Persian Adaptation of the SOAP Test of Sentence Comprehension

Purpose: Individuals with aphasia often struggle with comprehension, particularly for complex sentences where word order deviates from the language's expected word order (i.e., is noncanonical). Here, a valid measure sensitive to sentence-level comprehension impairments in English-speaking individuals with aphasia, the SOAP (Subject-relative, Object-relative, Active, Passive) test, was adapted and validated for Persian (P-SOAP). Method: The P-SOAP is a sentence–picture matching task with 45 sentences, each paired with three pictures (two semantically reversible and one distractor image) and adapted from English for the current study. In a case–control within-subject study, seven Persian speakers with aphasia (PswA) and seven neurotypical (control) participants heard sentences and chose the image that correctly depicted the sentence. Comprehension accuracy was compared across sentence types and participant groups. Results: All PswA showed significantly lower and at-chance accuracy compared to control participants on noncanonical sentences (averaging 56%–64% across passive and object-relative sentences), with higher performance that did not reliably differ between PswA and controls for canonical sentences (averaging 81%–82% across actives and subject-relatives). Conclusion: As was found in the English version of the test, the P-SOAP revealed impairment in sentence comprehension in PswA when syntactic complexity was higher, while control participants had high accuracy on all sentence types. Therefore, the P-SOAP can be employed in PswA to diagnose sentence-level comprehension impairments and thus opens avenues toward more targeted treatment.