DBS Has Sustained Positive Impact on Quality of Life in Severe Dystonia

Caroline Cassels

June 07, 2007

June 7, 2007 (Istanbul) — New research indicates pallidal deep brain stimulation (DBS) in severe, medically refractory dystonia patients has a sustained effect in improving physical symptoms and consequently has a positive, sustained impact on health-related quality of life (HRQoL).

Presented here at the 11th International Congress of Parkinson's Disease and Movement Disorders, interim analysis of 2-year follow-up data from the first randomized, sham-stimulation-controlled trial of DBS in dystonia showed neurostimulation improved patients' quality of life and reduced symptoms of psychological distress, including depression and anxiety, up to 2 years following surgery.

"These results clearly show DBS has a positive effect on quality of life even in patients with very longstanding and severe disease and that this is a sustained effect," said study investigator Jörg Müeller, MD, from Innsbruck Medical University, Austria.

Sustained Effect

Published in the New England Journal of Medicine in 2006 (Kupsch A et al. N Engl J Med. 2006;355:1978-1990), the multicenter study, which included 10 European centers, showed that at 6 months, dystonia patients with DBS experienced a significant improvement in physical functioning and HRQoL.

The study included 40 patients — 24 with general dystonia and 16 with segmental dystonia — all of whom received a surgically implanted device for DBS.

At baseline, patients were assessed using the Burke-Fahn-Mardsen Dystonia Rating Scale (BFMDRS) for both movement and disability. A visual analog scale was also used to assess pain and disability.

HRQoL was determined using the Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36), which evaluates physical and mental functioning. Cognitive and mental status was assessed using the Mattis Dementia Rating Scale, the Brief Psychiatric Rating Scale, and the Beck Depression and Anxiety Inventories.

Significant Improvement

The study's primary end point was a change in the severity of dystonia reflected by a change in the BFMDRS movement score 3 months after surgery. Secondary end points included changes in HRQoL, depression, anxiety scores, and adverse effects.

At baseline, said Dr. Mueller, all SF-36 domain scores were significantly lower in 92% of the patient group compared with data from a general population sample.

Following surgery, subjects were randomly assigned to either neurostimulation or sham stimulation for 3 months, with 20 subjects in each group. After the initial 3-month period, patients in the sham group were switched to active treatment and all subjects were subsequently reassessed at 6 months.

At 3 months, DBS resulted in significant improvement in the severity of movement and disability symptoms as well as improved HRQoL, vs no improvement among study subjects in the sham-stimulation group. Similar positive results were seen in the second 3-month study period when active stimulation was extended to the entire study population.

Encouraging Results

After 6 months of continuous DBS, the average BFMDRS movement score was reduced by 42% in patients with generalized dystonia and 53% in study subjects with segmental dystonia.

Furthermore, comparisons of baseline and 6-month data showed significant improvement in all SF-36 domains as well as in the Beck Depression Inventory score.

"At 6 months, there was significant improvement in all domains considered. None of the baseline factors we studied, such as pain, depression, disease severity, depression, and anxiety scores, were predictive of improvement. The only significant predictor of quantified improvement was DBS," said Dr. Muller.

The interim 2-year follow-up data are similarly encouraging, he said, where patients' scores have either been maintained or further improved, he added.

Commenting on the study, session chair Erik Wolters, MD, PhD, from Vrije Universiteit Medical Center, in Amsterdam, the Netherlands, said the study's results "offer hope to patients with this terrible disease."

11th International Congress of Parkinson's Disease and Movement Disorders: Oral Platform Presentation 4602: Abstract 14. June 3-7, 2007.

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