Postural control during stance in paraplegia: effects of medially linked versus unlinked knee-ankle-foot orthoses

Interjoint coordination between the ankle and hip joints during quiet standing in individuals with motor incomplete spinal cord injury

Individuals with motor incomplete spinal cord injuries (iSCI) often have impaired abilities to maintain upright balance. For able-bodied (AB) individuals, the ankle and hip joint accelerations are in antiphase to minimize the postural sway during quiet standing. Here we investigated how interjoint coordination between the ankle and hip joints was affected in individuals with iSCI, leading to their larger postural sway during quiet standing. Data from 16 individuals with iSCI, 14 age- and sex-matched AB individuals, and 13 young AB individuals were analyzed. The participants performed quiet standing during which kinematic and kinetic data were recorded. Postural sway was quantified using center-of-pressure velocity and center-of-mass acceleration. Individual ankle and hip joint kinematics were quantified, and the interjoint coordination was assessed using the cancellation index (CI), goal-equivalent variance (GEV), nongoal-equivalent variance (NGEV), and uncontrolled manifold (UCM) ratio. Individuals with iSCI displayed greater postural sway compared with AB individuals. The contribution of ankle angular acceleration toward one's sway was significantly greater for those with iSCI compared with AB groups. CI and the UCM ratios were not statistically different between the groups, while GEV and NGEV were significantly greater for the iSCI group compared with the AB groups. We demonstrated that individuals with iSCI show larger postural sway compared with the AB individuals during quiet standing, primarily due to larger ankle joint acceleration. We also demonstrated that the interjoint coordination between ankle and hip joint is not affected in individuals with iSCI, which is not successfully able to reduce the large COM acceleration.NEW & NOTEWORTHY There are limited studies investigating the biomechanics of standing balance for individuals with motor incomplete spinal cord injury (iSCI). Through our study, we found that these individuals with iSCI demonstrated increased postural sway primarily due to increased ankle joint accelerations. In addition, the ankle-hip coordination was equivalent between able-bodied individuals and those with motor incomplete spinal cord injury, which was not able to reduce the large body acceleration.

Development and validation of the Standing Balance Assessment for Individuals with Spinal Cord Injury (SBASCI) - A new outcome measure

BACKGROUND

Injury to the spinal cord results in standing balance impairment following variable sensorimotor loss. Standing balance training is a realistic goal for the majority of individuals with spinal cord injury (SCI) for which therapists need valid measures to assess standing ability in people with SCI that are relevant to functionality.

OBJECTIVE

The objective of the study was to develop an all inclusive Standing Balance Assessment for Individuals with Spinal Cord Injury (SBASCI) measure and to establish its initial psychometric properties.

METHODS

The study was carried out in three phases: Item development, scale development and scale evaluation. Literature review, focus group discussions and evaluation by experts resulted in the development of a 22-item SBASCI scale. The scale was administered on 120 participants with SCI. Exploratory factor analysis and item analysis were used to determine construct validity and internal consistency of the scale.

RESULTS

Content validity was established qualitatively and quantitatively. The scale shows high internal consistency reliability (Cronbach's alpha 0.96). The results of the exploratory factor analysis suggested a four factor structure retaining all the 22 items.

CONCLUSION

SBASCI is a valid and reliable scale to measure the standing balance of individuals with SCI. Further studies are required to establish other psychometric properties.

Effects of Two Different Hip-Knee-Ankle-Foot Orthoses on Postural Stability in Subjects with Spinal Cord Injury: A Pilot Study

Study Design

Pilot study.

Purpose

Evaluation of two different hip-knee-ankle-foot orthoses (HKAFOs; medial linkage reciprocating gait orthosis [MLRGO] and isocentric reciprocating gait orthosis [IRGO]) using gait and postural stability analysis in four subjects with spinal cord injury (SCI).

Overview of Literature

To the best of our knowledge, no study has evaluated postural stability in subjects with SCI when using MLRGO and IRGO.

Methods

The relative efficacy of each orthosis was evaluated with relevant gait parameters, and an assessment of postural stability and sway during usage was made. Each analysis was conducted following an appropriate period of training and acclimatization. The gait parameters employed in the study were walking speed, cadence, and endurance; these were recorded and analyzed using current, validated methods. Postural stability was assessed using a verified force plate measurement system, and a modified Falls Efficacy Scale (mFES) was used for the measurement of postural sway and the perceived fear of falling.

Results

Walking speed, cadence, and endurance increased with the use of both HKAFOs. When the two types of HKAFOs were compared, all the parameters showed a slight (but not significant) increase with the use of MLRGO compared with the use of IRGO. In contrast, there were slight but insignificant improvements in postural sway with the use of IRGO. However, although there were no significant differences between the two sets of mFES scores, there was a slightly reduced fear of falling with the use of MLRGO compared with the use of IRGO in the static standing position.

Conclusions

It is noteworthy that meaningful interpretations of results can only be drawn if a larger sample is employed. This pilot study showed no significant data; however, the results indicate that the use of MLRGO is superior to that of IRGO in terms of potential improvement in the mobility and confidence levels of subjects with SCI.

Current state of balance assessment during transferring, sitting, standing and walking activities for the spinal cord injured population: A systematic review

CONTEXT

Comprehensive balance measures with high clinical utility and sound psychometric properties are needed to inform the rehabilitation of individuals with spinal cord injury (SCI).

OBJECTIVE

To identify the balance measures used in the SCI population, and to evaluate their clinical utility, psychometric properties and comprehensiveness.

METHODS

Medline, PubMed, Embase, Scopus, Web of Science, and the Allied and Complementary Medicine Database were searched from the earliest record to October 19/16. Two researchers independently screened abstracts for articles including a balance measure and adults with SCI. Extracted data included participant characteristics and descriptions of balance measures. Quality was evaluated by considering study design, sampling method and adequacy of description of research participants. Clinical utility of all balance measures was evaluated. Comprehensiveness was evaluated using the modified Systems Framework for Postural Control.

RESULTS

2820 abstracts were returned and 127 articles included. Thirty-one balance measures were identified; 11 evaluated a biomechanical construct and 20 were balance scales. All balance scales had high clinical utility. The Berg Balance Scale and Functional Reach Test were valid and reliable, while the mini-BESTest was the most comprehensive.

CONCLUSION

No single measure had high clinical utility, strong psychometric properties and comprehensiveness. The mini-BESTest and/or Activity-based Balance Level Evaluation may fill this gap with further testing of their psychometric properties.

Optimization of an unpowered energy-stored exoskeleton for patients with spinal cord injury

The paper describes a novel unpowered energy-stored exoskeleton (ES-EXO) for spinal cord injured patients in consideration of patients' characteristics and injured levels. It proposed a method to optimize the energy-stored element to decrease the hip joint moment in walking. EMG patterns, ground reaction force and motion data from one participant with complete spinal cord injury at T10 were recorded. A combined human-ES-EXO model was built and the stored-energy element including locations and stiffness of springs were optimized in AnyBody Modeling System. Significant correlations between experimental and simulated muscle activations in without springs condition proved that the model was feasible. With optimized energy-stored elements, the hip flexion moment decreased by 37.2%, activations in abdominal muscles decreased and low back muscles slightly increased. The results suggest that ES-EXO could provide specific walking assistance for SCI patients through adjusting energy-stored elements according to patients' characteristics.

The influence of new reciprocating link medial linkage orthosis on walking and independence in a spinal cord injury patient

OBJECTIVES

The purpose of this paper is to describe the development and evaluation of a new medial linkage reciprocating gait orthosis (MLRGO) that incorporates a reciprocal mechanism and is sensitive to pelvic motion to potentially assist paraplegic patients to walk and provide functional independence.

CASE DESCRIPTION AND METHODS

The new orthosis was constructed and tested by a 20-year-old female paraplegic subject with transverse myelitis at T10 level, who was 4 years post injury and had also been an isocentric reciprocating gait orthosis (IRGO) user for 2 years. She received gait training for 12 weeks before undertaking gait analysis, and also completed a questionnaire that was designed to assess the perceived functionality of the new MLRGO when compared with an IRGO.

RESULTS

The results demonstrated improvements in gait velocity, step length and cadence, and also improvement in functional independence with the new orthosis compared with an IRGO.

CONCLUSION

The results demonstrated that this new MLRGO could be used for paraplegic patients who would like an improvement in functional independence and ambulation.

Evaluation of the performance of paraplegic subjects during walking with a new design of reciprocal gait orthosis

BACKGROUND

Spinal cord injury (SCI) influences a person's ability to stand and walk. Various orthoses have been developed to solve these standing and walking problems, however, patients still experience high energy consumption during walking and high forces on the upper limbs. A new reciprocal gait orthosis (RGO) was designed to address these problems. The aim of this study was to evaluate the performance of the new orthosis design with paraplegic subjects.

METHOD

Three paraplegic subjects with the lesion at level T12 and three able-bodied subjects were included in this study. Hip and pelvis range of motion and vertical ground reaction force were evaluated using the Qualysis motion analyzer system and a Kistler force plate. Energy consumption was measured with the Polar heart rate monitoring system. The differences between SCI individuals when walking with a Knee Ankle Foot Orthosis (KAFO) and the new RGO, and the differences between able-bodied and paraplegic subjects were evaluated by the use of paired sample and two sample t test, respectively.

RESULT

The results showed that energy consumption and gait analysis outcomes with new RGO orthosis were better than the KAFO. However, there was a large difference between paraplegic and able-bodied subjects while walking with the new orthosis.

CONCLUSION

The new RGO design performed better than a KAFO in terms of energy consumption, walking style and vertical ground reaction force. Therefore, it appears that RGO may be a useful orthosis for patients with paraplegia. Implications for Rehabilitation Walking and standing of the subjects with spinal cord injury (SCI) improve their physiological and physiological health. This study introduces a new type of orthosis design in order to improve the abilities of SCI subjects during walking and standing. It seems that the new design works better than available orthoses (KAFO).

The efficiency of mechanical orthoses in affecting parameters associated with daily living in spinal cord injury patients: a literature review

OBJECTIVE

The most simple and common approach in providing standing and walking by subjects with spinal cord injury (SCI) is the use of mechanical orthoses. These include traditional orthoses, medial linkage orthoses (MLOs) and reciprocating gait orthoses (RGOs). Independence, energy expenditure, gait parameters, system reliability and cosmesis are important factors in orthotic design. The aim of this review was to compare the evidence of existing mechanical orthoses to that of other types regarding these factors.

METHODS

The preferred reporting items for systematic reviews and meta-analyses (PRISMA) method was used by an experience researcher based on selected keywords and their composition and an electronic search was performed in well-known databases.

RESULTS

Twenty articles were selected for final evaluation. Many were case studies, and also had limited and heterogeneous sample sizes with different instruments used for evaluation. The results of the analysis demonstrated that independence and cosmesis are improved when using MLOs, but gait parameters, energy expenditure and stability are all improved when using RGOs.

CONCLUSION

Those mechanical orthoses which have reciprocal motion and congruency between the anatomical and orthotic joints have been shown to provide positive effects on patient lifestyles. However, further improvement is needed to more effectively meet the needs of SCI patients.

IMPLICATIONS FOR REHABILITATION

The most simple and traditional approach to enable standing and walking by people with SCI is use of purely mechanical orthoses. The most important factors that increase rejection rates of orthoses in paraplegia patients are excessive energy expenditure and increased applied force on upper limb joints. Improvement of the structure of mechanical orthoses is needed to improve independence, energy expenditure, and gait parameters, and is an important approach to improve ambulatory function in subjects with paraplegia.

The influence of ankle joint mobility when using an orthosis on stability in patients with spinal cord injury: a pilot study

OBJECTIVES

Perceived risk of falling is an important factor for people with spinal cord injury (SCI). This study investigated the influence of ankle joint motion on postural stability and walking in people with SCI when using an orthosis.

METHODS

Volunteer subjects with SCI (n=5) participated in this study. Each subject was fitted with an advanced reciprocating gait orthosis (ARGO) equipped with either solid or dorsiflexion-assist type ankle-foot orthosis (AFOs) and walked at their self-selected speed along a flat walkway to enable the comparison of walking speed, cadence and endurance. A force plate system and a modified Falls Efficacy Scale (MFES) were utilized to measure postural sway and the perceived fear of falling, respectively.

RESULTS

There were significant differences in the mean MFES scores between two types of orthosis (P=0.023). When using two crutches, there was no significant difference in static standing postural sway in the medio-lateral (M/L) direction (P=0.799), but significant difference in the antero-posterior (A/P) direction (P=0.014). However, during single crutch support, there was a significant difference in both M/L (P=0.019) and A/P (P=0.022) directions. Walking speed (7%) and endurance (5%) significantly increased when using the ARGO with dorsi flexion assisted AFOs. There was no significant deference between two types of orthoses in cadence (P=0.54).

CONCLUSIONS

Using an ARGO with dorsiflexion-assisted AFOs increased the fear of falling, but improved static postural stability and increased walking speed and endurance, and should therefore be considered as an effective orthosis during the rehabilitation of people with SCI.

Evaluation of the stability of normal subjects and patients with Perthes and spinal cord injury disorders during short and long periods of time

BACKGROUND

Stability during standing is achieved by a complex coordination process between various human systems. The stability of normal subjects and patients with various neuromuscular disorders has been evaluated by common methods based on force plate data analysis for one minute. However, most of the people frequently stand for a prolonged period during daily activities.

OBJECTIVES

This study aimed to evaluate the stability of subjects during a longer period of time. Moreover, the new method was introduced to analyze the stability of subjects with musculoskeletal disorders.

STUDY DESIGN

Experimental.

METHODS

Four groups of normal adults and children, individuals with spinal cord injury (SCI) and Perthes disease were recruited in this study. Stability of the subjects was evaluated by using parameters collected from centre of pressure (COP) sways obtained while subjects standing on force plate for one and then five minutes based on the old and new methods. Two sample t-test was used to compare the stability of the subjects by the commonly used method. The number of stable to unstable frames was selected for final analysis based on the new method.

RESULTS

Based on the traditional method, the SCI and Perthes patients were more stable than normal subjects (p < 0.05). Moreover, children were more unstable in the anteroposterior plane than adults. However, based on the new method, SCI and patients with Perthes disease were more unstable than normal adults. Moreover, in mediolateral direction the results of stability analysis with the new method differed from that of the traditional method.

CONCLUSION

The new method of stability analysis seems to be more sensitive and accurate than that of the traditional commonly used method. Based on the new method, stability is the ability of a subject to return from an unstable position to a stable one and to remain in a stable one for a certain period of time. Clinical relevance The results of this research can be used by most clinicians to evaluate the stability of subjects with various musculoskeletal disorders.

The ABLE scale: the development and psychometric properties of an outcome measure for the spinal cord injury population

BACKGROUND

A paucity of information exists on the psychometric properties of several balance outcome measures. With the exception of the Modified Functional Reach Test, none of these balance outcome measures were developed specifically for the population with spinal cord injury (SCI). A new balance assessment tool for people with SCI, the Activity-based Balance Level Evaluation (ABLE scale), was developed and tested.

OBJECTIVE

The purposes of this study were: (1) to develop a scale capturing the wide spectrum of functional ability following SCI and (2) to assess the initial psychometric properties of the scale using a Rasch analysis.

DESIGN

A methodological research design was used to test the initial psychometric properties of the ABLE scale.

METHODS

The Delphi technique was used to establish the original 28-item ABLE scale. People with SCI at each of 4 centers (n=104) were evaluated using the ABLE scale. A Rasch analysis was conducted to test for targeting, item difficulty, item bias, and unidimensionality. An analysis of variance was completed to test for discriminant validity.

RESULTS

The Rasch analysis revealed a scale with minimal floor and ceiling effects and a wide range of item difficulty capturing the large scope of functional capacity after SCI. Multiple redundancies of item difficulty were observed. Limitations All raters were experienced physical therapists, which may have skewed the results. The sample size of 104 participants precluded a principal component analysis.

CONCLUSION

Development of an all-inclusive clinical instrument assessing balance in the SCI population was accomplished using the Delphi technique. Modifications of the ABLE scale based on the Rasch analysis yielded a 28-item scale with minimal floor or ceiling effects. Larger studies using the revised scale and factor analyses are necessary to establish unidimensionality and reduction of the total item number.

Postural responses during falling with rapid reach-and-grasp balance reaction in patients with motor complete paraplegia

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To investigate the kinematic, kinetic and electromyographic (EMG) aspects of postural control during falling with rapid reach-and-grasp balance reaction in thoracic cord-injured individuals wearing knee-ankle-foot orthoses (KAFOs).

SETTING

Institutional Motion Analysis Laboratory.

METHODS

Seven T7-T12 cord-injured subjects with complete motor loss (ASIA classes A and B) participated in this study. Subjects with KAFOs first stood steady with a modified walker and then released their hold on the walker to maintain self-supported standing until falling with grasping. The center of pressure (COP), center of mass (COM) and joint angles were measured together with EMG of the triceps (TRI), T4 paraspinal and abdominal muscles.

RESULTS

After release of the walker, there was a rapid increase of COM-COP distance (that is, from 13.32+/-11.79 to 54.29+/-24.56 mm), with COM in front of COP during a forward fall, which was associated with the increases of T4 muscle activities. After the reach-and-grasp reaction, COM moved behind COP, which was associated with the increase of ankle dorsiflexion and the TRI and abdominal muscle activities.

CONCLUSION

The increase of upper back extensor muscle activity might not be enough to correct postural instability during unsupported stance in thoracic spinal cord injury with complete motor loss. The rapid reach-and-grasp reaction is an alternative compensatory mechanism to prevent falling to the ground.

Design and development of virtual reality based perceptual-motor rehabilitation scenarios

Virtual reality technology may provide new options for conducting perceptual-motor assessment within simulated 3D environments for persons with a wide range of disabilities. This paper outlines our work developing a series of game-like VR scenarios to assess and rehabilitate eye-hand coordination, range of motion and other relevant perceptual-motor activities. Our efforts have focused on building engaging game-based stereoscopic graphic scenarios that allow clients to participate in perceptual-motor rehabilitation by interacting with 3D stimuli within a full 360-degree space using a head mounted display or by way of a "face-forward" format using 3D projection displays. Exploratory work using multiple video sensors to detect and track 3D body motion, identify body postures and quantify motor performance is also described.

Stability analysis of paraplegic standing while wearing an orthosis

Paraplegics can maintain a standing posture, called the "C-posture", while wearing an orthosis. The significant feature of the C-posture is that the body's center of mass is located behind the hip joint. In this study, we investigate the C-posture mechanism and assess the relationship between posture and stability, the aim being to restore standing function. We first measured the standing postures of paraplegic subjects wearing an orthosis. The subjects maintained the standing posture for 30 s. Next, assuming the C-posture to be an equilibrium attractor in the musculoskeletal system, we used a dynamic model of the musculoskeletal system to analyze the relationship between posture and stability, and also to assess the influence of ankle stiffness. We calculated the standing posture on the basis of a return map. The calculated standing postures show some features of the C-posture. The stability analysis revealed that, despite a limitation in the range of stable postures, the C-posture is more stable than the postures of normal people. The results suggest that although the C-posture is an appropriate posture for paraplegic standing, sufficient ankle stiffness and an appropriate alignment of ankle angle are necessary and preventing hip flexion movements is desirable.

Development of a novel type of shoe to improve the efficiency of knee-ankle-foot orthoses with a medial single hip joint (Primewalk orthoses): a novel type of shoe for Primewalk orthosis

The purpose of the study was to develop and evaluate a new heel cushion in shoes for use with knee-ankle-foot orthoses having a medial single hip joint (Primewalk orthoses) in order to improve walking velocity and efficiency. Primewalk orthoses and shoes were made for a 24-year-old man having paraplegia with flaccid paresis (level T-7; grade A, ASIA impairment scale) of 2 years' duration. Walking exercises were assigned. Shoes were modified with the sole made of hard rubber and the addition of soft rubber heel cushions. The walking speed, centre of foot pressure during walking, and ground reaction force were evaluated. The patient also subjectively assessed the devices. The modifications to the shoes resulted in a 1.94-fold increase in walking speed (8.6 to 16.7 m/min), a 1.87-fold increase in step length (16.7 to 31.3 cm) and a 54.8% decrease in the physiological cost index (7.7 to 3.48 beats/min). The centre of foot pressure during walking was found to deviate towards the lateral margin of the foot. The horizontal rotation of the pelvis increased simultaneously. The patient reported increased amplitude of flail motion of the trunk and decreased burden to the upper limbs. It was concluded that the modified new heel cushion of the shoe provided freedom to the lower legs and thereby increased walking efficiency.

Use of an ankle-foot orthosis in a dog with traumatic sciatic neuropathy

Traumatic unilateral sciatic neuropathy secondary to a gunshot wound was diagnosed in a seven-month-old, intact male golden retriever. Findings on neurological assessment, performed after cardiovascular stabilisation, were incompatible with a return to normal limb function. An ankle-foot orthosis was used to correct excessive flexion of the digits and tarsus. This device greatly improved the dog's willingness to ambulate and could serve as an alternative to amputation in companion animals with severe sciatic axonotmesis or neurotmesis. Complications associated with chronic tibiotarsal hyperflexion necessitated a pantarsal arthrodesis one year after initial presentation; the dog also developed cranial cruciate disease in the affected limb three years after the gunshot injury.