Description
Previous research examining cognitive changes in manifest Huntington’s disease (HD) relative to healthy adults (HA) using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) revealed significantly lower total index scores for the HD group and most impairment in the Attention index. To our knowledge, our study is the first to measure cognitive changes in premanifest gene carriers for Huntington’s disease (PreHD), HD, and HA using the RBANS. Archival data were used in this study. Participants included 34 clinically diagnosed HD patients, 32 premanifest gene carriers for HD, and 25 demographically similar healthy adults. Participants were administered RBANS using standard procedures. Age-corrected index scores and total index scores were used as the dependent variables in our analyses. A one-way ANOVA was used to examine group differences in RBANS total scale of index scores (TSIS). A subsequent post-hoc Tukey test was used to explore specific differences between groups. A MANOVA test was used to examine group differences in RBANS cognitive domain index scores. Subsequent one-way ANOVAs were used to examine specific differences between groups. The effect size estimates for group differences were calculated using Cohen’s d. A one-way ANOVA revealed a main effect of group on RBANS TSIS. A Post-hoc test displayed significantly higher TSIS for HA and PreHD groups relative to HD group. No differences were found between HA and PreHD groups. A MANOVA revealed a main effect of group on RBANS domain index scores and subtest scores. Post-hoc analyses revealed HA and PreHD groups significantly outperformed the HD group in all domain indices, and all subtests except Picture Naming. Although statistical significance was not found between HA and PreHD groups, results from Cohen’s d effect size estimates showed moderate effect sizes. While RBANS is useful in detecting cognitive changes in manifest HD, further examination is required to examine the utility of RBANS for measuring cognitive changes during the premanifest stages. The moderate effect sizes found between HA and PreHD groups warrant future studies involving a larger sample. Moreover, the subtle cognitive deficits associated with PreHD warrant further exploration into the longitudinal cognitive changes in this group using RBANS.
