Neuropsychological rehabilitation (NR) is concerned with the amelioration of deficits caused by insult to the brain. It adopts a goal-planning approach and addresses real-life difficulties. Neuropsychology studies how the brain affects behavior, emotion, and cognition. Rehabilitation is a process whereby people who are disabled work together with professional staff, relatives, and others to achieve optimum physical, psychological, and vocational well-being. Rehabilitation is not synonymous with recovery, nor is it treatment. It is a two-way interactive process with professional staff and others who aim to remediate or alleviate difficulties, adopting a holistic approach in which cognition, emotion, and psychosocial problems are treated together, aided by an increasing use of technological aids. NR enables people with disabilities to achieve their optimum level of well-being, reduce problems in everyday life, and help them return to the most appropriate environments. There may also be some partial or limited recovery of function and certainly some substitution of function. Accepting that return of normal functioning is highly unlikely, rehabilitation finds ways to help people learn more efficiently, compensate for their difficulties, and, when necessary, modify the environment. While theoretical models have proved helpful, indeed essential, in identifying cognitive strengths and weaknesses, in explaining phenomena, and in making predictions about behavior, they are insufficient, on their own, to seriously influence rehabilitation aimed at making lives more adaptable to problems encountered in everyday living. NR should focus on goals relevant to a person’s individual everyday life, it should be implemented in the environment where the person lives, and have personally meaningful themes, activities, settings, and interactions. We know from numerous studies that NR can be clinically effective. Although rehabilitation can be expensive in the short term, there is evidence that it is cost-effective in the long term.
Sara B. Festini, Laura Zahodne, and Patricia A. Reuter-Lorenz
Cognitive neuroimaging studies often report that older adults display more activation of neural networks relative to younger adults, referred to as overactivation. Greater or more widespread activity frequently involves bilateral recruitment of both cerebral hemispheres, especially the frontal cortex. In many reports, overactivation has been associated with superior cognitive performance, suggesting that this activity may reflect compensatory processes that offset age-related decline and maintain behavior. Several theories have been proposed to account for age differences in brain activation, including the Hemispheric Asymmetry Reduction in Older Adults (HAROLD) model, the Posterior-Anterior Shift in Aging (PASA) theory, the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH), and the Scaffolding Theory of Aging and Cognition (STAC and STAC-r). Each model has a different explanatory scope with regard to compensatory processes, and each has been highly influential in the field. HAROLD contrasts the general pattern of bilateral prefrontal activation in older adults with that of more unilateral activation in younger adults. PASA describes both anterior (e.g., frontal) overactivation and posterior (e.g., occipital) underactivation in older adults relative to younger adults. CRUNCH emphasizes that the level or extent of brain activity can change in response to the level of task demand at any age. Finally, STAC and STAC-r take the broadest perspective to incorporate individual differences in brain structure, the capacity to implement functional scaffolding, and life-course neural enrichment and depletion factors to predict cognition and cognitive change across the lifespan. Extant empirical work has documented that compensatory overactivation can be observed in regions beyond the prefrontal cortex, that variations in task difficulty influence the degree of brain activation, and that younger adults can show compensatory overactivation under high mental demands. Additional research utilizing experimental designs (e.g., transcranial magnetic stimulation), longitudinal assessments, greater regional precision, both verbal and nonverbal material, and measures of individual difference factors will continue to refine our understanding of age-related activation differences and adjudicate among these various accounts of neurocognitive aging.
Margaret Kathleen Pichora-Fuller
Age-related hearing loss is heterogeneous. Multiple causes can damage the auditory system from periphery to cortex. There can be changes in thresholds for detecting sound and/or in the perception of supra-threshold sounds. Influenced by trends in neuroscience and gerontology, research has shifted from a relatively narrow modality-specific focus to a broader interest in how auditory aging interacts with other domains of aging. The importance of the connection between sensory and cognitive aging was reported based on findings from the Berlin Aging Study in the mid-1990s. Of the age-related sensory and motor declines that become more prevalent with age, hearing loss is the most common, and it is the most promising as an early marker for risk of cognitive decline and as a potentially modifiable mid-life risk factor for dementia. Hearing loss affects more than half of the population by 70 years of age and about 80% of people over 80 years of age. It is more prevalent in people with dementia than in peers with normal cognition. People with hearing loss can be up to five times more likely to develop dementia compared to those with normal hearing. Evidence from cross-sectional studies has confirmed significant correlations between hearing loss and cognitive decline in older adults. Longitudinal studies have demonstrated that hearing loss is associated with incident cognitive decline and dementia. Various biological, psychological, and social mechanisms have been hypothesized to account for these associations, but the causes remain unproven. Nevertheless, it is widely believed that there is a meaningful interface among sensory, motor, and cognitive dysfunctions in aging, with implications for issues spanning brain plasticity to quality of life. Experimental research investigating sensory-motor-cognitive interactions provides insights into how age-related declines in these domains may be exacerbated or compensated. Ongoing research on auditory aging and how it interfaces with cognitive aging is expected to increase knowledge of the neuroscience of aging, provide insights into how to optimize the everyday functioning of older adults, and inspire innovations in clinical practice and social policy.
Determining the mechanisms that underlie neurocognitive aging, such as compensation or dedifferentiation, and facilitating the development of effective strategies for cognitive improvement is essential due to the steadily rising aging population. One approach to study the characteristics of healthy aging comprises the assessment of functional connectivity, delineating markers of age-related neurocognitive plasticity. Functional connectivity paradigms characterize complex one-to-many (or many-to-many) structure–function relations, as higher-level cognitive processes are mediated by the interaction among a number of functionally related neural areas rather than localized to discrete brain regions. Task-related or resting-state interregional correlations of brain activity have been used as reliable indices of functional connectivity, delineating age-related alterations in a number of large-scale brain networks, which subserve attention, working memory, episodic retrieval, and task-switching. Together with behavioral and regional activation studies, connectivity studies and modeling approaches have contributed to our understanding of the mechanisms of age-related reorganization of distributed functional networks; specifically, reduced neural specificity (dedifferentiation) and associated impairment in inhibitory control and compensatory neural recruitment.