Morpho-syntactic processing of Arabic plurals after aphasia: dissecting lexical meaning from morpho-syntax within word boundaries

Within the domain of inflectional morpho-syntax, differential processing of regular and irregular forms has been found in healthy speakers and in aphasia. One view assumes that irregular forms are retrieved as full entities, while regular forms are compiled on-line. An alternative view holds that a single mechanism oversees regular and irregular forms. Arabic offers an opportunity to study this phenomenon, as Arabic nouns contain a consonantal root, delivering lexical meaning, and a vocalic pattern, delivering syntactic information, such as gender and number. The aim of this study is to investigate morpho-syntactic processing of regular (sound) and irregular (broken) Arabic plurals in patients with morpho-syntactic impairment. Three participants with acquired agrammatic aphasia produced plural forms in a picture-naming task. We measured overall response accuracy, then analysed lexical errors and morpho-syntactic errors, separately. Error analysis revealed different patterns of morpho-syntactic errors depending on the type of pluralization (sound vs broken). Omissions formed the vast majority of errors in sound plurals, while substitution was the only error mechanism that occurred in broken plurals. The dissociation was statistically significant for retrieval of morpho-syntactic information (vocalic pattern) but not for lexical meaning (consonantal root), suggesting that the participants' selective impairment was an effect of the morpho-syntax of plurals. These results suggest that irregular plurals forms are stored, while regular forms are derived. The current findings support the findings from other languages and provide a new analysis technique for data from languages with non-concatenative morpho-syntax

Clinical features distinguishing angle closure from pseudoplateau versus plateau iris

Purpose: To evaluate clinical aspects of patients with the diagnosis of plateau iris (PI) or pseudoplateau iris (PPI) made by ultrasound biomicroscopy (UBM) in order to determine if there are any clinical factors that can help differentiate between these two entities.Method: A retrospective cohort of consecutive UBM patients with the diagnosis of PI or PPI. The diagnosis of PI was based on an anteriorly positioned ciliary body that abutted the peripheral iris, a narrow (\u3c10 degrees) or closed angle for at least 180 degrees, and the anterior portion of the iris positioned anterior to scleral spur. The diagnosis of PPI was similar to plateau except that large or a cluster of small cysts had to be present in the iridociliary sulcus.Results: There were a total of 76 patients (29% male), 21 with PPI and 55 with PI. Patients with PPI were more likely to be male (p = 0.005), slightly younger (51.5 (SD 10.7) vs 57.9 (10.2) p = 0.0190), have a bumpy peripheral iris appearance (p = 0.003), have greater trabecular meshwork pigmentation (2.0 (0.7) vs 1.3 (0.6) p = 0.004) and have fewer clock hours of gonioscopic angle closure versus plateau iris patients (5.1 (4.3) vs 9.2 (4.2) p = 0.0009). Spherical equivalent was not significantly different between groups (0.50D (1.69) PPI vs 1.33D (2.42) PI; p = 0.187).Conclusions: In patients being referred to a UBM clinic for evaluation of angle-closure mechanism, younger males with a bumpy peripheral iris have a higher likelihood of having a diagnosis of pseudoplateau iris. However, clinical factors do not appear to discriminate well between PPI and PI. UBM is extremely helpful in confirming underlying mechanism and guiding therapy