Relations between executive function, language, and functional communication in severe aphasia

Background: Intervention in severe aphasia often means aiming for access to meaningful social interaction in spite of linguistic barriers that might not be treatable. This demands knowledge about the different factors that influence functional communication. Apart from linguistic ability, executive functions are thought to play an important role. Aims: To expand the understanding of the relations of executive functions and linguistic ability to functional communication in severe aphasia. Methods and Procedures: Executive functions, linguistic ability, and functional communication were assessed in 47 participants with severe aphasia. The results were analysed for the total sample and for a verbal and a nonverbal subgroup. Outcomes and Results: Impairment of executive function was found in 79% of the participants. There were moderate to strong correlations between all subtests of executive functions and linguistic ability. In the total sample, significant partial correlation was found between functional communication and verbal output. In the nonverbal subgroup, there was a significant partial correlation between executive function and functional communication, when controlling for linguistic ability. In the verbal subgroup, no relations were found between executive functions or language and functional communication. Conclusions: Impairments of executive functions are common in people with severe aphasia, and executive function and linguistic ability are closely related. The ability to produce verbal output is strongly related to functional communication, but in people with extreme limitation or total absence of verbal output, executive functions seem to be an important factor for functional communication. There is a large variation of executive functions and functional communication in people with severe aphasia, especially in the nonverbal subgroup. It is important that people with severe aphasia are given a complete and proper evaluation of their abilities, and that the possible importance of executive function to communication is considered in communication intervention.