Cognitive training for people with mild to moderate dementia

Background Cognitive impairment, a defining feature of dementia, plays an important role in the compromised functional independence that characterises the condition. Cognitive training (CT) is an approach that uses guided practice on structured tasks with the direct aim of improving or maintaining cognitive abilities. Objectives • To assess effects of CT on cognitive and non‐cognitive outcomes for people with mild to moderate dementia and their caregivers. • To compare effects of CT with those of other non‐pharmacological interventions, including cognitive stimulation or rehabilitation, for people with mild to moderate dementia and their caregivers. • To identify and explore factors related to intervention and trial design that may be associated with the efficacy of CT for people with mild to moderate dementia and their caregivers. Search methods We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group Specialised Register, on 5 July 2018. ALOIS contains records of clinical trials identified through monthly searches of several major healthcare databases and numerous trial registries and grey literature sources. In addition to this, we searched MEDLINE, Embase, PsycINFO, CINAHL, LILACS, Web of Science Core Collection, ClinicalTrials.gov, and the World Health Organization's trials portal, ICTRP, to ensure that searches were comprehensive and up‐to‐date. Selection criteria We included randomised controlled trials (RCTs) that described interventions for people with mild to moderate dementia and compared CT versus a control or alternative intervention. Data collection and analysis We extracted relevant data from published manuscripts and through contact with trial authors if required. We assessed risk of bias using the Cochrane 'Risk of bias' tool. We divided comparison conditions into active or passive control conditions and alternative treatments. We used a large number of measures and data to evaluate 19 outcomes at end of treatment, as well as 16 outcomes at follow‐up in the medium term; we pooled this information in meta‐analyses. We calculated pooled estimates of treatment effect using a random‐effects model, and we estimated statistical heterogeneity using a standard Chi² statistic. We graded the evidence using GradePro. Main results The 33 included trials were published between 1988 and 2018 and were conducted in 12 countries; most were unregistered, parallel‐group, single‐site RCTs, with samples ranging from 12 to 653 participants. Inte