A Neuropsychological Approach to Perception and Memory in Normal and Pathological Aging

Abstract

The neurophysiological mechanisms responsible for producing cognitive changes in old age are poorly understood. Chapters 1 and 2 mention a number of striking changes in neuronal physiology and structure that occur with normal aging and that are accelerated and more widespread during pathological states such as Alzheimer’s disease. Some of these, such as neurofibrillary tangles and senile plaques, are highly correlated with cognitive impairment; others, such as lipofuscin, are not; whereas still others, such as the production of chromatin, have an uncertain status in this regard. Whatever changes in cellular physiology are finally shown to be related to cognitive changes associated with aging, it must be borne in mind that these cellular changes do not affect psychological function directly but rather indirectly by altering the working of neuronal systems. From a psychologist’s point of view, then, the psychological consequences of neurophysiological or biochemical changes with age rrnghTbe best understood by focusing on the larger systems than on the microstructure of those systems. For example, although neurofibrillary degeneration is associated with cognitive deficits, the particular deficits that are noted in each individual will be determined by the brain structures that are most severely affected.