Deep brain stimulation (DBS) effectively reduces tremors in people with multiple sclerosis (MS). However, the treatment may lead to other worsening symptoms and speech problems, according to a review study.
These findings support using DBS for treating this common, disabling symptom of MS. Still, larger studies that used standardized measurements of tremors may help assess the risk-benefit ratio of using DBS on patients with MS.
The review study, “Deep brain stimulation for multiple sclerosis tremor: A systematic review and meta-analysis,” was published in the journal Multiple Sclerosis and Related Disorders.
Approximately 25% to 58% of patients with MS experience tremors. And, the tremors may become severe in 3% to 15% of patients. Tremors occur most commonly in the arms, legs, head, trunk, and vocal cords.
For many MS patients, tremors can be debilitating enough to severely impair their quality of life and are challenging to treat.
DBS has been successful in treating Parkinson’s disease and essential tremors. It has approval for such treatment. DBS has been successful in treating MS-related tremors in cases where other treatments have failed.
It involves the surgical implantation of electrodes in the brain to stimulate the thalamus with electric impulses. The thalamus is an area involved in motor function. The amount of stimulation is controlled by a pacemaker-like device placed under the skin near the collarbone.
However, the operation has some risks and may result in brain bleeding and infections. Some patients may also develop new symptoms, such as difficulties with balance, speech, and swallowing.
Recently, a group of researchers from Iran reviewed studies that investigated the impact of DBS on MS-associated tremors. A total of 1,663 studies had been conducted through March 2021. The team used 17 of those that covered 162 MS patients in their meta-analysis.
The studies were published between 1999 and 2018 and included 15 full studies and two conference abstracts. Most (58.8%) were conducted in the U.S. or the U.K.
The number of patients in each study ranged from three to 22, and their mean average age ranged from 36 to 46.5 years. Follow-up time varied between three months and 62.4 months (about five years).
Six studies applied objective tools to assess tremors, although the tools varied between studies. Two studies used the Fahn Tremor Rating Scale, one applied the Fahn-Tolosa-Marin Clinical Rating Scale, and another used the Clinical Rating Scale. The tremor disability score and the visual analog scale were used in one study each.
Results showed that the tremor reduction was 73% and that DBS led to a significant reduction in tremor scores. One study reported improvements in quality of life among patients showing tremor reductions following DBS.
These new findings offer some hope for MS patients for the relief of severe tremors.