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

Abstract

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.

Keywords: Clinical Dementia Rating; Nonpharmacological intervention; Old-old subjects.

Fig. 1

Procedure of subject recruitment. 295 out of 590 individuals were assessed with a CDR of 0.5 (MCI) in the Kurihara Project, a community-based study on dementia; 127 of the 295 people with MCI who provided informed consent were enrolled in the study. These participants were cluster randomized and assigned to three intervention groups: CI, PA or GRA. Each series of interventions consisted of 12 sessions and 12 home assignments (‘home work’). Each session was held once per week.

Fig. 2

Pre- and postintervention mean values of outcome measures for all participants. The MMSE, WF, TMT-A, 6-meter (6m) walk time and QOL Face Scale values of all participants improved significantly (p < 0.005, uncorrected for multiple comparisons).

Fig. 3

Pre- and postintervention mean values of the MMSE, 6-meter (6m) walk time, WF, TMT-A and QOL Face Scale for the CI, PA and GRA groups. Repeated-measures ANOVA revealed a significant effect of intervention type for the MMSE and 6-meter walk time (p < 0.05, uncorrected for multiple comparisons). The post hoc paired t test revealed a significant improvement in MMSE score for the CI group and in 6-meter walk time for the PA group (* p < 0.01, uncorrected for multiple comparisons; a). No effect of the intervention type was found for WF, TMT-A and QOL Face Scale (b).

Fig. 4

Pre- and postintervention mean values of the QOL Face Scale for the ‘enjoyable’ and ‘not enjoyable’ groups. Repeated-measures ANOVA revealed a significant effect of PRO without significant interactions with intervention type (p < 0.05, uncorrected for multiple comparisons). The post hoc paired t test showed a significant improvement in QOL Face Scale scores in the ‘enjoyable’ group (* p < 0.01, uncorrected for multiple comparisons). ns = Not significant.