Brain volume declines with age, increasing risk
Human brains shrink as they age. The effect is to increase your risk of brain injury in a crash. Nobody we know makes a helmet designed for seniors. You can look for one with thicker, less dense foam.
The studies below indicate that aging brains shrink, and become more prone to injury in a crash.
- Consequences of Brain Volume following Impact in Prediction of Subdural Hematoma evaluated with Numerical Techniques. Svein Kleiven, Hans von Holst (2002).
It was found that by reducing the brain size and thereby increasing the volume in the subdural space in the Finite Element model, a significant increase in relative motion between the skull and brain occurred, which correlated with the reduction of brain size.
- Experimental neurotraumatology--rotation. Krauland et al.(1981)
This study used superior halves of 25 cadaver heads, applying horizontal plane rotational accelerations. The relative motion between skull and brain increased with increasing age and degree of brain shrinkage.
- Brain volume decline in aging: evidence for a relation between socioeconomic status, preclinical Alzheimer disease, and reserve. Fotenos AF, et al.
Arch Neurol. 2008 Jan;65(1):113-20. doi: 10.1001/archneurol.2007.27.
Whole-brain volume adjusted for head size declined by 0.22% per year between the ages of 20 and 80 years with accelerated decline in advanced aging.
- Regional Brain Changes in Aging Healthy Adults: General Trends, Individual Differences and Modifiers Naftali Raz, Ulman Lindenberger, Karen M. Rodrigue,Kristen M. Kennedy, Denise Head, Adrienne Williamson,Cheryl Dahle, Denis Gerstorf and James D. Acker. Cerebral Cortex November 2005;15:1676--1689
"Age-related increases in the rate of decline are consistent
with the notion of nonlinear regional brain aging. Such increases
confirm the cross-sectional findings that suggested an inverted-U
trajectory of lifespan change, with volume increase in young
adulthood, plateau in middle age and precipitous decline in the
old age (Courchesne et al., 2000; Bartzokis et al., 2001; Jernigan
et al., 2001; Jernigan and Fennema-Notestine, 2004; Raz et al.,
2004b). The mid-fifties appear as a likely point of inflection of
age trend, with sizeable variation across individuals."
- Aerobic Exercise Training Increases Brain Volume in Aging Humans Stanley J. Colcombe, Kirk I. Erickson, Paige E. Scalf, Jenny S. Kim, Ruchika Prakash, Edward McAuley, Steriani Elavsky, David X. Marquez, Liang Hu and Arthur F. Kramer. Journal of Gerontology: MEDICAL SCIENCES 2006, Vol. 61A, No. 11, 1166-1170.
"Significant increases in brain volume, in both gray and white matter regions, were found as a function of fitness training for the older adults who participated in the aerobic fitness training but not for the older adults who participated in the stretching and toning (nonaerobic) control group. As predicted, no significant changes in either gray or white matter volume were detected for our younger participants."
In addition to those studies, Wayne State University brain injury researcher Voigt Hodgson (now deceased) told us many years ago that brains, like every other part of the body, become more brittle and less flexible with aging. He estimated that an over-65 brain was about twice as likely to be injured from a given g force as a younger brain. That is obviously a broad-brush statement, and we have not found any research to back that up. But Hodgson was one of the pioneers in his field, and his view is worth considering.
We are indebted to the late Roy Burek, then Managing Director of Charles Owen & Co (Bow) Ltd,
a UK manufacturer of equestrian helmets, for the research that identified the articles on this page.