ABSTRACT
The brain undergoes progressive changes in adult life, with these changes accelerating in the later years. The availability of neuroimaging techniques has opened up the possibility of studying these changes in large representative samples of elderly individuals, something not possible with post-mortem examinations. The introduction of computerised axial tomography (CT) was a major advance in the 1970s, but magnetic resonance imaging (MRI) has enhanced this capacity immeasurably. Structural neuroimaging provides data for structural-functional correlation in both healthy and diseased individuals, and enables a comparison of normative age-related changes with those due to neurodegenerative and other disorders. It also helps us understand which aspects of brain changes in the elderly are truly related to ageing, and which may in fact be due to age-related diseases. A differentiation of these is crucial for developing strategies for intervention. Advances in imaging technology have been paralleled by significant developments in the techniques of qualitative and quantitative analysis of neuroimaging. Similarly, research has progressed from cross-sectional to longitudinal studies, using repeated imaging to characterise the evolving changes in individual subjects. Such research has limitations due to differential selection criteria, sample sizes, imaging modality utilised, measurement methods and duration of longitudinal follow-up. Nonetheless, there are some consistent
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