The Role of Cognitive Reserve in Neurodegenerative Disorders: A Systematic Review of Neuroimaging Evidence

Le résumé fourni par la source

Neurodegenerative disorders are characterized by progressive brain changes that lead to significant cognitive and physical impairments. Although these conditions differ in their specific clinical features, they share common underlying mechanisms, including neuronal loss, disrupted neural signaling, and chronic inflammation. Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and multiple sclerosis (MS) represent key examples of these disorders, each illustrating different pathways through which neurodegeneration alters brain function (Drukker et al., 2021; Gadhave et al., 2024). The prevalence of these conditions is steadily increasing, largely due to rising life expectancy and the aging of the global population (World Alzheimer Report 2021: Journey through the Diagnosis of Dementia, 2021). Interestingly, individuals with similar levels of neuropathology can show different cognitive outcomes, suggesting the presence of compensatory mechanisms that help preserve function. One such mechanism is cognitive reserve (CR), defined as the brain’s capacity to adapt to damage by using lifelong experiences such as education, work, and leisure activities (Stern et al., 2019). Higher CR has been associated with delayed symptom onset and reduced clinical impact of neurodegeneration (Negash et al., n.d.; Pettigrew et al., 2017). CR may support this resilience by enabling the recruitment of alternative networks or more efficient neural pathways (de Souza-Talarico et al., 2016; McQuail et al., 2021). Advances in neuroimaging have further deepened understanding of CR, demonstrating how structural and functional brain characteristics contribute to the ability to cope with disease-related damage (Stern et al., 2019). Clarifying how CR interacts with molecular mechanisms, brain structure, and neural activity is essential for improving early detection and informing targeted preventive or therapeutic strategies. This systematic review will examine the role of CR as a protective factor in AD, PD, HD, and MS, with a particular focus on neuroimaging-based evidence. By synthesizing findings on brain structure, functional connectivity, and relevant biomarkers, this review aims to clarify the neural mechanisms through which CR influences disease progression. We hypothesize that neuroimaging studies will show that patients affected by neurodegenerative diseases with higher CR exhibit more efficient and flexible recruitment of neural networks. The protective effects of CR are expected to be observable across all four disorders, although they may involve disorder-specific neural pathways. Ultimately, a better understanding of these processes may help explain individual variability in cognitive trajectories and support the development of strategies to enhance resilience and improve quality of life for individuals affected by neurodegenerative conditions.

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