Skeletal muscle loss is a risk factor for developing dementia, according to a study presented at annual meeting of the Radiological Society of North America (RSNA).

Skeletal muscles make up about a third of a person’s total body mass. They are connected to bones and allow a wide range of movement. As people get older, they start to lose skeletal muscle mass.

Because the age-related skeleton muscle loss is often seen in older adults with dementia due to Alzheimer’s disease (AD), this study aimed to examine whether temporalis muscle loss (a measure of skeletal muscle loss) is associated with an increased risk of dementia due to AD in the elderly.

The temporalis muscle is located in the head and serves to move the lower jaw. Studies have shown that the thickness and area of ​​the temporalis muscles can be an indicator of muscle loss throughout the body.

“Measuring temporalis muscle size as a potential indicator of generalized skeletal muscle status provides an opportunity for skeletal muscle quantification without additional cost or burden in older adults who have previously undergone brain MRI for disease. neurological, such as mild dementia,” said the study’s lead author. , Kamyar Moradi, MD, postdoctoral scholar in the Russell H. Morgan Department of Radiology and Radiologic Sciences at Johns Hopkins University School of Medicine in Baltimore.

“This is the first longitudinal study demonstrating that skeletal muscle loss may contribute to the development of dementia.”

For the multidisciplinary research study, a collaboration between the Departments of Radiology and Neurology at Johns Hopkins Medical Institutions, Dr. Moradi and colleagues used baseline brain MRI scans from the Alzheimer’s Disease Neuroimaging Initiative cohort to quantify the skeletal muscle loss in 621 participants without dementia (mean age 77 years).

The researchers manually segmented the bilateral temporalis muscle on MRI images and calculated the total cross-sectional area (CSA) of these muscles. Participants were classified into two distinct groups: large CSAs (131 participants) and small CSAs (488 participants).

Outcomes included subsequent incidence of AD dementia, change in cognitive and functional scores, and changes in brain volume between groups. Median follow-up was 5.8 years.

Based on their analysis, smaller temporal CSA was associated with a higher incidence risk of AD dementia. Additionally, smaller temporal CSA was associated with greater decline in memory composite score, functional activity questionnaire score, and structural brain volumes during the follow-up period.

“We found that elderly people with smaller skeletal muscles are approximately 60% more likely to develop dementia when adjusted for other known risk factors,” said study co-senior author and professor of neurology Marilyn Albert , Ph.D.

According to Shadpour Demehri, MD, co-senior author and professor of radiology, the study demonstrates that this muscle change can be opportunistically analyzed by any conventional brain MRI, even when performed for other purposes, without incurring any additional costs or charges.

Dr Albert highlighted that early detection through readily available brain MRI could enable rapid interventions to combat skeletal muscle loss, such as physical activity, resistance training and nutritional support.

“These interventions can help prevent or slow muscle loss and, therefore, reduce the risk of cognitive decline and dementia” said Dr. Demehri.

Other co-authors are Hanzhang Lu, Ph.D., Yuxin Zhu, Ph.D., Soheil Mohammadi, MD, Sara Momtazmanesh, MD, and Eleanor M. Simonsick, Ph.D.