Balance is complicated process that involves both our body and mind. The body is constantly regulating visual, proprioceptive, and vestibular input, making automatic adjustments through the spinal cord and brain stem. We are unable to remain completely still and therefore are in a constant state of postural sway. This sway is caused by an attempt to keep the center of gravity within the base of support.

BALANCE BASICS

From a treatment perspective, it is important to understand how normal balance systems work. This involves the use of multisensory input (vestibular, visual, and somatosensory), which is processed through the central system and allows for feedback to the musculoskeletal system, resulting in the vestibulospinal reflex (VSR) and the vestibulo-ocular reflex (VOR). Once this information is processed through the central vestibular system, the VSR assists in maintaining our upright posture, and the VOR helps to stabilize our vision and focus during head movement. When these reflexes are not working correctly, it can result in dizziness, loss of balance, or both.

It also is important to recognize the areas that are correctable when establishing this treatment program. In evaluating the VSR response to multisensory organization, two particular methods are most commonly used. The first is the Sensory Organization Test, developed by Nashner, which utilizes specialized equipment with a moving platform and surround.¹ The second is the Clinical Test of Sensory Interaction and Balance (CTSIB), introduced by Shumway-Cook and Horak.² Both enable the clinician to get a better understanding of which sensory input a patient may depend on and which is demonstrating a deficit. The VOR can be clinically evaluated (passively and actively) to see if there is a loss of visual acuity during head movement. It is important to recognize a deficit in this area and how it can affect the balance during upright function with head movements.

A biomechanical evaluation also is very important to determine any limits in range of motion, flexibility, and strength. Without the necessary range of motion, flexibility, and strength, it becomes difficult for the geriatric patient to respond with the appropriate movement strategy needed to maintain balance.

IMPROVING GAIT AND BALANCE

Mobility itself can become impaired when balance becomes compromised. Much has been written on our balance systems. In brief, sensory input comes from the vestibular apparatus and somatosensory pathways. This information is then centrally processed in the vestibular nuclei and cerebellum. After processing through the vestibular nuclei and cerebellum, there is a motor output of this information that allows individuals to maintain their balance. When a patient presents with a complaint such as dizziness, the initial evaluation needs to not only include an investigation of the primary causes of balance dysfunction, but also must include an evaluation for additional pathological processes, which may mimic primary balance dysfunction. After the evaluation and determination of the diagnosis, a rehabilitative treatment plan is formulated.

With aging, a decline also is reported in the area of muscular strength, range of motion, and muscle flexibility. With these physiological changes and pathologies that present with age, an accumulation of deficits and significant changes in balance and mobility become more prevalent. Therefore, the need for a thorough evaluation of each patient is required to determine the major causes for loss of mobility, which is important in the development of an appropriate individualized treatment program.

Proper walking technique with the guidance of physical and occupational therapy, including specific muscle-strengthening exercises, has been shown to improve mobility and minimize falling. Use of walking aids such as canes and rolling walkers, with proper instruction, theoretically should improve mobility and prevent further falls. However, patient compliance due to the inconvenience of using these devices, and the labeling of frailty that goes along with it, may lead to further falls. An ankle foot orthotic (AFO) device will prevent excessive plantar flexion in those with foot drop and will help prevent falls.

ASSESSMENT TECHNOLOGIES

PTs use a wide range of techniques and rehabilitative technologies when working with patients. Before gait and balance training begins, an individual patient evaluation is obtained. This becomes the foundation for a comprehensive and individualized training program. The stepping stone from evaluation to initial training starts with a computerized balance technology device that provides objective assessment and retraining of the sensory and voluntary motor control of balance. With a PT, patients generally use this device to determine the location of their center of gravity; PTs use the device to acquire a baseline for ongoing therapy for each patient. The device provides visual biofeedback for patients, as well as objective data through graphs and numbers, enabling them to understand their condition.

The computerized balance technology provides individual results. By quantifying each patient's deficits, a PT determines the best therapy program for that patient. Crucial to a patient's rehabilitation process, the individual therapy programs illustrate how precise and effective computerized balance technology is for each patient.

In addition to assisting with the evaluation process, computerized balance technology also is a useful tool for treatment and training. Patients use it to learn how to shift their weight and build strength. Its primary use is to adapt, develop, and integrate a patient's sensory systems into their balance reactions.

An additional highlight of computerized balance technology is its appeal to a wide range of patient diagnoses and ages. Those suffering and recovering from stroke, spinal cord injury, head injuries, back pain, vertigo, pediatric developmentally delayed condition, limb amputation, and neuromuscular diseases are capable of using this machine.

Another advancement for evaluating and training patients includes a computer equipped with virtual reality software, a digital camera, and a monitor. The camera projects the patient's image on the monitor with a virtual background, such as a ski hill or a soccer field, and occupational settings, such as a factory.

More of a "hands-on" tool for patients, the digital virtual reality system is regarded as a valuable program by both PTs and patients because it places patients in more real-life situations. With the factory background, for example, patients take boxes off a conveyor belt and place them elsewhere. This exercise enables patients to work on weight-shifting and moving out of their base of support.

One of the most basic and initially used pieces of equipment is a highly mobile true partial weight-bearing system. Therapists use this device to help "un-weight" patients to allow easier lower-extremity movement. Patients are then capable of learning how to control pelvic movement and weight-shifting, and how to break down the components of walking with the system.

Body-weight support systems are another part of a neurorehabilitation program. These technologies are crucial for patients recovering from strokes, spinal cord injury, or head injuries, and in managing Parkinson's disease and other neuromuscular diseases.

One system consists of a harness and an electrical lift, and can be used on either land or a treadmill. Patients learn how to pattern correct lower-extremity movements, improving timing and lower-extremity coordination. PTs consider this equipment an excellent starting point for patients to build strength, balance, and the lower-extremity coordination they need for gait.

The other system is an electronically controlled pneumatic body-weight support system that allows modulation and control of ground reaction forces. It quantifies body-weight support levels in real time throughout the step cycle. This device provides stability during gait and helps progress weight-bearing according to the patient's needs. The system gives patients a real sense of falling without them actually doing so. Patients rely on PTs giving manual cues, and although this device is considered more labor intensive, the success rate is high.

PTs often regard the computerized balance technology unit and the specialized body-weight support system with a harness and an electrical lift among the most valuable pieces for their patients.

The objective feedback given by computerized balance technology and the wide scope of patients who have access to these two devices ensure the PTs' confidence in their effectiveness.

FALL PREVENTION

Traditional fall-prevention programs, including flexibility, range of motion, and weight training, focus on the musculoskeletal system. These traditional programs have not been very successful in preventing falls from occurring. Prevention programs that address higher-level cognitive processes while maintaining balance and posture appear to be nonexistent. Fall-remediation programs need to incorporate dual tasks, not strictly balance activities in a static environment. Once the needed musculoskeletal components are improved in therapy, balance activities need to include cognitive tasks.

Fall prevention and rehabilitation programs that are designed to prevent falls by improving balance need to include scenarios in which attention is drawn to another task while remaining upright. Older adults have more trouble attending to both cognitive tasks and postural control, and this becomes overwhelming as the task complexity increases. As a person ages, more cognitive and attention processing is needed to maintain balance during both standing and walking activities. With the interplay between balance and cognition, addressing cognition in balance restoration and fall prevention makes sense.

Recognizing external factors and detailed improvement of the environment may further prevent falls. A thorough home inspection will help define and correct environmental hazards for falls. A home physical therapy program will augment the safety hazard corrections. Installation of a raised toilet seat and appropriate grab bars in the bathroom and hallways, and improving lighting fixtures, are a few specific examples of improvements to the environment.

The program to improve balance is multifaceted with a focus on both improving clients' physical status as well as addressing their confidence level when performing activities of daily living. Ideally, the program should include exercise and graded functional activities to foster confidence in their ability to ambulate safely.

Carol Dunn, PT, is a staff therapist at Body Dynamics Physical Therapy in Rochester, NY. She has focused on working with patients who suffer from balance disorders for more than 10 years. For more information, contact .

References

1. Nashner L. Computerized dynamic posturography. In: Jacobson G, Newman C, Kartush J, eds. Handbook of Balance Function and Testing. St Louis: Mosby Yearbook; 1993:280–307.
2. Shumway-Cook A, Horak FB. Assessing the influence of sensory interaction on balance. Phys Ther. 1993;66:1548–1550.