Stimulating Parkinson's. Deep brain stimulation was more effective than the "best medical therapy" in improving on time without troubling dyskinesias, motor function, and quality of life at six months, in a significant new study (JAMA. 2009;301(1):63-73) but was associated with an increased risk of serious adverse events. The randomized, multicenter, controlled trial enrolled 255 patients with PD (Hoehn and Yahr stage > or = 2 while not taking medications). Of particular note, 25 percent of the patients were 70 or older, a population unrepresented in previous trials. These patients received either deep brain stimulation or best medical therapy, stratified by study site and patient age (< 70 years vs > or = 70 years) between May 2002 and October 2005.
Patients who received DBS added a mean of 4.6 hours per day of on time without troubling dyskinesia compared with 0 hours per day for patients who received best medical therapy. Motor function improved significantly (P< .001) with DBS versus best medical therapy, to the point that 71 percent of DBS patients and 32 percent of best medical therapy patients experienced clinically meaningful motor function improvements. At least one serious adverse event occurred in 49 deep brain stimulation patients and 15 best medical therapy patients.
For another component of the study, DBS was targeted to subthalamic nucleus or to the globus pallidus. Those results have not been released.
This is Spinal Cost. With a price tag of more than $100 billion, an obvious question emerges: Is spinal surgery worth it? A study published in the December 16th issue of the Annals of Internal Medicine came back with a mixed bag. For patients with spinal stenosis, a laminectomy, or surgical removal of some soft bone and tissue, it's a practical value. Unfortunately, for patients suffering from spinal stenosis with associated slipped vertebrae, the payback of spinal fusion surgery may not be enough to atone for the costs.
Researchers used the Quality Adjusted Life Year (QALY) scale to weigh the benefit to patients in comparison to direct and indirect costs of the surgical procedures over a two-year time following surgery. More than 3,900 patients participated in the randomized, controlled trial of surgery versus non-operative treatment, including 320 who underwent laminectomy and 344 who had spinal fusion. The researchers say that stenosis surgery using laminectomy cost $77,000 per QALY gained. In comparison, spinal fusion surgery for stenosis with slipped vertebrae cost about $115,000 for each QALY gained. $100,000 is the threshold at which procedures are considered to be cost effective in the US.
Botulism Toxin Structure E-xposed. Scientists at the US Department of Energy's Brookhaven National Laboratory say they have uncovered the atomic-level structure of a third subtype of botulinum neurotoxin, according to new research published online December 22, by the Journal of Molecular Biology. Previously, the group analyzed the molecular-level structures of various fragments of botulinum neurotoxin subtypes A to F, believing that in subtypes A and B, the three domains were set in identical fashion: with the binding and protein-cleaving domains "flanking" the translocation domain, indispensable for shifting the toxin into the cell.
Instead, the researchers say, the binding and protein-cleaving domains of subtype E both exist on the same side of the translocation domain. In addition, while all other subtypes are made of two protein chains, subtype E is a single-chain molecule. The scientists hope this will allow faster-acting vaccines and therapeutic agents to be developed more quickly.
Old News. Antidepressants in PD. Older antidepressants may not be the best choice for depression in patients with Parkinson's, according to a study published in the December 17th online edition of Neurology. For the study, researchers gave 52 people diagnosed with PD and depression either nortriptyline, a tricyclic antidepressant, paroxetine CR, a selective serotonin reuptake inhibitor (SSRI) or a placebo pill. The patients were tested for improvement of depression symptoms at two, four and eight weeks after starting treatment. Those who took nortriptyline were nearly five times more likely to see improvement in depression symptoms when compared with the people who took paroxetine CR, the study found.