According to Neurology Today (August 16, 2012) white matter damage or injury is no longer seen as typical aging. White matter refers to damage to the brain affecting our thinking or cortical brain areas. White matter is seen as a preclinical marker for cognitive decline and Alzheimer’s disease.
Microstructural white matter changes are identifying individuals who show no cognitive difficulties to be at risk for mild cognitive decline and dementia. Suggested is that the disease begins early and ten years before cognitive problems and poor memory are actually apparent (thus the term preclinical) in daily life. The take away point is that lesions (or impact to brain structures) involving as little as three percent of the white matter produces impairment in working memory in demented individuals. The diagnosis of vascular dementia is given when there is a clear relationship in the severity and pattern of cognitive impairment and the presence of diffuse subcortical cerebrovascular disease pathology (brain areas affected by the loss of adequate blood flow). The idea is that age related cognitive decline, a term seen on the MRI test results, is not normal aging and instead a marker of dementia and that further, more often, dementia is a mixed picture of neurodegenerative and vascular (heart related) pathologies.