Treating Myoclonus in HD Patients

HD Lighthouse Contributing Editor's Comment: Symptoms are variable in Huntington's Disease patients and so are individual reactions to medication. This is one of the few articles to discuss this issue.

Myoclonic twitching is caused by a rapid contraction and relaxation of the muscles. Chorea involves involuntary movements which are more sustained and flow from one muscle group to the next. Myoclonus is rare in HD patients compared to chorea but it does occur. The authors found that while valproic acid has not been reported to help with chorea, it was successful in treating myoclonus in seven out of eight patients with this symptom seen at their center.

The full article is available free online and can be found here: http://www.biomedcentral.com/content/pdf/1471-2377-6-11.pdf
--Marsha L. Miller, Ph.D.
Posted to the HDL: 05 Mar 2006

Chorea in Huntingtons Disease (HD) is usually treated with antidopaminergic neuroleptics like haloperidol, olanzapine and tiaprid or dopamine depleting drugs like tetrabenazine. Some patients with hyperkinesia, however, react to treatment with antidopaminergic drugs by developing extrapyramidal side effects. In earlier studies valproic acid showed no beneficial effect on involuntary choreatic movements. Myoclonus is rare in HD and is often overseen or misdiagnosed as chorea.

Methods:

In this report, we present eight patients whose main symptom is myoclonic hyperkinesia. All patients were treated with valproic acid and scored by using the Unified Huntington's Disease Rating Scale (UHDRS) motor score before and after treatment. In addition to this, two patients agreed to be videotaped.

Results:

In seven patients myoclonus and, therefore the UHDRS motor score improved in a dose dependent manner. In three of these patients antidopaminergic medication could be reduced.

Conclusions:

In the rare subgroup of HD patients suffering from myoclonic hyperkinesia, valproic acid is a possible alternative treatment.

Tracked on the Lighthouse:
myoclonus

Source: BMC Neurology 006 Feb 28;6(1):11

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