This cluster wait-list randomized controlled study investigates the effectiveness of Cognitive Stimulation Therapy (Hong Kong version) delivered by trained supportive staff and volunteers for people in maintaining the quality of life and cognition in people with mild-to-moderate cognitive impairment in community and residential care settings.

Non-pharmacological interventions such as cognitive training, cognitive rehabilitation, and cognitive stimulation aim at slowing down the cognitive decline experienced by a person with dementia. Cognitive stimulation involves a range of group activities and discussions to enhance general cognitive and social functioning. A meta-analysis of 15 studies with a total of 718 persons with dementia showed evidence of benefits of cognitive stimulation on cognitive function, quality of life, and self-reported well-being of the people with dementia . The benefits appeared to add on to medication effects. The clinical improvements in verbal and visual memory, orientation, and auditory comprehension after cognitive stimulation appeared to be able to translate into improvements in real world activity, as seen in enhancement of the communication and social interaction of persons with dementia.

In view of the current evidence, cognitive stimulation is recommended by the National Institute for Health and Clinical Excellence and the Alzheimer's Disease International as an evidence-based, non-pharmacological intervention to be offered to all people with mild-to-moderate dementia. A standard protocol of cognitive stimulation therapy with evidence is a 7-week intervention developed by Spector and her colleagues. It is a series of standardized, well-structured stimulating activities, implemented in a sensitive, respectful and person-centered manner. Group CST typically involves 14 sessions of 45-minute group activities that required cognitive processing delivered over a 7-week period (2 sessions per week, with approximately 45 mins per session). The group size was standardized to be 6 to 8 persons. People with dementia would participate in each of the 14 designated theme activities during each session. The activities aimed at stimulating and engaging persons with dementia in an active way, and providing an optimal learning environment and the positive social benefits of group therapy. Cognitive stimulation therapy can be delivered by non-specialist healthcare workers with minimum training . This allows CST to be used in low-resource environment. Manuals in different languages had been published for the group leaders to follow. Due to this advantage of high reproducibility with high quality evidence support, CST was widely adopted in over 20 countries.

In Hong Kong, there is currently no recommendations or routine provision of cognitive stimulation. In 2015, the standard group CST protocol was culturally adapted for and tested in Chinese people with dementia in Hong Kong (CST-HK). The observed improvements in cognitive outcome was in line with that of overseas studies. The protocol appeared to be feasible and acceptable to Hong Kong Chinese, with high attendance rate (92%) and low attrition rate (13%). Cultural issues identified in the pilot have been published and recommendations were made in adapting the protocol to the Hong Kong cultural settings. A Hong Kong Chinese version of the manual for CST group leaders has been published in 2017.

This study aims to investigate the effectiveness of CST-HK delivered by trained non-professional group leaders in maintaining the quality of life and cognition of people with mild-to-moderate cognitive impairment . As part of project evaluation, it aims to test the effectiveness of CST-HK compared with a wait-list control group who will receive care as usual during the waiting period.

Research Objectives The research aims to investigate the effectiveness of CST-HK among people with mild-to-moderate cognitive impairment in Hong Kong in a larger scale across service settings. It also aims to explore the effectiveness of CST-HK delivered by non-professional staff, as a possible solution to address the shortage of specialized healthcare manpower and increasing demands of non-pharmacological interventions for people with dementia.

Hypotheses The research hypothesized that, compared with the wait-list control group, the group who have received a 7-week (14-session) CST-HK intervention delivered by trained non-professional staff will show greater improvement or maintenance of (1) quality of life; and (2) cognitive performance.

Inclusion Criteria:

• Having a clinical diagnosis of mild-to-moderate dementia, or a cognitive assessment result suggestive of mild-to-moderate cognitive impairment;
• Being able to communicate and understand Cantonese;
• Being able to hear and see well enough to participate in cognitive stimulation activities;
• Having a caregiver who is able to give joint informed consent.

Exclusion Criteria:

• Having major illness(es) that would affect participation (e.g., clinically significant depressive symptoms or psychotic disorders);
• Having behavioural and psychological symptoms (e.g., aggression, inappropriate sexual behaviours, hallucination, delusion) that would interfere with participation in the intervention.