Setting aside the notion of determining the number of individual animals on the planet for a moment, merely determining the number of species on the Earth is challenging. Science has only been able to offer estimates thus far, and totals vary greatly.
People who have early onset Alzheimer's may be in any stage of dementia â early stage, middle stage or late stage. The disease affects each person differently and symptoms will vary. If you are experiencing memory problems: 1  Have a comprehensive medical evaluation with a doctor who specializes in Alzheimer's disease.
Brain diseases come in different forms. Infections, trauma, stroke, seizures, and tumors are some of the major categories of brain diseases. Here's an overview of various diseases of the brain. Brain diseases in the category of infections include: Meningitis: An inflammation of the lining around the brain or spinal cord, usually due to infection; Neck stiffness, headache, fever, and confusion are common symptoms.