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Biomedical subjects

B T Smith

Publications and source records attributed to B T Smith.

At least 19 recordsLinked to original sources

Patterns of lower extremity innervation in pediatric spinal cord injury.

STUDY DESIGN: Retrospective review. OBJECTIVES: To identify relationships between lower extremity innervation and level of injury, mechanism of injury, and age at injury in a pediatric population with spinal cord injury (SCI). Secondarily, relationships between innervation and completeness of injury, time since injury, race, and sex were evaluated. SETTING: Pediatric orthopedic referral hospital, Philadelphia, Pennsylvania. METHODS: Records of 190 subjects, ages 1-21 years, were reviewed. Data collected from the medical record included lower extremity muscle innervation, American Spinal Injury Association (ASIA) level and class, mechanism of injury, age at injury, time since injury, race, and sex. To determine innervation, lower extremity muscles had been tested using surface electrical stimulation and identified as being innervated or denervated. If a muscle responded weakly, strength duration testing was performed. For analysis via logistic regression, subjects were grouped based upon level and mechanism of injury. RESULTS: A relationship (P<0.0001) was found between ASIA level and lower extremity innervation of all muscles and between length of time since injury and lower extremity innervation for some muscles. Following multiple logistic regression, only ASIA level remained as an independent predictor of lower extremity innervation status. CONCLUSION: Our results show that lower extremity innervation does differ based on the level of the injury. Denervation began to be seen with injuries in the lower thoracic region and more predominantly with injuries in the lumbar region. This supports our hypothesis that the incidence of lower motor neuron injuries would increase as injuries became more caudal. Our hypotheses of a relationship between innervation status and mechanism of injury and age at injury were not supported. This information is important in determining treatment strategies, eligibility for electrical stimulation techniques, and potential regenerative strategies. SPONSORSHIP: This study was funded by Shriners Hospitals for Children, Grant #8530.

Adolescent↗

Implantable FES system for upright mobility and bladder and bowel function for individuals with spinal cord injury.

STUDY DESIGN: Postintervention. OBJECTIVES: To determine the effectiveness of the Praxis multifunctional implantable functional electrical stimulation (FES) system (Neopraxis Pty. Ltd, Lane Cove, NSW, Australia) to provide standing and stepping ability and bladder and bowel management for individuals with motor complete thoracic level spinal cord injuries (SCI). SETTING: Pediatric orthopedic hospital specializing in SCI. SUBJECTS: Three males, ages 17 and 21 years, with motor-complete thoracic level SCI and intact lower motor neurons to the muscles targeted for stimulation. METHODS: Each subject was successfully implanted with the Praxis FES system. All three subjects received electrodes for upright mobility and the first two subjects received additional electrodes for stimulated bladder and bowel management. Following training, subjects were evaluated in their ability to use FES for nine mobility activities. Acute and chronic experiments of the effect of stimulation on bowel and bladder function were also performed. RESULTS: All three subjects could independently stand up from the wheelchair and could walk at least 6 m using a swing through gait pattern. Two subjects were able to independently perform swing through gait for 6 min and one subject was able to independently ascend and descend stairs. Suppression of reflex bladder contractions by neuromodulation (subject 1) and stimulated contractions of the rectum (subject 2) were observed in acute experiments. When stimulation was applied over the course of several weeks, a positive effect on bowel function was measured. Stimulated bladder contractions were not achieved. CONCLUSION: The feasibility of using the Praxis FES system for upright mobility and aiding aspects of bladder and bowel function was demonstrated with three subjects with thoracic level SCI.

Adolescent↗

Implantation of the Freehand System during initial rehabilitation using minimally invasive techniques.

STUDY DESIGN: Series of four single subjects with and without intervention design. OBJECTIVES: To describe a minimally invasive surgical technique used to implant the Freehand System during initial spinal cord injury (SCI) rehabilitation and to report rehabilitation outcomes of four recently injured adolescents using the Freehand System. SETTING: Nonprofit children's hospital specializing in orthopedic and SCI care. METHODS: Four subjects with C5 tetraplegia between 13 and 16 years of age and between 9 and 16 weeks following traumatic SCI underwent implantation of the Freehand System using minimally invasive surgical techniques. Outcomes on muscle strength, pinch force, hand function, performance of activities of daily living and satisfaction with and without the Freehand System were collected. RESULTS: Each subject was successfully implanted with the Freehand System without perioperative complications and employed the Freehand System during therapy services and ad lib on the rehabilitation floor. At the last follow-up, every subject remained a motor candidate for the Freehand System. With the Freehand System, average lateral and palmar pinch force was 1.8 and 1.6 kg respectively; average pinch force without functional electrical stimulation (FES) was 0.29 kg. With the Freehand System, three subjects improved their rate of performance on The Upper Extremity Capabilities Questionnaire. All subjects increased their level of independence on The Quadriplegia Index of Function. On the Canadian Occupational Performance Measure (COPM) with the Freehand System, average performance and satisfaction scores improved for every patient. Three of the four subjects continued to use the system at home. CONCLUSION: This case series demonstrates that the Freehand System can vastly improve hand function and performance of rehabilitation activities within days after a minimally invasive implant procedure during initial SCI rehabilitation. Satisfaction with the Freehand System beyond initial rehabilitation is evidenced by continued use at home.

Activities of Daily Living↗

Implanted functional electrical stimulation: an alternative for standing and walking in pediatric spinal cord injury.

STUDY DESIGN: Post intervention, repeated measures design, comparing two interventions. SETTING: Orthopedic pediatric hospital specializing in spinal cord injury. METHODS: Nine subjects, ages 7-20 years, received an eight-channel implanted lower extremity functional electrical stimulation (FES) system for standing and walking. Electrodes were placed to stimulate hip and knee extension, and hip abduction and adduction. Standing and walking were achieved through constant stimulation to the implanted muscles, allowing a swing through gait pattern with an assistive device. After training with FES and long leg braces (LLB), subjects were tested in eight upright mobility activities, which were scored based upon completion time and level of independence. RESULTS: Seven subjects completed data collection. These subjects completed four activities faster (P<0.02) and five activities more independently (P<0.025) with FES as compared to LLB. Transitions between sitting and standing, which were scored in isolation for two mobility activities, were achieved faster and with more independence with FES. In addition, subjects reported preferring FES for the majority of activities. No activity required more time or more assistance to complete with FES as compared to LLB. CONCLUSION: The implanted FES system provided these subjects with enhanced functional abilities over traditional LLB and decreased the need for physical assistance by a caregiver, suggesting that it is a realistic alternative for upright mobility in a pediatric population with spinal cord injury.

Adolescent↗

Visualization of mismatch repair in bacterial cells.

We determined the localizations of mismatch repair proteins in living Bacillus subtilis cells. MutS-GFP colocalized with the chromosome in all cells and formed foci in a subset of cells. MutL-GFP formed foci in a subset of cells, and its localization was MutS dependent. The introduction of mismatches by growth in 2-aminopurine caused a replication-dependent increase in the number of cells with MutS and MutL foci. Approximately half of the MutS foci colocalized with DNA polymerase foci. We conclude that MutS is associated with the entire chromosome, poised to detect mismatches. After detection, it appears that mismatch repair foci assemble at mismatches as they emerge from the DNA polymerase and are then carried away from the replisome by continuing replication.

2-Aminopurine↗

An implantable upper extremity neuroprosthesis in a growing child with a C5 spinal cord injury.

OBJECTIVES: To implement a functional electrical stimulation (FES) hand neuroprosthesis called the Freehand System in a growing child with spinal cord injury (SCI) using extra lead wire to accommodate limb growth, and to evaluate the performance of the Freehand System during the subject's maturation. SETTING: Pediatric orthopedic hospital specializing in SCI rehabilitation. SUBJECT: Ten-year-old female patient with a C5 level SCI. METHOD: The Freehand System was implanted. Eight electrodes were implanted to targeted forearm and hand muscles to provide grasp and release function. The lead wire associated with each electrode was pathed subcutaneously up the arm with 4 cm of extra lead distributed throughout the path to accommodate expected limb growth. All leads were attached to a stimulator placed in the upper chest. Measures of lead unwinding, limb growth, stimulated muscle strength, and hand function were made at 6 and 16 months after implant. RESULTS: By 16 months post implant, the upper limb growth plates were closed and humeral and radial bone growth combined was 2.7 cm from the time of surgery. For all eight leads, lead unwinding in the upper arm was approximately 1.2 cm and was comparable to humeral bone growth (1.4 cm). Lead unwinding in the lower arm was also measurable for the two electrodes in hand muscles. Six of eight electrodes maintained grade 3 or better stimulated muscle strength throughout the growth period according to a manual muscle test. Of the two other electrodes, one appeared to have lost function due to depletion of excess lead. However, hand function with FES was comparable at 6 and 16 months post implant suggesting that growth did not negatively impact performance with the FES system. Hand function with FES was improved over voluntary hand function as well. Using the Freehand System, a pinch force of approximately 15 N was achieved compared to 1.3 N of voluntary tenodesis pinch force. Scores on the Functional Independence Measure (FIM) increased by 9 points when FES was used as compared to voluntary function. Improvements occurred primarily in eating and grooming. Independence in writing was achieved only with FES. CONCLUSIONS: For this child, hand function with the Freehand System was sustained over the growth period and was a significant functional improvement over voluntary hand function. By using excess lead wire, the Freehand System was successfully implemented before skeletal maturity, affording the child improved hand function earlier than would be otherwise indicated.

Arm↗

Regiochemical studies of the ring expansion reactions of hydroxy azides with cyclic ketones.

The regiochemistry of ring expansions of 2-substituted cyclic ketones using 1,2-azidoethanol and 1,3-azidopropanol was examined. It was determined that the reactions of ketones with an adjacent methyl or ethyl group are generally unselective, but that bulkier substituents lead to preferential migration of the more highly substituted carbon. In addition, it was found that ketones bearing inductively electron-withdrawing substituents (OMe, Ph, Br) undergo selective migration of the less highly substituted carbon. For some substrates, alternative reaction pathways were also identified.

Azides↗

Intraperoxisomal localization of very-long-chain fatty acyl-CoA synthetase: implication in X-adrenoleukodystrophy.

X-adrenoleukodystrophy (X-ALD) is a demyelinating disorder characterized by the accumulation of saturated very-long-chain (VLC) fatty acids (>C(22:0)) due to the impaired activity of VLC acyl-CoA synthetase (VLCAS). The gene responsible for X-ALD was found to code for a peroxisomal integral membrane protein (ALDP) that belongs to the ATP binding cassette superfamily of transporters. To understand the function of ALDP and how ALDP and VLCAS interrelate in the peroxisomal beta-oxidation of VLC fatty acids we investigated the peroxisomal topology of VLCAS protein. Antibodies raised against a peptide toward the C-terminus of VLCAS as well as against the N-terminus were used to define the intraperoxisomal localization and orientation of VLCAS in peroxisomes. Indirect immunofluorescent and electron microscopic studies show that peroxisomal VLCAS is localized on the matrix side. This finding was supported by protease protection assays and Western blot analysis of isolated peroxisomes. To further address the membrane topology of VLCAS, Western blot analysis of total membranes or integral membranes prepared from microsomes and peroxisomes indicates that VLCAS is a peripheral membrane-associated protein in peroxisomes, but an integral membrane in microsomes. Moreover, peroxisomes isolated from cultured skin fibroblasts from X-ALD patients with a mutation as well as a deletion in ALDP showed a normal amount of VLCAS. The consequence of VLCAS being localized to the luminal side of peroxisomes suggests that ALDP may be involved in stabilizing VLCAS activity, possibly through protein-protein interactions, and that loss or alterations in these interactions may account for the observed loss of peroxisomal VLCAS activity in X-ALD.

Adrenoleukodystrophy↗

Endotoxin induces structure-function alterations of rat liver peroxisomes: Kupffer cells released factors as possible modulators.

We report that endotoxin treatment results in decreased amounts of peroxisomes as well as changes in structure and function of peroxisomal membranes. Peroxisomes isolated from the liver of control and treated animals showed a marked decrease in total protein, but no significant alteration in the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) protein profile. However, the Western blot study of the peroxisomal beta-oxidation enzymes and catalase showed an increase in those enzymes in the peroxisomal peak of normal density in endotoxin-treated rats. Disintegration of peroxisomal membranes by carbonate treatment from endotoxin-treated liver and change in the fluidity of peroxisomal membranes suggests alterations in peroxisomal membrane structure. No such alterations were found in mitochondrial or microsomal membranes of endotoxin-treated livers. The lipid analysis of these organelles showed that the only organelle affected was the peroxisome, with a significant decrease in the phospholipid and cholesterol concentrations. To understand the mechanism of endotoxin-mediated alterations in peroxisomes, we studied the possible role of Kupffer cell secreted soluble factors (tumor necrosis factor alpha [TNF-alpha]) on the peroxisomal structure/function. Inactivation/elimination of Kupffer cells by gadolinium chloride before endotoxin treatment did not normalize the overall peroxisomal protein amount and the lipid composition of isolated peroxisomes. However, the levels of individual protein amount in remaining peroxisomes were normalized. Endotoxin also decreased peroxisomal beta-oxidation, and this was partially restored with gadolinium treatment. These results clearly show that peroxisomes are severely affected by endotoxin treatment and suggest that the damage to this organelle may contribute, at least in part, to endotoxin-induced hepatic cytotoxicity.

Animals↗

Mechanism of spreading of the highly related neurofibromatosis type 1 (NF1) pseudogenes on chromosomes 2, 14 and 22.

Neurofibromatosis type 1 (NF1) is a frequent hereditary disorder that involves tissues derived from the embryonic neural crest. Besides the functional gene on chromosome arm 17q, NF1-related sequences (pseudogenes) are present on a number of chromosomes including 2, 12, 14, 15, 18, 21, and 22. We elucidated the complete nucleotide sequence of the NF1 pseudogene on chromosome 22. Only the middle part of the functional gene but not exons 21-27a, encoding the functionally important GAP-related domain of the NF1 protein, is presented in this pseudogene. In addition to the two known NF1 pseudogenes on chromosome 14 we identified two novel variants. A phylogenetic tree was constructed, from which we concluded that the NF1 pseudogenes on chromosomes 2, 14, and 22 are closely related to each other. Clones containing one of these pseudogenes cross-hybridised with the other pseudogenes in this subset, but did not reveal any in situ hybridisation with the functional NF1 gene or with NF1 pseudogenes on other chromosomes. This suggests that their hybridisation specificity is mainly determined by homologous sequences flanking the pseudogenes. Strong support for this concept was obtained by sequence analysis of the flanking regions, which revealed more than 95% homology. We hypothesise that during evolution this subset of NF1 pseudogenes initially arose by duplication and transposition of the middle part of the functional NF1 gene to chromosome 2. Subsequently, a much larger fragment, including flanking sequences, was duplicated and gave rise to the current NF1 pseudogene copies on chromosomes 14 and 22.

Base Sequence↗

A role for the umuDC gene products of Escherichia coli in increasing resistance to DNA damage in stationary phase by inhibiting the transition to exponential growth.

The umuDC gene products, whose expression is induced by DNA-damaging treatments, have been extensively characterized for their role in SOS mutagenesis. We have recently presented evidence that supports a role for the umuDC gene products in the regulation of growth after DNA damage in exponentially growing cells, analogous to a prokaryotic DNA damage checkpoint. Our further characterization of the growth inhibition at 30 degrees C associated with constitutive expression of the umuDC gene products from a multicopy plasmid has shown that the umuDC gene products specifically inhibit the transition from stationary phase to exponential growth at the restrictive temperature of 30 degrees C and that this is correlated with a rapid inhibition of DNA synthesis. These observations led to the finding that physiologically relevant levels of the umuDC gene products, expressed from a single, SOS-regulated chromosomal copy of the operon, modulate the transition to rapid growth in E. coli cells that have experienced DNA damage while in stationary phase. This activity of the umuDC gene products is correlated with an increase in survival after UV irradiation. In a distinction from SOS mutagenesis, uncleaved UmuD together with UmuC is responsible for this activity. The umuDC-dependent increase in resistance in UV-irradiated stationary-phase cells appears to involve, at least in part, counteracting a Fis-dependent activity and thereby regulating the transition to rapid growth in cells that have experienced DNA damage. Thus, the umuDC gene products appear to increase DNA damage tolerance at least partially by regulating growth after DNA damage in both exponentially growing and stationary-phase cells.

Bacterial Proteins↗

The SOS response: recent insights into umuDC-dependent mutagenesis and DNA damage tolerance.

Be they prokaryotic or eukaryotic, organisms are exposed to a multitude of deoxyribonucleic acid (DNA) damaging agents ranging from ultraviolet (UV) light to fungal metabolites, like Aflatoxin B1. Furthermore, DNA damaging agents, such as reactive oxygen species, can be produced by cells themselves as metabolic byproducts and intermediates. Together, these agents pose a constant threat to an organism's genome. As a result, organisms have evolved a number of vitally important mechanisms to repair DNA damage in a high fidelity manner. They have also evolved systems (cell cycle checkpoints) that delay the resumption of the cell cycle after DNA damage to allow more time for these accurate processes to occur. If a cell cannot repair DNA damage accurately, a mutagenic event may occur. Most bacteria, including Escherichia coli, have evolved a coordinated response to these challenges to the integrity of their genomes. In E. coli, this inducible system is termed the SOS response, and it controls both accurate and potentially mutagenic DNA repair functions [reviewed comprehensively in () and also in ()]. Recent advances have focused attention on the umuD(+)C(+)-dependent, translesion DNA synthesis (TLS) process that is responsible for SOS mutagenesis (). Here we discuss the SOS response of E. coli and concentrate in particular on the roles of the umuD(+)C(+) gene products in promoting cell survival after DNA damage via TLS and a primitive DNA damage checkpoint.

Adaptation, Physiological↗

A model for a umuDC-dependent prokaryotic DNA damage checkpoint.

The products of the Escherichia coli umuDC operon are required for translesion synthesis, the mechanistic basis of most mutagenesis caused by UV radiation and many chemicals. The UmuD protein shares homology with LexA, the repressor of SOS-regulated loci, and similarly undergoes a facilitated autodigestion on interaction with the RecA/single-stranded DNA nucleoprotein filaments formed after a cell experiences DNA damage. This cleavage, in which Ser-60 of UmuD acts as the nucleophile, produces UmuD', the form active in translesion synthesis. Expression of the noncleavable UmuD(S60A) protein and UmuC was found to increase survival after UV irradiation, despite the inability of the UmuD(S60A) protein to participate in translesion synthesis; this survival increase is uvr(+) dependent. Additional observations that expression of the UmuD(S60A) protein and UmuC delayed the resumption of DNA replication and cell growth after UV irradiation lead us to propose that the uncleaved UmuD protein and UmuC delay the resumption of DNA replication, thereby allowing nucleotide excision repair additional time to repair the damage accurately before replication is attempted. After a UV dose of 20 J/m(2), uncleaved UmuD is the predominant form for approximately 20 min, after which UmuD' becomes the predominant form, suggesting that the umuDC gene products play two distinct and temporally separated roles in DNA damage tolerance, the first in cell-cycle control and the second in translesion synthesis over unrepaired or irreparable lesions. The relationship of these observations to the eukaryotic DNA damage checkpoint is discussed.

Bacterial Proteins↗

Comparison of functional electrical stimulation to long leg braces for upright mobility for children with complete thoracic level spinal injuries.

OBJECTIVE: To prospectively compare functional electrical stimulation (FES) to long leg braces (LLB) as a means of upright mobility for children with motor-complete thoracic level spinal cord injuries (SCIs). DESIGN: Intrasubject group comparison of two interventions. SETTING: Nonprofit pediatric orthopedic rehabilitation facility specializing in SCI. PATIENTS OR OTHER PARTICIPANTS: Convenience sample of five children between 9 and 18 years old with motor-complete thoracic level SCI. The hip and knee extensors were excitable by electrical stimulation. INTERVENTIONS: The FES system consisted of percutaneous intramuscular electrodes implanted to the hip and knee extensors and a push-button activated stimulator worn about the waist. Standing was accomplished by simultaneous stimulation of all implanted muscles. For foot and ankle stability, either ankle-foot orthoses (AFO) or supramalleolar orthoses were used. The LLB system consisted of a custom knee-ankle foot orthosis (KAFO) for four subjects and a custom reciprocating gait orthosis (RGO) for one subject who required bracing at the hip. For both interventions, either a front-wheeled walker or Lofstrand crutches were used as assistive devices. Each subject was trained in the use of both FES and LLB in seven standardized upright mobility activities: stand and reach, high transfer, toilet transfer, floor to stand, 6-meter walk, stair ascent, and stair descent. MAIN OUTCOME MEASURES: For each mobility activity, five repeated measures of level of independence, using the 7-point Functional Independence Measure (FIM) scale, and time to completion were recorded for each intervention. Subjects were also asked which intervention they preferred. RESULTS: For 94% of comparisons, subjects required equal (70%) or less (24%) assistance using FES as compared with LLB. Six of the seven mobility activities required less time to complete using FES, two activities at significant levels. The FES system was preferred in 62% of the cases, LLB were desired 27% of the time, and there was no preference in 11% of the cases. CONCLUSIONS: The FES system generally provided equal or greater independence in seven mobility activities as compared with LLB, provided faster sit-to-stand times, and was preferred over LLB in a majority of cases. Follow-up evaluations of both modes of upright mobility are needed to compare long-term performance and satisfaction.

Activities of Daily Living↗

Evaluation of the lower motor neuron integrity of upper extremity muscles in high level spinal cord injury.

PURPOSE: To evaluate the lower motor neuron (LMN) integrity of upper extremity muscles of persons with high tetraplegia (C1-C4) in order to determine muscles available for stimulation. METHODS: Fourteen subjects (23 arms) were evaluated for LMN integrity. Muscles that elicited a functional response (grade 3 or better) to surface electrical stimulation were considered to have intact LMN and good candidates for FES. Strength-duration (S-D) curves were generated on muscles that showed weak (less than grade 3) or no response to surface stimulation. Muscles were considered denervated if S-D curves were discontinuous or depicted steep, increasing amplitude for pulse durations greater than 1 m. RESULTS: Muscles for grasp and release had intact LMN in 19 of 23 (83%) arms. The wrist extensors and flexors and pronator were excitable in 17 (74%), 20 (87%) and 19 (83%) arms, respectively. The supinator demonstrated LMN lesion in 80% of the arms. Over 90% of the biceps muscles were unresponsive to electrical stimulation and 85% and 87% of the deltoid and supraspinatus muscles, respectively, were not electrically excitable. The latissimus dorsi and triceps muscles were typically innervated (78% and 91%, respectively) and slightly more than half (52%) of the pectoralis major muscles were excitable. CONCLUSION: These data suggest that application of FES in high tetraplegia for hand and arm function would require augmentation because of the inability to stimulate the elbow flexors, deltoid and rotator cuff muscles. These data also show that several paralyzed proximal muscles with intact LMN that have been historically transferred to address shoulder paralysis in other patient populations are available for transfer and stimulation in the population with high level spinal injuries.

Adolescent↗

Outcome of functional electrical stimulation in the rehabilitation of a child with C-5 tetraplegia.

Hand function was provided for a six-year-old child with C-5 American Spinal Injuries Association (ASIA) classification-A tetraplegia through a percutaneous intramuscular (i.m.) functional electrical stimulation (FES) system. In conjunction with implantation of 10 percutaneous i.m. electrodes for provision of grasp and release of her right hand, reconstructive surgery was performed to provide upper extremity positioning to optimize hand use. The subject participated in FES training over a nine-week period for approximately five hours weekly, with an additional five hours each week dedicated to exercise and conditioning of her arm muscles. Physical and functional assessments included range of motion (ROM), manual muscle testing (MMT), activities of daily living (ADL) abilities and the Canadian Occupational Performance Measure (COPM), used to evaluate the effect of stimulated hand function and surgical reconstruction on functional ability. These were conducted prior to FES and surgery and repeated after rehabilitation training. With rehabilitation and training, the child was able to control her FES system. Physical assessments revealed increased strength of both shoulders and more useful range of arm movement. Functional assessments show that the FES system enabled her to perform age-appropriate ADL that previously were achievable only with physical assistance. Her overall level of independence in ADL ability increased, as did self-rated levels of satisfaction and performance on chosen activities. Positive gains demonstrated here suggest the need for further studies of FES systems in young children with SCI.

Activities of Daily Living↗

A comparison of FES with KAFO for providing ambulation and upright mobility in a child with a complete thoracic spinal cord injury.

This study compared functional and physiologic measures of ambulation and upright mobility with functional electrical stimulation (FES) versus knee-ankle-foot-orthoses (KAFO) in an 11-year-old boy with a T-10 level spinal cord injury. The child was a limited community ambulator with bilateral KAFO and loftstrand crutches. The FES system consisted of percutaneous intramuscular electrodes controlled by a portable stimulator and thumbswitch, an AFO for ankle and foot support, and loftstrand crutches. The subject used a swing-through gait pattern with both modes of mobility. The Functional Independence Measure scoring system and time to completion were used to compare performance in 6 standardized activities: donning, high transfer, inaccessible toilet transfer, ascend/descend stairs, and floor-to-standing transfer. Ten repeated measures were performed for each mode. Physiologic measures included energy expenditure, postural stability using forceplates, and a Functional Standing Test (FST). The subject performed all 6 mobility activities independently with FES and KAFO. In 4 of 6 activities, there was a trend toward faster times with FES, but this was not statistically significant. Toilet transfers and stair descent were performed significantly faster with KAFO. There was no difference in completion times on the activities of the FST. Measures of postural sway suggested that the subject was more stable with KAFO during quiet standing, while the modes were equal during a dynamic activity (raising arm for functional use). Energy expenditure results revealed no significant difference in oxygen cost per meter but a significantly higher oxygen consumption rate per minute for FES. Ambulation with both modes was performed at levels consistent with strenuous exercise. Maximum ambulation distances were relatively equal while the subject's velocity was significantly faster with FES. Of note, the subject reported ceasing ambulation during maximum distance trials due to general fatigue when using FES and due to shoulder pain with KAFO ambulation. For this subject, FES provided a means of performing upright mobility tasks independently, comparable with that of KAFO, while providing a faster ambulation velocity and a potential means of cardiovascular training.

Activities of Daily Living↗