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.
Dementia causes. Dementias can be caused by brain cell death, and neurodegenerative disease - progressive brain cell death that happens over time - is associated with most dementias. However it is not known if the dementia causes the brain cell death, or the brain cell death causes the dementia. But, as well as progressive brain cell death, like that seen in Alzheimer's disease, dementia can be caused by a head injury, a stroke, or a brain tumor, among other causes.