Description

Mild Cognitive Impairment (MCI) is a clinical condition with a heterogeneous etiology and clinical course, characterized by objective cognitive deficits that are not severe enough to cause clear functional limitations or to warrant a diagnosis of dementia. MCI represents a risk factor for progression to dementia: annual conversion rates vary widely across studies, ranging from 2% to 31%, with an average of around 10%. In addition to patients with MCI who progress to dementia, some may show persistent but non-progressive cognitive deficits, while others may even return to normal cognitive functioning, while remaining at higher risk of future cognitive decline. In this context, early diagnosis and timely interventions to reduce the risk of dementia are crucial.

Various interventions have been proposed for the non-pharmacological management of MCI. A review of 14 studies on cognitive rehabilitation in MCI indicated that multimodal interventions and lifestyle-based approaches are the most promising in terms of improving objective cognitive performance (Huckans et al., 2013). Another meta-analysis on 26 studies confirmed the effectiveness of multimodal interventions, as well as multi-domain and memory-specific approaches (Sherman et al., 2017). Other factors, such as MCI subtype, intervention format (individual, group, or computerized), type of control (passive vs. active), follow-up duration (less or more than two weeks), and adjustment for repeated testing showed no appreciable effects on the outcomes. Regarding the dose-response effect of treatment, there is no consensus on the amount of training required for significant benefits. A review and meta-analysis on the relationship between treatment dose (defined by frequency, intensity, and duration) and outcomes found the most robust effects for multi-component approaches delivered 1-2 times per week, 30-60 minutes per session, over a total duration of 8-16 weeks (Shao et al., 2022). Finally, given the increasing role of information and communication technologies in healthcare, cognitive rehabilitation has started to include eHealth tools, which are also suitable for older adults and patients with MCI. Despite the encouraging results reported in the literature, outpatient cognitive rehabilitation for MCI is still limited by issues related to service accessibility.

This study aims to investigate the effectiveness of a multimodal group cognitive rehabilitation intevention designed to be accessible for patients with MCI and sustainable in clinical practice.

The primary objective of the study is to evaluate the effects of the intervention on cognitive, behavioural, and functional profile of patients with MCI, compared with an active control group. Outcome measures will be collected for all participants at T0 (baseline), T1 (after 12 weeks of intervention), and T2 (3 months after the end of the intervention and approximately 6 months from baseline), in order to assess both short-term and long-term effects of the intervention. The secondary objective is to explore the relationship between changes in outcome measures in the experimental group following the intervention and patients' demographic and clinical characteristics, including age, sex, cognitive reserve, MCI subtype, and time since diagnosis, with the aim of identifying potential predictors of a stronger response to the treatment. Treatment accessibility, which guided the study design, will be evaluated though dropout and attendance rates, use of the provided tools and responses to the final satisfaction questionnaire.

The experimental group will receive a multimodal cognitive rehabilitation intervention, including (a) a multi-domain cognitive training and (b) a lifestyle intervention, consisting of psychoeducational sessions on neuroprotective factors and supported by the use of a web-based application accessible via computer and tablet. The intervention program will be delivered in small groups formed according to the presence of memory impairment, with two 60-minute sessions per week for a total of 12 weeks. The multimodal approach, including multi-domain cognitive rehabilitation and lifestyle interventions, was selected based on the best available evidence in the literature. A multi-domain format also makes the program well-suited for group delivery, where some heterogeneity in cognitive profiles can still be expected among participants within each subgroup. The limited intervention intensity and duration, the use of technology, and the use of groups not highly homogeneous aimed to enhance accessibility, sustainability and transferability in clinical practice.

The control group will receive an informational booklet on the 14 protective factors for dementia described by the Lancet Commission, including practical daily-life recommendations to reduce risk.

This study has a mixed design consisting of a between-subjects factor ("Group," with two levels: experimental and control) and a within-subjects factor ("Assessment Time," with three levels: T0, T1, and T2).

To evaluate the effect of the treatment on outcome measures assessing the cognitive, behavioral, and functional profile of patients with MCI, compared with an active control group, a series of repeated-measures analyses of variance (ANOVA) will be performed. In the event of a violation of the assumption of normality, assessed using the Kolmogorov-Smirnov test, either data normalization procedures (e.g., logarithmic transformation) or non-parametric tests (e.g., Kruskal-Wallis) will be adopted.

To explore the relationship between changes in outcome measures in the experimental group and patients' demographic and clinical data, correlations will be conducted between the difference in scores obtained at T0 and T1 and the variables age, cognitive reserve, and time since diagnosis; an independent-samples t-test will be performed for the variable gender; and a one-way ANOVA will be conducted to evaluate the MCI subtype effect.

Sample size was determined through a power analysis conducted with the G\*Power software, with a 10% oversampling to compensate for potential dropouts. Forty patients with MCI and their informants will be recruited and randomly assigned to the experimental or control group using stratified randomization based on memory impairment. Participants in the experimental group will be further divided into small subgroups according to the stratification factor.