Effectiveness of exercise interventions to improve long-term patient-relevant cognitive and non-cognitive outcomes in patients with mild cognitive impairment: protocol of a systematic review.

Ana Isabel Gonzalez Gonzalez, Mirjam Dieckelmann, Andrea Siebenhofer

Keywords: exercise intervention, mild cognitive impairment, patient-relevant outcomes, long-term effects, systematic review

Background:
Mild Cognitive Impairment (MCI) is acknowledged to be a psychiatric disorder best described as a syndrome with characteristic clinical symptoms. MCI patients have an elevated risk of developing dementia over time with a yearly conversion rate of 15-41%. Since severe states of dementia are costlier, the cost of care may be substantially reduced by delaying the onset of dementia in patients with MCI using secondary preventive measures such as exercise.

Research questions:
What is the effectiveness of exercise interventions to improve long-term patient-relevant cognitive and non-cognitive outcomes in patients with MCI?

Method:
We will systematically search five electronic databases from 1995 onwards to identify trials reporting on the effectiveness of exercise interventions to improve long-term (12 months+) patient-relevant cognitive and non-cognitive outcomes in adults (50+ years) with MCI (all causes).
Two independent reviewers will screen titles/abstracts/full texts, extract data from the selected studies and present evidence in terms of study/population/intervention/comparator characteristics and long-term patient-relevant cognitive and non-cognitive outcomes. Risk of bias (RoB) will be independently assessed by two reviewers using the Cochrane Collaboration RoB 2.0 tool. Additionally, the reporting quality of the exercise interventions will be assessed using the Consensus on Exercise Reporting Template (CERT). The quality of evidence for every outcome will be evaluated using the GRADE approach.
A quantitative synthesis will only be conducted if studies are homogeneous enough for effect sizes to be pooled. Where quantitative analysis is not applicable, data will be represented in tabular form and synthesized narratively.

Results:
This review will allow a detailed quality assessment of interventional research that investigates the effect of exercise in patients with MCI, highlights methodological shortcomings, and makes recommendations for future RCTs in this field of research.

Conclusions:
To the best of our knowledge, no systematic review exists that evaluates long-term patient-relevant, cognitive and non-cognitive effects of exercise interventions in MCI populations.

Points for discussion:
Recommendations based on the effectiveness of exercise interventions in patients with MCI

Recommendations for future RCTs on the effectiveness of exercise interventions in patients with MCI