AGING AND THE LOSS OF GRAMMATICAL FORMS: A CROSS-SECTIONAL STUDY OF LANGUAGE PERFORMANCE; DONNA KYNETTE and SUSAN KEMPER
Current models of language development commonly assume that there are few changes in linguistic ability across the adult years (Menyuk, 1977). This assumption, however, is not based on actual research; as Cohen (1979) observed, 'Geriatric psycholinguistics is virtually an unexplored territory' (p. 412). Some information about adults' linguistic abilities is provided by aphasia test norms.
Typically, the normative data compares the performance of brain-damaged and age-matched normal adults (Schuell et 01., 1964; Swisher and Sarno, 1969; Duffy et 01., 1976; Schewan, 1979; Borod et 01., 1980); this research finds little appreciable decline across the life span on measures of spelling, color and body-part naming,' picture description, sentence repetition, answering general-knowledge questions, and the comprehension of words and simple sentences. The normative data is limited to basic linguistic abilities and to normative samples averaging around 60 years of age (Davis, 1984). Some investigators have examined the performance of adults on tests of specific linguistic forms. Comprehension does appear to drop off in the 60s and 70s for complex syntactic constructions (Walsh and Baldwin, 1977; Feier and Gerstman, 1980). Age-related declines in the ability to draw inferences from texts have also been observed (Cohen, 1979; Taub,
1979; Belmore, 1981; Cohen and Faulkner, 1981). Age-related effects have not typically been observed in sentence production tasks (Nebes and Andrews-Kulis, 1976; Yorkston and Beukelman, 1980; Walker et 01., 1981) although only a limited set of variables, e.g. speed, fluency and clarity, have been investigated.
The following research was undertaken as a detailed investigation of the spontaneous speech of active, healthy adults between the ages of 50 and 90 years. This age range was chosen to compare the performance of middle-aged (50 and 60 year olds) and elderly (70 and 80 year olds) adults (Kausler, 1982). Sixteen different measures of syntactic structure, verb tense, form class, lexical use and disfluency were examined. These variables were chosen to represent a range of linguistic skills and to provide a comprehensive profile of the adults' spoken language. Performance on the lexical and disfluency measures was not expected to vary with age (Schaie, 1980).Performance on the syntactic, tense and form class measures was expected to decline with age, reflecting attentional and memory limitations (Craik, 1977; Kausler, 1982).