A new clinical study from the Pacific Neuroscience Institute (PNI) has identified a significant relationship between muscular strength, mobility, and brain volume in individuals with Alzheimer’s disease, reinforcing the role of physical function as a modifiable factor in brain health.
The study, published in the Journal of Alzheimer’s Disease, used MRI-based brain volumetric analysis with Neuroreader® to quantify regional brain atrophy and examine its association with frailty-related measures.
Study Objective
The researchers investigated whether handgrip strength and mobility correlate with brain atrophy in patients diagnosed with Alzheimer’s disease dementia. The primary goal was to understand how physical frailty relates to structural brain changes measurable on MRI.
Methods
The study included 38 participants with Alzheimer’s disease dementia who had biomarker-confirmed amyloidosis and cognitive impairment.
Key assessments included:
- Handgrip strength (dominant and non-dominant hands) measured with a dynamometer
- Handgrip asymmetry calculations
- Two-Minute Walk Test (2MWT) to evaluate mobility
- Classification of participants as frail vs. non-frail
All participants underwent brain MRI, with regional brain volumes quantified using Neuroreader®. Statistical models adjusted for age, sex, education, handedness, body mass index, and head size to evaluate associations between physical performance and brain structure volumes.
Results
The study found consistent relationships between physical performance and larger brain volumes:
- Higher non-dominant handgrip strength was associated with larger hippocampal volumes (p = 0.02)
- Higher dominant handgrip strength correlated with increased frontal lobe volumes (p = 0.02)
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Higher 2MWT scores were linked to larger volumes in the:
- Hippocampus (p = 0.04)
- Frontal lobe (p = 0.01)
- Temporal lobe (p = 0.03)
- Parietal lobe (p = 0.009)
- Occipital lobe (p = 0.005)
Participants classified as frail demonstrated reduced frontal, temporal, and parietal lobe volumes compared to non-frail individuals.
Clinical and Research Implications
“We showed in our study that participants who were not frail were likely to have larger brain volumes and this is possible with volumetric quantification on MRI.”
— Cyrus A. Raji, MD, PhD, Assistant Professor of Radiology, Washington University in St. Louis
Lead author Somayeh Meysami, MD, emphasized that frailty-related factors may represent modifiable risks for brain health, stating that strength and mobility were directly associated with brain regions involved in cognition.
Co-senior author David Merrill, MD, Director of the Pacific Brain Health Center at PNI, noted that the findings support ongoing efforts to integrate physical health, diagnostic imaging, and cognitive interventions to optimize brain health in Alzheimer’s disease.
Publication Details
- Journal: Journal of Alzheimer’s Disease
- Publication Date: December 14, 2022
- DOI: 10.3233/JAD-220886
- Upcoming: To be included in the JAD Handbook on the Prevention of Dementia (2023)