Stiff-person syndrome, an unusual nondystonic disorder causing severe axial muscle spasm, causes stiffness of the legs and buttock muscles, slow propulsion, and lumbar lordosis; there is sometimes a mild superimposed ataxic disturbance of gait (see Chap. 46). Another unusual disorder affecting the body position during walking is camptocormia, a severe forward bending of the trunk at the waist that is symptomatic of either a dystonia, Parkinson disease, or one of several muscle diseases that focally weaken the extensors of the spine. Kyphosis due to spinal deformities does the same and all of these conditions cause the patient to walk while looking at the ground beneath the feet, but they rarely cause falling.
Waddling (Gluteal, or Trendelenburg) Gait
This gait is characteristic of the gluteal muscle weakness that is seen in the progressive muscular dystrophies, but it occurs as well in chronic forms of spinal muscular atrophy, in certain inflammatory myopathies, lumbosacral nerve root compression, and with congenital dislocation of the hips.
In normal walking, as weight is placed alternately on each leg, the hip is fixated by the gluteal muscles, particularly the gluteus medius, allowing for a slight rise of the opposite hip and tilt of the trunk to the weight-bearing side. With weakness of the glutei, however, there is a failure to stabilize the weight-bearing hip, causing it to bulge outward and the opposite side of the pelvis to drop, with inclination of the trunk to that side. The alternation in lateral trunk movements results in the roll or waddle. With unilateral gluteal weakness, often the result of damage to the first sacral nerve root, tilting and dropping of the pelvis (“pelvic ptosis”) is apparent on only one side as the patient overlifts the leg when walking.
In several of the muscular dystrophies, an accentuation of lumbar lordosis is often seen. Also, childhood cases may be complicated by muscular contractures, leading to an equinovarus position of the foot, so that the waddle is combined with walking on the toes (“toe walking”).
This unusual fast tremor of the legs may devastate gait. As discussed in Chapter 4, “Disorders of Movement and Posture”, it is present only when the patient stands or exerts force with the legs while seated. The tremor ceases upon walking. In reaction to a perception of severe imbalance, which is characteristic of the disorder, the patient assumes a widened and often stiff-legged stance.
Gait Disorder in Normal Pressure Hydrocephalus (See Also Chap. 29)
Progressive difficulty in walking is typically the initial and most prominent symptom of normal pressure hydrocephalus (NPH). However, the gait disturbance in NPH has few specific features. Certainly, it cannot be categorized as ataxic or spastic or what has been described as “apraxic” gait; nor does it have more than a superficial resemblance to parkinsonian gait. Its main early features—slowness in lifting the feet from the floor (called in some texts “magnetic gait”), reduced cadence, widened base, and short steps—may be misconstrued as compensations observed in patients with all manner of gait disorders. Patients with the gait disorder of NPH may complain of a sense of imbalance or vague dizziness, but most have difficulty in articulating the exact problem.