Accuracy of Heart Rate and Respiratory Rate Measurements Using Two Types of Wearable Devices.

Objectives: Wearable devices such as fitness trackers have become popular in the healthcare field. Tracking heart rate and respiratory rate, in addition to physical activity, may provide an accurate picture of daily health. We believe that a combination of two types of devices can simultaneously measure and record physical activity, heart rate, and respiratory rate. However, the measurement accuracies of these two types of devices are not clear. This study aimed to determine the measurement accuracies of two wearable devices for heart and respiratory rate measurements. Methods: Ten healthy men performed incremental load tests (ILTs) and constant load tests (CLTs) on a cycle ergometer. The heart and respiratory rates were measured using wrist-worn (Silmee W22, TDK, Japan, Tokyo) and respiratory tracking devices (Spire Stone, Spire Health, San Francisco, CA, USA), respectively. A 12-lead electrocardiograph and the breath-by-breath method were used as external standards for heart and respiratory rates, respectively. Results: Bland-Altman analysis showed that heart rate had a fixed bias at rest and during ILT and CLT and had a proportional bias during CLT. The standard error values of the regression at rest and during CLT were less than 10 bpm for heart rate and less than 5.0 /min for respiratory rate. During ILT, the standard error was greater than 10 bpm for heart rate and approximately 5.0 /min for respiratory rate. Conclusions: The heart and respiratory rate measurements obtained using wearable devices were accurate within the practical margin of error.

Development of a Gait Rehabilitation Robot Using an Exoskeleton and Functional Electrical Stimulation: Validation in a Pseudo-paraplegic Model.

OBJECTIVE: We have developed a robot for gait rehabilitation of paraplegics for use in combination with functional electrical stimulation (FES). The purpose of this study was to verify whether the robot-derived torque can be reduced by using FES in a healthy-person pseudo-paraplegic model. METHODS: Nine healthy participants (22-36 years old) participated in this study. The robot exoskeleton was designed based on the hip-knee-ankle-foot orthosis for paraplegia. Participants walked on a treadmill using a rehabilitation lift to support their weight. The bilateral quadriceps femoris and hamstrings were stimulated using FES. The participants walked both with and without FES, and two walking speeds, 0.8 and 1.2 km/h, were used. Participants walked for 1 min in each of the four conditions: (a) 0.8 km/h without FES, (b) 0.8 km/h with FES, (c) 1.2 km/h without FES, and (d) 1.2 km/h with FES. The required robot torques in these conditions were compared for each hip and knee joint. The maximum torque was compared using one-way analysis of variance to determine whether there was a difference in the amount of assist torque for each gait cycle. RESULTS: Walking with the exoskeleton robot in combination with FES significantly reduced the torque in hip and knee joints, except for the right hip during extension. CONCLUSIONS: In the healthy-participant pseudo-paraplegic model, walking with FES showed a reduction in the robot-derived torque at both the hip and knee joints. Our rehabilitation robot combined with FES has the potential to assist paraplegics with various degrees of muscle weakness and thereby provide effective rehabilitation.

Aphasia testing (auditory comprehension domain) using a new eye-tracking system in healthy participants.

Sakai R, Koike Y, Saito K, Matsunaga T, Shimada Y, Miyakoshi N. Aphasia testing (auditory comprehension domain) using a new eye-tracking system in healthy participants. Jpn J Compr Rehabil Sci 2022; 13: 31-35. Objective: We administered a conventional pointing-method test with eye-tracking to evaluate items associated with auditory comprehension and examined the concordance between the obtained results. Methods: The enrolled participants were 10 healthy volunteers. We performed tests after extracting auditory comprehension items from the SLTA, the WAB, and the Supplementary tests for the SLTA using the eye-tracking system and the pointing method. Results: The mean test duration was 9 min 51 s ± 1 min 41 s (mean ± SD), and the percentage of correct answers was 100% and in perfect agreement for the pointing method and the eye-tracking system. The mean response time was 0.96 ± 0.36 s for the pointing method and -0.39 ± 0.21 s for the eye-tracking system. Hence, the latter was faster than the former, and examinees completed their responses before listening to the end of the questions. Conclusion: The new eye-tracking system makes it possible to perform aphasia tests (auditory comprehension items) comparable to the conventional pointing method.

Diagnostic Accuracy of the Mobile Assessment of Varus Thrust Using Nine-axis Inertial Measurement Units.

OBJECTIVES: The purpose of this study was to clarify the diagnostic accuracy of the mobile assessment of varus thrust using inertial measurement units (IMUs). METHODS: A total of 80 knees in 49 patients were enrolled in this study. On visual analysis of gait to determine the presence or absence of varus thrust, 23 knees were assigned to the Present group, 17 to the Ambiguous group, and 40 to the Absent group. The peak knee varus angular velocities (PVVs), measured by quantitative gait analysis using nine-axis IMUs, were compared between these three groups. A receiver operating characteristic curve for the relationship between the visual assessment of varus thrust (Present and Ambiguous) and the measured PVV was created, and the cut-off PVV for visualized varus thrust was determined as the highest point for both sensitivity and specificity. RESULTS: The mean PVVs were significantly different between the three groups (Present, 47.7 ± 8.2 degree/s, Ambiguous, 34.1 ± 10.5 degree/s, and Absent, 28.1 ± 8.3 degree/s, respectively, ANOVA P=0.000). The PVV cut-off value for visualized varus thrust was 28.1 degree/s, yielding a sensitivity of 0.957 and a specificity of 0.579. CONCLUSIONS: A PVV <28.1 degree/s is useful for ruling out varus thrust during gait. This quantitative varus thrust assessment method using IMUs has clinical utility as a screening test.

Comparison of the Effects of Native Vitamin D and Eldecalcitol on Muscular Strength and Dynamic Balance in Patients with Postmenopausal Osteoporosis.

OBJECTIVES: Previous studies have suggested that the effects of vitamin D in preventing osteoporotic fractures result in part from its influence on fall prevention. However, the effects of vitamin D on dynamic balance as a contributor to fall prevention have not been fully evaluated. Moreover, few studies have compared the effects of native and active forms of vitamin D. The objective of this preliminary randomized prospective study was to compare the effects of native vitamin D and eldecalcitol on muscular strength and dynamic balance in postmenopausal patients undergoing denosumab treatment for osteoporosis. METHODS: A total of 30 women with postmenopausal osteoporosis were randomly assigned to a native D group (administered denosumab and native vitamin D with calcium) or an ELD group (administered denosumab and eldecalcitol) and were followed up for 6 months. The following parameters were compared: the strengths of the back extensor and lower extremity muscles; static balance evaluated using the one-leg standing test; and dynamic balance evaluated using the 10-m walk test, the functional reach test, the timed up and go test, and the total length of the trajectory of the center of gravity (LNG) measured using a dynamic sitting balance measurement device. RESULTS: Compared to baseline measurements, back extensor and knee extensor strengths had significantly increased after 6 months of treatment in the native D group (P<0.05) but not in the ELD group. In contrast, LNG significantly improved in both groups after 6 months (P<0.05). No significant differences between the two groups were seen in any of these measured parameters after treatment. CONCLUSIONS: Both native vitamin D + denosumab and eldecalcitol + denosumab were effective for improving dynamic sitting balance in postmenopausal women with osteoporosis.

Relationship between Dynamic Trunk Balance and the Balance Evaluation Systems Test in Elderly Women.

OBJECTIVE: Falls are major contributors to elderly subjects becoming bedridden. Consequently, it is important to evaluate and minimize the risk of falls in the elderly. Trunk stability is important for balance function and is related to fall prevention in elderly women. We developed a balance-measuring device that uses a dynamic sitting position to safely measure balance function. The Balance Evaluation Systems Test (BESTest) is useful method to assess balance function, a recently developed balance evaluation test that can detect minor balance problems not captured by previous tests. The purpose of the present study was to examine the relationship between dynamic trunk balance and findings of the BESTest in elderly women. METHODS: Thirty-one healthy women aged 60 years or more participated in this study. The evaluation items were the BESTest total score, scores for each of the six elements of the BESTest, dynamic sitting balance, static postural balance, and muscle strength. RESULTS: The mean total BESTest score was 85.4 points. The mean total trajectory length of the center of gravity (COG) during the dynamic sitting balance test was 1447.5 mm. A negative correlation (r=-0.481, P= 0.006) was observed between the total COG trajectory length and the BESTest score. A negative correlation was also found between the total COG trajectory length and biomechanical constraints (r=-0.492, P=0.005) and anticipatory postural adjustments (r=-0.532, P=0.002). There were no correlations between the dynamic sitting balance total COG trajectory length and the stationary standing COG trajectory length or muscle strength. CONCLUSIONS: In elderly women, the total COG trajectory length during dynamic sitting was negatively correlated with the BESTest total score.

Reference values for the locomotive syndrome risk test quantifying mobility of 8681 adults aged 20-89 years: A cross-sectional nationwide study in Japan.

BACKGROUND: The locomotive syndrome risk test was developed to quantify the decrease in mobility among adults, which could eventually lead to disability. The purpose of this study was to establish reference values for the locomotive syndrome risk test for adults and investigate the influence of age and sex. METHODS: We analyzed 8681 independent community dwellers (3607 men, 5074 women). Data pertaining to locomotive syndrome risk test (the two-step test, the stand-up test, and the 25-question geriatric locomotive function scale [GLFS-25]) scores were collected from seven administrative areas of Japan. RESULTS: The reference values of the three test scores were generated and all three test scores gradually decreased among young-to-middle-aged individuals and rapidly decreased in individuals aged over 60 years. The stand-up test score began decreasing significantly from the age of 30 years. The trajectories of decrease in the two-step test score with age was slightly different between men and women especially among the middle-aged individuals. The two physical test scores were more sensitive to aging than the self-reported test score. CONCLUSION: The reference values generated in this study could be employed to determine whether an individual has mobility comparable to independent community dwellers of the same age and sex.

Development of a Rehabilitation Robot Combined with Functional Electrical Stimulation Controlled by Non-disabled Lower Extremity in Hemiplegic Gait.

OBJECTIVE: We developed a rehabilitation robot to assist hemiplegics with gait exercises. The robot was combined with functional electrical stimulation (FES) of the affected side and was controlled by a real-time-feedback system that attempted to replicate the lower extremity movements of the non-affected limb on the affected side. We measured the reproducibility of the non-affected limb movements on the affected side using FES in non-disabled individuals and evaluated the smoothness of the resulting motion. METHOD: Ten healthy men participated in this study. The left side was defined as the non-affected side. The measured hip and knee joint angles of the non-affected side were reproduced on the pseudo-paralytic side using the robot's motors. The right quadriceps was stimulated with FES. Joint angles were measured with a motion capture system. We assessed the reproducibility of the amplitude from the maximum angle of flexion to extension during the walking cycle. The smoothness of the motion was evaluated using the angular jerk cost (AJC). RESULTS: The amplitude reproduction (%) was 87.9 ± 6.2 (mean ± standard deviation) and 71.5 ± 10.7 for the hip and knee joints, respectively. The walking cycle reproduction rate was 99.9 ± 0.1 and 99.8 ± 0.2 for the hip and knee joints, respectively. There were no statistically significant differences between results with FES versus those without FES. The AJC of the robot side was significantly smaller than that of the non-affected side. CONCLUSIONS: A master-slave gait rehabilitation system has not previously been attempted in hemiplegic patients. Our rehabilitation robot showed high reproducibility of motion on the affected side.

Evaluation of Sagittal Spine-Pelvis-Lower Limb Alignment in Elderly Women with Pelvic Retroversion while Standing and Walking Using a Three-Dimensional Musculoskeletal Model.

STUDY DESIGN: In vivo biomechanical study using a three-dimensional (3D) musculoskeletal model for elderly individuals with or without pelvic retroversion. PURPOSE: To evaluate the effect of pelvic retroversion on the sagittal alignment of the spine, pelvis, and lower limb in elderly females while standing and walking. OVERVIEW OF LITERATURE: Patients with hip-spine syndrome have concurrent hip-joint and spine diseases. However, the dynamic sagittal alignment between the hip joint and spine has rarely been investigated. We used a 3D musculoskeletal model to evaluate global spinopelvic parameters, including spinal inclination and pelvic tilt (PT). METHODS: A total of 32 ambulant females (mean age=78 years) without assistance were enrolled in the study. On the basis of the radiographic measurement for PT, participants were divided into the pelvic retroversion group (R-group; PT≥20°) and the normal group (N-group; PT<20°). A 3D musculoskeletal motion analysis system was used to analyze the calculated value for the alignment of spine, pelvis, and lower limb, including calculated (C)-PT, sagittal vertical axis (C-SVA), pelvic incidence, lumbar lordosis, T1 pelvic angle (C-TPA), as well as knee and hip flexion angles while standing and walking. RESULTS: While standing, C-PT and C-TPA in the R-group were significantly larger than those in the N-group. Hip angle was significantly smaller in the R-group than in the N-group, unlike knee angle, which did not show difference. While walking, C-SVA and C-TPA were significantly increased, whereas C-PT decreased compared with those while standing. The maximum hip-flexion angle was significantly smaller in the R-group than in the N-group. There was a significant correlation between the radiographic and calculated parameters. CONCLUSIONS: The 3D musculoskeletal model was useful in evaluating the sagittal alignment of the spine, pelvis, and leg. Spinopelvic sagittal alignment showed deterioration while walking. C-PT was significantly decreased while walking in the R-group, indicating possible compensatory mechanisms attempting to increase coverage of the femoral head. The reduction in the hip flexion angle in the R-group was also considered as a compensatory mechanism.

Impact of pulmonary rehabilitation on postoperative complications in patients with lung cancer and chronic obstructive pulmonary disease.

BACKGROUND: Given the extent of the surgical indications for pulmonary lobectomy in breathless patients, preoperative care and evaluation of pulmonary function are increasingly necessary. The aim of this study was to assess the contribution of preoperative pulmonary rehabilitation (PR) for reducing the incidence of postoperative pulmonary complications in non-small cell lung cancer (NSCLC) patients with chronic obstructive pulmonary disease (COPD). METHODS: The records of 116 patients with COPD, including 51 patients who received PR, were retrospectively analyzed. Pulmonary function testing, including slow vital capacity (VC) and forced expiratory volume in one second (FEV1 ), was obtained preoperatively, after PR, and at one and six months postoperatively. The recovery rate of postoperative pulmonary function was standardized for functional loss associated with the different resected lung volumes. Propensity score analysis generated matched pairs of 31 patients divided into PR and non-PR groups. RESULTS: The PR period was 18.7 ± 12.7 days in COPD patients. Preoperative pulmonary function was significantly improved after PR (VC 5.3%, FEV1 5.5%; P < 0.05). The FEV1 recovery rate one month after surgery was significantly better in the PR (101.6%; P < 0.001) than in the non-PR group (93.9%). In logistic regression analysis, predicted postoperative FEV1 , predicted postoperative %FEV1 , and PR were independent factors related to postoperative pulmonary complications after pulmonary lobectomy (odds ratio 18.9, 16.1, and 13.9, respectively; P < 0.05). CONCLUSIONS: PR improved the recovery rate of pulmonary function after lobectomy in the early period, and may decrease postoperative pulmonary complications.

Postcontraction hyperemia after electrical stimulation: potential utility in rehabilitation of patients with upper extremity paralysis.

The purpose of this study was to compare postcontraction hyperemia after electrical stimulation between patients with upper extremity paralysis caused by upper motor neuron diseases and healthy controls. Thirteen healthy controls and eleven patients with upper extremity paralysis were enrolled. The blood flow in the basilic vein was measured by ultrasound before the electrical stimulation of the biceps brachii muscle and 30 s after the stimulation. The stimulation was performed at 10 mA and at a frequency of 70 Hz for 20 s. The mean blood flow in the healthy control group and in upper extremity paralysis group before the electrical stimulation was 60 ± 20 mL/min (mean ± SD) and 48 ± 25 mL/min, respectively. After the stimulation, blood flow in both groups increased to 117 ± 23 mL/min and 81 ± 41 mL/min, respectively. We show that it is possible to measure postcontraction hyperemia using an ultrasound system. In addition, blood flow in both groups increased after the electrical stimulation because of postcontraction hyperemia. These findings suggest that evaluating post contraction hyperemia in patients with upper extremity paralysis can assess rehabilitation effects.

Eldecalcitol improves muscle strength and dynamic balance in postmenopausal women with osteoporosis: an open-label randomized controlled study.

The antifracture efficacy of vitamin D in osteoporosis is due to its direct action on bones and indirect extraskeletal effects to prevent falls. Eldecalcitol is an analog of active vitamin D3 that improves bone mineral density and reduces the risk of osteoporotic fractures. However, the effects of eldecalcitol on muscle strength and static and dynamic postural balance are unclear. In this open-label randomized controlled study, we assessed the effects of eldecalcitol on muscle strength and static and dynamic postural balance in 50 postmenopausal women (mean age 74 years) with osteoporosis treated with bisphosphonate. Participants were randomly divided into a bisphosphonate group (alendronate at 35 mg/week; n = 25) or an eldecalcitol group (eldecalcitol at 0.75 µg/day and alendronate at 35 mg/week; n = 25) and were followed up for 6 months. Trunk muscle strength, including back extensor strength and iliopsoas muscle strength, was measured. Static standing balance was evaluated and the one leg standing test was performed to assess static postural balance. Dynamic sitting balance was evaluated and the 10-m walk test, functional reach test, and timed up and go test were performed to assess dynamic postural balance. At 6 months, there were no significant changes in any measure of muscle strength or balance in the bisphosphonate group, whereas eldecalcitol significantly increased back extensor strength (p = 0.012) and iliopsoas muscle strength (p = 0.035). Eldecalcitol also significantly improved findings on the timed up and go test (p = 0.001) and dynamic sitting balance (p = 0.015) at 6 months. These results with eldecalcitol may have an impact on prevention of falls.

The impact of high-frequency magnetic stimulation of peripheral nerves: muscle hardness, venous blood flow, and motor function of upper extremity in healthy subjects.

The purpose of this study was to investigate the impact of high-frequency peripheral nerve magnetic stimulation on the upper limb function. Twenty-five healthy adults (16 men and 9 women) participated in this study. The radial nerve of the non-dominant hand was stimulated by high-frequency magnetic stimulation device. A total of 600 impulses were applied at a frequency of 20 Hz and intensity of 1.2 resting motor threshold (rMT). At three time points (before, immediately after, and 15 min after stimulation), muscle hardness of the extensor digitorum muscle on the stimulated side was measured using a mechanical tissue hardness meter and a shear wave imaging device, cephalic venous blood flow on the stimulated side was measured using an ultrasound system, and the Box and Block test (BBT) was performed. Mechanical tissue hardness results did not show any significant differences between before, immediately after, and 15 min after stimulation. Measurements via shear wave imaging showed that muscle hardness significantly decreased both immediately and 15 min after stimulation compared to before stimulation (P < 0.05). Peripheral venous blood flow and BBT score significantly increased both immediately and 15 min after stimulation compared to before stimulation (P < 0.01). High-frequency peripheral nerve magnetic stimulation can achieve effects similar to electrical stimulation in a less invasive manner, and may therefore become an important element in next-generation rehabilitation.

Evaluation of trunk stability in the sitting position using a new device.

The purpose of this study was to evaluate trunk stability in seated elderly and young individuals using a new device that inclines a seat while tracking the center of pressure (CoP). We evaluated the locus of CoP, locus length, locus length per second, enveloped area, root mean square area, and locus length per unit area (LNG/AREA). LNG/AREA, which reflects postural adjustments controlled by the spinal proprioceptive reflexes of the lower limbs, was not significantly different between young and elderly individuals. Our device measured trunk stability without influence from the lower extremities, which explains why LNG/AREA did not significantly differ between young and elderly individuals. These findings indicate that the new device can be used to quantify dynamic trunk stability.

Effect of electrical stimulation therapy on upper extremity functional recovery and cerebral cortical changes in patients with chronic hemiplegia.

Hemiplegia is a common sequel of stroke and assisted living care is needed in many cases. The purpose of this study was to evaluate the effect of using surface electrode stimulation device in rehabilitation, in terms of functional improvement in upper limb and the changes in brain activation related to central nervous system reconstruction. Five patients with chronic hemiplegia received electrical stimulation therapy using the orthosis-type surface electrode stimulation device for 12 weeks. Training time was 30 min/day for the first weeks, and increased 30 min/day in every 4 weeks. Upper limb outcome measures included Brunnstrom stage, range of motion, Fugl-Meyer assessment and manual function test. Brain activation was measured using functional MRI. After therapy with therapeutic electrical stimulation (TES) for 12 weeks upper limb function improved in all cases. The results of brain activation showed two patterns. In the first, the stimulation produced an activity in the bilateral somatosensory cortices (SMC), which was seen to continue over time. The second, activation was bilateral and extensive before stimulation, but localized to the SMC after intervention. Treatment with TES using an orthosis-type electrode stimulation device improves upper limb function in chronic hemiplegia patients. The present findings suggest that there are not only efferent but also afferent effects that may promote central nervous system remodeling.

Hybrid control of powered orthosis and functional neuromuscular stimulation for restoring gait.

The restoration of motor functions of patients with spinal cord injury (SCI) is one of important subjects for study. For this purpose, methods of functional neuromuscular stimulation (FNS) have been investigated in medical science and practice during these three decades. However, we have not achieved complete restoration of motor functions in SCI patients. On the other hand, we have achieved useful devices in human-scaled transportation by using power assist technology. Thus, applying power assist technology to the problem of restoring motor functions is one of possible solutions and sounds practical. In this paper, we propose a new hybrid system to combine power assist technology and FNS for restoring motor functions of lower extremity in SCI patients. Both powered orthosis and FNS are used to generate and control the joints moments of lower extremity in the proposed hybrid system. The main role of powered orthosis to compensate the joints moments generated by FNS and to enhance the controllability of FNS with the actuators. The proposed hybrid control system has been experimentally evaluated in gait motions by measuring the angle trajectories and generated moments around the knee and hip joints in the cases when only actuators are used and both FNS and actuators of the orthosis are used. The results prove that the control method for the hybrid system is useful to restore motor functions of lower extremity in SCI patients.

Development of FES-rowing machine.

As per present social needs, assisting machines are very much needed for persons of advanced age. We analyzed and developed a fitness apparatus suitable for meeting the requirement of elderly people. The proposed apparatus consists of a rowing machine and Functional Electrical Stimulation (FES), that can be used to exercise every muscle of a person of advanced age. The rowing mechanism was actually developed to train rowers and can train the legs and upper body parts most effectively. Move over FES can assist the exercise of the legs by using surface electrical stimulation. An experiment was conducted and the results prove that the developed apparatus can train the muscles of the person of advanced age effectively and can compensate exercise shortage.

Clinical results of rehabilitation for accessory nerve palsy after radical neck dissection.

CONCLUSIONS: Occupational therapy significantly improves shoulder range of motion in patients with accessory nerve palsy after radical neck dissection, but it has limited effects on the associated pain. OBJECTIVE: To evaluate the outcome of occupational therapy rehabilitation for patients with accessory nerve palsy. PATIENTS AND METHODS: The occupational therapy group involved 35 shoulders of 29 patients with accessory nerve palsy after radical neck dissection; the control group included 10 shoulders of 9 patients who did not receive occupational therapy. All patients had a malignant tumor in the head or neck that necessitated radical neck dissection. We collected data pertaining to resting pain, motion pain, and the active and passive range of motion during shoulder flexion and abduction. RESULTS: Occupational therapy did not adequately relieve resting or motion pain, but all patients achieved independence in activities of daily living and housekeeping activities. Although occupational therapy significantly improved shoulder elevation for all movements, shoulder elevation was significantly better for flexion than for active and passive abduction.

Reduction of muscle fatigue by catchlike-inducing intermittent electrical stimulation in rat skeletal muscle.

Catchlike property is the force enhancement produced when a brief, high-frequency burst of pulses is added to a constant low-frequency stimulation. In functional electrical stimulation, constant low-frequency stimulation of approximately 20 Hz has primarily been used to reduce muscle fatigue. The purpose of this study was to investigate the effects of catchlike-inducing intermittent stimulation on muscle fatigue in relation to continuous intermittent low-frequency stimulation. Twenty-two adult male Wistar ST rats were randomly assigned into the constant frequency stimulation (CFS) group or the catchlike-inducing stimulation (CIS) group. In the CFS group, constant low-frequency stimulation of 20 Hz was applied intermittently (4 seconds "ON"/15 seconds "OFF"). In the CIS group, a single electrical burst of 100 Hz was applied at the start of the every 4-second period of stimulation. The muscle fatigue test lasted for 16 min and isometric muscle force, muscle fatigue, and muscular workload were evaluated. CIS significantly increased the maximum muscular force (under fatigued condition) and workload, and significantly decreased muscle fatigue (p < 0.05). The results of this study suggest that catchlike-inducing intermittent electrical stimulation is useful in the clinical administration of functional electrical stimulation.

Hybrid functional electrical stimulation with medial linkage knee-ankle-foot orthoses in complete paraplegics.

We have previously restored ambulation in paraplegics by performing hybrid functional electrical stimulation (FES) with medial linkage knee-ankle-foot orthosis (MLKAFO). The most common MLKAFO (hinge-type MLKAFO) has the hypothetical axis that is lower than the physiological hip joint position, resulting in slow velocity and short step length. A new MLKAFO (sliding-type MLKAFO), which uses sliding medial linkages, has been developed to correct the axial discrepancy of the hinge-type MLKAFO that causes limited hip joint excursion. There have been reports of instability associated with sliding medial linkages, but the mechanism of this instability is unclear. The purpose of the present study was to evaluate the effects of FES with MLKAFOs on ambulation in paraplegics. Two complete paraplegic patients (levels T8 and T12, respectively) participated in this study. Kinematics data during ambulation were obtained using a motion analysis system. We measured gait velocity and hip progression during the standing phase. The sliding-type MLKAFO produced faster gait velocity than did the hinge-type MLKAFO, but it caused pelvis instability without FES. Pelvis instability was controlled by hybrid FES using the sliding-type MLKAFO. With hybrid FES, the sliding-type MLKAFO provides better gait performance than the hinge-type MLKAFO, but the hinge-type MLKAFO provides greater pelvis stability during walking. Moreover, FES provides sufficient propulsion to allow the complete paraplegics to walk.