Laura Krisa

Agreement of repeated motor and sensory scores at individual myotomes and dermatomes in young persons with spinal cord injury

Study design:A prospective repeated measures multicenter study to determine reliability at individual spinal levels when applied to young persons with spinal cord injury (SCI).Objectives:To evaluate intra- and inter-rater agreement of repeated motor and sensory scores at individual spinal levels.Setting:Shriners Hospitals for Children—Philadelphia and Chicago, USAMethods:A total 189 youth with complete and incomplete SCI underwent four neurological exams by two different raters. Agreement between and within raters for each myotome and dermatome was evaluated for complete and incomplete SCI separately. Intraclass correlation coefficients and 95% confidence intervals were calculated.Results:Overall, both intra- and inter-rater agreement resulted in moderate-to-high agreement among myotomes. Subjects with complete SCI had moderate agreement for light touch (LT) and pin prick (PP) testing, whereas subjects with incomplete SCI had >60.0% of dermatomes resulting in poor agreement for PP testing.Conclusion:Overall, moderate-to-high agreement was found for muscle strength comparisons and moderate-to-poor agreement was found for PP and LT.

Spatially selective 2D RF inner field of view (iFOV) diffusion kurtosis imaging (DKI) of the pediatric spinal cord

Magnetic resonance based diffusion imaging has been gaining more utility and clinical relevance over the past decade. Using conventional echo planar techniques, it is possible to acquire and characterize water diffusion within the central nervous system (CNS); namely in the form of Diffusion Weighted Imaging (DWI) and Diffusion Tensor Imaging (DTI). While each modality provides valuable clinical information in terms of the presence of diffusion and its directionality, both techniques are limited to assuming an ideal Gaussian distribution for water displacement with no intermolecular interactions. This assumption neglects pathological processes that are not Gaussian therefore reducing the amount of potentially clinically relevant information. Additions to the Gaussian distribution measured by the excess kurtosis, or peakedness, of the probabilistic model provide a better understanding of the underlying cellular structure. The objective of this work is to provide mathematical and experimental evidence that Diffusion Kurtosis Imaging (DKI) can offer additional information about the micromolecular environment of the pediatric spinal cord. This is accomplished by a more thorough characterization of the nature of random water displacement within the cord. A novel DKI imaging sequence based on a tilted 2D spatially selective radio frequency pulse providing reduced field of view (FOV) imaging was developed, implemented, and optimized on a 3 Tesla MRI scanner, and tested on pediatric subjects (healthy subjects: 15; patients with spinal cord injury (SCI):5). Software was developed and validated for post processing of the DKI images and estimation of the tensor parameters. The results show statistically significant differences in mean kurtosis (p < 0.01) and radial kurtosis (p < 0.01) between healthy subjects and subjects with SCI. DKI provides incremental and novel information over conventional diffusion acquisitions when coupled with higher order estimation algorithms.

Forelimb Locomotor Rating Scale for Behavioral Assessment of Recovery after Unilateral Cervical Spinal Cord Injury in Rats

BACKGROUND Cervical spinal cord injury (SCI) models in rats have become increasingly useful because of their translational potential. The goal of this study was to design, develop and validate a quick and reliable forelimb locomotor rating scale for adult rats with unilateral cervical SCI injury. NEW METHOD Adult female rats were subjected to a C5 unilateral mild contusion (n=10), moderate contusion (n=10) or hemisection injury (n=9). Forelimb locomotion was evaluated before injury, four times during the first week (Days 2, 3, 4 and 7) and weekly for up to 8 weeks post-injury. Scoring categories were identified and animals were ranked based on their performance in these categories. The scale was validated for its usefulness by comparing animals with different injury models (dorsolateral funiculotomy C3/4), levels of injury (moderate contusion C4) and sex (male - moderate contusion C3/4) and also by correlating FLS scores with other established behavioral tests (grid walking and kinetic tests). RESULTS AND COMPARISON WITH EXISTING METHODS Forelimb performance on both the grid-walking and kinetic tests was positively correlated with the forelimb locomotor rating scale (FLS). Histological analysis established a positive correlation between the spared tissue and the observed FLS score. Our results show that the new rating scale can reliably detect forelimb deficits and recovery predicted by other behavioral tests. Furthermore, the new method provides reproducible data between trained and naïve examiners. CONCLUSION In summary, the proposed rating scale is a useful tool for assessment of injury and treatments designed to enhance recovery after unilateral cervical SCI.

Diffusion Tensor Imaging of the Normal Cervical and Thoracic Pediatric Spinal Cord

BACKGROUND AND PURPOSE: DTI data of the normal healthy spinal cord in children are limited compared with adults and are typically focused on the cervical spinal cord. The purpose of this study was the following: to investigate the feasibility of obtaining repeatable DTI parameters along the entire cervical and thoracic spinal cord as a function of age in typically developing pediatric subjects; to analyze the DTI parameters among different transverse levels of the cervical and thoracic spinal cord; and to examine the sex differences in DTI parameters along the cervical and thoracic spinal cord. MATERIALS AND METHODS: Twenty-two subjects underwent 2 identical scans by using a 3T MR imaging scanner. Axial diffusion tensor images were acquired by using 2 overlapping slabs to cover the cervical and thoracic spinal cord. After postprocessing, DTI parameters were calculated by using ROIs drawn on the whole cord along the entire spinal cord for both scans. RESULTS: An increase in fractional anisotropy and a decrease in mean diffusivity, axial diffusivity, and radial diffusivity were observed with age along the entire spinal cord. Significantly lower fractional anisotropy and higher mean diffusivity values were observed in the lower cervical cord compared with the upper cervical cord. Axial diffusivity values in the cervical cord were higher compared with the thoracic cord. No statistically significant sex differences were observed for all DTI parameters. There was a moderate-to-strong repeatability for all DTI parameters. CONCLUSIONS: This study provides an initial understanding of DTI values of the spinal cord relevant to age and sex and shows that obtaining repeatable DTI values of the entire cord in children is feasible.

Cerebral Activation During the Test of Spinal Cord Injury Severity in Children: an fMRI Methodological Study

BACKGROUND The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) are internationally accepted to determine and classify the extent of motor and sensory impairment along with severity (ASIA Impairment Scale [AIS]) following spinal cord injury (SCI). The anorectal examination is a component of the ISNCSCI that determines injury severity. There is a void in the health care literature on the validity of the anorectal examination as an indication of SCI severity. OBJECTIVE To validate the use of functional magnetic resonance imagining (fMRI) for the purpose of classifying the severity of SCI in children. METHODS Seventeen patients, with the average age of 14.3 years, underwent 1 complete ISNCSCI examination. Subjects also underwent the anorectal portion of this exam while fMRI data were collected using a 3.0 Tesla Siemens Verio Scanner. Cortical areas of activation were analyzed for possible differences of cortical involvement between complete (AIS A) and incomplete (AIS B, C, and D) SCI subjects. Anxiety/anticipation of the test was also assessed. RESULTS This study established an fMRI imaging protocol that captures the cortical locations and intensity of activation during the test of sacral sparing. In addition to developing the data acquisition protocol, we also established the postacquisition preprocessing and statistical analysis parameters using SPM8. CONCLUSION Preliminary findings indicate that fMRI is a useful tool in evaluating the validity of the anorectal examination in determining SCI severity. Assessment of which cortical regions are activated during the testing procedure provides an indication of which pathways are transmitting information to the brain.

Amphetamine-Enhanced Motor Training after Cervical Contusion Injury

Individually, motor training, pharmacological interventions, and housing animals in an enriched environment (EE) following spinal cord injury (SCI) result in limited functional improvement but, when combined, may enhance motor function. Here, we tested amphetamine (AMPH)-enhanced skilled motor training following a unilateral C3-C4 contusion injury on the qualitative components of reaching and on skilled forelimb function, as assessed using single-pellet and staircase reaching tasks. Kinematic analysis evaluated the quality of the reach, and unskilled locomotor function was also tested. Animals receiving AMPH and skilled forelimb training performed better than operated control animals on qualitative reaching, but not on skilled reaching. Those that received the combination treatment and were housed in EE cages showed significantly less improvement in qualitative reaching and grasping. Kinematic analysis revealed a decrease in digit abduction during skilled reaching among all groups, with no differences among groups. Kinematics provided no evidence that improved function was related to improved quality of reach. There was no evidence of neuroprotection in the cervical spinal cord. The absence of evidence for kinematic improvement or neuroprotection suggested that AMPH-enhanced motor training is due primarily to supraspinal effects, an enhancement of attention during skilled motor training, or plasticity in supraspinal circuitry involved with motor control.

Reduced Field of View Diffusion Tensor Imaging and Fiber Tractography of the Pediatric Cervical and Thoracic Spinal Cord Injury

The aim of this study is to assess the utility and effectiveness of diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) of the entire pediatric cervical and thoracic spinal cord toward discrimination of typically developing (TD) controls and subjects with spinal cord injury (SCI). A total of 43 pediatric subjects, including 23 TD subjects ranging in age from 6 to 16 years old and 20 subjects with SCI ranging in age from 7 to 16 years, were recruited and scanned using a 3.0 Tesla magnetic resonance scanner. Reduced field of view diffusion tensor images were acquired axially to cover the entire spinal cord across two slabs. For DTI analysis, motion correction was performed by coregistration of the diffusion-weighted images to the reference image (b0). Streamline deterministic tractography results were generated from the preprocessed data. DTI and DTT parameters of the whole cord, including fractional anisotropy (FA), mean diffusivity (MD), tract length, and tract density, were calculated, averaged across the whole spinal cord, and compared between the TD and SCI groups. Statistically significant decreases have been shown in FA (TD = 0.46 ± 0.11; SCI = 0.37 ± 0.09; p < 0.0001) and tract density (TD = 405.93 ± 243.84; SCI = 268.90 ± 270.34; p < 0.0001). However, the mean length of tracts and MD did not show significant differences. When investigating differences in DTI and DTT parameters above and below the injury site, it was shown that the FA and tract density in patients with cervical SCI decreased significantly in the thoracic region. An identical trend was observed in the cervical region for patients with thoracic SCI as well. When comparing TD and SCI subjects, FA and tract density were the most sensitive parameters in detecting functional changes of the spinal cord in chronic pediatric SCI. The results show that both DTI and DTT have the potential to be imaging biomarkers in the diagnosis of SCI.

Locomotor Training in the Pediatric Spinal Cord Injury Population: A Systematic Review of the Literature

Background: The restoration of walking ability in the spinal cord injury (SCI) population is an increasingly important goal in physical therapy. Locomotor training (LT) is often implemented with the aim to restore ambulation. At this point, there are no guidelines for LT in the pediatric SCI population. Objectives: The aim of this review is to further narrow the effects of LT to the pediatric SCI population and develop recommendations for pediatric LT. Methods: A thorough search was performed using the following databases: Scopus, CINAHL, PubMed, and Ovid. Studies were selected based on the following inclusion criteria: pediatric SCI population, articles published within last 10 years, human subjects, and LT. Studies looking at other neurological disorders and subjects who were not previously ambulatory were excluded. Five students and one Faculty Research Advisor from the universitys Doctor of Physical Therapy Program evaluated the inclusion criteria, conducted a risk of bias assessment using the Downs and Black checklist, and extracted the results. Results: Six studies were selected for this review. They showed gains in distance, gait speed, walking independence, and participation. There were variations in results when comparing gains in injury level based on the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). Conclusions: Currently there is insufficient evidence to determine the best clinical practice guidelines for rehabilitation using LT within the pediatric SCI population.

Diffusion tensor imaging in pediatric transverse myelitis: A case study

Transverse myelitis is diagnosed based on the presence of spinal cord inflammation and the absence of infection to the central nervous system. In support of these criteria, patients undergo lumbar puncture to determine Cerebrospinal Fluid (CSF) pleocytosis and un-enhanced or Gadolinium-enhanced spinal Magnetic Resonance Imaging (MRI). We present the case of an 11~year-old previously healthy male who underwent a series of lab tests and MRI scans before a definite diagnosis of transverse myelitis four years prior to this study. The patient still shows deficits at the C4 cord level according to International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) examination, however, his MRI results are negative, and his Diffusion Tensor Imaging (DTI) results are close to values reported in healthy subjects.

Using a Limited Number of Dermatomes as a Predictor of the 56-Dermatome Test of the International Standards for Neurological Classification of Spinal Cord Injury in the Pediatric Population

BACKGROUND For young children with spinal cord injury (SCI), the sensory exam of the International Standards for the Neurological Classification of Spinal Cord Injury (ISNCSCI) is long and arduous, often making it impossible to complete. OBJECTIVES In this study, we determine whether an abbreviated sensory exam provides comparable information to the full 56-dermatome exam. METHOD A total of 726 56-dermatome sensory exams were completed with 190 children and youth with SCI ranging in age from 3 to 21 years. The cohort was randomly split into test and validation groups. For the test group, a principal component analysis (PCA) was carried out separately for pin prick (PP) and light touch (LT) scores. From the PCA, a hierarchical cluster analysis was performed to identify the most influential set of 4, 8, 12, and 16 dermatomes. From the sensory exam data obtained from the validation group, a linear regression was performed to compare the limited-dermatome composite scores to the total 56-dermatome scores. RESULTS For both LT and PP, the 16-dermatome test resulted in the best fit (0.86 and 0.87, respectively) with the 56-dermatome test and was comprised of dermatomes from both the left (7 dermatomes) and right (9 dermatomes) sides and at least 1 dermatome from each vertebral region bilaterally (cervical, thoracic, lumbar, sacral). CONCLUSION A 16-dermatome sensory exam provided a good correlation to the 56-dermatome exam. The shortened exam may be useful for evaluating children with SCI who cannot tolerate the full examination.