Abstract
PURPOSE: This study had three objectives: (a) to verify if Grodzinsky et al.'s (1993) findings of worse comprehension of personal than reflexive pronouns can be replicated in a larger meta-analysis of individual participant data, (b) to examine if the heterogeneity found in the patterns of pronoun comprehension in agrammatism can be attributed to task effects, and (c) to evaluate the risk of bias in the reviewed studies. METHOD: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic literature search was performed to identify studies examining the personal-reflexive pronoun dissociation in agrammatic comprehension. Seven studies met the search criteria and were included in the meta-analysis. For each participant, individual accuracy scores for the comprehension of personal and reflexive pronouns were extracted in addition to information on the study methods. Individual accuracy data were analyzed using the Fisher's exact test and the binomial test. The risk of bias in the studies was assessed using an adapted version of the Newcastle-Ottawa Quality Assessment Scale. RESULTS: The meta-analysis had three main findings: (a) The majority of the persons with agrammatic aphasia (89%) had no dissociation between the comprehension of personal and reflexive pronouns; (b) 8% revealed a pattern consistent with a neuropsychological dissociation, faring worse on the comprehension of personal than reflexive pronouns; and (c) 2% performed worse on reflexive than personal pronouns. The type of the task used affected pronoun comprehension accuracy and accounted for the heterogeneity in the patterns of pronoun comprehension attested across the different participants. CONCLUSIONS: Taken together, the meta-analysis did not support a dissociation between personal and reflexive pronoun comprehension in agrammatic comprehension. When confirmed, the dissociation was driven by task effects. The clinical implications of these findings were discussed together with implications to minimize the risk of bias in future examinations of the topic.