medical therapy (n = 134), which included management by movement disorder 
> neurologists, who monitored medication use and nonpharmacological therapy 
> (e.g., physical, occupational, and speech therapy).
> The researchers found that at 6 months, deep brain stimulation patients 
> gained an average of 4.6 hours per day of on time (the time of good 
> symptom control or unimpeded motor function) without troubling dyskinesia 
> (involuntary movements), while the average change for the best medical 
> therapy group was 0 hours. Motor function improved significantly with deep 
> brain stimulation compared with best medical therapy, with 71 percent of 
> deep brain stimulation patients vs. 32 percent of best medical therapy 
> patients experiencing clinically meaningful motor function improvements at 
> 6 months, while 3 percent of deep brain stimulation patients and 21 
> percent of best medical therapy patients had clinically worsening scores.
> Compared with patients in the best medical therapy group, patients in the 
> deep brain stimulation group experienced significant improvements in the 
> summary measure of quality of life and on 7 of 8 PD quality-of-life 
> scores. Neurocognitive testing revealed small decrements in some areas of 
> information processing for patients receiving deep brain stimulation vs. 
> best medical therapy.
> The overall risk of experiencing a serious adverse event was 3.8 times 
> higher in deep brain stimulation patients than in best medical therapy 
> patients. Forty-nine deep brain stimulation patients (40 percent) 
> experienced 82 serious adverse events. Fifteen best medical therapy 
> patients (11 percent) experienced 19 serious adverse events. The most 
> common serious adverse event was surgical site infection, with other 
> serious adverse events including nervous system disorders, psychiatric 
> disorders, device-related complications and cardiac disorders.
> "The clinical significance of the adverse events and minor neurocognitive 
> changes observed in patients in the deep brain stimulation group and, more 
> importantly, whether patients who undergo deep brain stimulation view 
> improvement in motor function and quality of life as outweighing adverse 
> events, remain to be explored. More detailed analyses of adverse events 
> and neurocognitive functioning following the conclusion of phase 2 of this 
> study will shed light on these issues. Caution should be exercised, 
> however, against overstating or understating the risks of deep brain 
> stimulation for patients with PD. Physicians must continue to weigh the 
> potential short-term and long-term risks with the benefits of deep brain 
> stimulation in each patient," the authors conclude.
> Editorial: Neurostimulation for Parkinson Disease
> In an accompanying editorial, Günther Deuschl, M.D., Ph.D., of the 
> Universitätsklinikum Schleswig-Holstein, Kiel, Germany, comments on the 
> findings of Weaver and colleagues.
> "Although deep brain stimulation is the most important innovation for 
> treatment of advanced PD since the discovery of levodopa [drug used to 
> treat PD], many questions are still unanswered. For instance, the optimal 
> timing for the implantation is unknown. The majority of patients undergo 
> deep brain stimulation surgery more than 10 years after disease onset when 
> the patients are already incapable of working and when the disease-related 
> psychosocial decline has already begun. As quality of life is improved 
> with this treatment it may improve psychosocial functioning in general for 
> these advanced stages. With the aging of the general population, PD will 
> become even more common and patients with PD will get older. Therefore, 
> the present results showing similar efficacy and tolerability of deep 
> brain stimulation in younger and older patients must be replicated because 
> it is at variance with some other reports demonstrating lower rates of 
> operative and postoperative complications in younger patients."
> "Overall the results of this important study by Weaver et al have 
> convincingly confirmed the 6-month efficacy of deep brain stimulation for 
> advanced PD in the largest patient group studied thus far. However, this 
> study, along with previous research on this therapy, shows that such 
> progress cannot be made without costs in terms of adverse effects."
>
> JAMA and Archives Journals (2009, January 9). Deep Brain Stimulation 
> Treatment For Advanced Parkinson's Disease Patients Provides Benefits, 
> Risks. ScienceDaily. Retrieved January 10, 2009, from 
> http://www.sciencedaily.com­ /releases/2009/01/090106161510.htm
>
> Rayilyn Brown
> Director AZNPF
> Arizona Chapter National Parkinson Foundation
> [log in to unmask]
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