A Cluster Randomized Controlled Trial of Nonpharmacological Interventions for Old-Old Subjects with a Clinical Dementia Rating of 0.5: The Kurihara Project

Background: Evidence as to the benefits of nonpharmacological interventions for the boundary state between normal aging and dementia [mild cognitive impairment or a Clinical Dementia Rating (CDR) of 0.5] remains weak due to a lack of positive controls. Aims: To directly compare the effects of cognitive interventions (CI), physical activities (PA) and a group reminiscence approach (GRA), we conducted a pilot study on the basis of a cluster randomized controlled trial design. Method: A total of 127 participants aged >74 years with a CDR of 0.5 were cluster randomized into three groups for CI, PA and GRA. The intervention lasted 12 weeks and consisted of weekly group sessions and home assignments. Mini-Mental State Examination (MMSE), Trail Making Test part A (TMT-A), word fluency (WF), 6-meter walk time and Quality of Life (QOL) Face Scale scores were evaluated as primary outcomes. Results: Methodology-related benefits of CI and PA were found for MMSE scores and walk time, respectively. TMT-A, WF and QOL Face Scale scores improved irrespective of the methodologies used. Conclusions: Our findings suggest that CI and PA may be beneficial to cognitive and physical abilities, respectively. Executive functions and QOL may improve irrespective of the intervention methodologies used.