Which disease specifically attacks the brain and results in impaired memory and thinking?

Alzheimer's disease specifically targets the brain, leading to progressive cognitive decline that significantly affects memory and thinking abilities. It is characterized by the buildup of proteins in the brain that cause neuronal damage and the subsequent loss of functional brain cells. As the disease advances, individuals experience greater difficulty with memory recall, reasoning, and eventually recognizing familiar faces or places, which distinctly separates it from other conditions listed.

Autism, while it involves the brain and can affect cognitive function, primarily impacts social interactions and communication rather than causing a global decline in memory and thinking in the way Alzheimer's does. Encephalitis is an inflammation of the brain usually caused by an infection and can lead to severe symptoms, but it does not specifically result in the gradual decline associated with memory and cognitive function that characterizes Alzheimer's. Bell's palsy is primarily related to facial muscle weakness due to nerve inflammation and does not directly affect cognitive abilities or memory. Thus, Alzheimer's is the most accurate choice regarding diseases that impair memory and thinking specifically.