Memory for emotional information in sporadic and Type 8 amyotrophic lateral sclerosis.

Abstract

Objective: Amyotrophic lateral sclerosis (ALS) is often shown to cause episodic memory deficits. Here, we investigated whether such memory deficits are differentially expressed according to the emotional valence of stimuli and whether they are similarly reproduced in both individuals with sporadic ALS (sALS) and familial Type 8 ALS (ALS8). Method: Twenty individuals with sALS, 18 individuals with ALS8, and 19 healthy controls were recruited for the study. After a neuropsychological and psychopathological assessment, all participants responded to a recognition memory test wherein images varying in terms of valence were initially shown. After a short interval, the images were shown again intermixed with new images, and the participants’ task was to indicate whether each image was “old” or “new” and to estimate the confidence in their responses. Results: Both the sALS and the ALS8 groups showed significantly lower recognition of positive relative to negative valence images (d = 0.92 and d = 0.74, respectively), an effect that was completely absent for healthy controls (d = 0.17). These effects were qualified by a significant interaction involving the factors of valence and group (ηp2 = 0.12). Conclusions: The current findings demonstrate that sALS and ALS8 are associated with decreased recognition of emotional information, an effect that is nonetheless restricted to positive valence stimuli.