Education moderates the association between motor involvement and executive status in ALS

Background: This study aimed to determine whether educational attainment-a common proxy of cognitive reserve (CR)-influences the association between motor and cognitive/behavioural outcomes in a large cohort of ALS patients without dementia.

Methods: N = 726 ALS patients without FTD were assessed for motor (ALSFRS-R), cognitive (Edinburgh Cognitive and Behavioural ALS Screen, ECAS) and behavioural outcomes (ECAS-Carer Interview, ECAS-CI). CR was operationalized via educational attainment (in years). Moderation models were run on each subscale of the cognitive section of the ECAS and on the ECAS-CI by addressing ALSFRS-R as the predictor and education as the moderator.

Results: Education was associated with both the ALSFRS-R and all the cognitive subscales of the ECAS, while not with the ECAS-CI. As to moderation models, a significant Education*ALSFRS-R interaction was detected solely with regard to the ECAS-Executive-with its simple slope-based decomposition revealing that higher ALSFRS-R scores were associated with higher scores on the ECAS-Executive for patients with low (p < 0.001) and average (p = 0.007), while not high, levels of education.

Discussion: Education seems to moderate the association between motor involvement and executive status in ALS patients without dementia, thus possibly exerting a protective role towards both motor function and cognition in this population.