Manipulating hemispheric attentional mechanisms to modulate word retrieval in aphasia

Abstract

Background: Emerging evidence suggests that left hemisphere damage may create an attentional bias towards stimuli initially processed in the right hemisphere. Aims: The current study aimed to investigate whether this hemispheric attentional bias influences spoken word production in a picture–word interference task. Methods & Procedures: Two participants with aphasia and seven healthy controls named centrally presented pictures that were preceded by a distractor word which appeared in either the left or right visual field 200 ms prior to the picture. Distractor words were semantically related, phonologically related, unrelated, or the name of the picture. Results were analysed in terms of response times and accuracy. Outcomes & Results: A greater overall facilitation effect was found in the left visual field/right hemisphere condition for both participants with aphasia, however this varied depending on distractor condition. These results are consistent with an attentional bias towards linguistic stimuli initially presented to the right hemisphere. In contrast, the results of the control group suggest a reduction in the lateralisation of language processing to the left hemisphere in healthy ageing. Conclusions: These results suggest that spoken word production may be influenced by changes in attentional mechanisms following left hemisphere damage in aphasia, as well as changes in hemispheric lateralisation and inhibition in healthy ageing. Identifying attentional conditions that optimise language performance in aphasia may have implications for new treatments in language rehabilitation.