Gait and Balance Problems
Gait and balance problems exist when a disease process, trauma, or aging result in the inability to control one's center of gravity (COG) over the base of support (BOS) in static or dynamic tasks and environments.
Any number of factors may contribute to gait and balance problems. Postural control, the task that involves controlling one's position in space, involves maintaining a relationship among the body, the task at hand, and the given environment. Difficulty in maintaining an appropriate relationship may occur due to:
- impaired sensory processes (visual, vestibular, somatosensory)
- inadequate neuromuscular responses (signaling of brain to/from muscle)
- musculoskeletal problems (impaired range of motion, strength, flexibility)
- decreased cognition (inability to anticipate or adapt to postural needs)
Due to the wide variety of factors, many individuals can be affected with gait and balance problems at some point in their lives. Inability of peripheral sensory receptors to gain information about the environment results in the inability to use that information for postural control. This type of loss may occur in people who have visual, vestibular, or somatosensory deficits not based in the central nervous system (CNS). Examples include, but are not limited to, diabetic retinopathy, cataracts, glaucoma, temporal bone fracture, acoustic neuroma, Ménière's disease, spinal cord injury, peripheral neuropathy, and amputation.
The CNS is responsible for integrating the environmental information that is supplied through peripheral sensory receptors; this is called sensory processing. Motor planning, on the other hand, is an individual's ability to plan movement to accomplish a task. Individuals who have experienced injury to the CNS in the form of a stroke, brain trauma, or disease process like multiple sclerosis, Parkinson's or cerebellar ataxia, may exhibit gait and balance problems due to difficulty with sensory processing and/or motor planning.
Musculoskeletal problems, whether orthopedic or neurologic in origin, can contribute to balance and gait difficulties because certain levels of mobility and strength are required to execute movements within functional parameters. Automatic postural strategies, such as an ankle or hip strategy, operate to keep the body over the center of gravity when a disturbance to balance is presented. The larger the disturbance is, the more intense the response. If there is inadequate range of motion at the
ankle, or weakness in hip musculature, these strategies cannot be adequately used.
Impaired cognition is an important contributor to balance and gait problems. Poor attention, decreased judgment and slow processing can increase risk of loss of balance. Without awareness of environmental hazards and necessary safety precautions, patients who have had a stroke or brain trauma have an increased propensity to fall.
Cerebellar lesions are one cause of disturbed balance. Depending upon the area affected, the disturbance may be slight or severe. The cerebellum also contains proprioceptive feedback loops, in addition to receiving input from the spinal cord. When these areas are affected, the postural changes that take place affect balance. It is very common to find gait problems in conjunction with cerebellar lesions; in one study, 60% of patients with cerebellar problems displayed ataxic gait, which resembles intoxicated gait.
Basal ganglia dysfunction
The basal ganglia are three nuclei at the base of the cerebral cortex. It appears that the basal ganglia play a large role in preparing an individual for motion. This may include preparing the cortex, setting postural reflexes, and organizing sensory input. When there is dysfunction in this area, such as in Parkinson's or Huntington's disease, disturbances in central sensory processing, along with rigidity and akinesia (inability to move), contribute to postural instability and gait difficulties.
Hemiplegia (paralysis of one side of the body) as a result of a cerebrovascular accident, or stroke, is also a common cause of balance and gait difficulties. Loss of trunk control results in the inability to maintain weight evenly over the pelvis. In the early stages of recovery, along with upper extremity dysfunction, lower extremity positioning in standing may be marked by pelvic depression, hip and knee flexion (decreasing the angle of the joints), and ankle plantarflexion on the affected side. Later, extensor patterns (increasing the angle of the joints) become more available, and the pelvis may be elevated, with the knee hyperextended and ankle plantarflexed. Sensory loss may manifest itself in many ways, from loss of discrimination and localization to complete neglect of the affected side. All of these factors contribute to balance and gait problems due to inadequate sensory processing, musculoskeletal tightness or weakness, and/or cognitive deficits.
While problems with central processing of vestibular input can create balance and gait difficulties in individuals with CNS problems, peripheral vestibular hypo-function (the under-functioning of inner ear structures associated with balance) also is a common contributor to balance deficits. Peripheral vestibular hypofunction may result from temporal bone fracture, acoustic neuroma, ototoxicity (damage to the eighth cranial nerve due to aminoglycoside antibiotics), or unknown causes. One or both sides may be damaged, resulting in dizziness and vertigo that lead to decreased balance.
Although these are some of the main pathologies that are known to cause balance and gait problems, any disease process or trauma resulting in impairments of sensory processing, neuromuscular response, musculoskeletal
The pathologies that underlie gait and balance problems are diagnosed by physicians using a variety of methods, including signs and symptoms, diagnosis of exclusion, imaging, etc. Discussion of specific diagnostic criteria for each disease process that could contribute to a balance disorder is beyond the scope of this entry.
A physical therapy diagnosis of decreased balance or abnormal gait is made based on a thorough examination that includes a patient history and systems review. In addition, tests and measures may be used to assess any or all of the following possible contributors to balance and gait disturbances: aerobic endurance, cognitive status, cranial and peripheral nerve integrity, assistive devices, muscle strength, range of motion, posture, reflexes, sensory integrity, and functional abilities. Balance, gait, and locomotion may be tested in a variety of ways, which usually include observation or video analysis of quiet standing, active standing, or functional activities. In some clinical tests such as the Clinical Test for Sensory Interaction on Balance, the physical therapist will purposefully manipulate the environment to change one component of sensory feedback (e.g., the patient stands on foam to challenge the somatosensory system). In some cases, the physical therapist manipulates the individual (e.g., the Hallpike-Dix maneuver). Other tests include a variety of functional skills that must be completed. A large number of balance tests exist; the key is choosing the right one. It is important to understand the purpose of a test before using it and to match that purpose with the impairments and goals of the patient or client being tested. For example, a test that measures stability in quiet standing may be appropriate for a patient who is recovering from a stroke, but not so appropriate for an athlete training to return to professional sports.
Medical and surgical management of pathologies underlying balance and gait disturbances includes, but is not limited to, the following:
- levo-dihydroxy-phenylalanine (L-dopa) and/or amantadine for Parkinson's disease
- surgery to alter connectivity in the basal ganglia in Parkinson's
- dopamine antagonists in Huntington's choreaanti-spasticity medication (diazepam, baclofen, dantrolene) for patients who have had a stroke, head injury or other neurological insult
- particle repositioning maneuvers for benign paroxysmal positional vertigo (dizziness)
- surgery for Ménière's disease or acoustic neuroma (a tumor in the auditory canal)
These interventions can help to decrease the contributors to balance and gait disorders such as dyskinesia (impaired ability to move voluntarily), rigidity, hypertonicity (diminished muscle tone), or vertigo. Balance and gait, however, often must be retrained using physical therapy. Successful treatment intervention based on theories of motor learning addresses the interactions of the individual, task and environment. In the individual, it is important to recognize what impairments contribute to difficulties, and whether or not they can be realistically corrected or if compensation will be necessary. The patient must be evaluated for cognitive ability to relearn balance skills, and for the level he or she is at in learning a skill (acquisition, refinement, or retention/transfer). In evaluating a task, the clinician must determine what is predominantly required—mobility, stability or both— and the timing, force and duration needed. The environment also must be analyzed and manipulated to best aid the patient in preparing for function in the real world.
Treatments may involve the manipulation of sensory input while performing a task. This may be done for any of the three systems responsible for providing sensory feedback. For example, to encourage use of vestibular input, visual and somatosensory information may be challenged. Visual input is challenged by taking it away(e.g., eyes closed) or by destabilization (e.g., involving head and eye movements in the task). Unstable surfaces(e.g., rocker board or rough terrain) or compliant surfaces(e.g., foam) help to challenge somatosensory input. Vestibular input may be manipulated by changing the position of the vestibular organ (e.g., neck extension or repeated head movements).
Other physical therapy treatment for balance and gait focuses on the patient's ability to control his or her COG over the BOS. Exercises related to functional activities are performed and progressed according to patient ability. Initially, treatment may begin with practicing the ability to establish static balance in a position with a wide BOS, such as sitting and using hands for support. Eventually, the BOS is narrowed and/or destabilized to train automatic, anticipatory and voluntary postural responses. This type of progression can take place in sitting, standing, walking, etc., with or without the addition of such concurrent tasks as putting on a shoe while sitting or reading signs on a wall while walking. Specific balance
Ankle strategy—An automatic posture response in which the body moves as a unit over the feet to control postural sway.
Base of support—The location on a body or object where most of the weight is supported.
Center of gravity—The center of weight in a body or object.
Hip strategy—An automatic posture response in which control comes from the pelvis and trunk.
Posturography—The study of posture and its effects on health.
Somatosensory system—The components of the central and peripheral nervous systems that process information about the muscles, pain, temperature, pressure and joint position.
Vestibular system—Interaction among the inner ear structures associated with balance and position sense, and the central nervous system.
Visual system—Components that transmit information from the retina to the brain.
training on a force plate designed to provide visual feedback about a patient's COG has not been shown to be convincingly more effective than conventional physical therapy in adults with hemiplegia. This may be due to the fact that weight shifting on a force plate may not carry over to such higher-level tasks as walking.
Prognosis depends on the cause of pathology, level of impairment, and such other factors as comorbidity. The basal ganglia disorders are progressive; therefore, while medical and physical therapy management may be effective in slowing the decline of function and training compensatory strategies, the overall prognosis is fair at best. Cerebellar lesions or cerebral stroke may allow for slight to significant return to function, depending upon the extent of the damage to the brain tissues. In a study on gait recovery following stroke, prognostic indicators included the ability to weight shift immediately poststroke; and later in recovery, affected knee extension strength. In true orthopedic cases with no neurological involvement, recovery may be less complicated if it depends purely on restoration of range of motion or strength to a musculoskeletal structure.
Health care team roles
Upon diagnosis of pathology by a physician and referral of an individual to physical therapy, the physical therapist is responsible for examination, evaluation, diagnosis, prognosis, and intervention.
The examination includes a patient history and systems review of cardiovascular, pulmonary, integumentary, musculoskeletal, neuromuscular and/or cognitive status. Physical therapists also use a wide variety of tests and measures to determine extent of impairment and functional limitations. Some of the more common balance tests used include: Romberg, Functional Reach, Clinical Test for Sensory Interaction on Balance, Berg Balance Scale, Get Up and Go, Tinetti Performance Oriented Assessments of Balance and Gait, Fugl-Meyer Sensorimotor Assessment of Balance Performance, Functional Obstacle Course, and posturography. These tests assess tasks ranging from quiet and active standing to the ability to maneuver an obstacle course of different floor surfaces, obstacles and stairs.
Evaluation, diagnosis and prognosis
The therapist must use his or her clinical judgment and expertise to establish a physical therapy diagnosis and prognosis, including the plan of care. The diagnosis indicates the primary dysfunction(s) toward which intervention will be directed. The prognosis and plan of care must encompass many factors such as current level of function, comorbidity, familial and social considerations and overall health.
Intervention includes treatment of any impairments that hinder function, as described in the treatment section above. In addition, patient education is of utmost importance. Education may include information regarding: the prognosis and plan of care, specific exercises to perform outside of therapy sessions, fall and injury prevention, compensatory strategies, assistive or adaptive device recommendations and usage, and social/community resources.
Gait and balance problems, as discussed earlier, are usually impairments resulting from a pathological process. In some cases, such as in Parkinson's or multiple sclerosis, intentional prevention of pathology is difficult because its causes are not completely understood. Some causes, however, may be modified. For example,
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American Physical Therapy Association. 1111 North Fairfax Street, Alexandria, VA 22314-1488. (703)684-2782. <http://www.apta.org>.
Net Wellness Consumer Health Information. Ask an Expert website. Apr. 12, 2001. <http://188.8.131.52/expert2000/public>.
Peggy Campbell Torpey, MPT