Deep-brain stimulation in Parkinson’s disease: long-term efficacy and safety – What happened this year
Benabid AL, Chabardes S, Seigneuret E Deep-brain stimulation in Parkinson’s disease: long-term efficacy and safety – What happened this year , 2005 Dec; 18(6):623-30
These authors reviewed 260 articles from 2/04-3/05 involving PD and DBS looking at what researchers have covered and discovered over a year. It should be noted that this article is not a meta-analysis of the literature but simply a review of content and new discoveries. They discuss that the debate over neuroprotective factors, methodology, and placement continue to be controversial issues. The authors noted that in the reviewed articles there is consensus in regard to beneficial effects of stimulation, stability of effects, inclusion criteria, that other conditions may not respond to stimulation, and that stimulation mimics the effects of ablative surgery as well as dopatherapy. They indicated that patients undergoing brain stimulation experienced improvement in gait, balance, and sleep. They reported that quality of life is greatly linked to improved motor symptoms and not as much to improved cognitive or social difficulties, which is not surprising as the stimulation treatments are not purported to improve cognition or social support. The authors completed a cost analysis and found that over the course of 5-7 years that surgical options are cheaper than medications. They discussed the debate regarding stimulator placement, which continues as the studies looking at placement are usually completed on small groups, there are team differences (sites have different methods, outcomes, etc. which makes it hard to compare to each other), patients may not have severe symptoms, and research has shown between the placement sites (STN vs. GPi) a lack of difference on various measures. This article also discussed other diseases that are under review for treatment with DBS (Essential tremor, Obsessive Compulsive Disorder). The authors also discussed side effects of surgery (hypophonia, swallowing, weight gain) as well as surgical complications (stroke 1.15%) due to infections, misplaced leads, and hardware problems. The article also mentions psychological complications such as increased apathy yet mildly improved depression. It is unclear why there are psychological complications such as is it due to the surgery, improper programming, poor stimulator placement, or poor patient selection criteria. Overall they concluded that DBS has been shown to be a reliable and valid treatment with stable effects. However, they stated that the debate sadly continues regarding very important information for DBS (location, subcomponents of the surgical procedures, side effects, questionable neuroprotective effects, and the exact mechanism of action) and suggested that these problems will only be solved with methodological improvement.