Automatic postural responses in individuals with peripheral neuropathy and ankle-foot orthoses

The effect of augmented somatosensory feedback on standing postural sway

Impaired balance resulting from reduced postural control occurs with aging and various medical conditions. Sensory input for balance control is provided by the visual, vestibular and somatosensory systems. Previous research suggests that increased proprioceptive feedback from various lower extremity devices improves balance. Mixed results have been reported with the use of orthoses such as ankle foot orthoses (AFOs). In this study, 20 healthy subjects wore footplates in their shoes or straps around their lower legs in order to imitate the somatosensory feedback produced by wearing AFOs, but without providing ankle restriction. Subjects' standing balance was assessed using force plates and computerized dynamic posturography (the sensory organization test-SOT) to determine if either the footplates or the lower-leg straps would affect standing balance. The results revealed no significant difference with the use of the footplates, however, wearing the straps resulted in reduced postural sway for conditions when visual cue deprivation was combined with manipulation of somatosensory or vestibular feedback. This effect was more pronounced in participants with the poorest baseline measures of balance. These findings suggest that lower extremity devices, such as AFOs, may augment somatosensory feedback that could improve balance during challenging sensory deprivation conditions, independent of orthotic support at the ankle.

Effects of foot and ankle devices on balance, gait and falls in adults with sensory perception loss: a systematic review

BACKGROUND

Foot and ankle devices are being developed as a method of preventing people with sensory perception loss sustaining a fall. Such devices are believed to work by reducing the likelihood of a fall by improving the balance and gait of the user.

OBJECTIVES

The objective of the review was to evaluate the effectiveness of foot and ankle devices for the prevention of falls and the improvement of balance and gait in adults with sensory perception loss.

INCLUSION CRITERIA TYPES OF PARTICIPANTS

Participants were community-dwelling adults with bilateral pathological sensory perception loss.

TYPES OF INTERVENTION(S)/PHENOMENA OF INTEREST

The current review evaluated any foot or ankle device, including but not restricted to, all types of footwear (therapeutic and retail), insoles (customized and prefabricated) and ankle-foot orthoses (AFOs).

TYPES OF STUDIES

In the absence of randomized controlled trials (RCT), the review considered experimental and epidemiological study designs, except case series, individual case reports and descriptive cross-sectional studies.

OUTCOMES

The primary outcome was number of falls. Secondary outcome measures were clinical or laboratory measures of balance or gait.

SEARCH STRATEGY

A search for published and unpublished literature from inception to March 2015 written in the English language was conducted across a number of major electronic databases. A three-step search strategy was developed using MeSH terminology and keywords to ensure all that relevant materials are captured.

METHODOLOGICAL QUALITY

Methodological quality of included studies was assessed by two reviewers, who appraised each study independently, using standardized Joanna Briggs Institute (JBI) critical appraisal tools.

DATA EXTRACTION

Quantitative data were extracted from the studies that were identified as meeting the criteria for methodological quality using the standardized JBI data extraction tools.

DATA SYNTHESIS

Due to the heterogeneity of populations, interventions and outcome measures, meta-analyses were not possible and results are presented in narrative form.

RESULTS

Nine trials (from 10 papers) involving 238 participants, (14 with multiple sclerosis and 16 with idiopathic peripheral neuropathy, 150 with diabetic neuropathy) and 58 controls were included in the review. No study reported falls as an outcome measure. The results of the included studies found that in people with sensory perception loss, postural sway improved with vibrating insoles and AFO, altering the softness and texture of the top cover had no effect on postural sway, wearing footwear over long distances or AFOs improved step-to-step consistency, and no foot and ankle device was reported to have a negative effect on the balance or gait of people with sensory perception loss. The methodological quality of the included studies was poor. No study used a randomized controlled trial (RCT) methodology. No study incorporated a follow-up period or tested the intervention within the context of the intended clinical environment.

CONCLUSION

There is limited evidence to suggest that footwear and insole devices can artificially alter postural stability and may reduce the step-to-step variability in adults with sensory perception loss. Varying the material properties of an insole does not notably affect static balance or gait.

Rocker outsole shoe is not a threat to postural stability in patients with diabetic neuropathy

BACKGROUND

Rocker outsole shoes are commonly prescribed to patients with diabetic neuropathy to offload a particular area of the foot sole, thereby decreasing the risk of foot ulceration. Contrary to this, some evidence has reported a postural destabilising effect of these shoes in healthy adults.

OBJECTIVE

To explore the postural stability of patients with diabetic neuropathy who wear a rocker outsole shoe.

STUDY DESIGN

Quasi-experimental.

METHOD

In total, 17 patients with diabetic neuropathy (aged 49.29 ± 7.48 years; 7 female, 10 males) participated in this study. A Motor Control Test measuring centre of force displacement, response strength scale and response latency in medium and large perturbations was conducted using the EquiTest system to evaluate postural stability while wearing a baseline shoe (without a rocker outsole) or a rocker outsole shoe (with a toe-only rocker sole).

RESULTS

No significant difference was observed between the shoe conditions in centre of force displacement and response latency of the participants (p > 0.05). The results indicated a significant increase in the response strength scale of participants by the rocker outsole, for medium forward and backward and large forward perturbations (p = 0.014, p = 0.001 and p = 0.027, respectively).

CONCLUSION

When the immediate effect is a concern, the rocker outsole shoe did not negatively affect postural stability in patients with diabetic neuropathy.

CLINICAL RELEVANCE

This article will provide objective evidence about the effect of rocker outsole on postural balance in diabetic patients. In prescription of rocker outsole to prevent plantar ulceration of diabetic foot, immediate postural destabilising is not a concern.

Diabetic foot and exercise therapy: step by step the role of rigid posture and biomechanics treatment

Lower extremity ulcers represent a serious and costly complication of diabetes mellitus. Many factors contribute to the development of diabetic foot. Peripheral neuropathy and peripheral vascular disease are the main causes of foot ulceration and contribute in turn to the growth of additional risk factors such as limited joint mobility, muscular alterations and foot deformities. Moreover, a deficit of balance, posture and biomechanics can be present, in particular in patients at high risk for ulceration. The result of this process may be the development of a vicious cycle which leads to abnormal distribution of the foot's plantar pressures in static and dynamic postural conditions. This review shows that some of these risk factors significantly improve after a few weeks of exercise therapy (ET) intervention. Accordingly it has been suggested that ET can be an important weapon in the prevention of foot ulcer. The aim of ET can relate to one or more alterations typically found in diabetic patients, although greater attention should be paid to the evaluation and possible correction of body balance, rigid posture and biomechanics. Some of the most important limitations of ET are difficult access to therapy, patient compliance and the transitoriness of the results if the training stops. Many proposals have been made to overcome such limitations. In particular, it is important that specialized centers offer the opportunity to participate in ET and during the treatment the team should work to change the patient's lifestyle by improving the execution of appropriate daily physical activity.

Static ankle-foot orthosis improves static balance and gait functions in hemiplegic patients after stroke

The purpose was to examine the effects of static anterior and posterior ankle-foot orthoses (AAFOs & PAFOs) using with regular shoes on improving static and gait function in patients recovering from stroke. Static and dynamic balance control were measured under four conditions: barefeet, wearing regular shoes only, and wearing regular shoes with AAFOs or PAFOs. The results indicated that wearing regular shoes markedly increased the center of pressure (CoP) sway (p < 0.05) in static standing conditions. Both AAFOs and PAFOs decreased CoP sway and increased bilateral limb loading symmetry compared to barefoot and wearing shoes alone (p < 0.05). PAFOs decreased CoP sway more than AAFOs (p > 0.05) and also boosted medial-lateral weight shifting more effectively (p < 0.05). Both types of AFOs increased walking efficiency but influenced the roll-over shape of the CoP adversely during level walking. The conclusions are that both AAFOs and PAFOs improved static and dynamic balance control when they were used with regular shoes and PAFOs appeared to be more efficient than AAFOs. Shoes worn daily with AFOs is a key consideration influencing balance control in stroke patients. However, AFOs with static design impeded the function of the three rocker systems of the foot during ambulation.

Influence of modified solid ankle-foot orthosis to be used with and without shoe on dynamic balance and gait characteristic in asymptomatic people

BACKGROUND

Ankle-foot orthoses are usually used in combination with footwear. Shoe design can have a significant effect on kinematics of the lower limb joints and line of action of the ground reaction force during walking. But, ankle-foot orthosis-footwear combination is not appropriate for indoor barefoot walking in some Asian cultures. In this study, we have modified a solid ankle-foot orthosis in order to set it in the same position as a solid ankle-foot orthosis-footwear combination.

OBJECTIVE

To investigate the effect of a modified solid ankle-foot orthosis; a solid ankle-foot orthosis which can be locked in different positions on gait and balance performance in comparison with a conventional solid ankle-foot orthosis, a common solid ankle-foot orthosis-shoe combination in asymptomatic adults.

STUDY DESIGN

Cross sectional.

METHODS

Two standard solid ankle-foot orthoses were manufactured with the ankle joint in neutral position. Then, one of these solid ankle-foot orthoses was modified in order to allow locking in a different alignment. Walk across, limit of stability, and sit-to-stand tests of the balance master system were performed while participants wore the modified solid ankle-foot orthosis aligned in 5°-7° anterior inclination without a shoe and a conventional solid ankle-foot orthosis-shoe combination.

RESULTS

There was no significant change in walking speed, step length, and step width with the conventional and modified solid ankle-foot orthoses. In addition, movement velocity and maximum excursion of the center of gravity during the limit of stability test were not different, although the maximal forward excursion of the center of gravity was longer when wearing the modified solid ankle-foot orthosis compared to the conventional solid ankle-foot orthosis-shoe combination (P = 0.000). Sway velocity of the center of gravity did not change during the sit-to-stand test.

CONCLUSION

The results demonstrated that the modified solid ankle-foot orthosis had the same effects as the conventional solid ankle-foot orthosis-shoe combination on the gait and balance performance of asymptomatic adults. Clinical relevance The findings of the present study can be used as the basis for further investigations on the efficacy of the modified solid ankle-foot orthoses in different neuromuscular populations in order to help people who do not wear shoes at home, as is the custom in some Asian cultures.

Auxiliary sensory cues improve automatic postural responses in individuals with diabetic neuropathy

BACKGROUND

A loss of sensation in the lower limbs, observed in individuals with diabetes as well as elderly individuals, contributes to postural instability, altered gait patterns, increased risk of falling, and decreased quality of life.

OBJECTIVE

To determine if somatosensory cues delivered to sensate areas of the lower limbs above the ankle joints enhance the control of posture in individuals with peripheral neuropathy.

METHODS

Twelve subjects with sensory neuropathy due to diabetes participated in static and dynamic balance tests with and without auxiliary sensory cues provided to the lower limbs without stabilizing the ankle joints. During the tests the subjects were required to stand on a fixed or moving computer-controlled platform with their eyes open or closed. Equilibrium scores and response latency were obtained.

RESULTS

For all tests, equilibrium scores were significantly larger in experiments with auxiliary sensory cues in comparison with conditions without cues (P < .05). Smaller latency scores were recorded in conditions with auxiliary sensory information. The results indicate that auxiliary sensory cues improved automatic postural responses.

CONCLUSIONS

The observed enhancement of automatic postural responses has clinical implications that aid in the understanding of postural control in individuals with peripheral neuropathy. Future controlled trials could examine whether devices that provide auxiliary sensory cues can improve balance, mobility, and the performance of daily activities.

Ankle-Foot Orthoses: Proprioceptive Inputs and Balance Implications

Individuals with a loss of sensation in the lower limbs frequently experience postural instability, altered gait patterns, and an increased risk of falling culminating in a decreased quality of life. Previous studies have documented that using ankle-foot orthoses (AFOs) help such individuals to maintain their balance. This study was conducted to investigate whether somatosensory cues delivered to the intact tissues of the lower limbs above the ankle joints enhance the control of posture in individuals with peripheral neuropathy. The study involved 12 individuals with sensory neuropathy because of diabetes who participated in static and dynamic balance tests with and without specially designed AFOs that provided auxiliary sensory cues to the lower limbs without stabilizing the ankle joints. During the tests, the subjects were required to alternately stand on a fixed and moving platform with their eyes alternately open or closed. Equilibrium scores and response latencies were obtained. The results showed that equilibrium scores were significantly higher in experiments with the specially modified AFOs compared with conditions without AFOs. Smaller latency scores were recorded in conditions with AFOs as well. The outcome indicates that AFOs that substitute for the lack of proprioceptive feedback may improve automatic postural responses in individuals with diabetic peripheral neuropathy. It also highlights the need for further research focused on the design of assistive means that could improve the balance and the performance of activities of daily living in individuals with proprioceptive deficits.

The effect of reduced somatosensation on standing balance: a systematic review

The objective of this review is to identify and review publications describing the impact of reduced somatosensation on balance. Based on knowledge of the association between specific somatosensory loss and deterioration of balance, conclusions can be made about role of somatosensation in standing balance. A systematic literature review is presented in which publications from the years 1993 through 2007 were searched in Medline and Embase. Medical Subject Headings (MESH) terms and free text words (related to balance, somatosensory loss, and lower limb) were used to perform the searches. Fifteen articles were selected for detailed review based on predetermined inclusion criteria, and three of the included articles described the effect of experimentally reduced somatosensation on balance in healthy subjects. Ten of the articles described balance in diabetic neuropathy (DN). The last two included articles described balance in Charcot-Marie-Tooth (CMT) disease type 1A (CMT1A) or type 2 (CMT2). The literature indicates that the tactile sensation is reduced in DN, CMT1A, and CMT2 and when the plantar surface of the feet was hypothermically anesthetized. Joint motion sensation seems to be impaired in patients with DN, and passive joint position sensation appears to be reduced in healthy subjects with anesthesia of ankle and foot from prolonged ischemia. This reduced somatosensation seems to have a negative effect on balance in patients with DN and CMT2; however, this appeared not to be the case in patients with CMT1A and in healthy subjects.

Foot and ankle compression improves joint position sense but not bipedal stance in older people

This study investigates the effects of foot and ankle compression on joint position sense (JPS) and balance in older people and young adults. 12 independently living healthy older persons (77-93 years) were recruited from a senior accommodation facility. 15 young adults (19-24 years) also participated. Compression was applied at the ankles and feet using medical compression hosiery. The mean velocity of the centre of pressure (CoP) displacements and the root mean square of the CoP velocity in both anteroposterior and mediolateral directions, were measured with a foot pressure plate. In older people, ankle compression was associated with an improvement of JPS towards normal values. However, a concurrent deterioration of their balance was found. In young adults compression had no effect on either JPS or balance.