Effect of Exercise on Gait and Balance in Peripheral Neuropathy

Effect of Exercise on Gait and Balance in Peripheral Neuropathy

The purpose of this study is to find out if participation in one of the study groups: functional balance training, Tai Chi, or education, results in better outcomes overall. The outcomes that we are primarily interested in are related to walking ability and balance.

Since the 1970's, researchers and epidemiologists have documented that patient falls are a high-risk, high volume, high cost adverse events contributing to morbidity, mortality, decreased quality of life, and premature nursing home placement. Despite thousands of research studies published on patient falls, few studies have focused on the effectiveness of interventions , and fall rates and associated injuries among the elderly continue to rise. Impaired gait and balance (referred to as impaired stability) is one of the most significant causes and consequences of falls. Persons with peripheral neuropathy represent one of the largest patient populations with impaired stability. Lower limb peripheral neuropathy (LLPN) includes sensory and motor impairments that result in impaired gait and balance, jeopardizing safe mobility. Emerging evidence suggests that exercise programs can be effective in improving gait and balance in general fall risk populations, as well as reducing falls and fall-related injuries. Exercise interventions have been designed to reduce fall risk and promote successful aging. These interventions come in many forms, but the most common interventions are exercise training and Tai Chi, offered individually and in small group formats. Further research is needed to gain insight into the underlying mechanisms of different type of exercises and their impact on stability in veterans with LLPN. Research is needed to determine the type or combination of types of exercise to produce a more normal and/or stable gait in this high-risk patient population. Researchers are beginning to document that exercise interventions positively influence a person's fall self efficacy, i.e. self confidence for avoiding a fall, an important factor in understanding and examining a persons' behaviors related to fall risks. The emphasis on functionally based interventions has led to inappropriate broad groupings of older persons with mobility disorders. A weakness of previous studies was that they aggregated heterogeneous patient populations, resulting in neurological and musculoskeletal diagnostic heterogeneity and the confounding of results. Focusing on a homogeneous patient population is necessary to distinguish unique sensory, gait and balance deficits that contribute to impaired stability and mobility risk, as well as to better understand unique responses to treatment that are clouded when diverse patients are aggregated. We will target veterans with LLPN--one of the largest groups of patients referred to our Falls Clinic, and an understudied population with respect to safe patient mobility. This will allow us to design targeted interventions likely to be more effective than those tested on heterogeneous elderly populations, where visual and vestibular input to compensate for impaired proprioception were not taken into account.

The goal of this study is to improve successful adaptation to aging and quality of life in veterans with lower limb peripheral neuropathy (LLPN). Functional Balance Training and Tai Chi, the two exercise interventions tested in this study, have been documented to improve gait and balance, and decrease falls and associated fall-related injuries in the general elderly population. We are interested in whether one or both of these exercise interventions (successful in general elderly populations) would be effective in a special subpopulation of elderly, namely persons with LLPN.

The purpose of this study is to compare the effectiveness of these two exercise interventions and an education control group. Effectiveness will be assessed by studying the impact of interventions on (1) composite measures of stability (gait and balance), (2) fall self-efficacy, and (3) patient acceptance. Given the well-documented links between falls and fall-related injuries (ultimate outcomes) our study will focus on stability (intermediate outcome). Because falls and fall-related injuries are relatively rare events, examining stability as an outcome will allow us to have sufficient power to test our hypotheses with a relatively small sample size thereby decreasing the cost and duration of the study without sacrificing the rigor of the research design.

Inclusion Criteria:

• Corrected vision not worse than 20/50 to have visual acuity to read and follow instructions.
• Ability to ambulate household distances with or without an assistive device. This reflects a minimum functional status for ambulation as primary mode of mobility.
• Symptoms and Signs consistent with LLPN as determined by the Michigan Diabetic Neuropathy Scale (Score greater than 6, presence of mild PN). The Michigan Diabetic Neuropathy Score quantifies sensory impairment, muscle strength, and reflexes, using vibration, filament, pin prick, and physical touch. Scale ranges from 0-46, with higher score indicating great severity of PN. The score is used to stratify severity of PN, and takes approximately 10-15 minutes to complete. Testing aspects elicit sensation from small and moderate nerve fibers, and is more sensitive to mild to moderate sensory neuropathy. This test was selected rather than the gold standard EMG in order to screen for study subjects, is less invasive, and reduces the burden of subject screening for inclusion into this study.

Exclusion Criteria:

• Cognitive impairment with MMSE score less than 24, level 24 and below scores indicated cognitive impairments, limiting ability to remember instructions.
• Metastatic cancer, limits ability to complete the intensity and duration of the study.
• Central neurological dysfunction e.g. diagnosis of hemiparesis, cerebellar dysfunction, Parkinson's disease as determined by medical record review. These neurological impairments impair gait and balance, and would jeopardize safety if randomized to an intervention group.
• Lower extremity amputation, a physical disability that results in altered postural balance.
• Lower extremity abnormality other than peripheral neuropathy, such as foot drop, as participation in class would compromise patient safety.
• Mobility limitations due to altered lower extremity skin integrity/ulcer, where pain would limit gait and weight-bearing would be contraindicated such as stasis and foot ulcers or claudication.
• Medically unstable upon exam, i.e. poorly controlled blood pressure and blood sugar, coronary artery disease, where group participation would compromise medical status.