Among elderly persons without apparent neurologic disease, falls constitute a major health problem. Approximately 30 percent suffer one or more falls each year; this figure rises to 40 percent among those older than age 80 years and to more than 50 percent among elderly persons living in nursing homes. According to Tinetti and Speechley, 10 to 15 percent of falls in the elderly result in fractures and other serious injuries; they are reportedly an underlying cause of about 9,500 deaths annually in the United States.
Several factors, some mentioned earlier in regard to deterioration of gait, are responsible for the inordinately high rate of falling among older persons. Impairment of visual function and particularly of vestibular function with normal aging are important contributors. In a group of 34 elderly patients who were free of neurologic disease, postural hypotension, and leg deformities, Weiner and colleagues found a moderate or severe degree of postural reflex impairment in two-thirds. The failure to make rapid postural adjustments, which is a product of aging alone, accounts for the occurrence of falls in the course of usual activities such as walking, changing position, or descending stairs. Orthostatic hypotension, often because of antihypertensive agents and the use of sedative drugs, is another important cause of falling in the elderly.
Of course, falling is an even more prominent feature of certain age-related neurologic diseases: stroke, Parkinson disease, normal-pressure hydrocephalus, and progressive supranuclear palsy, among others.
Other Restricted Motor Abnormalities in the Aged
These are too numerous to be more than catalogued. They reflect the many ways in which the motor system can deteriorate. Compulsive, repetitive movements are the most frequent: mouthing movements, stereotyped grimacing, protrusion of the tongue, side-to-side or to-and-fro tremor of the head, odd vocalizations such as sniffing, snorting, and bleating. In some respects these disorders resemble tics (quasivoluntary movements to relieve tension), but careful observation shows that they are not really voluntary. Haloperidol, tetrabenazine, and other drugs of this class have an unpredictable therapeutic effect, seeming at times to benefit the patient perhaps in part by the superimposition of a drug-induced rigidity.
Old age is thought always to carry a liability to tremulousness, and indeed, one sees this association with some frequency. The head, chin, or hands tremble and the voice quavers, yet there is not the usual slowness and poverty of movement, facial impassivity, or flexed posture that would stamp the condition as parkinsonian. Some instances of tremor are clearly familial, having appeared or worsened only late in life. However, the relation of tremulousness to aging is sometimes open to doubt. Charcot, in a review of over 2,000 elderly inhabitants of the Salpêtrière
Hospital, could find only about 30 with tremor. Some cases probably represent the exaggeration or emergence of essential tremor, but many cases cannot be explained on this basis. Spastic or spasmodic dysphonia, a disorder of middle and late life characterized by spasm of all the throat muscles on attempted speech, is discussed in Chap. 4.
Not to be minimized are the limitations of movement and gait that result from degenerative orthopedic conditions that accompany aging, foremost limitations in the range of motion of the hips, knees, and spine. These contribute greatly to the aforementioned global appearance of truncal and limb control of the aged. Some peculiar aspects that have come to our attention because they simulate neurological problems include a “tall-man” syndrome, in which a gentleman may not be able to arise from a chair because the knees cannot be flexed adequately to plant the feet behind the trunk and push off to stand.
Morphologic and Physiologic Changes in the Aging Nervous System