Brain changes in ageing
- Created by: sarah_mocha
- Created on: 07-05-18 22:31
View mindmap
- Ageing (brain changes)
- Grey matter
- Grey matter in the brain begins to decline from the early age of 20 (Ge et al, 2002)
- Structural neuroimaging studies have shown a significant negative correlation between age and grey matter volume (Good et al, 2001)
- Significant correlation between grey matter volume and several cerebrovasular risk factors such as systolic blood pressure and BMI (Taki et al, 2011)
- Grey matter volume decline found in patients with several diseases such as Alzheimer's (Rombouts et al, 2000), semantic dementia (Mummery et al, 2000), and depression (Taki et al, 2005)
- BMI influences grey matter volume + decline (Taki et al, 2011)
- Obesity associated with decreased grey matter volume in men (Taki et al, 2011)
- Degenerative changes such as shrinkage or loss of neurons, and loss of dendritic arborisation
- Age-related loss of grey matter volume is involved with age-related cognitive change (Brickman et al, 2007)
- Greatest effects in the frontal lobe (Allen et al, 2005)
- Brain size
- Volume of the brain declines with age at a rate of 5% per decade after the age of 40 (Svennerholm et al, 1997)
- In individuals with very mild dementia, atrophy rate of brain volume is more than double that of age-matched normal elderly people (Fotenos et al, 2005)
- Shrinkage particularly in the frontal cortex (Peters, 2006)
- Shrinkage rate increases with age and increase after about age 50
- Risk factors
- Obesity
- Associated with poor cognitive function (Jeong et al, 2005)
- Risk factor for Alzheimer's disease (Gustafson et al, 2003)
- Age-related neuronal loss appears to be accelerated by a number of vascular factors that increase ischemia. Obesity has been related to ischemia and to a variety of vascular pathologies that could be related to atrophy
- May lead to increased cortisol secretion (Bjorntorp, 2001) which can lead to brain volume decrease
- Smoking heightens risk of vascular disorders that can cause stroke, and constricts arteries that deliver oxygen to the brain
- Cortisol, the stress hormone, damages the brain over time. Socialising in old age may be protective by lessening stress
- Obesity
- White matter
- Brain ageing is marked by degradation of white matter including myelin pallor, loss of myelinated fibres, and malformation of myelin sheaths (Gunning-Dixon et al, 2009)
- Presence of white matter hyperintensities is common among normal elderly adults
- Vascular risk factors, such as hypertension accounts for much variability in severity of white matter hyperintensities
- Relative frontal lobe white matter volume mediated the association between age and performance on tasks of memory and executive functions (Brickman et al, 2006)
- Severity of white matter hyperintensities is associated with poorer performance in age-sensitive domains like executive function, episodic memory and processing speed (Gunning-Dixon & Raz, 2000)
- Several longitudinal studies support the role of white matter hyperintensities in age-related declines in executive skills (Kramer et al, 2007)
- Increase subcortical white matter lesions associated with decreased executive function (Anderton, 2002)
- White matter lesions increase with age and are associated with increased cardio-vascular risk, reduction in cerebral blood flow, cerebral reactivity, and vascular density, and poor cognition
- Grey matter
Comments
No comments have yet been made