After reading about the health of one of the books yesterday.
I found one of the diseases suffered by most people in the aging process.
The disease is dementia.  

Dementia is a condition of progressive collapse of intellectual ability after achieving the highest growth and development (age 15 years) due to organic brain disorders, followed by the collapse behavior and personality, manifested in the form of impaired cognitive functions such as memory, orientation, sense of heart and formation of the conceptual mind.
The main cause of the symptoms of dementia is Alzheimer's disease, vascular disease (blood vessel), Lewy body dementia and ten percent of which are caused by other diseases.
* The whole range of cognitive function is damaged.
* Initially impaired short-term memory.
* Personality and behavioral disorders, mood swings
* Motorcycle and focal neurologic deficit
* Easily offended, hostility, agitation and seizures
* Psychotic disorders: hallucinations, illusions, delusions & paranoia
* Agnosia, apraxia, aphasia
* ADL (Activities of Daily Living) hard
* Difficulty regulate the use of financial
* Not able to go home when traveling
* Forgot to put important items
* Difficult bathing, eating, dressing, toileting
* Patients can walk away from the house and could not go home
* Easy to fall, poor balance
* Finally, paralysis, urinary incontinence & alvi
* Unable to eat and swallow
* Comma and death
Fifty to sixty percent of the causes of dementia is Alzheimer's disease.
Alzhaimer is a condition in which nerve cells in the brain die, making the signal from the brain can not be transmitted properly.
Alzheimer's sufferers experiencing memory impairment, the ability to make decisions and also a decrease in the thinking process.
Dementia can occur at any age, but more in the elderly (ca. 5% for the age range 65-74 years and 40% for those aged > 85 years).

Maybe this is common in our grandparents .