Everyday Functioning in Huntington's Disease: A Laboratory-Based Study of Financial Management Capacity.

One important limitation of prior studies examining functional decline in Huntington's disease (HD) has been the reliance on self-reported measures of ability. Since report-based methods can be biased by lack of insight, depression, and cognitive impairment, contrasting self-reported ability with measures that assess capacity may lead to a more comprehensive estimation of real-world functioning. The present study examined self-reported ability to perform instrumental activities of daily living (iADLs) and performance-based financial management capacity in 20 patients diagnosed with mild-moderate Huntington's disease (HD) and 20 demographically similar healthy adults. HD patients reported significantly greater declines in their ability to manage finances. On the capacity measure of financial management, HD patients performed significantly below healthy adults. Additionally, in the HD group there were no significant correlations between self-reported ability and capacity measures of financial management. HD patients endorsed declines in global iADL ability and exhibited deficits in functional capacity when performing a financial management task. Capacity measures may aid in assessing the extent to which HD patients accurately estimate real-world iADL performance, and the present findings suggest that such measures of capacity may be related to the cognitive, but not motor or affective, symptoms of HD.

The Visual Spatial Learning Test: differential impairment during the premanifest and manifest stages of Huntington's disease.

Visual spatial memory was assessed using the Visual Spatial Learning Test (VSLT) in individuals with mild to moderate Huntington's disease (HD), pre-manifest gene carriers for HD, and demographically similar controls. The VSLT has been demonstrated to be a valid, normed measure of non-verbal memory involving minimal motoric responses. The VSLT assesses immediate and delayed memory for designs, positions of the designs, and design/position associations. The HD group was significantly impaired (p < .05) relative to both the control and Pre-HD groups on immediate and delayed memory for the designs, positions, and design/position associations. Although there were no differences between the Pre-HD and control groups on immediate or delayed memory for designs or positions, the Pre-HD group was significantly impaired (p < .05) relative to the control group on immediate and delayed memory for design/position associations. The results offer novel insight into a relatively unexamined memory deficit that may occur in gene carriers for HD prior to phenoconversion. The data indicate that the VSLT may be a useful measure of visuospatial memory during the premanifest and manifest stages of HD.

"Forgetting to remember" in Huntington's disease: a study of laboratory, semi-naturalistic, and self-perceptions of prospective memory.

Prospective memory (PM) is dependent on executive processes known to be impaired in Huntington's disease (HD); however, no study to the authors' knowledge has investigated PM in this group. We examined performance-based, semi-naturalistic, and self-reported PM in 20 individuals diagnosed with mild-moderate HD and 20 demographically similar controls. Relative to controls, HD participants demonstrated significantly lower scores in time-based PM, event-based PM (at a trend level), and the semi-naturalistic PM trial, all of which were marked by omission errors. HD participants demonstrated comparable recognition memory for the PM intentions relative to controls. HD and control participants also showed comparable scores in self-reported PM complaints. The results suggest that HD is associated with deficits in the strategic aspects of PM. HD-associated PM deficits also are evident in real-world situations, which may relate to an apparent meta-memory deficit for PM functioning as indicated by HD participants' overestimation of their PM performance on self-report.

The effect of interference on temporal order memory in premanifest and manifest Huntington's disease.

BACKGROUND: Frontal-striatal dysfunction has been linked to cognitive impairment in Huntington's disease (HD). The frontal lobes play a role in memory for the temporal order in which items occur in a sequence. However, little is known about temporal order memory in HD or how it may be affected by interference. OBJECTIVE: The study assessed temporal order memory in patients with manifest HD (n = 20), premanifest gene carriers for HD (Pre-HD; n = 18), and controls (n = 25) using a computerized radial 8-arm maze. METHODS: On the sample phase of each trial, participants viewed a random sequence of circles appearing one at a time at the end of each arm. On the choice phase, participants viewed two sample phase circles and chose the circle occurring earliest in the sequence. Manipulations of the temporal lag (defined as the number of circles occurring in the sample phase sequence between the two choice phase circles) were conducted to systematically vary interference. Temporally proximal lags were hypothesized to generate more interference relative to temporally distal lags. RESULTS: The Pre-HD group was significantly impaired (p < 0.05) compared to controls on proximal temporal lags (high interference) but matched controls on distal lags (low interference). HD patients improved as a function of increased lag but demonstrated significant impairments (p < 0.05) across lags relative to controls. CONCLUSIONS: Temporal order memory is differentially affected by interference during the premanifest and manifest stages of HD. The study identifies a fundamental, yet relatively unexamined, deficit associated with HD.