Cognitive intervention (CI) has been known to improve cognition and to delay cognitive decline. However, the previous CI was mostly provided as a group session. Therefore elderly with subjective memory complaints (SMC) have difficulty in regularly attending sessions or participating in group-based classes. Additionally, experienced instructors for traditional CI may be unavailable in some centers. Considering these reasons, we have developed 23 programs for smartphone-based CI with a chat-bot for those with SMC. The programs included cognitive training programs for attention, memory, visuospatial, calculation, language and frontal executive functions.

A single-blind randomized controlled trial was conducted in 72 elderly with SMC. Participants were randomized into the two groups: the smartphone based CI with chat-bot (n=37) group and control group without CI (control) (n=35) groups. The interventions comprised 60-min-session per day for 12 weeks. The primary outcome was the changes in fractional anisotropy (FA) measured by diffusion tensor imaging while the secondary outcome was the changes of cognitive function measured using the Cambridge Neuropsychological Test Automated Battery. Tract-based spatial statistics analysis was used to compare the changes of diffusion values between the two groups.

There were no baseline demographic and clinical differences between the CI and the control groups. After a 12-week CI, the CI group showed increased FA on several association fibers including superior longitudinal fasciculus than the control group. In addition CI group also demonstrated improvement in the memory and frontal executive function than the control group.

This suggests that the smartphone based CI with a chat-bot could help improve the memory and frontal executive function in older adults with SMC, which might be associated with the changes of white matter integrity.