Clinically AD is characterized by sinister onset, slowly progressive and sporadic disorder, with episodic memory; instrumental signs include aphasia, apraxia, and agnosia, together with general cognitive symptoms, such as impaired judgment, decision-making, and orientation [103]. There are two opinions about the onset of aging. One view is that, it is genetically programmed developmental processes, like the cell senescence, the neuro-endocrine and immunological changes.
