The Age-of-Acquisition Effect in Patients with Language Impairments

The age of acquisition (AoA) effect refers to the finding that words learned early in life are processed faster than words learned later in life. The influence of AoA has been found using many tasks, including picture naming, lexical decision, and eye-tracking methodology (Juhasz, 2005). Patients with language impairments such as aphasia, Alzheimer’s disease, dyslexia, dysgraphia, and those who have received an anterior temporal lobectomy are all influenced by AoA. The words that these patients successfully produce are often early-acquired, and when an error is committed, it is usually the result of a failure to retrieve a later-acquired word, suggesting that early-acquired words are better preserved in the mental lexicon than later-acquired words. The robust AoA effects found in these patient populations suggest that it could be an important tool for making more accurate diagnoses and constructing more effective treatment plans. The studies described in this review also shed light on