Cognitive stimulation to improve cognitive functioning in people with dementia.

BACKGROUND

Cognitive stimulation (CS) is an intervention for people with dementia offering a range of enjoyable activities providing general stimulation for thinking, concentration and memory, usually in a social setting, such as a small group. CS is distinguished from other approaches such as cognitive training and cognitive rehabilitation by its broad focus and social elements, aiming to improve domains such as quality of life (QoL) and mood as well as cognitive function. Recommended in various guidelines and widely implemented internationally, questions remain regarding different modes of delivery and the clinical significance of any benefits. A systematic review of CS is important to clarify its effectiveness and place practice recommendations on a sound evidence base. This review was last updated in 2012.

OBJECTIVES

To evaluate the evidence for the effectiveness of CS for people with dementia, including any negative effects, on cognition and other relevant outcomes, accounting where possible for differences in its implementation.

SEARCH METHODS

We identified trials from a search of the Cochrane Dementia and Cognitive Improvement Group Specialized Register, last searched on 3 March 2022. We used the search terms: cognitive stimulation, reality orientation, memory therapy, memory groups, memory support, memory stimulation, global stimulation, cognitive psychostimulation. We performed supplementary searches in a number of major healthcare databases and trial registers to ensure the search was up-to-date and comprehensive.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) of CS for dementia published in peer review journals in the English language incorporating a measure of cognitive change.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. As CS is a psychosocial intervention, we did not expect those receiving or delivering CS to be blinded to the nature of the intervention. Where necessary, we contacted study authors requesting data not provided in the papers. Where appropriate, we undertook subgroup analysis by modality (individual versus group), number of sessions and frequency, setting (community versus care home), type of control condition and dementia severity. We used GRADE methods to assess the overall quality of evidence for each outcome.

MAIN RESULTS

We included 37 RCTs (with 2766 participants), 26 published since the previous update. Most evaluated CS groups; eight examined individual CS. Participants' median age was 79.7 years. Sixteen studies included participants resident in care homes or hospitals. Study quality showed indications of improvement since the previous review, with few areas of high risk of bias. Assessors were clearly blinded to treatment allocation in most studies (81%) and most studies (81%) reported use of a treatment manual by those delivering the intervention. However, in a substantial number of studies (59%), we could not find details on all aspects of the randomisation procedures, leading us to rate the risk of selection bias as unclear. We entered data in the meta-analyses from 36 studies (2704 participants; CS: 1432, controls: 1272). The primary analysis was on changes evident immediately following the treatment period (median length 10 weeks; range 4 to 52 weeks). Only eight studies provided data allowing evaluation of whether effects were subsequently maintained (four at 6- to 12-week follow-up; four at 8- to 12-month follow-up). No negative effects were reported. Overall, we found moderate-quality evidence for a small benefit in cognition associated with CS (standardised mean difference (SMD) 0.40, 95% CI 0.25 to 0.55). In the 25 studies, with 1893 participants, reporting the widely used MMSE (Mini-Mental State Examination) test for cognitive function in dementia, there was moderate-quality evidence of a clinically important difference of 1.99 points between CS and controls (95% CI: 1.24, 2.74). In secondary analyses, with smaller total sample sizes, again examining the difference between CS and controls on changes immediately following the intervention period, we found moderate-quality evidence of a slight improvement in self-reported QoL (18 studies, 1584 participants; SMD: 0.25 [95% CI: 0.07, 0.42]) as well as in QoL ratings made by proxies (staff or caregivers). We found high-quality evidence for clinically relevant improvements in staff/interviewer ratings of communication and social interaction (5 studies, 702 participants; SMD: 0.53 [95% CI: 0.36, 0.70]) and for slight benefits in instrumental Activities of Daily Living, self-reported depressed mood, staff/interviewer-rated anxiety and general behaviour rating scales. We found moderate-quality evidence for slight improvements in behaviour that challenges and in basic Activities of Daily Living and low-quality evidence for a slight improvement in staff/interviewer-rated depressed mood. A few studies reported a range of outcomes for family caregivers. We found moderate-quality evidence that overall CS made little or no difference to caregivers' mood or anxiety. We found a high level of inconsistency between studies in relation to both cognitive outcomes and QoL. In exploratory subgroup analyses, we did not identify an effect of modality (group versus individual) or, for group studies, of setting (community versus care home), total number of group sessions or type of control condition (treatment-as-usual versus active controls). However, we did find improvements in cognition were larger where group sessions were more frequent (twice weekly or more versus once weekly) and where average severity of dementia among participants at the start of the intervention was 'mild' rather than 'moderate'. Imbalance in numbers of studies and participants between subgroups and residual inconsistency requires these exploratory findings to be interpreted cautiously.

AUTHORS' CONCLUSIONS: In this updated review, now with a much more extensive evidence base, we have again identified small, short-term cognitive benefits for people with mild to moderate dementia participating in CS programmes. From a smaller number of studies, we have also found clinically relevant improvements in communication and social interaction and slight benefits in a range of outcomes including QoL, mood and behaviour that challenges. There are relatively few studies of individual CS, and further research is needed to delineate the effectiveness of different delivery methods (including digital and remote, individual and group) and of multi-component programmes. We have identified that the frequency of group sessions and level of dementia severity may influence the outcomes of CS, and these aspects should be studied further. There remains an evidence gap in relation to the potential benefits of longer-term CS programmes and their clinical significance.