Background: Cognitive frailty is an at-risk state of dementia that it can be reversed by manipulating the lifestyle factors, such as cognitive activity and nutrition/dietary pattern. Their protective effects depend on a prolonged adherence to these factors. However, in the literature, most of the cognitive interventions are centred-based and supervised. Nutrition intervention depends on the provision of supplement or a complimentary supply of food. There is a lack of interventions with components of sustaining cognitive and nutrition training effect for the community-dwelling older people with cognitive frailty in home settings.

Objectives: This study aims to examine the feasibility and preliminary effects of a gamified, home-based, cognitive-nutritional training (GAHOCON) programme for community-dwelling older people with cognitive frailty on protective diet adherence, cognitive function, frailty nutrition, and body composition.

Methods: This study employs a pilot randomized controlled trial design. Recruitment will be conducted in elderly community centres. Participants who are aged ≥ 60 years, community-dwelling, and having cognitive frailty will be recruited. Participants will be randomized into either intervention or control group at a 1:1 ratio by permuted block randomization with a block size of 8 people. In the intervention group, participants will attend both centre-based training for one month and home-based training for 2 months. Health education on cognitive frailty and nutrition are included in the centre-based training. GAHOCON is included in the home-based training. The gamified cognitive-nutritional training employs digital gaming technology to develop a programme by combining cognitive training and nutrition education to promote the health of older people cognitive frailty. In the control group, participants will attend only the centre-based training. For the outcomes, this study will measure the feasibility in terms of the willingness of participants to be randomized, study participation rate, follow-up rates, response rates to questionnaires, adherence rate, level of participation of the tablet-based training, and time needed for data collection. Adherence to protective diets, cognitive function, frailty, nutrition, and body composition will be measured at baseline (T0), immediately after the completion of the intervention (T1). Convenience sampling will be employed to recruit 30-40 subjects for pilot testing. Feasibility indexes will be reported by descriptive statistics, such as mean with standard deviation and frequency with percentage. To test the hypothesis on the effects, a non-parametric test (i.e., Wilcoxon Signed-rank test) will be used to compare the outcome variables across time points to test the within-group effect in both groups separately. The level of significance was 0.05.

Significance: If this intervention is feasible and effective, this is going to provide a first of its kind home-based intervention to promote both cognitive functions and modify the dietary pattern of older people with cognitive frailty. First, it changes the cognitive training mode from a centre-based and supervised one to a home-based, self-paced, and tele-monitored one. Home-based training enables a more sustainable engagement of training for older people. This is particularly important during the COVID-19 pandemic period when all the elderly centres are closed. Home-based interventions are more accessible and convenient. It also solves the problem of space limitation in elderly centres in the community that more beneficiaries can be covered in space-limiting elderly centres. Second, it changes the mode of nutritional intervention from a supplement-based one to a daily-diet-based one. This intervention could enhance the nutrition and change their dietary pattern of community-dwelling older people with cognitive frailty by engaging them to protective diets, which ensures the sustainability of the beneficial effects of the protective diets towards cognitive frailty. Third, it changes the training mode from a training- and learning-oriented one to a gaming-oriented one. It brings more joy to community-dwelling older people even at the time when they are at home. It also fosters training adherence.

Inclusion Criteria:

1. Age ≥ 60 years,

2. Community-dwelling, as defined by living at home without staying in long-term care facilities (e.g., nursing home) in the last 12 months as reported by the participants,

3. Cognitive frailty, as defined by co-existence of mild cognitive impairment and physical frailty,7

   1. Mild cognitive impairment, measured by Montreal Cognitive Assessment (MoCA) score ≤ 25 and Clinical Dementia Rating (CDR) score = 0.5,35,36 and
   2. Frailty status from pre-frail to frail, measured by Fried Frailty Phenotype score ≥ 1.37

4. Poor Mediterranean diet adherence, measured by MDS score < 30.5 (i.e., the mean MDS of community-dwelling older people reported in a local study),20 and

5. Functionally independent on food preparation, as defined by Lawton Instrumental Activity of Daily Living score ≥ 15/18 with the sub-score on Meal Preparation = 2/2.38,39

Exclusion Criteria:

1. Diagnosed dementia, according to subjects' medical record, or
2. Probable dementia, as defined by MoCA ≤ 18,35,36
3. Low vision (at least one eye with visual acuity < 20/60) or without corrective lens, because all training are visual-based and blurred vision negatively affects cognitive performance in cognitive training and assessment.40

Outcome assessors at both pre- and post-observations will be blinded to the group label.