International spinal cord injury musculoskeletal basic data set.

OBJECTIVES: To develop an International Spinal Cord Injury (SCI) Musculoskeletal Basic Data Set as part of the International SCI Data Sets to facilitate consistent collection and reporting of basic musculoskeletal findings in the SCI population. SETTING: International. METHODS: A first draft of an SCI Musculoskeletal Basic Data Set was developed by an international working group. This was reviewed by many different organizations, societies and individuals over 9 months. Revised versions were created successively. RESULTS: The final version of the International SCI Musculoskeletal Basic Data Set contains questions on neuro-musculoskeletal history before spinal cord lesion; presence of spasticity/spasms; treatment for spasticity within the last 4 weeks; fracture(s) since the spinal cord lesion; heterotopic ossification; contracture; the location of degenerative neuromuscular and skeletal changes due to overuse after SCI; SCI-related neuromuscular scoliosis; the method(s) used to determine the presence of neuromuscular scoliosis; surgical treatment of the scoliosis; other musculoskeletal problems; if any of the musculoskeletal challenges above interfere with activities of daily living. Instructions for data collection and the data collection form are freely available on the International Spinal Cord Society (ISCoS) website (www.iscos.org.uk). CONCLUSION: The International SCI Musculoskeletal Basic Data Set will facilitate consistent collection and reporting of basic musculoskeletal findings in the SCI population.

State of the Science in Spinal Cord Injury Rehabilitation 2011: informing a new research agenda.

STUDY DESIGN: This manuscript summarizes recommendations from the State of the Science Conference in Spinal Cord Injury Rehabilitation 2011. OBJECTIVES: To develop an agenda for spinal cord injury (SCI) rehabilitation research in the next decade. SETTING: Participants scheduled planning meetings and then gathered at the 2011 joint meeting of the American Spinal Injury Association and International Spinal Cord Society in Washington DC. METHODS: Recommendations were made by an international, multidisciplinary team that met in large plenary sessions and breakout groups during the meeting. RESULTS: Recommendations are organized by conference track, including neurological and functional recovery; technology issues; aging with spinal cord injury; and employment, psychosocial and quality of life issues. CONCLUSION: A number of themes emerged across the conference tracks, including the need for improved measures of process and outcome constructs, application of qualitative and quantitative research designs, and use of contemporary statistical analytic approaches. Participants emphasized the value of collaborative research that uses the latest methods, techniques and information.

Neurophysiological assessment of lower-limb voluntary control in incomplete spinal cord injury.

STUDY DESIGN: Cross-sectional retrospective study of a neurophysiological method of voluntary motor control characterization. OBJECTIVES: This study was undertaken to validate the surface electromyography (sEMG)-based voluntary response index (VRI) as an objective, quantitative, laboratory measure of spinal cord injury severity in terms of voluntary motor control disruption. SETTING: VA Medical Centers in Houston and Dallas Texas, USA. METHODS: A total of 67 subjects with incomplete spinal cord injury (iSCI), American Spinal Injury Association Impairment Scale (AIS)-C (n = 32) and -D (n = 35) were studied. sEMG recorded during a standardized protocol including eight lower-limb voluntary motor tasks was analyzed using the VRI method that relates multi-muscle activation patterns of SCI persons to those of healthy-subject prototypes (n = 15). The VRI is composed of a measure of the amount of the sEMG activity (magnitude) and the distribution of activity across muscle groups compared to that of healthy subjects for each motor task (similarity index, SI). These resulting VRI components, normalized magnitude and SI, were compared to AIS clinical findings in this study. Receiver operating characteristic analysis was performed to determine the SI values best separating AIS-C and AIS-D subjects. RESULTS: Magnitude and SI for AIS-C subjects had mean values of 0.27 +/- 0.32 and 0.65 +/- 0.21, respectively. Both parameters were significantly larger in the AIS-D subjects (0.78 +/- 0.43 and 0.93 +/- 0.06), respectively (P < 0.01). An SI value of 0.85 was found to separate AIS-C and AIS-D groups with a sensitivity of 0.89 and a specificity of 0.81. Further, the VRI of each leg strongly correlated with the respective AIS motor score (0.80, r < 0.01). CONCLUSIONS: In the domains of voluntary motor control, the sEMG-based VRI demonstrated adequate face validity and sensitivity to injury severity as currently measured by the AIS. SPONSORSHIP: Veterans Affairs Medical Center.

Rapid concerted evolution of nuclear ribosomal DNA in two Tragopogon allopolyploids of recent and recurrent origin.

We investigated concerted evolution of rRNA genes in multiple populations of Tragopogon mirus and T. miscellus, two allotetraploids that formed recurrently within the last 80 years following the introduction of three diploids (T. dubius, T. pratensis, and T. porrifolius) from Europe to North America. Using the earliest herbarium specimens of the allotetraploids (1949 and 1953) to represent the genomic condition near the time of polyploidization, we found that the parental rDNA repeats were inherited in roughly equal numbers. In contrast, in most present-day populations of both tetraploids, the rDNA of T. dubius origin is reduced and may occupy as little as 5% of total rDNA in some individuals. However, in two populations of T. mirus the repeats of T. dubius origin outnumber the repeats of the second diploid parent (T. porrifolius), indicating bidirectional concerted evolution within a single species. In plants of T. miscellus having a low rDNA contribution from T. dubius, the rDNA of T. dubius was nonetheless expressed. We have apparently caught homogenization of rDNA repeats (concerted evolution) in the act, although it has not proceeded to completion in any allopolyploid population yet examined.

Neurophysiological examination of the corticospinal system and voluntary motor control in motor-incomplete human spinal cord injury.

This study employed neurophysiological methods to relate the condition of the corticospinal system with the voluntary control of lower-limb muscles in persons with motor-incomplete spinal cord injury. It consisted of two phases. In a group of ten healthy subjects, single and paired transcranial magnetic stimulation (TMS) of the motor cortex was used to study the behavior of the resulting motor evoked potentials (MEP) in lower-limb muscles. Interstimulus intervals (ISIs) of 15-100 ms were examined for augmentation of test MEPs by threshold or subthreshold conditioning stimuli. The second phase of this study examined eight incomplete spinal cord injured (iSCI) subjects, American Spinal Injury Association Impairment Scale C (n = 5) and D (n = 3) in whom voluntary motor control was quantified using the surface EMG (sEMG) based Voluntary Response Index (VRI). The VRI is calculated to characterize relative output patterns across ten lower-limb muscles recorded during a standard protocol of elementary voluntary motor tasks. VRI components were calculated by comparing the distribution of sEMG in iSCI subjects with prototype patterns collected from 15 healthy subjects using the same rigidly administered protocol, The resulting similarity index (SI) and magnitude values provided the measure of voluntary motor control. Corticospinal system connections were characterized by the thresholds for MEPs in key muscles. Key muscles were those that function as the prime-movers, or agonists for the voluntary movements from which the VRI data were calculated. Results include healthy-subject data that showed significant increases in conditioned MEP responses with paired stimuli of 15-50 ms ISI. Stimulus pairs of 75 and 100 ms showed no increase in MEP peak amplitude over that of the single-pulse conditioning stimulus alone, usually no response. For the iSCI subjects, 42% of the agonists responded to single-pulse TMS and 25% required paired-pulse TMS to produce an MEP. American Spinal Injury Association Impairment Scale component motor scores for agonist muscles, Quadriceps, Tibialis Anterior, and Triceps Surae, were significantly lower where MEPs could not be obtained (p < 0.05). VRI values were also significantly lower for motor tasks with agonists that had no resting MEP (p < 0.01). Therefore, the presence of a demonstrable connection between the motor cortex and spinal motor neurons in persons with SCI was related to the quality of post-injury voluntary motor control as assessed by the VRI.

Clinical neurophysiological assessment of residual motor control in post-spinal cord injury paralysis.

OBJECTIVE: This study was designed to characterize the rudimentary residual lower-limb motor control that can exist in clinically paralyzed spinal-cord-injured individuals. METHODS: Sixty-seven paralyzed spinal-cord-injured subjects were studied using surface electromyography recorded from muscles of the lower limbs and analyzed for responses to a rigidly administered protocol of reinforcement maneuvers, voluntary movement attempts, vibration, or the ability to volitionally suppress withdrawal evoked by plantar surface stimulation. RESULTS: Markers for the subclinical discomplete motor syndrome were found in 64% of the subjects. The tonic vibration response was recorded in 37%, volitional plantar surface stimulation response suppression in 27%, and reinforcement maneuver responses in 6% of the subjects. Three subjects, 4%, produced reliable but very low amplitude surface electromyography during the voluntary movement segment of the protocol. Surface electromyography recorded during passive leg movement was related to Ashworth scores as was the tonic vibration response marker (P < 0.05). CONCLUSIONS: Multimuscle surface electromyography patterns recorded during a rigidly administered protocol of motor tasks can be used to differentiate between clinically paralyzed spinal-cord-injured individuals using subclinical motor output to identify the translesional neural connections that remain available for intervention testing and treatment planning after spinal cord injury.

Toward an objective interpretation of surface EMG patterns: a voluntary response index (VRI).

Individuals with incomplete spinal cord injuries (SCI) retain varying degrees of voluntary motor control. The complexity of the motor control system and the nature of the recording biophysics have inhibited efforts to develop objective measures of voluntary motor control. This paper proposes the definition and use of a voluntary response index (VRI) calculated from quantitative analysis of surface electromyographic (sEMG) data recorded during defined voluntary movement as a sensitive measure of voluntary motor control in such individuals. The VRI is comprised of two numeric values, one derived from the total muscle activity recorded for the voluntary motor task (magnitude), and the other from the sEMG distribution across the recorded muscles (similarity index (SI)). Calculated as a vector, the distribution of sEMG from the test subject is compared to the average vector calculated from sEMG recordings of the same motor task from 10 neurologically intact subjects in a protocol called brain motor control assessment (BMCA). To evaluate the stability of the VRI, a group of five healthy subjects were individually compared to the prototype, average healthy-subject vectors for all of the maneuvers. To evaluate the sensitivity of this method, the VRI was obtained from two SCI subjects participating in other research studies. One was undergoing supported treadmill ambulation training, and the other a controlled withdrawal of anti-spasticity medications. The supported treadmill training patient's VRI, calculated from pre- and post-training BMCA recordings, reflected the qualitative changes in sEMG patterns and functional improvement of motor control. The VRI of the patient followed by serial BMCA during medication withdrawal also reflected changes in the motor control as a result of changes in anti-spasticity medication. To validate this index for clinical use, serial studies using larger numbers of subjects with compromised motor control should be performed.

Supported treadmill ambulation training after spinal cord injury: a pilot study.

OBJECTIVES: To conduct a pilot study of weight-supported ambulation training after incomplete spinal cord injury (SCI), and to assess its safety. DESIGN: Quasiexperimental, repeated measures, single group. SETTING: Veterans Affairs medical center. PATIENTS: Three subjects with incomplete, chronic, thoracic SCIs; 2 classified as D on the American Spinal Injury Association (ASIA) impairment scale and 1 as ASIA impairment scale C. INTERVENTION: Subjects participated in 12 weeks of training assisted by 2 physical therapists. The training consisted of walking on a treadmill while supported by a harness and a pneumatic suspension device. Support started at 40% of body weight and a treadmill speed of.16kmph, and progressed by reducing support and increasing treadmill speed and continuous treadmill walking time up to 20 minutes. Training was conducted for 1 hour per day, 5 days per week for 3 months. Treadmill walking occurred for 20 minutes during the sessions. MAIN OUTCOME MEASURES: Gait function (speed, endurance, walking status, use of assistive device and orthotics); oxygen costs of walking; brain motor control assessment; self-report indices; ASIA classification; muscle function test; and safety. RESULTS: All 3 subjects increased gait speed (.118m/s initially to.318m/s after training 12wk), and gait endurance (20.3m/5min initially to 63.5m/5min). The oxygen costs decreased from 1.96 to 1.33mL x kg(-1) x m(-1) after 12 weeks of training. CONCLUSIONS: This pilot study suggests that supported treadmill ambulation training can improve gait for individuals with incomplete SCIs by using objective gait measures. The self-report indices used have promise as patient-centered outcome measures of this new form of gait training. A larger, controlled study of this technique is warranted.

Equipment specifications for supported treadmill ambulation training.

Supported Treadmill Ambulation Training (STAT) is a mode of therapy for gait retraining for patients with spinal cord injuries or other upper motor neuron dysfunction. The STAT program involves simultaneously supporting a portion of the patient's weight while gait training on a treadmill. STAT has been successful in improving the gait of many research subjects, but has not been widely applied in clinical practice. The goal of this study was to acquire practical, clinically useful information regarding this therapeutic intervention in order to remove barriers to its use. This manuscript enumerates equipment specifications for the treadmill, body weight support (BWS) system, and harness. The ergonomics of the work space are also considered, since the therapist(s) will need access to the patient's legs during therapy. The specific recommendations were determined through prior clinical experience, consultation of anthropometric tables, and application of engineering principles. The guidelines listed are intended to facilitate safe and effective application of the therapy at minimum hardware cost.

Altered motor control and spasticity after spinal cord injury: subjective and objective assessment.

This study of measures of spasticity, or altered motor control, compares the clinically used Ashworth scale with a method based on surface electromyographic (sEMG) recordings called brain motor control assessment (BMCA) in a group of 97 subjects with spinal cord injury (SCI) and varying levels of motor dysfunction. In this paper, we describe how sEMG-derived scores relate to the severity of spasticity as judged clinically. When sEMG data from passive movements from the BMCA were analyzed by Ashworth category, we found that when the sEMG data were averaged for a limb, there was a significant difference between scores for those with Ashworth 0 vs. 2 and 3, and 1 vs. 2 and 3 (p<0.001), but not between 0 and 1. Analysis of the individual muscle scores improved the discrimination between Ashworth categories. Superiority of sEMG data over Ashworth category as an objective quantification of altered motor control ("spasticity") is argued.

Intravenous infusion of 4-AP in chronic spinal cord injured subjects.

STUDY DESIGN: A prospective double blind cross over trial of intravenous 4-Aminopyridine (4-AP). OBJECTIVE: To determine the efficacy of this drug in the treatment of spinal cord injured (SCI) patients for neurologic impairment, pain and spasticity. SETTING: The post anesthesia care unit (PACU) of a tertiary care acute hospital. METHODS: Twelve paraplegic patients were enrolled in a double blind cross over intravenous trial of 4-Aminopyridine (4-AP). Thirty milligrams of 4-AP or placebo were administered over a 2 h period. Patients were serially examined during and after the infusion clinically for pain, sensorimotor function, hypertonicity and motor control using electromyography (EMG). Samples of blood and cerebrospinal fluid (CSF) were also analyzed at similar intervals. RESULTS: Despite penetration of 4-AP into the CSF, no significant differences were noted in the clinical and EMG parameters at the times measured. Individual changes in sensory function were reported by some patients in both the placebo and 4-AP trials, however mean values were not robust. Frequently, patients complained of unpleasant symptoms during the 4-AP infusion. CONCLUSION: The intravenous route may not be the best way to administer this drug as no short term benefits were observed.

Relating clinical and neurophysiological assessment of spasticity by machine learning.

Spasticity following spinal cord injury (SCI) is most often assessed clinically using a five-point Ashworth score (AS). A more objective assessment of altered motor control may be achieved by using a comprehensive protocol based on a surface electromyographic (sEMG) activity recorded from thigh and leg muscles. However, the relationship between the clinical and neurophysiological assessments is still unknown. In this paper we employ three different classification methods to investigate this relationship. The experimental results indicate that, if the appropriate set of sEMG features is used, the neurophysiological assessment is related to clinical findings and can be used to predict the AS. A comprehensive sEMG assessment may be proven useful as an objective method of evaluating the effectiveness of various interventions and for follow-up of SCI patients.

Gabapentin for the treatment of spasticity in patients with spinal cord injury.

Our serendipitous observations suggested that some patients with spasticity appeared to have improved following the administration of the anticonvulsant drug gabapentin. As some patients with spasticity are either refractory to or intolerant of established medical treatments, we conducted this study to investigate the effect of gabapentin on spasticity in patients with spinal cord injury. Twenty-five patients with spinal cord injury and spasticity received oral gabapentin (2400 mg over 48 h) in a randomized, double blind, placebo-controlled crossover study. We assessed responses by measuring the Ashworth spasticity scale, muscle stretch reflexes, presence of clonus and reflex response to noxious stimuli. Patient ratings were obtained using a Likert Scale. Administration of gabapentin, but not placebo, was associated with an 11% reduction in spasticity as measured by the Ashworth Scale (P = 0.04) and by a 20% reduction in the Likert Scale (P = 0.0013). Significant changes were not obtained for the other measures. The data obtained suggest that gabapentin may be useful in the management of spasticity associated with spinal cord injury.

Effectiveness of gabapentin in controlling spasticity: a quantitative study.

The purpose of this investigation was to study the effectiveness of gabapentin in controlling spasticity in persons with spinal cord injury (SCI) using a surface EMG-based quantitative assessment technique called the brain motor control assessment (BMCA). Six men from a Veterans Affairs Medical Center with spasticity due to traumatic SCI were studied as part of a multi-center, placebo-controlled, cross-over, clinical trial of gabapentin. Spasticity was evaluated using multi-channel surface EMG recordings of muscles in the lower extremities, abdomen and low back before and during treatment with oral gabapentin or placebo. Gabapentin or placebo was given orally in doses 400 mg three times daily for 48 h. Following a 10 day wash-out period subjects were crossed-over to receive the medication not received the first time. This was followed by an elective open-label extension. Group results during the controlled trial did not reach statistical significance at the dosage used. One subject demonstrated a dramatic improvement in spasticity that was apparent both clinically and with the BMCA. Other subjects demonstrated modest improvements which were seen in the BMCA but not recognized clinically. During the open label extension, the four subjects who participated experienced important clinical improvements with higher doses (to 3600 mg/day). These improvements were often in components of spasticity in which the BMCA had detected subclinical changes during the cross-over trial. A seventh subject was studied using the BMCA at doses of 1200 mg T.I.D. gabapentin, off gabapentin and 800 mg T.I.D. gabapentin and demonstrated quantitatively a dose-related effect with higher doses of gabapentin which matched clinical observations. Gabapentin at doses of 400 mg T.I.D. may be effective in controlling some features of spasticity in persons with SCI. Higher doses provide greater control of spasticity, and controlled studies using higher doses are needed to evaluate gabapentin's efficacy.

Motor control physiology below spinal cord injury: residual volitional control of motor units in paretic and paralyzed muscles.

We have described motor control in people with different degrees of SCI by using surface polyelectromyographic recordings during single- and multijoint volitional motor tasks. We have shown that neurobiologic conditions of the injured spinal cord can be expressed in two main categories: "new anatomy" and "reduced anatomy". The evidence for a variety of definite features of motor control elicited by volitional effort for the performance of a present or even clinically absent motor task suggests that we can benefit from animal experimental neurobiologic studies while we are progressing toward the application of this new knowledge for the restoration of impaired spinal cord function in humans. Reports on the successfully enhanced regenerating capabilities of the axons and improved connectivity within neuronal circuits after SCI encourage us to intensify our efforts in parallel with studies on the recovery processes found in experimentally induced lesions in animals, as well as in accidentally induced SCI in humans.

Consistency of multi-channel surface EMG recordings: Application in spinal cord injured subjects.

We evaluated the consistency of serial polyelectromyographic recordings of altered motor control in spinal cord injured (SCI) individuals. Using 12 pairs of surface electrodes placed over major muscle groups of lower limb and trunk, we examined voluntary and involuntary and phasic and tonic features of motor control using a standardized protocol for brain motor control assessment (BMCA). The surface electromyographic (EMG) data were digitized and analysed on the basis of the root mean square (RMS) envelope of activity, with the exception of phasic tendon tap responses which were evaluated from full bandwidth EMG data. The average amplitudes of responses were calculated. The median correlation of the results from two successive examinations 1-2 weeks apart for all subjects was 0.98. Further analysis was based on ratios of corresponding elements from the two studies. Noise from null responses was suppressed by incorporating a threshold parameter T set to 1 muV(RMS). With this value, pairs of studies in 52 subjects were virtually identical (mean ratio of 1.02 +/- 0.1). Z-scores from two case studies in which pharmacological and physiological interventions changed motor control demonstrated the utility of the procedure. This method offers a reliable and appropriate means of studying altered motor control which is sensitive to changes induced after interventions.

Intracortical inhibition of lower limb motor-evoked potentials after paired transcranial magnetic stimulation.

The aim of the present study was to determine the characteristics of intracortical inhibition in the motor cortex areas representing lower limb muscles using paired transcranial magnetic (TMS) and transcranial electrical stimulation (TES) in healthy subjects. In the first paradigm (n=8), paired magnetic stimuli were delivered through a double cone coil and motor evoked potentials (MEPs) were recorded from quadriceps (Q) and tibialis anterior (TA) muscles during relaxation. The conditioning stimulus strength was 5% of the maximum stimulator output below the threshold MEP evoked during weak voluntary contraction of TA (33+/-5%). The test stimulus (67+/-2%) was 10% of the stimulator output above the MEP threshold in the relaxed TA. Interstimulus intervals (ISIs) from 1-15 ms were examined. Conditioned TA MEPs were significantly suppressed (P<0.01) at ISIs of less than 5 ms (relative amplitude from 20-50% of the control). TA MEPs tended to be only slightly facilitated at 9-ms and 10-ms ISIs. The degree of MEP suppression was not different between right and left TA muscles despite the significant difference in size of the control responses (P<0.001). Also, conditioned MEPs were not significantly different between Q and TA. The time course of TA MEP suppression, using electrical test stimuli, was similar to that found using TMS. In the second paradigm (n=2), the suppression of TA MEPs at 2, 3, and 4 ms ISIs was examined at three conditioning intensities with the test stimulation kept constant. For the pooled 2- to 4-ms ISI data, relative amplitudes were 34+/-6%, 61+/-5%, and 98+/-9% for conditioning intensities of 0.95, 0.90, and 0.85x active threshold, respectively (P<0.01). In conclusion, the suppression of lower limb MEPs following paired TMS showed similar characteristics to the intracortical inhibition previously described for the hand motor area.

Motor control after spinal cord injury: assessment using surface EMG.

The brain motor control assessment (BMCA) protocol is a comprehensive multichannel surface EMG recording used to characterize motor control features in persons with upper motor neuron dysfunction. Key information is contained in the overall temporal pattern of motor unit activity, observed in the EMG (RMS) envelope. In paralysis, a rudimentary form of suprasegmental control of tonic and phasic reflexes can be demonstrated. EMG patterns evoked by voluntary and passive maneuvers and by volitional modulation of reflex responses reveal features of motor control not apparent in the clinical examination. Such subclinical findings may explain paradoxically different responses in apparently similar SCI subjects, and may be used to monitor spontaneous or induced changes. The recording protocol, examples of EMG patterns, and their prevalence in 40 spinal cord injured (SCI) subjects are presented, and compared with 5 healthy subjects.