Awareness of Memory Deficits in Early Stage Huntington's Disease

Abstract

Patients with Huntington's disease (HD) are often described as unaware of their motor symptoms, their behavioral disorders or their cognitive deficits, including memory. Nevertheless, because patients with Parkinson's disease (PD) remain aware of their memory deficits despite striatal dysfunction, we hypothesize that early stage HD patients in whom degeneration predominates in the striatum can accurately judge their own memory disorders whereas more advanced patients cannot. In order to test our hypothesis, we compared subjective questionnaires of memory deficits (in HD patients and in their proxies) and objective measures of memory dysfunction in patients. Forty-six patients with manifest HD attending the out-patient department of the French National Reference Center for HD and thirty-three proxies were enrolled. We found that HD patients at an early stage of the disease (Stage 1) were more accurate than their proxies at evaluating their own memory deficits, independently from their depression level. The proxies were more influenced by patients' functional decline rather than by patients' memory deficits. Patients with moderate disease (Stage 2) misestimated their memory deficits compared to their proxies, whose judgment was nonetheless influenced by the severity of both functional decline and depression. Contrasting subjective memory ratings from the patients and their objective memory performance, we demonstrate that although HD patients are often reported to be unaware of their neurological, cognitive and behavioral symptoms, it is not the case for memory deficits at an early stage. Loss of awareness of memory deficits in HD is associated with the severity of the disease in terms of CAG repeats, functional decline, motor dysfunction and cognitive impairment, including memory deficits and executive dysfunction.