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.
For this reason, and because symptoms could signal any of a number of diagnoses, it is always worthwhile seeing a doctor. Alzheimer's disease is a neurological disorder in which the death of brain cells causes memory loss and cognitive decline.A neurodegenerative type of dementia, the disease starts mild and gets progressively worse.or this reason, and because symptoms could signal any of a number of diagnoses, it is always worthwhile seeing a doctor. Alzheimer's disease is a neurological disorder in which the death of brain cells causes memory loss and cognitive decline.