Chapter 024. Gait and Balance Disorders (Part 2)

Disorders of GaitThe heterogeneity of gait disorders observed in clinical practice reflects the large network of neural systems involved in the task. There is the potential for abnormalities to develop, and walking is vulnerable to neurologic disease at every level. Gait disorders have been classified descriptively, based on the abnormal physiology and biomechanics. One problem with this approach is that many failing gaits look fundamentally similar. This overlap reflects common patterns of adaptation to threatened balance stability and declining performance. The gait disorder observed clinically must be viewed as the product of a neurologic deficit and a functional adaptation....
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Chapter 024. Gait and Balance Disorders (Part 2) Chapter 024. Gait and Balance Disorders (Part 2) Disorders of Gait The heterogeneity of gait disorders observed in clinical practice reflects thelarge network of neural systems involved in the task. There is the potential forabnormalities to develop, and walking is vulnerable to neurologic disease at everylevel. Gait disorders have been classified descriptively, based on the abnormalphysiology and biomechanics. One problem with this approach is that manyfailing gaits look fundamentally similar. This overlap reflects common patterns ofadaptation to threatened balance stability and declining performance. The gaitdisorder observed clinically must be viewed as the product of a neurologic deficitand a functional adaptation. Unique features of the failing gait are oftenoverwhelmed by the adaptive response. Some of the common patterns of abnormalgait are summarized below. Gait disorders can also be classified by etiology, aslisted in Table 24-1. Table 24-1 Etiology of Gait Disorder Cases PercentSensory deficits 22 18.3Myelopathy 20 16.7Multiple infarcts 18 15.0Parkinsonism 14 11.7Cerebellar degeneration 8 6.7Hydrocephalus 8 6.7Toxic/metabolic 3 2.5Psychogenic 4 3.3Other 6 5.0 Unknown cause 17 14.2 Total 120 100% Source: Reproduced with permission from Masdeu et al. Cautious Gait The term cautious gait is used to describe the patient who walks with anabbreviated stride and lowered center of mass, as if walking on a slippery surface.This disorder is both common and nonspecific. It is, in essence, an adaptation to aperceived postural threat. A fear of falling may be associated. In one study, thisdisorder was observed in more than one-third of older patients with a higher levelgait disturbance. Physical therapy often improves walking to the degree thatfollow-up observation may reveal a more specific underlying disorder. Stiff-Legged Gait Spastic gait is characterized by stiffness in the legs, an imbalance of muscletone, and a tendency to circumduct and scuff the feet. The disorder reflectscompromise of corticospinal command and overactivity of spinal reflexes. Thepatient may walk on his or her toes. In extreme instances, the legs cross due toincreased tone in the adductors. Upper motor neuron signs are present on physicalexamination. Shoes often reflect an uneven pattern of wear across the outside. Thedisorder may be cerebral or spinal in origin. Myelopathy from cervical spondylosis is a common cause of spastic orspastic-ataxic gait. Demyelinating disease and trauma are the leading causes ofmyelopathy in younger patients. In a chronic progressive myelopathy of unknowncause, workup with laboratory and imaging tests may establish a diagnosis ofmultiple sclerosis. A family history should suggest hereditary spastic paraplegia(HSP). Genetic testing is now available for some of the common HSP mutations.Tropical spastic paraparesis related to the retrovirus HTLV-I is endemic in parts ofthe Caribbean and South America. A structural lesion, such as tumor or spinalvascular malformation, should be excluded with appropriate testing. Spinal corddisorders are discussed in detail in Chap. 372. With cerebral spasticity asymmetry is common, involvement of the upperextremities is usually observed, and dysarthria is often an associated feature.Common causes include vascular disease (stroke), multiple sclerosis, and perinatalinjury to the nervous system (cerebral palsy). Other stiff-legged gaits include dystonia (Chap. 382) and stiff-personsyndrome. Dystonia is a disorder characterized by sustained muscle contractions,resulting in repetitive twisting movements and abnormal posture. It often has agenetic basis. Dystonic spasms produce plantar flexion and inversion of the feet,sometimes with torsion of the trunk. In autoimmune stiff-person syndrome, thereis exaggerated lordosis of the lumbar spine and overactivation of antagonistmuscles, which restricts trunk and lower limb movement and results in a woodenor fixed posture.