Cognition Symptoms: Huntington's impairs "thinking" skills that are mostly related to the ability to plan and organize thoughts. There is particular difficulty with "multitasking" or shifting frames of thought. Long term memory is less affected.

Cognition Treatments: There are studies in HD mice models showing that environmental enrichment [Hockly E 2002] and voluntary exercise give significant cognitive benefit.

Studies in Parkinson's have shown that anticholinesterase drugs originally approved for use in Alzheimer's give cognitive benefits in this disease [Maidment I 2006]. However two small trials in Huntington's have given inconsistent results. Rivastigmine (Exelon®) appeared to give small benefit [de Tommaso M 2007] while donepezil (Aricept®) did not [Cubo E 2006]. Both of these drugs have side effects that probably outweigh any potential benefit.

There have been 2 small placebo controlled trials in Huntington's testing citalopram (Celexa®) and atomoxetine (Strattera®). Neither study showed benefit. Though a memantine (Namenda®) trial was performed, no results have been published.

References

Hockly E, Cordery PM, Woodman B, Mahal A, van Dellen A, Blakemore C, Lewis CM, Hannan AJ, Bates GP. Environmental enrichment slows disease progression in R6/2 Huntington's disease mice. Ann Neurol. 2002 Feb;51(2):235-42. PubMed abstract

Maidment I, Fox C, Boustani M. Cholinesterase inhibitors for Parkinson's disease dementia. Cochrane Database Syst Rev. 2006 Jan 25;(1):CD004747. PubMed abstract

de Tommaso M, Difruscolo O, Sciruicchio V, Specchio N, Livrea P. Two years' follow-up of rivastigmine treatment in Huntington disease. Clin Neuropharmacol. 2007 Jan-Feb;30(1):43-6. PubMed abstract

Cubo E, Shannon KM, Tracy D, Jaglin JA, Bernard BA, Wuu J, Leurgans SE. Effect of donepezil on motor and cognitive function in Huntington disease. Neurology. 2006 Oct 10;67(7):1268-71. PubMed abstract