The average age for cataract surgery is approximately 73 to 75 years old. But cataracts can occur in the 30s, 40s, and 50s. Of course the older the patient gets the more common the cataracts.
Two neurotransmitters seem to play a role in Alzheimer's Disease: acetylcholine and glutamate. Acetylcholine (ACh) activates muscles and helps with arousal, short-term memory, and learning. Individuals with AD have low levels of ACh.
Alzheimer's disease - Causes. Causes of Alzheimer's disease. Alzheimer's disease is caused by parts of the brain shrinking (atrophy), which affects the structure and function of particular brain areas. It's not known exactly what causes this process to begin. However, in the brains of people with Alzheimer's disease, scientists have found amyloid plaques (abnormal deposits of protein), neurofibrillary tangles (containing tau) and imbalances in a chemical called acetylcholine.