Cerebral changes improved by physical activity during cognitive decline: A systematic review on MRI studies

Area of Science:

• Neuroscience
• Gerontology
• Radiology

Background:

• Current treatments for late-life cognitive impairment and dementia are limited, with no cure for brain degeneration or cognitive decline reversal.
• Physical activity is a potential non-pharmacological intervention, but its effects on brain integrity in cognitive decline are not well understood.
• Understanding cerebral alterations beyond clinical improvement is crucial for disease processes and effective treatments.

Purpose of the Study:

• To systematically review how physical activity and fitness influence brain architecture in mild cognitive impairment (MCI) and Alzheimer's disease (AD) compared to healthy elderly individuals.
• To evaluate Magnetic Resonance Imaging (MRI) findings across different exercise modalities and fitness levels.
• To assess the methodological quality of intervention studies in cognitive decline.

Main Methods:

• Systematic review of interventional (aerobic, coordinative, resistance exercise) and observational studies.
• Inclusion of studies combining physical activity/fitness with Magnetic Resonance Imaging (MRI) techniques (volumetric, structural, DTI, fMRI, CBF).
• Methodological evaluation of interventional studies in cognitive decline versus normal aging.

Main Results:

• Aerobic exercise was the most common intervention (9 studies) in MCI/AD.
• Interventions in MCI/AD demonstrated higher methodological quality than those in healthy elderly.
• Aerobic exercise and fitness primarily impact brain regions vulnerable to neurodegeneration, including frontal, temporal, and parietal areas like the hippocampus and prefrontal cortex.

Conclusions:

• Physical activity, especially aerobic exercise, positively influences brain structures affected by neurodegeneration in MCI and AD.
• General fitness appears to have a global cerebral effect, while shorter interventions (3-6 months) may target specific regions like the hippocampus.
• Further research is needed on diverse exercise modalities (resistance, coordinative, multicomponent, dancing) and advanced imaging techniques for a comprehensive understanding of physical activity's cerebral impact.