Cognitive Profiles Across Normal and Unhealthy Ageing

Normal cognitive ageingCognitive ageing is a gradual process across the developmental span where cognitive domains deteriorate. This chapter attempts to outline the changes observed in memory, attention, processing speed, executive functioning, and language during normal ageingAgeing, explained by neuroanatomical changes and relevant hypotheses, and compared against individuals who age unhealthily. Cognitive functionsCognitive functions typically decline, although semantic memory experiences improvement in normal ageingAgeing, exhibiting good vocabulary, knowledge and verbal discourse, and language employs semantic memory to preserve syntactic processes. Attention and executive functioning declines may be explained by age-related hypotheses regarding compensatory neuronal mechanisms (e.g., hemispheric symmetry), attentional resources (allocated by executive functioning) and frontal lobe deficits. In unhealthy cognitive ageingCognitive ageing, induced by neurodegenerativeNeurodegenerative diseases like mild cognitive impairmentMild cognitive impairment and Alzheimer’s diseaseAlzheimer's disease (AD), decline is abnormal and rapid, observing greater decay across the associated brain regions. Additionally, successful cognitive ageingCognitive ageing may be mitigated by cognitive reserve, a hypothesis explaining that engagement in advantageous activities throughout the developmental span may slow cognitive declineCognitive decline even among the unhealthy agers.