Abstract
INTRODUCTION: Instruments for the assessment of syntax in Brazilian Portuguese remain scarce, despite their crucial role in identifying comprehension and production deficits in clinical populations. This study aimed to develop a computerized version of the Test for the Assessment of Syntactic Processing in Comprehension (TASComp) and to investigate validity evidence related to sentence reading comprehension among Brazilian adults. METHODS: Procedures included stimulus adaptation for the PsyToolkit platform, content validation by expert judges, and psychometric analyses of a final version administered to 102 healthy adults, stratified by in-person (n = 45) and online (n = 57) administration modalities. RESULTS: The TASComp demonstrated satisfactory content validity, with a Scale Content Validity Index (S-CVI) of 0.87 and adequate internal consistency (KR-20 = 0.66). Syntactic complexity effects were confirmed by significant differences in the results of reversible passives vs. irreversible (t = 3.08, p = 0.003, d = 0.31), object clefts vs. subject clefts (t = 5.30, p < 0.001, d = 0.53), and center-embedded vs. right-branching relatives for both subject clauses (t = 6.80, p < 0.001, d = 0.67) and object clauses (t = 3.52, p = 0.001, d = 0.35). Additionally, right-branching subject relatives were more accurate than right-branching object relatives (t = 3,78; p < 0.001, d = 0.37). No significant differences in accuracy were found between in-person and online administration modalities across all sentence types (p > 0.05). The beta regression model revealed that years of education (χ2 (1) 35 = 15.74, p < 0.001) and age (χ2 (1) = 7.98, p = 0.01) were significant predictors of comprehension accuracy, while the administration modality was not (χ2 (1) = 0.27, p = 0.61). DISCUSSION: Validity evidence based on response processes was observed, as the instrument successfully discriminated between levels of syntactic complexity, with significant performance differences in structures that impose high working memory demands, such as object clefts and center-embedded and object relative clauses. No significant differences were found between administration modalities (in-person vs. online), indicating that both modes assess sentence reading comprehension without compromising psychometric quality. Furthermore, the findings demonstrate that age and years of education significantly impact syntactic processing and reading comprehension. CONCLUSION: TASComp demonstrates adequate validity of evidence and clinical relevance. The instrument shows promise for detecting subtle language deficits that are often overlooked by other assessments, due to its inclusion of a wide range of 46 complex syntactic structures.