Question: There are certain aspects of brain injury which can be difficult to diagnose and treat effectively. Balance problems seem to be one of the most difficult because of involvement of several etiologic factors. Are there effective treatments for balance problems resulting from brain injury?
Answer: Brain Injury Source, Volume 3, Issue 2, Ask the Doctor
by Nathan D. Zasler, M.D., FAAPM&R, FXADEP, DAAPM, CIME
I would like to thank you for your question which may require a longer rather than shorter answer, given the broad scope of problems that may produce balance dysfunction following brain injury.
Balance is a complex, integrative function involving not only the production and reception of adequate sensory information, but the appropriate interpretation of that information as well. Planning and execution of movement to achieve upright posture also plays a part. Some have defined balance as the ability to control the center of gravity over the base of support in a given sensory environment. The center of gravity is an imaginary point in space where the sum of all the forces acting upon it is zero. In a person with normal balance standing at rest, the center of gravity is located just forward of the spine at about the second sacral level. Our center of gravity moves as we move. Within any given base of support, there is a limited distance a body can move without falling, which occurs when the center of gravity exceeds the base of support, or establishing a new base of support by reaching or stepping.
There are a number of variables that must be assessed when analyzing balance dysfunction following brain injury. From a sensory perspective, the body receives both peripheral and central sensory information. The primary peripheral sensory receptors are in the somatosensory, visual and vestibular systems. When any of these systems are not functioning optimally, balance can be adversely affected.
With regard to central sensory perception, there often can be a mismatch between information provided from one part of the brain relative to another. A prime example of this type of mismatch is when one has post-traumatic benign paroxysmal positional vertigo (BPPV). This produces what has been termed sensory conflict, which occurs when information between sides or systems is not synchronized. This type of deficit can also lead to imbalance. Deficits in central motor planning seen after brain injury may also be responsible for balance impairments. Deficits in peripheral motor function may also result in balance impairments. Specifically, orthopedic problems such as deconditioning or deficits in range of motion due to contracture may impede balance. Motor components of balance must also be considered, from the most basic to the most complex spinal and/or central reflexes, the latter including the vestibuloocular reflex (VOR) and vestibulospinal reflex (VSR). Additionally, automatic postural responses contribute to the motor components of planning. These are typically broken down into four automatic postural responses or strategies, including ankle, hip, suspensory and stepping/reaching strategies. Another group of postural responses is so-called anticipatory postural responses which are similar to automatic postural responses, except that they occur before the actual perturbation of balance occurs. Volitional postural responses are under conscious control and involve self-initiated disturbances of the center of gravity to accomplish a goal.
Clinical assessment of balance should include assessment of quiet standing, active standing and assessment of responses to sensory manipulation. Various functional scales have been used to rate disability associated with balance dysfunction. These scales frequently are not designed specifically for persons with balance dysfunction due to traumatic brain injury. There are also a number of "combination" tests or batteries that are used in the assessment of balance, such as the Fugl-Meyer Sensory Motor Assessment of Balance Performance and the Fragely Graybiel Ataxia Test Battery.
In order to adequately treat balance problems due to brain injury, one must incorporate information garnered from an adequate neurologic and musculoskeletal evaluation, preferably done by both a physician and a physical therapist. Additional information acquired from other specialists may be important in adequately defining impairment and disability associated with brain injury that may be contributory to balance dysfunction. Such evaluations may include neuro-ophthalmologic, neuro-optometric, otolaryngological, neurosurgical and neurological assessments, among others. Various types of high tech instrumentation may be necessary to fully evaluate the etiology of balance impairments following ABI including, but not limited, to static and dynamic brain and/or spinal cord imaging studies, electronystagmography with calorics, functional balance evaluation via posturographic assessment and brain stem auditory evoked potentials, among others.
Methods of treating balance dysfunction are as variable as the problems that may mediate it. Locomotor training may be combined with unilateral deweighting of the body to reduce the load borne by the lower limb and improve balance associated with a hemiplegic gait. Locomotor training can also be combined with functional electrical stimulation and/or biofeedback. Traditional as well as neurodevelopmental orthotics may facilitate balance through improvement of gait dynamics and efficiency. Given that spasticity and/or ataxia as well as other movement disorders following ABI may adversely impact on balance function, techniques utilizing local approaches such as nerve blocks and/or distal limb weighting may be of benefit as can a variety of enteral (orally taken) medications. Surgical treatments to improve balance may focus on correction of joint and limb contractures and/or improvement in gait biomechanics. Balance problems may be due to defective proprioceptive feedback from the lower extremities requiring the individual to be trained to rely more heavily on visual cues. Various inner ear problems following cranial trauma can produce imbalance including post-traumatic Meniere's disease (also known as perilymphatic hydrops), perilymphatic fistula and/or benign positional vertigo (BPPV). These problems can be addressed through a variety of techniques including the Epley maneuver and vestibular habituation therapies.
Treatment plans should be designed to reach specific goals on both a short- and long-term basis. Treatment should not occur in a vacuum; the treating physician and therapist(s) must have an understanding of the underlying neuropathologic correlates of the balance impairment, and accordingly, an understanding of prognosis for the impairments contributing to the balance dysfunction.
A thorough understanding of the integrative nature of ABI-related balance dysfunction is important in terms of knowing what type of treatment may best ameliorate the condition, in addition to what the likely prognosis is for the treatment. Lifelong treatment for balance dysfunction certainly does not make sense in the context of what we understand regarding neurologic recovery following brain injury. There are many individuals, however, who will continue to make progress for several years following a brain injury, where ongoing improvements are seen in balance function during that time. This is particularly true in persons with absence of significant risk factors for hypoxicischemic injury and with primary pathology of diffuse axonal injury in the absence of any significant focal cortical confusional injury.
My own experience as a clinician is that many of the "high tech" testing and treatment devices are not necessary to provide good functionally oriented balance rehabilitation. What is required is knowledge and understanding of how brain injury may affect balance and the complexity of the system integration that goes into normal balance function. Many times, the practitioner must develop a creative approach to dealing with these problems, based on a foundation of comprehension of neuropathology and its implications on treatment and prognosis for the balance disorder.
Clearly, as part of a good balance retraining program, a therapeutic program should also include safety education and, as appropriate, environmental modifications. I would also note that once an individual is in the post-acute period, many therapeutic interventions could be done in the home as part of a home therapy program and/or in the community.
There will be individuals who have severe balance problems that prevent them from functional ambulation. Balance can even produce significant disability to persons who use
wheelchairs and their impairments must be addressed in a way that allows them to function in the least restrictive environment, while at the same time providing optimal functional and safe mobility.
I hope my response helps provide you some further insights into the complexity of balance dysfunction following brain injury and the potential for amelioration of some of these often disabling deficits.
Thanks again for your question.
Nathan D. Zasler, M.D., FAAPM&R, FXADEP, DAAPM, CIME