Enhanced performance on a sentence comprehension task in congenitally blind adults

People born blind habitually experience linguistic utterances in the absence of visual cues. Neuroimaging evidence suggests that congenitally blind individuals also activate "visual" cortices during sentence comprehension. Do blind individuals show superior performance on sentence processing tasks? Congenitally blind (n = 25) and age and education matched sighted (n = 52) participants answered yes/no who-did-what-to-whom questions for auditorily presented sentences, some of which contained a grammatical complexity manipulation (long-distance movement dependency or garden path). Short-term memory was measured with a forward and backward letter-span task. A battery of control tasks included two speeded math tasks and vocabulary and reading tasks from Woodcock Johnson III. The blind group outperformed the sighted group on the sentence comprehension task, particularly for garden-path sentences, and on short-term memory span tasks, but performed similar to the sighted group on control tasks. Sentence comprehension performance was not correlated with working memory span performance, suggesting independent enhancements.