Angela Gall

Disability, atrophy and cortical reorganization following spinal cord injury

The impact of traumatic spinal cord injury on structural integrity, cortical reorganization and ensuing disability is variable and may depend on a dynamic interaction between the severity of local damage and the capacity of the brain for plastic reorganization. We investigated trauma-induced anatomical changes in the spinal cord and brain, and explored their relationship to functional changes in sensorimotor cortex. Structural changes were assessed using cross-sectional cord area, voxel-based morphometry and voxel-based cortical thickness of T1-weighted images in 10 subjects with cervical spinal cord injury and 16 controls. Cortical activation in response to right-sided (i) handgrip; and (ii) median and tibial nerve stimulation were assessed using functional magnetic resonance imaging. Regression analyses explored associations between cord area, grey and white matter volume, cortical activations and thickness, and disability. Subjects with spinal cord injury had impaired upper and lower limb function bilaterally, a 30% reduced cord area, smaller white matter volume in the pyramids and left cerebellar peduncle, and smaller grey matter volume and cortical thinning in the leg area of the primary motor and sensory cortex compared with controls. Functional magnetic resonance imaging revealed increased activation in the left primary motor cortex leg area during handgrip and the left primary sensory cortex face area during median nerve stimulation in subjects with spinal cord injury compared with controls, but no increased activation following tibial nerve stimulation. A smaller cervical cord area was associated with impaired upper limb function and increased activations with handgrip and median nerve stimulation, but reduced activations with tibial nerve stimulation. Increased sensory deficits were associated with increased activations in the left primary sensory cortex face area due to median nerve stimulation. In conclusion, spinal cord injury leads to cord atrophy, cortical atrophy of primary motor and sensory cortex, and cortical reorganization of the sensorimotor system. The degree of cortical reorganization is predicted by spinal atrophy and is associated with significant disability.

The relationship between bladder management and health-related quality of life in patients with spinal cord injury in the UK

Study design:Cross-sectional study.Objectives:(1) To assess the relationship between bladder management methods and the health-related quality of life (HRQL) in patients with spinal cord injury (SCI). (2) To identify any correlation between the two questionnaires used to assess the quality of life (one validated for SCI and one validated for bladder symptoms).Setting:Spinal Cord Injury Centre, Royal National Orthopaedic Hospital, Middlesex, UK.Methods:This study is based on two questionnaires with results collected from 142 people with SCI. The two questionnaires were based on information from the Short-Form 36-Item Health Survey (SF-36) and the Kings Health Questionnaire and included demographic characteristics, bladder management methods and the frequency of incontinence.Results:There is a moderate correlation between the results of the SF-36 and the Kings Health Questionnaire. Only 21% SCI patients report normal voiding without any other form of bladder management. The type of bladder management may influence the HRQL in patients with SCI. Clean intermittent catheterization by attendant, indwelling transurethral catheterization and indwelling suprapubic catheterization are the three groups with the worst mental status. In addition, the frequency of incontinence is a strong influence on HRQL.Conclusions:The results of this study may provide a general baseline HRQL for patients with SCI. Our findings show the relationships between bladder management methods and quality of life in patients with SCI. In addition, the impact of incontinence on quality of life was also confirmed.

Action of 5 Hz repetitive transcranial magnetic stimulation on sensory, motor and autonomic function in human spinal cord injury

OBJECTIVE To assess the effectiveness of physiological outcome measures in detecting functional change in the degree of impairment of spinal cord injury (SCI) following repetitive transcranial magnetic stimulation (rTMS) of the sensorimotor cortex. METHODS Subjects with complete or incomplete cervical (or T1) SCI received real and sham rTMS in a randomised placebo-controlled single-blinded cross-over trial. rTMS at sub-threshold intensity for upper-limb muscles was applied (5 Hz, 900 stimuli) on 5 consecutive days. Assessments made before and for 2 weeks after treatment comprised the ASIA (American Spinal Injuries Association) impairment scale (AIS), the Action Research Arm Test (ARAT), a peg-board test, electrical perceptual test (EPT), motor evoked potentials, cortical silent period, cardiovascular and sympathetic skin responses. RESULTS There were no significant differences in AIS outcomes between real and sham rTMS. The ARAT was increased at 1h after real rTMS compared to baseline. Active motor threshold for the most caudally innervated hand muscle was increased at 72 and 120 h compared to baseline. Persistent reductions in EPT to rTMS occurred in two individuals. CONCLUSIONS Changes in cortical motor threshold measures may accompany functional gains to rTMS in SCI subjects. SIGNIFICANCE Electrophysiological measures may provide a useful adjunct to ASIA impairment scales.

Development of quantitative and sensitive assessments of physiological and functional outcome during recovery from spinal cord injury: a clinical initiative

The ability to detect physiological changes associated with treatments to effect axonal regeneration, or novel rehabilitation strategies, for spinal cord injury will be challenging using the widely employed American Spinal Injuries Association (ASIA) impairment scales (AIS) for sensory and motor function. Despite many revisions to the AIS standard neurological assessment, there remains a perceived need for more sensitive, quantitative and objective outcome measures. The purpose of Stage 1 of the Clinical Initiative was to develop these tools and then, in Stage 2 to test them for reliability against natural recovery and treatments expected to produce functional improvements in those with complete or incomplete spinal cord injury (SCI). Here we review aspects of the progress made by four teams involved in Stage 2. The strategies employed by the individual teams were (1) application of repetitive transcranial magnetic stimulation (rTMS) to the motor cortex in stable (chronic) SCI with intent to induce functional improvement of upper limb function, (2) a tele-rehabilitation approach using functional electrical stimulation to provide hand opening and grip allowing incomplete SCI subjects to deploy an instrumented manipulandum for hand and arm exercises and to play computer games, (3) weight-assisted treadmill walking therapy (WAT) comparing outcomes in acute and chronic groups of incomplete SCI patients receiving robotic assisted treadmill therapy, and (4) longitudinal monitoring of the natural progress of recovery in incomplete SCI subjects using motor tests for the lower extremity to investigate strength and coordination.

Pressure changes under the ischial tuberosities of seated individuals during sacral nerve root stimulation

Neuromuscular stimulation via the sacral nerve roots is proposed for prevention of ischial pressure ulcers following a spinal cord injury (SCI). Acute effects of sacral functional magnetic stimulation (FMS) on seat interface pressure changes were investigated in five nondisabled volunteers. Similar effects were demonstrated with functional electrical stimulation in people with SCI who used a sacral anterior root stimulator implant. The results indicated that sacral nerve root stimulation, either by FMS or implanted electrical stimulation, induced gluteus maximus contraction and mild pelvic tilt sufficient for clinically significant reductions in ischial pressures during sitting.

Changes in the structural and material properties of the tibia in patients with spinal cord injury

Study design:A cross-sectional study.Objectives:To measure the change of structural and material properties at different sites of the tibia in spinal cord-injured patients using peripheral quantitative computerised tomography (pQCT).Setting:Orthopaedic research centre (UK).Methods:Thirty-one subjects were measured—eight with acute spinal cord injury (SCI), nine with chronic SCI and fourteen able-bodied controls. pQCT scans were performed at 2% (proximal), 34% (diaphyseal) and 96% (distal) along the tibia from the tibial plateau. Structural measures of bone were calculated, and volumetric bone mineral density (vBMD) was also measured at all three levels. Muscle cross-sectional area was measured at the diaphyseal level.Results:Structurally, there were changes in the cortical bone; in the diaphysis, the shape of the cross-section changed to offer less resistance to AP bending, and the cross-sectional area of the cortical shell decreased both proximally and distally. There were corresponding changes in vBMD in the anterior aspect of the cortical diaphysis, as well as proximal and distal trabecular bone. Changes in muscle occurred more rapidly than changes in bone.Conclusion:There were clear changes of both structure and material at all three levels of the tibia in chronic SCI patients. These changes were consistent with specific adaptations to reduced local mechanical loading conditions. To assess fracture risk in SCI and also to monitor the effect of therapeutic interventions, the structure of the bone should be considered in addition to trabecular bone mineral density.

Light touch and pin prick disparity in the International Standard for Neurological Classification of Spinal Cord Injury (ISNCSCI)

Study design:Retrospective review.Objectives:The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) assesses cutaneous sensibility through light touch (LT) and sharp-dull discrimination, referred to as pin prick (PP). This project aimed to confirm a tendency for LT to score higher than PP in SCI subjects and discuss possible reasons for such disparity.Setting:Single site cohort study, the London Spinal Cord Injury Centre, United Kingdom.Methods:A retrospective analysis of LT and PP scores of 99 spinal cord injury subjects at the time of discharge (median 5 months) from acute care and rehabilitation in the London Spinal Cord Injury Centre was conducted. Subjects were aged 10–88 years (median 44 years; 78 men, 74 traumatic, 25 non-traumatic). There were 40 American Spinal Injury Association (ASIA) Impairment Scale (AIS) A, 7 B, 18 C and 34 D subjects.Results:A disparity (P<0.001) was found between LT (64.5±3.2, mean±s.e.) and PP (54.7±2.9) AIS sensory scores. A similar difference in score (LT>PP) was registered both for traumatic and non-traumatic injury, but was greater for incomplete than for complete injury. Despite the difference, LT was well correlated with PP (R=0.87, P<0.001). Spinal segmental level of injury was determined more frequently by PP alone (43 of 99) than by LT (10 of 99) alone.Conclusion:The discrepancies between LT and PP could relate to the greater complexity of the PP test or a difference in the extent of injury to the posterior columns (LT) and spinothalamic (PP) tracts. Further interpretation would benefit from additional electrophysiological sensory tests.

Linking wheelchair kinetics to glenohumeral joint demand during everyday accessibility activities

The aim of the study was to investigate if push-rim kinetics could be used as markers of glenohumeral joint demand during manual wheelchair accessibility activities; demonstrating a method of biomechanical analysis that could be used away from the laboratory. Propulsion forces, trunk and upper limb kinematics and surface electromyography were recorded during four propulsion tasks (level, 2.5% cross slope, 6.5% incline and 12% incline). Kinetic and kinematic data were applied to an OpenSim musculoskeletal model of the trunk and upper limb, to enable calculation of glenohumeral joint contact force. Results demonstrated a positive correlation between propulsion forces and glenohumeral joint contact forces. Both propulsion forces and joint contact forces increased as the task became more challenging. Participants demonstrated increases in trunk flexion angle as the requirement for force application increased, significantly so in the 12% incline. There were significant increases in both resultant glenohumeral joint contact forces and peak and mean normalized muscle activity levels during the incline tasks. This study demonstrated the high demand placed on the glenohumeral joint during accessibility tasks, especially as the gradient of incline increases. A lightweight instrumented wheelchair wheel has potential to guide the user to minimize upper limb demand during daily activity.

A systematic review of electrical stimulation for pressure ulcer prevention and treatment in people with spinal cord injuries

Abstract Context Electrical stimulation (ES) can confer benefit to pressure ulcer (PU) prevention and treatment in spinal cord injuries (SCIs). However, clinical guidelines regarding the use of ES for PU management in SCI remain limited. Objectives To critically appraise and synthesize the research evidence on ES for PU prevention and treatment in SCI. Method Review was limited to peer-reviewed studies published in English from 1970 to July 2013. Studies included randomized controlled trials (RCTs), non-RCTs, prospective cohort studies, case series, case control, and case report studies. Target population included adults with SCI. Interventions of any type of ES were accepted. Any outcome measuring effectiveness of PU prevention and treatment was included. Methodological quality was evaluated using established instruments. Results Twenty-seven studies were included, 9 of 27 studies were RCTs. Six RCTs were therapeutic trials. ES enhanced PU healing in all 11 therapeutic studies. Two types of ES modalities were identified in therapeutic studies (surface electrodes, anal probe), four types of modalities in preventive studies (surface electrodes, ES shorts, sacral anterior nerve root implant, neuromuscular ES implant). Conclusion The methodological quality of the studies was poor, in particular for prevention studies. A significant effect of ES on enhancement of PU healing is shown in limited Grade I evidence. The great variability in ES parameters, stimulating locations, and outcome measure leads to an inability to advocate any one standard approach for PU therapy or prevention. Future research is suggested to improve the design of ES devices, standardize ES parameters, and conduct more rigorous trials.

Can FES-rowing mediate bone mineral density in SCI: a pilot study

Study design:A single case study.Objectives:To compare proximal tibia trabecular bone mineral density (BMD) of a participant with complete spinal cord injury (SCI), long-termed functional electrical stimulation-rowing (FES-R) trained, with previously reported SCI and non-SCI group norms. To estimate lower limb joint contact forces (JCFs) in the FES-R trained participant.Setting:UK University and orthopaedic hospital research centre.Methods:Bilateral proximal tibial trabecular BMD of the FES-R trained participant was measured using peripheral quantitative computerised tomography, and the data were compared with SCI and non-SCI groups. An instrumented four-channel FES-R system was used to measure the lower limb JCFs in the FES-R trained participant.Results:Structurally, proximal tibial trabecular BMD was higher in the FES-R trained participant compared with the SCI group, but was less than the non-SCI group. Furthermore, left (184.7 mg cm−3) and right (160.7 mg cm−3) BMD were well above the threshold associated with non-traumatic fracture. The knee JCFs were above the threshold known to mediate BMD in SCI, but below threshold at the hip and ankle.Conclusion:As pathological fractures predominate in the distal femur and proximal tibia in chronic SCI patients, the fact that the FES-R trained participant’s knee JCFs were above those known to partially prevent bone loss, suggests that FES-R training may provide therapeutic benefit. Although the elevated bilateral proximal tibial BMD of the FES-R participant provides circumstantial evidence of osteogenesis, this single case precludes any statement on the clinical significance. Further investigations are required involving larger numbers and additional channels of FES to increase loading at the hip and ankle.