Aging affects all aspects of the nervous system, from mental status to motor and sensory function and reflexes. Brain volume, cortical brain cells, and intrinsic regional connecting networks decrease, and both microanatomical and biochemical changes have been identified. Nevertheless, most older adults maintain their self-esteem and adapt well to their changing capacities and circumstances.

Mental Status. 

Although older adults generally perform well on mental status examinations, they may display selected impairments, especially at advanced ages. Many older people complain about memory problems. This is usually from "benign forgetfulness," which can occur at any age. This term refers to difficulty recalling the names of people or objects or details of specific events. Identifying this common phenomenon can allay fear of Alzheimer disease. Older adults also retrieve and process data more slowly and take longer to learn new information. Their motor responses may slow and their ability to perform complex tasks may diminish.

Frequently, the clinician must try to distinguish these age-related changes from manifestations of mental disorders that are prevalent in older adults like depression and dementia. Diagnosis can be difficult because both mood disturbances and cognitive changes can alter the patient's ability to recognize or report symptoms. Older patients are also more susceptible to delirium, a temporary state of confusion that may be the first clue to infection, problems with medications, or impending dementia. It is important to recognize these conditions promptly to delay functional decline. Recall that sensory and motor findings in older patients that are physiologic, such as the changes in hearing; vision; extraocular movements; and pupillary size, shape, and reactivity, are abnormal 

in younger adults.

Motor System. 

Changes in the motor system are common. Older adults move and react with less speed and agility and skeletal muscles decrease in bulk. The hands of an older patient often look thin and bony due to atrophy of the interosseous muscles that leaves concavities or grooves. Muscle wasting tends to appear first between the thumb and the hand (first and second metacarpals), then affects the other metacarpals (see pp. 741–742). It may also flatten the thenar and hypothenar eminences of the palms. Arm and leg muscles can show signs of atrophy, exaggerating the apparent size of adjacent joints. Muscle strength, though diminished, is relatively well maintained.

Occasionally, older adults develop a benign essential tremor in the head, jaw, lips, or hands that may be confused with parkinsonism. Unlike parkinsonian tremors, however, benign tremors are slightly faster and disappear at rest, and there is no associated muscle rigidity.

Position and Vibratory Sense; Reflexes. 

Aging can also affect vibratory and position sense and reflexes. Older adults frequently lose some or all vibration sense in the feet and ankles (but not in the fingers or over the shins). Less commonly, position sense may diminish or disappear. The gag reflex may be decreased or absent. Abdominal reflexes may diminish or disappear. Ankle reflexes may be symmetrically decreased or absent, even when reinforced. Less commonly, knee reflexes are similarly affected. Partly because of musculoskeletal changes in the feet, the plantar responses become less obvious and more difficult to interpret. If there are associated abnormal neurologic findings, or if atrophy and reflex changes are asymmetric, search for an explanation other than aging.

Older adults experience the death of loved ones and friends, retirement from valued employment, diminution in income, and often growing social isolation in addition to physiologic changes and decreased physical capacity. Including the impact of these significant life events in the assessment of mood and affect and addressing these issues may improve the patient's quality of life.

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