Functional communication and non-linguistic factors in severe aphasia : Associations and assessment

Severe post-stroke aphasia implies impairment of the ability to speak and write, and impairments of language comprehension, severely restricting the communication of the individual. Intervention in severe aphasia often entails aiming for access to meaningful social interaction and participation, in spite of the linguistic impairments. This demands knowledge about the non-linguistic factors that influence the communication of people with severe aphasia (PWSA). Assessment in PWSA is a challenge due to the linguistic impairments, thus the issue of measurement is intertwined with the study of non-linguistic factors in PWSA. The overall aim of this thesis was to explore the relationship between functional communication, language and three non-linguistic factors; executive function, self-efficacy, and resilience, in PWSA. An additional aim was to investigate the assessment of these non-linguistic factors in PWSA. Studies I and IV were quantitative studies investigating the relations of functional communication and language to executive function (study I), and to self-efficacy and resilience (study IV). In study II, two methods for measuring executive functions were compared; standardised neuropsychological screening and informant reports. Study III was a qualitative study exploring the informants’ understanding of the questionnaire used for informant reports in study II. The results demonstrated that there is large variation in executive function and functional communication in PWSA, especially in the nonverbal subgroup. In this subgroup, there is an association between executive functions and functional communication. It is important that PWSA are given thorough evaluation of their abilities, and that the impact of executive dysfunction is considered in communication intervention. Focusing on assessment of executive functions in PWSA, results of study II and III demonstrated that informant reports of executive function do not measure the same construct as, and cannot be used as a substitute for, standardised neuropsychological tests. The quantitative results of informant reports should be interpreted with caution, since it is uncertain whether the responses represent executive functions. The use of informant reports does not solve the problem of aphasia being a confounding factor in assessment of executive function. Study IV indicated that assessment of self-efficacy and resilience is, with proper adaptation, possible in a majority of PWSA. PWSA seem to have decreased self-efficacy and self-rated resilience compared to general populations. No clear associations with severity of language impairment or functional communication were found, but this issue needs further exploration.