Longitudinal Trajectories and Normative Language Standards in Older Adults With Normal Cognitive Status

Abstract

Objective: To determine the longitudinal trajectories and normative standards of language in older adults. Method: Participants were drawn from the cognitively normal (CN) subgroup of the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD) cohort, a fairly representative cohort of the older Greek population. Language was assessed via semantic (SVF) and phonemic verbal fluency (PVF), Boston Naming Test–short form (BNT-sf), verbal comprehension and repetition, and a composite language z-score. Both baseline and longitudinal associations of language performance with age, sex, and education were explored with linear regression and generalized estimated equations. Results: A total of 1,607 individuals (73.82 years ± 5.43, 60% women), with a mean educational attainment of 8.17 years (±4.86) were CN at baseline. Baseline analysis revealed a continuum of language decline with higher age and lower educational attainment. Women performed better in composite and SVF tasks. A subgroup of 761 participants with available assessments after 3.07 years remained CN at follow-up. Each additional year of education mitigated composite language decline by.004 of a SD per year. Education additionally mitigated yearly reductions in SVF (by.049) and repetition (by.018) totals. Intriguingly, educational attainment was inversely related to the rate of PVF decline over time (β = −.063). Women exhibited a more precipitous course of decline in SVF totals (.355 per year). Age was not related to differential rates of language decline in any measure. No significant longitudinal associations emerged for comprehension and BNT-sf. Conclusions: Lower educational attainment (but not aging) was associated with steeper language decline, mainly driven by SVF and verbal repetition. © 2022 American Psychological Association