Poster 23: Characterization of Frontal Lobe Behavioral Syndromes in Huntington's Disease (HD)

Abstract

Frontal lobe changes are a common feature of Huntington's disease (HD). The Frontal Systems Behavior Scale (FrSBe; Grace & Malloy, 2001) is a rating scale that measures behaviors associated with frontal lobe damage. Three behavioral syndromes—apathy, disinhibition, and executive dysfunction—are quantified as subscales. The FrSBe can be used to discriminate patterns of frontal impairment at two different time points (i.e., Before Diagnosis and Current). In the present study, 24 HD patients completed the FrSBe self-report form. Raw scores were converted into z-scores based on previously reported norms (Grace & Malloy, 2001). Paired t-tests were conducted to test for differences in Before Diagnosis and Current self-ratings on all three subscales. Change scores were calculated by subtracting the Before Diagnosis ratings from the Current ratings for each subscale. Paired t-test analyses revealed that ratings were significantly different for all three subscales: apathy (t = −5.58, p p p after the diagnosis of HD as compared to before diagnosis. The overall magnitude of the change was largest in the domain of apathy (mean z-score change = 2.69), followed by executive dysfunction (mean z-score change = 1.46), and disinhibition (mean z-score change = 0.62). Generally, apathy, executive dysfunction, and disinhibition ratings before HD diagnosis appear similar to that of a non-clinical sample and fall within normal range. HD patients report elevated rates of apathy, executive dysfunction, and disinhibition symptoms after diagnosis. Overall, behaviors associated with frontal lobe damage appear to be prominent in HD, and these findings suggest that the greatest change, according to patient ratings, may occur within the domain of apathy.