Neurological Examination of the Older Adult

Joseph I. Sirven

Elliott L. Mancall

The neurologic examination, for the most part, is an exercise in detailed observation, consisting of two tasks: (a) localizing the part of the nervous system that is malfunctioning, and (b) identifying the cause for that malfunction. Every aspect of the patient’s behavior, including the way he or she sits, speaks, and responds, tells the physician about nervous system function. However, in older adults, the parameters of a normal neurologic examination require redefining, and the results from a neurologic examination must be considered within the context of known age-related changes. Thus, findings in older patients that suggest pathology may not be pertinent if such findings occur frequently at advanced ages. Table 2-1 describes the normal morphologic and physiologic changes in the aging nervous system.

In his seminal papers on the neurologic changes in the aged, Critchley (2,3) identified several changes that occur in the neurologic examination. These were subsequently confirmed by other reviews (1,4). Changes tend to affect the visual, auditory, olfactory, motor, and sensory nervous systems. The most consistent of the neurologic signs of aging are shown in Table 2-2.

MENTAL STATUS EXAMINATION

Changes in mental status functioning that occur with aging may be apparent on formal standardized tests of mental status, but they are difficult to detect clinically. Older patients are generally alert and have normal levels of consciousness. It is abnormal for an older patient not to maintain orientation to time, place, and situation. Judgment is expected to be normal, and calculations and thought content are equally unaffected unless a pathologic process is present. Remote and recent memory is usually normal; however, the speed of processing and retrieving information slows. Thus, when abnormalities of speech or language are noted, an underlying brain lesion must be considered. For a detailed discussion regarding mental functioning, see Chapter 6.

Table 2-1. Age-Related Nervous System Changes

Neuroanatomic Location	Change
Anterior horn cells, sensory ganglion	Decline of 25%
Brain weight	Weight decline of 233 g from third decade to sixth to seventh decade
Hippocampus	Neuronal loss and gliosis by 27%
Neuronal cytoplasm	Increased accumulation of lipofuscin granules
Nerve roots	Accumulation of amyloid
Blood vessels and flow	Hyalinization of the walls of small blood vessels
	Cerebral flow declines with age with an increase in cerebrovascular resistance
Neurotransmitters	Decline in the concentrations of acetylcholine, norepinephrine, dopamine, and gamma-aminobutyric acid
Muscles and peripheral nerves	Skeletal muscle fiber loss with concomitant atrophy
	Myelin changes occur with a decrease in conduction velocity
	Loss of motor and sensory axons

CRANIAL NERVE CHANGES

Cranial nerve abnormalities are rarely associated with normal aging, yet important exceptions are seen. Changes in hearing, particularly progressive hearing loss (presbycusis), especially for high tones, are commonly observed, as is a decline in speech discrimination. These changes are secondary to a reduction in the number of hair cells in the organ of Corti. Similarly, olfaction generally declines symmetrically with age; the key to a pathologic process is finding asymmetric loss. Changes in visual acuity are almost always related to abnormalities in the eye and do not reflect changes in visual neural circuits. Pathologic conditions (e.g., cataracts, glaucoma, and other
causes) must be sought in patients complaining of diminished vision and not be attributed to normal aging. Aging does not cause a change in the appearance of the retina. Thus, funduscopic changes should be considered abnormal, and consideration should be given to systemic causes such as diabetes.

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