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 is characterized by a progressive loss of brain cells and other irregularities of the brain. Other causes. Other possible causes of memory loss include an underactive or overactive thyroid gland and infections such as HIV, tuberculosis, and syphilis that affect the brain.