The effects of age of language acquisition on verbal memory tests in a sample of older adults immigrants

The present study investigated the effect of age of language acquisition (ALA) and language usage (LU) on neuropsychological measures that purportedly assess working memory and episodic memory. A random sample of 196 elderly Israelis were administered the California Verbal Learning Test (CVLT-II), Wechsler's Logical Memory Test (LMT), Boston Naming Test (BNT), Wechsler's Digit Span Test (DST), and the Mini Mental Status Exam (MMSE) as part of a large normative study. Analysis of the data shows that ALA predicted the performance on the first trial of the word list learning (CVLT-II) but none of the other indexes. It also predicted the performance on the BNT and to some degree the performance on the DST. LU correlated with the delayed word list free recall but none of the other word list indexes. On a task that requires the recall of stories (LMT), level of education was the best predictor of both the immediate and delayed recall scores. Additional analysis showed that when subjects are divided into early (before the age of 16) and late ALA, differences in performance on LMT, a measure that requires higher order lexical processing, emerged. The results of this study demonstrate that when assessing memory functions in immigrant populations, the language in which the task is administered and the age of language acquisition should be taken into account, particularly if the immigrant acquired the host country language after the age of 16.