ABSTRACT
In aging the central nervous system faces a number of challenges to the homeostatic mechanisms which facilitate the maintenance of its structure and function (Table 17.1). Aging is usually associated with a slowly progressive decline in memory, cognitive function, reaction times and other functions. The precise cause of this decline is not known. In addition to the cumulative effects of a life time of events the neurodegenerative diseases (NDDs) are very common in the elderly. It has even been suggested that Alzheimer’s disease (AD), which achieves a prevalence of close to 50% in those over 80-90 years of age, is an inevitable consequence of brain aging. An alternative view is that ‘normal’ aging is not associated with a decline in brain function, but that the studies documenting an age-related decline simply reflect inclusion of people in the early stages of NDDs such as AD. Currently, there is great interest in the clinical concept of age-related mild cognitive impairment (MCI) because it comprises a group at high-risk of progressing to dementia whether due to AD or other pathology. Patients with MCI therefore represent a target for preventative therapy to preserve cognitive function.
