What defines Alzheimer's disease?

Alzheimer's disease is characterized as a condition leading to progressive dementia. It is a neurodegenerative disorder that primarily affects memory, thinking, and behavior. As the disease advances, individuals may exhibit increasing cognitive decline, which eventually impacts their ability to perform everyday activities. The hallmark of Alzheimer's involves the accumulation of amyloid plaques and tau tangles in the brain, leading to neuronal damage and cognitive impairment.

In contrast, the other options refer to different medical conditions. A degenerative muscle condition pertains to diseases affecting muscle strength and function, which is unrelated to cognitive processes. An autoimmune disorder affecting the nervous system involves the immune system mistakenly attacking its own tissues, but this doesn't specifically define Alzheimer's. A congenital spinal defect is a structural abnormality present at birth, which does not relate to the degenerative and progressive nature of dementia seen in Alzheimer's disease.