Which condition is characterized by impaired blood flow to the brain?

Vascular dementia is specifically characterized by impaired blood flow to the brain, which can lead to damage to brain cells. This impaired circulation results from various factors, including stroke, small vessel disease, or other conditions that block blood flow to the brain. Such interruptions in blood supply can lead to cognitive decline, memory loss, and other symptoms commonly associated with dementia.

In contrast, the other forms of dementia listed have different underlying causes. Psychoactive dementia is not a widely recognized category of dementia in medical literature, and its definition can vary. Frontotemporal dementia is primarily related to the degeneration of the frontal and temporal lobes and is typically linked to specific genetic mutations and protein deposits rather than blood flow issues. Alzheimer's disease is characterized by the buildup of amyloid plaques and tau tangles in the brain, impacting memory and cognitive function without the primary role of impaired blood flow. Thus, the distinguishing feature of vascular dementia is the clear link to blood flow disruption in the brain.