Search

Prospective experimental.The aim of this study was to develop a quantitative sensory test (QST) that could be used for assessing the level and the density (degree of impairment) of spinal cord injury (SCI) and for monitoring neurological changes in patients with SCI.National Spinal Injuries Centre, Stoke Mandeville Hospital, Buckinghamshire Hospitals NHS Trust, UK.Perceptual threshold to 3 Hz cutaneous electrical stimulation was measured in 30 control subjects and in 45 patients with SCI at American Spinal Injuries Association (ASIA) sensory key points for selected dermatomes between C3 and S2 bilaterally. Electrical perceptual threshold (EPT) was recorded as the lowest ascending stimulus intensity out of three tests at which the subject reported sensation. The level of SCI according to EPT results was established for right and left sides as the most caudal spinal segment at which patient's EPT was within the control range (mean +/- 2 standard deviation (SD)). The level of SCI, according to EPT, was then compared with clinical sensory level derived according to ASIA classification.In the control group, EPT depended on the dermatome tested and was lowest for T1 (1.01 +/- 0.23 mA, mean +/- SD) and highest for L5 (3.32 +/- 1.14 mA). There was strong correlation between corresponding right and left dermatomes and between repeated assessments. In the SCI group, the level of lesion according to EPT and clinical testing was the same in 43 of the 90 tests (48%). In 37 cases (41%), the EPT level was higher than the clinical level, and in 10 cases (11%), it was lower. Below the level of lesion in incomplete SCI and in the zone of partial preservation in complete SCI, the EPT values in most dermatomes were raised compared with the control group.EPT is a simple, reproducible QST that can assess both the level and the density of SCI. It seems to add sensitivity and resolution to the standard clinical testing and could be a useful adjunct in longitudinal monitoring of patients with SCI for research purposes during natural recovery and therapeutic interventions.International Spinal Research Trust (ISRT), UK, Grant CLI001.

Study design: Longitudinal. Objectives: (1) To perform standard clinical neurological examinations and establish the pattern of clinical change with time following incomplete spinal cord injury (iSCI). (2) To establish the pattern of change in corticospinal electrophysiological function with time after iSCI. (3) To correlate clinical with electrophysiological findings. Setting: The National Spinal Injuries Centre, Stoke Mandeville Hospital, Aylesbury, UK and Imperial College School of Medicine, Charing Cross Hospital, London, UK. Methods: Neurological assessments and classification were performed according to American Spinal Injuries Association and International Medical Society of Paraplegia (ASIA/IMSOP) standards. Twenty-one patients (ages 18–72 years) with iSCI (level C2–C7, ASIA impairment grades C–D) and 10 healthy control subjects (ages 27–57 years) were studied. Electrophysiological tests of corticospinal function were carried out using transcranial magnetic stimulation (TMS) of the motor cortex and electromyographic (EMG) recordings from thenar muscles. Both tests were performed on a number of occasions, beginning 19–384 days and ending 124–1109 days post-injury, and the group data were pooled into time epochs of 50 or 100 days post-injury for analysis. Seven of the patients were studied on seven or more occasions and were also assessed individually. Results: Individual and pooled data indicated that neurological scores improved progressively and tended to stabilise by around 300 days post-injury. When the patients were first assessed, the mean latency for motor evoked potentials (MEPs) and inhibition of voluntary EMG were significantly different from control values. There was no significant change in latency on subsequent sessions for either the grouped or individual patient data. There was no correlation between clinical assessment and electrophysiological data. Conclusion: We conclude that the weakened inhibition seen following iSCI is established within a few days of the time of spinal cord trauma. We argue that reduced corticospinal inhibition may be a prerequisite for the recovery of useful motor function. Sponsorship: The work was supported by a project grant from The Wellcome Trust. Spinal Cord (2000) 38, 292–300.

STUDY DESIGN Cross-sectional clinical review. OBJECTIVES To assess the relationship between late spinal deformity in childhood onset spinal cord injury (SCI) and level of spinal cord lesion, severity of lesion, age at onset, duration of paralysis and pelvic deformities. SETTING People with spinal cord injury (onset in childhood) treated and followed up at the National Spinal Injuries Center (identified from case notes review, contacted and agreed to participate). METHOD One hundred and eighty-nine subjects satisfying study inclusion criteria (acute onset SCI before the 16th birthday) were identified by case note review of 8200 records. Eighty formed the group attending for clinical review including whole spine radiographs (AP and lateral). Clinical examination included neurological status and joint range of movements. Demographic data was recorded. RESULTS Scoliosis occurred more frequently and was more severe in those injured at a younger age, 38 degrees, compared with 24 degrees in those injured later (P

Synchronisation of motor unit discharges is commonly seen in hand muscles of normal man but is absent following neurologically complete spinal cord injury and reduced after stroke. These findings support the notion that some corticospinal inputs to motoneurones are shared and contribute to the observed synchrony of discharge. In this study we have examined motor unit discharge in hand muscles below the level of an incomplete spinal cord injury in an attempt to relate strength of synchrony to the integrity of the corticospinal tract. Eight patients with incomplete spinal cord injury (neurological level C3-C7) and eight control subjects took part in the study. The patients had sustained injury 14-191 weeks prior to the recordings and had since regained good motor function in their hands. Two concentric needle electrodes were inserted into the first dorsal interosseus muscle which subjects were instructed to contract weakly so that potentials from individual motor units could be reliably identified on both recordings. Synchrony was detected by constructing cross-correlograms between the discharges of pairs of individual motor units. The amount of synchronous firing was determined from the magnitude of any peak in the cross-correlogram, as the probability above chance (XP) of one motor unit firing with respect to the other and vice versa. The degree of synchrony was lower (P < 0.05) in the patient group (mean XP 0.06) than in the control group (mean XP 0.09). The incidence of significant synchrony was lower in the patient group (41.8 %) than in the control group (92.9 %). The mean (+/- S.E.M.) frequency of motor unit discharge was slightly lower (P < 0.05) in patients (9.7 +/- 0.4 impulses s-1) than controls (10.8 +/- 0.5 impulses s-1). The mean width of synchrony peaks was narrower (P < 0.05) in patients (11.4 +/- 1.1 ms) than controls (13.2 +/- 0.6 ms). We conclude that the weaker synchrony of motor unit discharge in incomplete spinal cord injury may reflect permanent damage to some corticospinal axons.

A study of 3178 individuals injured in Britain between 1943 and 1990 and surviving the first year post-injury was conducted to evaluate the homogeneity of mortality risk ratios within groups based on varying degrees of neurological injury level and completeness of the injury. The study shows that it is less than optimal to combine individuals into neurological groupings of C1-C4 ABC, C5-C8 ABC and T1-S5 ABC since the risk ratios are not homogeneous within these groups. Similarly, combining individuals into neurological groupings of tetraplegia complete, tetraplegia incomplete, paraplegia complete and paraplegia incomplete may not be appropriate for the same reasons. The consequence of performing a survival analysis using either of the traditional sets of groups is to dilute the risk ratios for a subset of individuals within a particular group, thereby providing less discrimination between neurological groups. Cox proportional hazards regression was employed to determine a set of neurological groupings with homogeneous risk ratios within a group while providing better differentiation between groups.

The aims of this study were to examine long-term survival in a population-based sample of spinal cord injury (SCI) survivors in Great Britain, identify risk factors contributing to deaths and explore trends in cause of death over the decades following SCI. Current survival status was successfully identified in 92.3% of the study sample. Standardised mortality ratios (SMRs) were calculated and compared with a similar USA study. Relative risk ratio analysis showed that higher mortality risk was associated with higher neurologic level and completeness of spinal cord injury, older age at injury and earlier year of injury. For the entire fifty year time period, the leading cause of death was related to the respiratory system; urinary deaths ranked second followed by heart disease related deaths, but patterns in causes of death changed over time. In the early decades of injury, urinary deaths ranked first, heart disease deaths second and respiratory deaths third. In the last two decades of injury, respiratory deaths ranked first, heart related deaths were second, injury related deaths ranked third and urinary deaths fourth. This study also raises the question of examining alternative neurological groupings for future mortality risk analysis.

In sympathetic denervation due to primary autonomic failure, ingestion of food causes a fall in blood pressure (BP) and exacerbates postural hypotension. It is not known whether these responses occur in tetraplegics with physiologically complete cervical spinal cord transection, who also have sympathetic dysfunction because of disruption of descending spinal sympathetic pathways. We, therefore, studied the effect of a liquid meal on BP, heart rate (HR) and neurohormonal levels in tetraplegics. Paraplegics with low lesions and without sympathetic dysfunction served as controls. After food ingestion, there was no fall in BP in tetraplegics or in controls. HR did not change in either group. After fund, plasma noradrenaline was unchanged in tetraplegics, but rose in controls, while plasma renin activity (PRA) rose in tetraplegics but not in controls. The fall in BP and rise in HR on head-up tilt after the meal in tetraplegics was similar to that before the meal. There was no change in PRA following pre-prandial tilt in either group; post-prandial tilt raised levels in the tetraplegics, unlike in controls. Thus there is considerable variance in the responses to food between tetraplegics and paraplegic controls, and even greater differences when compared with published data in other autonomic disorders with sympathetic dysfunction; this may relate to the site and the nature of the sympathetic lesion and the ability to activate compensatory mechanisms.

Study design: Preliminary longitudinal clinical trial. Objectives: To test the efficacy of repetitive transcranial magnetic stimulation (rTMS) in modulating corticospinal inhibition and improving recovery in stable incomplete spinal cord injury (iSCI). Setting: National Spinal Injuries Centre, Stoke Mandeville Hospital, Bucks, UK and Division of Neuroscience, Imperial College Faculty of Medicine, Charing Cross Hospital, London, UK. Methods: Four stable iSCI patients were treated with rTMS over the occipital cortex (sham treatment) and then over the motor cortex (real treatment). Patients were assessed using electrophysiological, clinical and functional measures before treatment, during sham treatment, during the therapeutic treatment and during a 3-week follow-up period. Results: Cortical inhibition was reduced during the treatment week. Perceptual threshold to electrical stimulation of the skin, ASIA clinical measures of motor and sensory function and time to complete a peg-board improved and remained improved into the follow-up period. Conclusion: In this preliminary trial, rTMS has been shown to alter cortical inhibition in iSCI and improve the clinical and functional outcome. Sponsorship: This work was supported by the International Spinal Research Trust.

Study design: Case report of two subjects. Objective: Charcot joints of the spine as a cause of Autonomic Dysreflexia in spinal cord lesions. Setting: Stoke Mandeville Hospital, UK. Method: Two patients with long standing spinal cord lesions developed symptoms of headaches and sweating associated with sitting up and transfers. In both cases no other cause was found to account for Autonomic Dysreflexia. Result: Charcot Joints of the spine below the level of injury were demonstrated in both cases and symptoms resolved with prolonged bed rest. Conclusion: As care of spinally injured patients continues to improve, they live longer and lead a more active lifestyle, it is expected that the incidence and prevalence of Charcot's joints will increase. Therefore the knowledge and heightened awareness of this entity, early diagnosis and detection with plain X-rays for urinary surveillance, may reduce the morbidity in spinal cord injured patients.

The case histories of two patients who had had a spinal cord injury (SCI) were selected by the senior author and sent to four experts in the field of SCI. Based on the 1992 American Spinal Injury Association (ASIA) and International Medical Society of Paraplegia (IMSOP) standards, the four participants plus the senior author recorded the motor and sensory scores, the ASIA impairment scale (AIS), the neurological level (NL) and the zone of partial preservation (ZPP). Several minor scoring errors occurred among the participants, especially with motor scores when key muscles could not be tested due to pain, or external immobilization devices. Difficulties with interpretation occurred with the motor levels and the ZPP for the patient with a complete injury. This exercise points to the need for all examiners of SCI patients to thoroughly familiarize themselves with the standards and to use the motor and sensory scores to arrive at a NL and ZPP. They also indicate a need to revise the standards to clarify the determination of sensory levels and how to score muscles whose strength is inhibited by pain.