Language and Aging

Presenter: Loraine K. Obler, Ph.D.

Language Changes in Healthy and Brain-Damaged Older Adults

Biography

Loraine K. Obler is a Distinguished Professor in the Program in Speech and Hearing Sciences, with a joint appointment in the Linguistics Program, at the City University of New York Graduate School and University Center. In addition, she co-heads the Language in the Aging Brain Laboratory of the Boston University School of Medicine Harold Goodglass Aphasia Research Center at the Boston VA Healthcare Center. In addition to the study of language changes associated with healthy aging and Alzheimer's disease, her research interests include neurolinguistic study of bilingualism, cross-language study of agrammatism, and neuropsychology of talent as it relates to dyslexia and individual differences in second-language acquisition. The books she has co-authored or co-edited include Language and the Brain (with K. Gjerlow, Cambridge University Press, 1999), Language and Communication in the Elderly (with M.L. Albert, D.C. Heath and Co., 1980), Neurobehavior of Language and Cognition: Studies of Normal Aging and Brain Damage (with L. Connor, Kluwer Academic Publishers, 2000), and The Bilingual Brain: Neuropsychological and Neurolinguistic Aspects of Bilingualism (with M.L. Albert, Academic Press, 1978).

Abstract

The language changes seen in healthy aging are subtle because they can be masked in daily interactions; those in people who have brain damage are more striking. The most pronounced language changes associated with healthy aging are those involving lexical retrieval. Significant decline in abilities to locate specific nouns and verbs is seen in group studies by the 8th decade of life, but longitudinal analyses document subtle changes as early as the late 4th decade. The naming decline associated with healthy aging shows substantial variability across individuals and results primarily from difficulty locating the phonological shape of words, although there is evidence of some amount of semantic deterioration, of the type seen more markedly in Alzheimer's Dementia, in the 8th decade as well. Interestingly, early-childhood second-language acquisition seems to delay age-related naming decline in the second language, while later second-language acquisition is associated with second-language attrition over the years.

Comprehension of auditorily presented sentence-length materials declines in healthy older individuals as well, at least from the 6th decade, and this decline cannot be entirely attributed to the hearing decline associated with aging in our society. However, it may more easily be masked in daily communication than the specific-word-retrieval problem, because so much of communication is redundant. By contrast to lexical retrieval and auditory comprehension, other areas of language processing (e.g. metalinguistic abilities, syntax, self-monitoring for speech errors) have not shown age-related decline although some of these abilities are strikingly impaired in Alzheimer's Dementia.

The picture of language decline in Alzheimer's Dementia is one of relative sparing of the most automatic aspects of language: phonology, syntax, reading aloud, while semantically based aspects (e.g., comprehension, speech self-monitoring, word choice) are progressively impaired. Certain low-level pragmatic skills (e.g., formulaic language, eye contact with one's interlocutor) are spared, while others (making inferences, choosing the right language to use with one's interlocutor in the case of bilinguals) deteriorate from middle stages of the disease.

The language changes associated with aphasia manifest somewhat differently at different periods of the life span. The classic aphasia syndromes are associated with older adulthood. Yet unexplained is the finding across a dozen research teams worldwide that stroke-related onset of Broca's aphasia is, on average, a decade earlier than that of Wernicke's aphasia. In bilinguals or polyglots who become aphasic, when differential recovery of their languages is seen, it is the language most used around the time of the aphasia onset that recovers first for individuals under age 65; for older aphasics more variability is seen.

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