[Age-related changes of sensory system].

Pathological processes usually superimpose on physiological aging even in the sensory system including visual, hearing, olfactory, taste and somatosensory functions. Representative changes of age-related changes are presbyopia, cataracts, and presbyacusis. Reduced sense of smell is seen in normal aging, but the prominent reduction detected by the odor stick identification test is noticed especially in early stage of Alzheimer or Parkinson disease. Reduced sense of taste is well-known especially in salty sense, while the changes of sweet, bitter, and sour tastes are different among individuals. Finally, deep sensation of vibration and proprioception is decreased with age as well as superficial sensation (touch, temperature, pain). As a result, impaired sensory system could induce deterioration of the activities of daily living and quality of life in the elderly.