BackgroundHuntington's disease (HD) is a fatal inherited neurodegenerative disease, caused by a

Self-awareness of memory function is relatively well preserved in PD, but is negatively affected by depressive symptoms. Patient-proxy discrepancies increase also with disease severity, degree of memory problems and cognitive control deficits. Caregivers seem to be unaware of the specificity of memory problems in PD and report only some of them, mainly those related to verbal recall.

Individuals suffering from Huntington's disease (HD) have been shown to present with poor self-awareness of a variety of symptoms. The aim of this study was to better assess the self-awareness of motor symptoms and activities of daily living (ADL) impairment in HD, in comparison to Parkinson's disease (PD) and cervical dystonia (CD). In particular, the anosognosia/anosodiaphoria of involuntary movements has been investigated. Self-awareness was tested in 23 patients with HD by comparing patient and caregiver ratings in reference to clinical control groups (25 PD with dyskinesias, PDdys; 21 PD without dyskinesias, PDndys; and 20 with CD). Patients were assessed neurologically by relevant rating scales. Self-awareness was tested using a scale based on 15 films demonstrating 3 types of motor symptoms (chorea/dyskinesias, parkinsonism, torticollis) as well as the Self-Assessment Parkinson's Disease Disability Scale. General cognitive status, verbal learning, cognitive control, and mood were also analyzed. Our results indicate that self-awareness of choreic movements was affected more severely in HD than in PDdys, despite comparable cognitive status. Patient-proxy agreement on ADL impairment was roughly similar in all clinical groups. The results are discussed in the context of orbitofrontal-limbic pathology as a potential trigger of anosognosia/anosodiaphoria in individuals with HD.

The genetic factors studied were not associated with cognitive status in PD patients. Only age and Hcy plasma levels were found to be independent risk factors predisposing individuals to PD dementia. However, COMT: rs4680: A>G and rs4633: C>T polymorphisms were found to significantly affect PD risk, and the MTHFR 677C>T polymorphism helped determine plasma Hcy concentrations.

Huntington disease patients underestimate memory dysfunction. These results add to the previous reports on poor insight in HD in other domains and suggest that anosognosia in HD, albeit usually rather mild, may be a generalized phenomenon.