Unawareness of Deficits in Huntington's Disease

Abstract

People with Huntington's disease (HD) may show reduced awareness of physical and mental changes in themselves. This article reviews the evidence for loss of awareness (anosognosia) in an attempt to elucidate its characteristics and possible underlying mechanisms. It is shown that defective awareness occurs across domains. People with HD may under-report the presence or severity of involuntary movements, under-estimate cognitive impairment and deny behavioural change. Nevertheless, awareness is not all or none. Moreover, it may be affected differentially for different symptom domains and emerge at different stages of disease, raising the possibility of distinct contributory mechanisms. Findings of an inverse relationship between insight and severity of disease suggest that cognitive impairment, in particular executive dysfunction, may be an important contributory factor. Evidence has accrued to support this argument. However, cognitive impairment cannot fully account for patients' lack of awareness of involuntary movements. Findings that patients accurately report consequences but not the experience of involuntary movements, and better acknowledge their presence when watching videotapes of themselves suggests that physiological factors play an important role. The putative role of denial as a coping mechanism is discussed. Recognition by clinicians of deficient self-awareness is crucial because of its implications for diagnosis and optimal clinical management of HD.

Clinical Management of Neuropsychiatric Symptoms of Huntington Disease: Expert-Based Consensus Guidelines on Agitation, Anxiety, Apathy, Psychosis and Sleep Disorders

“…There were commonalities across all five symptom domains considered, and these can be considered 'general principles' in the management of neuropsychiatric symptoms in HD. For example, it is recommended to obtain information from both the patient and the carer, as it is well known that people with HD may have impaired awareness of their condition [25,26]. As in any other neurologic and/or psychiatric illness, the identification and treatment of co-morbid medical conditions and possible environmental triggers are always key factors to address in the management of all neuropsychiatric symptoms associated with HD.…”

Self-awareness and the medial temporal lobe in neurodegenerative diseases

“…Patients with neurodegenerative diseases tend to overestimate their functional abilities in various domains (e.g. cognition, behaviour, socio-emotion, daily life activities) (Eslinger et al, 2005;Roberts et al, 2009, Sitek et al, 2014and Starkstein, 2014 for reviews).…”

NeuroQuery, comprehensive meta-analysis of human brain mapping

“…Moreover, some concepts of interest may not have been investigated by themselves, or only in very few studies: rare diseases, or tasks involving a combination of mental processes that have not been studied together. For instance, there is evidence of agnosia in Huntington's disease [Sitek et al, 2014], but it has not been studied with brain imaging. To compile a brain map from the literature for such queries, it is necessary to interpolate between studies only partly related to the query.…”