Preserving Prospective Memory in Daily Life: A Systematic Review and Meta-Analysis of Mnemonic Strategy, Cognitive Training, External Memory Aid, and Combination Interventions

Objective: To preserve or improve independent functioning in older adults and those with neurocognitive impairments, researchers and clinicians need to address prospective memory deficits. To be effective, prospective memory interventions must restore (or circumvent) the underlying attention and memory mechanisms that are impaired by aging, brain injury, and neurodegeneration. We evaluated two decades of prospective memory interventions for efficacy, time/resource costs, and ecological validity. Method: We systematically reviewed 73 prospective memory intervention studies of middle- to older-aged healthy adults and clinical groups (N = 3,749). We also rated the ecological validity of each study's prospective memory assessment/task using a newly developed scale. When possible (72% of studies), we estimated effect sizes using random-effects models and Hedges' g. Results: We identified four categories of prospective memory interventions, including mnemonic strategy, cognitive training, external memory aid, and combination interventions. Mnemonic strategy (g = .450) and cognitive training (g = .538) interventions demonstrated efficacy. Combination interventions showed mixed results (g = .254), underscoring that "more is not always better." External memory aids demonstrated very positive outcomes (g = .805), though often with small-sample, case-series designs. Prospective memory assessments had high ecological validity in external memory aid studies (84%), but not in mnemonic strategy (14%), cognitive training (20%), or combination intervention (50%) studies, p = .001, eta(2)(p) = .33. Conclusions: Everyday prospective memory can be meaningfully improved, perhaps particularly with external memory aids, but larger trials are required to optimize treatments, increase adherence, and broaden implementation in daily life.