Cognitive deficits (intellectual disability) begin in childhood and cause impaired ability to learn and function. Impairment level is categorized as mild, moderate, severe, or profound. Causes include genetic abnormalities such as Down syndrome, premature birth, exposure to toxins, and others. Symptoms include developmental delay, behavioral issues, or difficulties in school. There is no specific treatment, but some may benefit from dietary changes, medications, and therapies.
Dementia is a blanket term to describe significant cognitive and memory decay that could be caused by a number of different conditions. A stroke is a bleed or blockage in the blood vessels that may starve parts of the brain of oxygen. Thought and memory impairment due to a stroke is called vascular dementia. Medications and behavioral therapy may prevent further strokes and slow cognitive decline, but stroke damage cannot be repaired after more than a few hours after the event.