Common brain diseases include dementia, Alzheimer's disease and Parkinson's disease, according to WebMD. These are neurodegenerative brain diseases. Other brain diseases include seizure disorders such as epilepsy and brain diseases that result from infections, such as meningitis.
Strokes are also common brain diseases, explains WebMD. There are several different types of stroke, including ischemic stroke, hemorrhagic stroke and transient ischemic attack. All of these conditions deprive the brain of blood flow and oxygen. In an ischemic stroke, a blood clot interrupts the flow of blood. The clot can develop in the brain or break off from a distant site and be caught in a blood vessel in the brain. In a hemorrhagic stroke, a blood vessel may bleed and damage the brain tissue. A transient ischemic attack occurs when blood and oxygen to the brain are temporarily interrupted. The person experiences the symptoms of a stroke, but these symptoms clear up within 24 hours, and the brain is left undamaged.
Dementia is a catch-all term for a decline in cognitive and mental function severe enough to impact the person's daily life, notes the Alzheimer's Association. Alzheimer's disease is a specific type of dementia. As of 2015, it is progressive and incurable.