Ladan Ghazi Saidi, Zoha Deldar, Ricardo Carrillo-Meza, Kiley Allgood, Alison Gansemer, Mariah Gentz, Amor Sofia Calderón-Hernández, Yunju Im, Cary R Savage, Douglas H Schultz
The available evidence suggests that adult L2 learning engages dynamic and use-dependent neuroplastic processes, characterized by an interaction between functional reorganization and more gradual structural adaptation. While the adult brain retains a notable capacity for learning-related change, the expression of plasticity appears sensitive to age, training intensity, and methodological factors. Functional reorganization may represent a relatively preserved marker of plasticity in later adulthood. However, claims regarding durable structural change and cognitive reserve require further longitudinal investigation.
INTRODUCTION: Given cognitive benefits observed in lifelong bilinguals, a key question is whether L2 learning can boost cognition in later life.
METHODS: In a pre-post intervention study, we assessed cognitive effects of learning a new language in older adults as measured by global cognition and domain-specific cognitive tests.
RESULTS AND DISCUSSION: While the MMSE, MoCA, and domain-specific measures (Stroop, Simon, nonword repetition, phonemic fluency, and semantic fluency) did not show significant whole-group pre-post change, a number of individual participants improved on all or some of these measures. Further, both linear regression and machine learning models indicated that participants with lower baseline scores on the MMSE, MoCA, phonemic fluency, and semantic fluency showed greater improvement in post-intervention measurements, reflecting greater cognitive gains, with phonemic fluency emerging as the best predictor of intervention outcome. A post hoc, adherence-sensitive analysis further indicated a +1.225-point MoCA advantage in completers relative to non-completers, consistent with an adherence-associated pattern. Machine learning analyses confirmed that cognitive gains were heterogeneous across participants and that the most responsive outcomes were reaction-time-based executive measures, particularly the Stroop task and Symbol Digit Substitution Test (SDST). Cluster analysis showed that the top improver profile combined lower baseline executive performance with markedly higher engagement and lesson completion.
CONCLUSION: These results provide preliminary evidence that engagement in a structured and sustained L2-learning program may be associated with measurable pre-post cognitive changes in some older adults, especially when baseline performance leaves room for improvement. Further, high intervention adherence and engagement are critical to the extent of cognitive benefits derived from L2 learning interventions. Clinically, structured language learning programs that emphasize adherence, dose, and fidelity appear promising for older adults, especially those with emerging decline. These results are noteworthy, given the scarcity of effective options to improve cognitive health in aging, and the fact that L2 learning is low-cost and broadly accessible.