Gait Disorders and Ataxia

Peripheral neuropathy refers to lack of sensation (or in a number of cases, burning, tingling pain) beginning in the bottom of the feet (often in the toes), spreading gradually up the legs symmetrically.

Peripheral neuropathy affects the balance because we are very reliant on the information coming from the bottom of the feet to tell us where the ground is, and we are nearly continuously making micro-adjustments in our feet, toes, and ankles to maintain our center of gravity. If the sensory information coming from the feet is absent or delayed, these adjustments either do not occur or are delayed, causing patients to lose their balance or stagger.

Diagnosis: Most cases of peripheral neuropathy can be diagnosed clinically but occasionally nerve conduction studies are required. This entails applying an electrical current to the nerve, stimulating the nerve, and measuring the response down the nerve. There is no damage to the nerve with electrical stimulation and typically only a mild, temporary discomfort associated. Certain blood tests are usually required to assess for the cause of neuropathy. The most common causes of neuropathy are diabetes, vitamin B12 deficiency, alcohol-related, and age-related.

Treatment: Treatment of sensory ataxia depends on the cause of the neuropathy. For example, vitamin B12 deficiency is treated with vitamin B12 supplementation (typically starting with injections then switching to oral); diabetic neuropathy is managed by maintaining tight sugar control. Regardless of the cause of neuropathy, balance and gait are often improved by physical therapy.

Subtle changes in the gait (a person’s manner of walking) are one of the first symptoms and signs of PD. Patients may not be aware of these changes but astute family members can point out slightly reduced arm swing on one side, reduced stride length or clearance from the floor (causing the appearance of dragging one leg) and stooped posture. Shuffling gait is sometimes better heard than seen, especially since it is commonly asymmetric at onset.

Balance is often affected in Parkinson’s disease, with many patients having a delayed righting reflex causing them to fall backwards spontaneously or when pulled. The stooped posture which is typical of Parkinson’s disease causes the center of gravity to move away from the center of mass, resulting in a gait where the upper body is propelling forward movement and the feet have to move quickly to catch up. These small, short, quickening steps are known as festinating gait. The balance is primarily affected on turns, resulting in increased steps to turn around, known as turning en bloc. Freezing gait refers to the gait getting stuck, with the legs seeming to be stuck to the floor.

Atypical parkinsonism refers to conditions with symptoms similar to that of PD (rigidity, tremor, slow or delayed movements), as well as other symptoms. Two examples, progressive supranuclear palsy (PSP) and primary freezing of gait (FOG), are commonly associated with frequent falls early in the course of the disease.

Clinically, certain gait disorders can be described as gait apraxia, where the strength, sensation and coordination are intact but the act of “putting it all together” in the brain is problematic. The gait may appear to be a combination of awkward, magnetic (stuck to the floor), cautious, slow, and shuffling. This is also known as a frontal gait disorder, referring to the frontal lobe conditions which often cause gait apraxia. Patients with a suspected frontal gait disorder should undergo brain imaging to assess for evidence of specific brain conditions that can affect the frontal lobe and its connections.

Common causes of frontal gait disorders include vascular disease, Alzheimer’s disease, and hydrocephalus.

Vascular disease is easily diagnosed via MRI and is notable for lesions in the white matter caused by shutting down of small blood vessels in the brain, usually caused by risk factors such as smoking, high blood pressure, high cholesterol and diabetes. Even in the absence of these risk factors, the aging process alone can cause these lesions. These lesions are not necessarily associated with stroke-like events or stroke-like symptoms, and therefore may be considered silent strokes, accumulating slowly and gradually over the years and eventually affecting gait and balance.

Treatment of vascular causes of gait disorders includes management of risk factors by quitting smoking, keeping blood pressure and cholesterol in the normal range, and keeping sugar under good control. Medications such as aspirin may reduce the formation of blood clots, but it is not clear whether this would have a major effect on the gait disorder, unfortunately. Patients do improve with physical therapy and balance training.

Alzheimer’s disease is the most common cause of dementia. Initially this presents with memory loss and difficulty taking care of activities of daily living, but gradually over the years, the gait and balance are affected. The best description is that the patient forgets how to walk, getting stuck in their steps. Most patients with advanced Alzheimer’s require wheelchairs by the end of the disease. Treatment of Alzheimer’s disease includes donepezil (Aricept), rivastigmine (Exelon), and memantine (Namenda). Patients may improve somewhat with physical therapy and gait training.

Hydrocephalus refers to excess water (fluid) in the ventricles of the brain. Cerebrospinal fluid (CSF) normally exists inside and around the brain to cushion the brain. There is a system of creating and reabsorbing CSF which usually keeps the fluid levels optimized, but in hydrocephalus there is either too much fluid being produced or a blockage in the absorption. Excess fluid in the brain can put pressure on the deep structures of the brain, including the fibers that connect the cortex (outer brain lobes) to the thalamus (relay station) and brainstem / spinal cord.

Normal pressure hydrocephalus (NPH) differs from other causes of hydrocephalus in that there is no blockage of the flow of fluid, thus the fluid is under normal pressure. NPH is suspected based on findings on MRI of enlarged ventricles and the appearance of fluid seeping into the brain from the ventricles; the diagnosis is confirmed based on response of symptoms after drainage of spinal fluid via a lumbar puncture. If the results are unclear, longer periods and volumes of drainage may be necessary.

Garni Barkhoudarian, MD, and Daniel Franc, MD, PhD, at the Pacific Adult Hydrocephalus Center specialize in the diagnosis and treatment of hydrocephalus. Treatment of NPH involves more permanent drainage of CSF, shunting away from the brain and into the abdominal space using an internalized ventriculoparietal shunt (VP shunt). Shunts are typically implanted with programmable valves to help fine-tune the amount of CSF drainage. This is conducted with subjective and objective tests during routine follow-up visits, typically upwards of 3-6 months after surgery.

Ataxic gait refers to a staggering gait, with variability of the step timing and distance between the steps. Ataxic gait disorders occur due to dysfunction of the cerebellum, the part of the brain that is responsible for coordination of movements.

Typical causes of cerebellar ataxia include strokes in the cerebellum, alcohol intoxication or chronic alcohol abuse, and multiple system atrophy – cerebellar type (MSA-C). Multiple sclerosis (MS) can also cause cerebellar ataxia when there are lesions in the cerebellum.

More rare causes include spinocerebellar ataxia (SCA), of which there are 60+ subtypes and more being identified via genetic testing on a frequent basis, and autosomal recessive cerebellar ataxia (ARCA), a genetic cause of ataxia in which both parents are carriers. Family history may not reveal any patterns, especially in a small family, even though the cause is genetic. Other clinical signs and symptoms may point to a specific spinocerebellar ataxia syndrome, e.g., eye movement abnormalities, sensory neuropathy, seizures, or cognitive decline.

Diagnostic tests include MRI of the brain, blood work, DaTscan if there are signs of parkinsonism, genetic testing, and sometimes nerve conduction studies.

Treatment depends on the underlying cause but typically involves physical therapy and avoidance of alcohol intake. Unfortunately there are no medications that boost the balance or cerebellar function.

After a fall or near-fall, patients often modify their gait patterns for fear of falling, resulting in what is called cautious gait. If you imagine a person walking on ice, you can get a good picture of a cautious gait: legs are further apart, stiff-legged, slow, feet kept closer to the ground, arms held out with reduced arm swing. These symptoms often improve somewhat when holding onto a companion’s arm. Patients with cautious gait disorders improve greatly with physical therapy and balance training.

At Pacific Movement Disorders Center, we work closely with physical therapists at Performance Therapy, located across the street from our clinic at Providence Saint John’s Health Center. They have physical therapists who specialize in gait and balance improvement, utilizing the latest technologies including the Alter-G treadmill. This technique allows patients to improve their gait pattern in a reduced-gravity setting, eliminating the risk of falls.

Muscular problems such as myopathy can cause weakness in the leg muscles, resulting in legs “giving way” or knees buckling. Pelvic girdle weakness can cause a waddling gait. (Pregnant women often have a waddling gait due to stretching of the pelvis.) Compression of the nerve or nerve root (peroneal neuropathy or lumbar radiculopathy, respectively) that gives information to the anterior calf muscle can cause weakness in elevating the foot, causing foot drop. This may manifest as a steppage gait where the patient tries to compensate for the foot drop by lifting the leg higher at the level of the hip.

Treatment for these conditions depends on the underlying cause. Some causes of myopathy are treated with immunosuppressant medication; some causes of nerve or nerve root compression require surgical decompression. Physical therapy for foot drop may include nerve or muscle stimulation, depending on the cause. The use of an ankle-foot orthotic (foot brace) helps patients minimize the risk of falls from foot drop. Regardless of cause, the mainstay of treatment for gait disorders caused by nerve or muscle disorders involves physical therapy with a strengthening and conditioning program.

Problems in the spinal cord or brain can cause the muscles to be too tight and not relaxed enough, resulting in a stiff-legged or cross-legged gait known as a spastic or scissoring gait. Spasticity most commonly occurs after a stroke, where it typically affects one half of the body. Spasticity can also affect both legs in the case of multiple sclerosis (MS), or metabolic or degenerative causes of spinal cord disease.

Treatment for spastic gait includes anti-spasmodic medications such as baclofen, tizanidine (Xanaflex), cyclobenzaprine (Flexeril) and carisoprodol (Soma). However, these medications often cause drowsiness, dizziness and muscle weakness.

Injection of botulinum toxin (Botox or Xeomin) can significantly reduce muscle overactivity without causing any sedation. By relaxing tight muscles, botulinum toxin injections result in a smoother gait and less spasm in the feet, legs or thighs. At Pacific Movement Disorders Center, we provide EMG-guided botulinum toxin injections to target the most overactive muscles of the legs. Injections take about 20-30 minutes and are repeated 3-4 times per year.

Conditions affecting the inner ear cause trouble with equilibrium and symptoms of room spinning, known as vertigo. Often this is a severe but temporary affliction, as seen in cases of benign paroxysmal positional vertigo or vestibular neuritis. Chronic vestibular dysfunction can cause gait imbalance, but can be treated with vestibular therapy, a specialized form of physical therapy. Vestibular diseases should be evaluated by an ear-nose-throat specialist to assess for conditions such as Meniere’s disease. Our colleagues have expertise in vestibular testing and treatment of Meniere’s disease and related inner-ear conditions.