Effects of a Multicomponent Exercise Intervention on Physical and Cognitive Function of Older Adults With Dementia

Dementia is a leading cause of death and disability that was declared as one of the greatest health and social care challenges of the 21st century. Regular physical activity and exercise have been proposed as a non-pharmacological strategy in disease prevention and management. Multicomponent Training (MT) combines aerobic, strength, balance, and postural exercises and might be an effective training to improve both functional capacity and cognitive function in individuals with dementia (IwD). Nevertheless, data on the effects of MT in IwD are still limited and the extent to which IwD can retain improvements after an exercise intervention still needs to be elucidated. The aim of "Body \& Brain" study is to investigate the effects of a 6-month MT intervention and 3-month detraining on the physical and cognitive function of IwD. Additionally, we aim to explore the impact of this intervention on psychosocial factors and physiologic markers related to dementia.

Although exercise interventions for IwD seem to be feasible and well tolerated, resulting in positive effects on ADL functionality for people at mild-to-moderate stages \[1, 2\], the therapeutic role of physical activity, particularly exercise, after dementia diagnosis still needs further evidence \[3-5\], - especially when considering community-based contexts and caregivers as participants on exercise sessions \[6\]. It also matters to highlight that the dose-dependent relationship remains unclear \[1, 7, 8\]. Therefore, research is needed to identify the triad: stage/type of dementia, FITT variables (frequency, intensity, type, and time) of exercise intervention, and target outcome \[7, 9\]. Regarding exercise modality, Multicomponent Training (MT) \[10\] - combining aerobics, strength and balance exercises - seems to be effective at improving functional and cognitive performances in older adults with neurodegenerative disorders, particularly dementia \[11-13\]. Exercise programs previously developed by our group confirmed that a 6-month MT intervention can positively impact the physical and cognitive function of institutionalized older adults with AD \[14, 15\] and can be beneficial in physical fitness and ADL functionality performance among community-dwelling patients \[9, 16\]. However, the extent to which IwD can retain these improvements after the cessation of MT intervention still need to be elucidated \[17\] in order to understand how detraining affects functionality and cognition following the cessation of MT stimulus.

This study is a quasi-experimental controlled trial using a parallel-group design. The study sample consists of community-dwelling individuals aged ≥ 60 years who are clinically diagnosed with dementia or major neurocognitive disorder. Participants will be either allocated into the intervention group or the control group. The intervention group will participate in MT biweekly exercise sessions, whereas the control group will receive monthly sessions regarding physical activity and health-related topics for 6 months. The main outcomes will be physical function as measured by the Short Physical Performance Battery (SPPB) and cognitive function evaluated using the Alzheimer Disease Assessment Scale - Cognitive (ADAS-Cog) at baseline, after 6-months and 3-months after the end of intervention. Secondary outcomes will be body composition, physical fitness, daily functionality, quality of life, neuropsychiatric symptoms and caregiver's burden. Cardiovascular, inflammatory and neurotrophic blood-based biomarkers, and arterial stiffness will also be evaluated in subsamples.

Eligibility Criteria:
Inclusion Criteria:

* Individuals aged ≥ 60 years capable of walking autonomously without an assistive device or human assistance;
* Individuals diagnosed with dementia or major neurocognitive disorder using accepted diagnostic criteria such as that established by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR or DSM-5), ICD-10, or the NINCDS-ADRDA; by a physician for at least for 6-months.

Exclusion Criteria:

* Individuals diagnosed with certain disorders or conditions in which exercise is contraindicated such as unstable or ongoing cardiovascular and/or respiratory disorder;
* Hospitalized individuals and/or recovering from surgery or rehabilitation;
* Individuals presenting an advanced stage of dementia (e.g., scored 3-points in CDR or ≤ 10 points on MMSE) that could affect physical performance in the exercise training sessions or testing procedures.