Cognitive and memory training in adults at risk of dementia: A Systematic Review
1 School of Psychiatry, University of New South Wales, RandwickNSW 2031, Australia
2 Brain and Aging Research Program, University of New South Wales, Randwick NSW 2031, Australia
3 Regenerative Neuroscience Group, School of Psychiatry, University of New South Wales, Randwick NSW 2031, Australia
4 Neuropsychiatric Institute, Prince of Wales Hospital, Randwick NSW 2031, Australia
5 Exercise Health and Performance Faculty Research Group, Sydney Medical School, The University of Sydney, Lidcombe NSW 2141, Australia
6 Hebrew Senior Life, Boston, MA, and Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston 02130, MA, USA
BMC Geriatrics 2011, 11:55 doi:10.1186/1471-2318-11-55Published: 25 September 2011
Effective non-pharmacological cognitive interventions to prevent Alzheimer's dementia or slow its progression are an urgent international priority. The aim of this review was to evaluate cognitive training trials in individuals with mild cognitive impairment (MCI), and evaluate the efficacy of training in memory strategies or cognitive exercises to determine if cognitive training could benefit individuals at risk of developing dementia.
A systematic review of eligible trials was undertaken, followed by effect size analysis. Cognitive training was differentiated from other cognitive interventions not meeting generally accepted definitions, and included both cognitive exercises and memory strategies.
Ten studies enrolling a total of 305 subjects met criteria for cognitive training in MCI. Only five of the studies were randomized controlled trials. Meta-analysis was not considered appropriate due to the heterogeneity of interventions. Moderate effects on memory outcomes were identified in seven trials. Cognitive exercises (relative effect sizes ranged from .10 to 1.21) may lead to greater benefits than memory strategies (.88 to -1.18) on memory.
Previous conclusions of a lack of efficacy for cognitive training in MCI may have been influenced by not clearly defining the intervention. Our systematic review found that cognitive exercises can produce moderate-to-large beneficial effects on memory-related outcomes. However, the number of high quality RCTs remains low, and so further trials must be a priority. Several suggestions for the better design of cognitive training trials are provided.