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.
The intensive research aiming at curing Parkinson's disease with stem cells is a good example for the various strategies, successful results, and remaining challenges of stem cell-based brain repair. Parkinson's disease is a progressive disorder of motor control that affects roughly 2% of persons 65 years and older.