Using the LASSI-L to Detect Robust Interference Effects in Premanifest Huntington Disease.

ABSTRACT

BACKGROUND: Diagnosis of manifest Huntington disease (HD) is based primarily on motor symptoms, but premanifest HD (preHD) is often associated with subtle cognitive decline. The Loewenstein-Acevedo Scales for Semantic Interference and Learning (LASSI-L) is a validated verbal learning test that can be used to detect early cognitive decline. OBJECTIVE: To determine the utility of the LASSI-L for detecting early cognitive decline in individuals with preHD and to compare the results of the LASSI-L with those of commonly used neuropsychological tests in HD. METHOD: We administered the LASSI-L to 13 individuals with preHD and 13 healthy controls matched for age, sex, and education as part of a longitudinal study of disease progression. For comparison purposes, we administered the Mini-Mental State Examination; Stroop Color and Word Test; Symbol Digit Modalities Test; Trail-Making Test, Parts A and B; and category fluency (animals) task. RESULTS: Five of the seven sections on the LASSI-L captured group differences Proactive Semantic Interference (PSI; P < 0.001), Failure to Recover From PSI ( P = 0.038), Retroactive Semantic Interference (RSI; P = 0.013), Delayed Recall ( P < 0.001), and B1 Cued Recall Intrusions ( P = 0.036). Using a false discovery rate of <0.05, PSI, RSI, and Delayed Recall remained significant. CONCLUSION: The LASSI-L is a sensitive instrument for detecting early interference effects in individuals with preHD that outperforms commonly used neuropsychological tests. The LASSI-L could be a useful addition to clinical and research protocols involving individuals with preHD.