A Novel Dual-Language Touch-Screen Intervention to Slow Down Cognitive Decline in Older Adults: A Randomized Controlled Trial

Background and objectives: Bilingualism has been suggested to protect older adults from cognitive aging and delay the onset of dementia. However, no studies have systematically explored bilingual usage as a tool to mitigate age-related cognitive decline. We developed the Dual-Language Intervention in Semantic memory-Computerized (DISC), a novel cognitive training program with three training tasks (object categorization, verbal fluency, and utility of things) designed specifically for older adults that featured two modes: single-language (SL) exposure mode and dual-language (DL) exposure mode.

Research design and methods: The final sample included 50 cognitively healthy (CH; 33 female, M _age = 72.93 years, range = 53.08-87.43 years) and 48 cognitively impaired (CI; 35 female, M _age = 80.93 years, range = 62.31-96.67 years) older adults, randomly assigned them into one of three groups: SL group, DL group, and control group (no training). Participants in SL and DL groups used DISC in either SL mode (i.e., training instructions were spoken in only one language throughout the entire training) or DL mode (i.e., training instructions alternated between two languages), respectively, for 24 sessions. Participants in the control group were asked to continue with their normal daily activities (e.g., playing bingo and reading newspapers).

Results: For CH older adults, we found significant improvements in the Rey Auditory Verbal Learning Test (RAVLT) Trial 5 score and the Clock Drawing Test score in the DL group but not in the SL and control groups posttraining compared with pretraining. For CI older adults, there was a delayed improvement in the RAVLT Trial 1, six months later.

Discussion and implications: Our findings provided novel evidence that implementing DL cognitive training benefits CH older adult's late verbal learning and visuospatial construction skills, and a delayed improvement in CI older adults' early verbal learning abilities.