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

Abstract

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.

What do people respond to when rating executive function? – a cognitive interviewing investigation of BRIEF-A informant ratings in severe aphasia

“…There are both theoretical and empirical reasons to believe that executive function, as measured with standardised neuropsychological tests, is important to functional communication in severe aphasia [17][18][19]. However, the aspects of executive function that are important to functional communication seem not to be captured by BRIEF-A informant ratings [32].…”

“…In addition, the results of the BRIEF-A ratings did not show any relationship to functional communication. Relationships between functional communication and executive function, when measured with neuropsychological tests, have been previously reported [17,18]. Thus, BRIEF-A does not seem to be sensitive to the aspects of executive function that are important to functional communication.…”

“…Persons with severe aphasia (PWSA) have severely limited or absent verbal output, paired with varying levels of language comprehension impairment. In stroke survivors with severe aphasia, an additional executive dysfunction has negative impact on quality of life [15], language rehabilitation outcome [16] and functional communication [17,18]. In severe aphasia, the individuals need to have the strategic competence to bypass their limitations by using compensatory strategies as well as making the most out of the limited linguistic ability they have [19], in order to make themselves understood.…”

The verbal, non-verbal and structural bases of functional communication abilities in aphasia

“…Previous research has used tests or rating scales to elucidate the relationship between functional communication and language impairments ( Irwin et al , 2002 ) and/or other cognitive impairments ( Fridriksson et al , 2006 ; Fucetola et al , 2006 ; Purdy and Koch, 2006 ; Murray, 2012 ; Meier et al , 2017 ; Olsson et al , 2019 ; Spitzer et al , 2019 ), as well as to assess or predict the outcome after stroke ( van de Sandt-Koenderman et al , 2008 ; Blom-Smink et al , 2017 ). Unsurprisingly, a close association between functional communication and the severity of the language impairment ( Fucetola et al , 2006 ; Meier et al , 2017 ), especially with phonology or speech production abilities ( Irwin et al , 2002 ; Fridriksson et al , 2006 ; Blom-Smink et al , 2017 ), is usually reported.…”

“…Thus, some of the inconsistencies in previous findings could stem from differences between functional communication measures and their ability to grade all levels of remaining communication ability. Second, functional communication abilities have been compared with either an overall measure of verbal or non-verbal impairment severity (composite scores of several tests/screening measure; van de Sandt-Koenderman et al , 2008 ; Meier et al , 2017 ; Olsson et al , 2019 ), or to performance in individual tests ( Fridriksson et al , 2006 ; Purdy and Koch, 2006 ; Murray, 2012 ). Thus, a more detailed consideration of how functional communication relates to the different components of patients’ verbal and non-verbal cognitive profiles is needed.…”