The Association between Executive Function and Performing Instrumental Daily Activities in People with Intellectual Disabilities

Institutionalized individuals with intellectual disabilities have few opportunities to participate in instrumental activities of daily living (IADLs), which probably affects higher cognitive functions, or vice versa. The objectives of this study were to evaluate the possible difference in the ability to perform IADLs and executive functioning between individuals with and without intellectual disabilities and to determine if executive functions are associated with the performance of IADLs in people with intellectual disabilities. This was a multi-center cross-sectional study, conducted between July 2019 and May 2020. Participants with intellectual disabilities were recruited from four centers for people with intellectual disabilities. Adults without these disabilities were gathered from several community centers. The sample consisted of 90 individuals with moderate intellectual disabilities and 79 individuals with no intellectual disability. Executive functions were evaluated using the Wechsler Adult Intelligence Scale—WAIS-IV, the INECO Frontal Screening test, the Semantic Verbal Fluency Test, and the Behavioural Assessment of the Dysexecutive Syndrome—BADS—Scale. The performance of the IADLs was assessed by the Lawton and Brody Scale. The results showed that the higher the function in instrumental activities, the lower the impairment of executive functions. Executive functions accounted for 81% of the total variance in the ability to perform the IADLs. In conclusion, individuals with moderate intellectual disabilities demonstrated limitations in executing the IADLs, which were partially associated with low performance in executive functions. This information could help in the development of evidence-based intervention programs and facilitate the formulation of appropriate support strategies to enhance participation in these activities.