Sentence comprehension deficits in aphasia disorders: A systematic review of mapping therapy

Patients with aphasia (PWA), particularly those with agrammatic aphasia, experience problems in sentence comprehension. Studies have found that Mapping Therapy (MT) can improve sentence processing in PWA. This paper aims to review the literature on therapeutic studies using MT for the treatment of sentence processing in PWA. All studies on the treatment of sentence comprehension using MT were found by searching Cochrane Library, ISI Web of Knowledge, Google Scholar, Pubmed, and Scopus from 1986 until December 2023, with the combination of these search keywords: 'aphasia, sentence, comprehension, mapping therapy, treatment, rehabilitation'. All studies (single-subject or group design) on the treatment of sentence comprehension using MT in PWA were reviewed. An adaptation of the Cochrane Collaboration's risk of bias (RoB) tool was used to assess the risk of bias (RoB) in the reviewed studies. A total of 14 studies on 81 participants were selected and reviewed. All studies (13 studies) had employed a single-subject design, except for one study that had used a group design. Twelve studies (86%) showed that MT is effective in the remediation of sentence comprehension in PWA. Generalization to untrained sentences similar to the trained structure was also observed in 12 studies (86%). Generalization to untrained structures (usually passive sentences) was limited. In addition, cross-modal improvement in sentence production was observed in 8 studies (57%). This review highlights the need for a more detailed investigation of the effect of MT on cross-modal generalization using elicited production of the sentence types trained during comprehension treatment.