Evidence of a neurologically based “denial of illness” in patients with Huntington's disease

Abstract

Patients diagnosed with Huntington's Disease (HD) commonly show a denial of symptoms and an unawareness of the motoric, cognitive, and emotional changes that accompany this disease. To examine if this denial has a neurological component to it, 19 patients who received a positive diagnosis of HD from the presymptomatic HD clinic at the University of Connecticut Medical School, and 14 consecutive patients referred for neuropsychological testing with nonHD diagnoses, were administered a simple, eight-item self-report test that asked them to rate their cognitive and motoric abilities. Two staff members, both of whom met with the patients and were familiar with the neuropsychological test results, similarly rated the patients' deficits. HD patients were then divided into “high” (HA) vs. “low” (LA) anosognosia groups based on differences between their self-ratings and staff ratings, and given a neuropsychological battery. Correlation's between the two investigators found that the eight-item scale was highly reliable across investigators (R = .89). HD patients were significantly different from controls in their self-rating of their own capabilities in comparison to staff ratings (p < .05). ANOVA found the HA HD patients to be impaired relative to the LA HD group on a number of neuropsychological measures, including the Wisconsin Card Sorting Test and various measures pertaining to visual-spatial ability on the Wechsler Adult Intelligence Scale — Revised. These findings suggest that a component of the “illness denial” that HD patients exhibit, and that traditionally have been attributed to “psychodynamic” factors, likely have a neurological component to them. Implications of these findings for teams who are preparing to provide anosognostic HD patients with positive results regarding their HD workup is discussed.