Gait and Balance Problems Health Article

Definition

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.

Description

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

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

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.