Individual differences in autistic children’s homograph reading: Evidence from Hebrew

Background and aims:On average, autistic individuals make more errors than control participants when reading aloudsentences containing heterophonic homographs—written words with multiple meanings and pronunciations. This findingis widely interpreted within the framework of ‘‘weak central coherence’’ as evidence for impaired sentence-level com-prehension resulting in a failure to disambiguate the homograph meaning. However, consistent findings at the group levelbelie considerable individual variation. Our aim here was to determine whether that variation was reliable and whether itcould be predicted.Methods:We developed a Hebrew version of the homograph-reading test, containing many more items than is possiblein English. The test was administered to 18 native-Hebrew speaking autistic children and adolescents, along with abattery of reading and language assessments.Results:Participants with autism showed wide individual variation in performance on the homograph-reading task.Using a mixed random effects logistic regression analysis, we showed that measures of autism severity, single wordreading, and single word comprehension all left reliable individual variation unaccounted for and none accounted forvariation beyond that associated with the child’s age. Instead, homograph reading was best predicted by performance ona picture naming task, which accounted for unique variation beyond age and each of the other predictors.Conclusions:Poor performance of autistic individuals on the English version of the homograph-reading task has untilnow been characterized as evidence for a comprehension deficit in autism. However, the results of the current study leadus to propose a new working hypothesis—that difficulties affecting some autistic individuals reflect impairment in the useof semantics to guide the selection of the appropriate phonological form during speech production. This hypothesis isconsistent with the strong association between homograph reading and picture naming. It may also help explain theinconsistent pattern of results across studies using different measures of linguistic ‘‘central coherence.’’Implications:The results of this preliminary study should be replicated before firm conclusions are drawn.Nonetheless, the study serves to emphasize the importance of considering within-group as well as between-groupvariations in studies of autism. It also provides a worked example showing how mixed random effect analyses can beused to explore individual differences, distinguishing between genuine variation and psychometric noise