Misfolded Proteins and Cognitive Decline: Mechanistic Insights into Neurodegenerative Disorders.

Cognitive decline represents one of the most common clinical manifestations of neurodegenerative diseases (NDs), substantially affecting the quality of life of both patients and their families. Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis are major NDs characterized by a progressive degeneration of the central nervous system, with functional impairments extending beyond motor symptoms to multiple cognitive domains, including memory, attention, language, and executive functions. Increasing evidence highlights misfolded protein accumulation as a key driver of neuronal dysfunction and cognitive deterioration. This narrative review examines the major cognitive deficits associated with these disorders, focusing on the underlying molecular mechanisms, particularly protein aggregation, as well as clinical manifestations and their effects on daily life. Furthermore, current diagnostic tools and emerging therapeutic options for mitigating cognitive decline will be further discussed.