Design fluency subsequent to onset of aphasia: a distinct pattern of executive function difficulties?

ABSTRACT

Background: Executive function problems commonly co-occur with aphasia and influence language and communication performance as well as aphasia treatment outcomes and prognosis. Prior research, however, has focused on a restricted set of executive skills.

Aims: This study examined further the integrity of executive functioning and its relationship to language performance in individuals with aphasia by utilising a design fluency measure, which assesses executive skills like initiation, planning, and cognitive flexibility. To examine domain-general versus domain-specific executive problems and determine the distinctiveness of the aphasic group’s performance pattern, adults with right hemisphere brain damage (RHD) were included. The hypotheses examined were: (a) compared to adults with no brain damage, the aphasic and RHD groups would display design fluency impairments; (b) the design fluency performances of aphasic and RHD groups would be quantitatively but not qualitatively similar; and (c) the design fluency performances of the aphasic and RHD groups would be related to their language abilities, as well as their performance of other executive and cognitive measures.

Methods and Procedures: Participants with aphasia, RHD, or no brain damage completed the Ruff Figural Fluency Test (RFFT; Ruff, 1996), the results of which were quantitatively (i.e., number of unique designs, a perseverative error ratio) and qualitatively analysed (i.e., number and maximum length of orderly patterns, design complexity, number, and types of non-repetition errors), along with a formal cognitive-linguistic test battery and a verbal fluency task.

Outcomes and Results: The traditional, quantitative RFFT scores of the aphasia, and RHD groups were significantly lower than those of the control group. Only the RHD group significantly differed from the control group when qualitative RFFT variables were analysed. RFFT performances correlated with language and other cognitive test scores, with some differences in the number and nature of these associations across the aphasic and RHD groups.

Conclusions: The current design fluency findings indicated that executive function deficits involving initiation, planning, self-monitoring, and cognitive flexibility commonly co-occur with aphasia. These results supported previous research by identifying executive function impairments in many, however, not all individuals with aphasia, and by confirming influential associations between executive function and language, and communication measures. Inclusion of individuals with RHD indicated that such executive function difficulties and a potent relationship between executive functioning and language skills are not only unique to those with aphasia but also prevalent in other patient populations and consistent with the contribution of domain-general factors in acquired cognitive impairments.

KEYWORDS:

• Aphasia
• executive functioning
• design fluency

Acknowledgements

This study was funded in part by RO1-DC03886 from NIDCD, awarded to the author.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

This work was supported by the [RO1-DC03886]; NIDCD; National Institute on Deafness and Other Communication Disorders [RO1-DC03886].