Written by Marcia J. Egles, MD. In a study of 167 healthy men and women with no signs of dementia, those who participated in higher levels of physical activity demonstrated better motor function.

A recent study suggests that physical activity may be protective to motor function in older adults. Motor function is the ability to move, and is generated by motor pathways in the brain.

The brain is composed of white matter and grey matter. A type of abnormality or “spot” seen on MRI and CT images of the brain is a white matter “hyperintensity”. White matter hyperintensities are found on the brain scans of 94% of persons over the age of 82 (2). They are more common and extensive in patients with cardiovascular risk factors and symptomatic cerebrovascular disease (3). White matter hyperintensities can be measured quantitatively and non-invasively by brain scans and have been proposed as a useful end point in clinical trials (4).

Motor impairment, or loss of mobility, is common in older adults (5). While several studies have shown that higher levels of physical activity are associated with better motor function in older adults (6), the neurological basis for this beneficial effect has been unclear. A recent study from the Rush Memory and Aging Project reports that higher levels of physical activity may reduce the effect of white matter hyperintensity burden on motor function in healthy older adults (1).

Community-dwelling participants from the Chicago area were chosen from the larger Rush Memory and Aging Project, an ongoing study of aging and dementia. The 167 subjects were healthy women (65% of the group) and men aged 60 to 96 years (average age of 80) who were without signs of dementia.

The participants underwent a range of baseline cognitive tests as well as MRI brain scans. Physical activity of the individuals was determined not only by self-reported questionnaires, but also by “actigraphy” with wrist monitors. Motor function was tested by both upper extremity tests such as finger tapping and seven lower extremity function tests. Automated methods were used to assess the amounts of white matter hyperintensities on MRI brain scans.

Higher white matter hyperintensity volumes were associated with poorer motor function scores (p=0.006). Consistent with previous studies (6), total daily activity was positively associated with higher motor function (p=0.002). The total daily activity modified the association between white matter hyperintensities and motor function (p=0.007). Those with the highest levels of activity (top 10 percentile) showed the least burden of white matter hyperintensities with no associations between white matter hyperintensities and motor function. By contrast, higher white matter burden was associated with poorer motor function in persons with average and low levels of activity.

The study’s data suggest that daily physical activity may provide a reserve against harmful effects of white matter hyperintensities on motor function. The authors emphasize the importance of an active lifestyle in older adults.

Source: Fleischman, Debra A., et al. “Physical activity, motor function, and white matter hyperintensity burden in healthy older adults.” Neurology 84.13 (2015): 1294-1300.

©2015 American Academy of Neurology.

Posted March19, 2015. r/aj

Marcia Egles, MD, graduated from Vanderbilt University School of Medicine in 1986. She completed her residency in Internal Medicine at St. Louis University Hospital. Dr. Egles is certified in Internal Medicine and is a member of the American College of Physicians. She resides in Avon, IN with her husband and two sons.

References:

  1. Fleischman, Debra A. et al, Physical activity, motor function, and white matter hyperintensity burden in healthy older adults, Neurology, 84, March 31, 2015. P. 1-7.
  2. Garde E, Mortensen EL, Krabbe K, Rostrup E, Larsson HB. Relation between age-related decline in intelligence and cerebral white-matter hyperintensities in healthy octogenarians: a longitudinal study. Lancet 2000;356:628-34.
  3. Launer LJ. Epidemiology of white matter lesions. Top Magn Reson Imaging 2004;15:365-7.
  4. Schmidt R, Scheltens P, Erkinjuntti T, Pantoni L, Markus HS, Wallin A, et al. White matter lesion progression: a surrogate endpoint for trials in cerebral small-vessel disease. Neurology 2004;63:139-44.
  5. Verghese J, LeValley A, Hall CB, Katz MJ, Ambrose AF,Lipton RB. Epidemiology of gait disorders in community-residing older adults. J Am Geriatr Soc2006;54:255–261.
  6. Pahor M, Guralnik JM, Ambrosius WT, et al. Effect of structured physical activity on prevention of major mobility disability in older adults: the LIFE Study randomized clinical trial. JAMA 2014;311:2387–2396.