Neurologically Intact Research Articles

Erroneous Compensation for Long-Latency Feedback Delays as Origin of Essential Tremor.

Essential tremor (ET), a movement disorder characterized by involuntary oscillations of the limbs during movement, remains to date not well understood. It has been recently suggested that the tremor originates from impaired delay compensation, affecting movement representation and online control. Here we tested this hypothesis directly with 24 ET patients (14 female; 10 male) and 28 neurologically intact (NI) human volunteers (17 female; 11 male) in an upper limb postural perturbation task. After maintaining their hand in a visual target, participants experienced perturbations of unpredictable direction and magnitude and were instructed to counter the perturbation and steer their hand back to the starting position. In comparison with NI volunteers, ET patients' early muscular responses (short and long-latency responses, 20-50 and 50-100 ms, respectively) were preserved or even slightly increased. However, they exhibited perturbation-dependent deficits when stopping and stabilizing their hand in the final target supporting the hypothesis that the tremor was generated by the feedback controller. We show in a computational model that errors in delay compensation accumulating over time produced the same small increase in initial feedback response followed by oscillations that scaled with the perturbation magnitude as observed in ET population. Our experimental results therefore validate the computational hypothesis that inaccurate delay compensation in long-latency pathways could be the origin of the tremor.

Spatial mapping of posture-dependent resistance to passive displacement of the hypertonic arm post-stroke

BackgroundMuscles in the post-stroke arm commonly demonstrate abnormal reflexes that result in increased position- and velocity-dependent resistance to movement. We sought to develop a reliable way to quantify mechanical consequences of abnormal neuromuscular mechanisms throughout the reachable workspace in the hemiparetic arm post-stroke.MethodsSurvivors of hemiparetic stroke (HS) and neurologically intact (NI) control subjects were instructed to relax as a robotic device repositioned the hand of their hemiparetic arm between several testing locations that sampled the arm's passive range of motion. During transitions, the robot induced motions at either the shoulder or elbow joint at three speeds: very slow (6°/s), medium (30°/s), and fast (90°/s). The robot held the hand at the testing location for at least 20 s after each transition. We recorded and analyzed hand force and electromyographic activations from selected muscles spanning the shoulder and elbow joints during and after transitions.ResultsHand forces and electromyographic activations were invariantly small at all speeds and all sample times in NI control subjects but varied systematically by transport speed during and shortly after movement in the HS subjects. Velocity-dependent resistance to stretch diminished within 2 s after movement ceased in the hemiparetic arms. Hand forces and EMGs changed very little from 2 s after the movement ended onward, exhibiting dependence on limb posture but no systematic dependence on movement speed or direction. Although each HS subject displayed a unique field of hand forces and EMG responses across the workspace after movement ceased, the magnitude of steady-state hand forces was generally greater near the outer boundaries of the workspace than in the center of the workspace for the HS group but not the NI group.ConclusionsIn the HS group, electromyographic activations exhibited abnormalities consistent with stroke-related decreases in the stretch reflex thresholds. These observations were consistent across repeated testing days. We expect that the approach described here will enable future studies to elucidate stroke's impact on the interaction between the neural mechanisms mediating control of upper extremity posture and movement during goal-directed actions such as reaching and pointing with the arm and hand.

Corticomuscular coherence is reduced in relation to dorsiflexion fatigability to the same extent in adults with cerebral palsy as in neurologically intact adults.

Fatigue is frequent in adults with cerebral palsy (CP) and it is unclear whether this is due to altered corticospinal drive. We aimed to compare changes in corticospinal drive following sustained muscle contractions in adults with CP and neurologically intact (NI) adults. Fourteen adults with CP [age 37.6 (10.1), seven females, GMFCS levels I-II] and ten NI adults [age 35.4 (10.3), 6 females] performed 1-min static dorsiflexion at 30% of maximal voluntary contraction (MVC) before and after a submaximal contraction at 60% MVC. Electroencephalography (EEG) and electromyography (EMG) from the anterior tibial muscle were analyzed to quantify the coupling, expressed by corticomuscular coherence (CMC). Adults with CP had lower MVCs but similar time to exhaustion during the relative load of the fatigability trial. Both groups exhibited fatigability-related changes in EMG median frequency and EMG amplitude. The CP group showed lower beta band (16-35Hz) CMC before fatigability, but both groups decreased beta band CMC following fatigability. There was a linear correlation between decrease of beta band CMC and fatigability-related increase in EMG. Fatigability following static contraction until failure was related to decreased beta band CMC in both NI adults and adults with CP. Our findings indicate that compensatory mechanisms to fatigability are present in both groups, and that fatigability affects the corticospinal drive in the same way. We suggest that the perceived physical fatigue in CP is related to the high relative load of activities of daily living rather than any particular physiological mechanism.

Quantitative MRI and Clinical Assessment of Muscle Function in Adults With Cerebral Palsy.

Aim: To relate quantitative magnetic resonance imaging (MRI) of ankle plantar flexor muscles to clinical functional tests in adults with cerebral palsy (CP) and neurologically intact (NI) adults.Methods: Eleven adults with CP (aged 41 ± 12, GMFCS level I-II) and 11 NI adults (aged 35 ± 10) participated in this case-control study. We used MRI to assess muscle volume and composition of the triceps surae muscles. We quantified muscle function as maximal voluntary plantarflexion (MVC) torque and countermovement jump (CMJ) height.Results: Compared to NI adults, the MRI intramuscular fat fraction estimate was significantly higher and MRI muscle volume and functional abilities (MVC and CMJ) significantly lower in adults with CP. In NI adults, but not adults with CP, MRI muscle volume correlated significantly with MVC and CMJ. In adults with CP, the estimate of intramuscular fat levels correlated significantly with jump height in a CMJ.Discussion: This study shows reduced muscle volume and altered muscle composition in adults with CP. Muscle composition appears to provide a better marker than muscle volume of reduced muscle function and impaired performance in this population. Measurements of muscle composition could be used in the assessment of neuromuscular impairments and in the determination of rehabilitation protocols in individuals with neurological disorders.

Increased Ankle Plantar Flexor Stiffness Is Associated With Reduced Mechanical Response to Stretch in Adults With CP

Hyperexcitable stretch reflexes are often not present despite of other signs of spasticity in people with brain lesion. Here we looked for evidence that increased resistance to length change of the plantar flexor muscle-fascicles may contribute to a reduction in the stretch reflex response in adults with cerebral palsy (CP). A total of 17 neurologically intact (NI) adults (mean age 36.1; 12 female) and 13 ambulant adults with CP (7 unilateral; mean age 33.1; 5 female) participated in the study. Subjects were seated in a chair with the examined foot attached to a foot plate, which could be moved by a computer-controlled electromotor. An ultrasound probe was placed over the medial aspect of the leg to measure the length of medial gastrocnemius muscle fascicles. Slow (7 deg/s) and fast (200 deg/s) stretches with amplitude 6 deg of the plantar flexors were applied over an ankle range of 70 deg at 10 deg intervals between 60 and 130 deg plantarflexion. It was checked by EMG electrodes that the slow stretches were sufficiently slow not to elicit any activity and that the fast stretches were sufficiently quick to elicit a maximal stretch reflex in both groups. The torque elicited by the stretches was measured together with changes in the length of medial gastrocnemius muscle fascicles. Muscle fascicles increased significantly in length with increasing dorsiflexion position in both populations (p < 0.001), but the fascicles were shorter in the CP population at all positions. Slow stretches elicited significantly larger torque and significantly smaller length change of muscle fascicles as the ankle joint position was moved more towards dorsiflexion in CP than in NI (p < 0.001). Fast stretches elicited larger torque responses at ankle joint positions of 80–100 deg in the NI than in the CP group (p < 0.01). A significant negative correlation was observed between the torque response and muscle fascicle length change to slow stretch in CP (p < 0.05), but not in NI. These findings support that increased passive resistance of the ankle plantar flexor muscle-tendon unit and development of contractures may conceal stretch reflex response in adults with CP. We argue that this should be taken into account in the neurological examination of spasticity.

Bladder and bowel responses to lumbosacral epidural stimulation in uninjured and transected anesthetized rats

Spinal cord epidural stimulation (scES) mapping at L5-S1 was performed to identify parameters for bladder and bowel inhibition and/or contraction. Using spinally intact and chronic transected rats of both sexes in acute urethane-anesthetized terminal preparations, scES was systematically applied using a modified Specify 5–6–5 (Medtronic) electrode during bladder filling/emptying cycles while recording bladder and colorectal pressures and external urethral and anal sphincter electromyography activity. The results indicate frequency-dependent effects on void volume, micturition, bowel peristalsis, and sphincter activity just above visualized movement threshold intensities that differed depending upon neurological intactness, with some sex-dependent differences. Thereafter, a custom-designed miniature 15-electrode array designed for greater selectivity was tested and exhibited the same frequency-dependent urinary effects over a much smaller surface area without any concurrent movements. Thus, select activation of autonomic nervous system circuitries with scES is a promising neuromodulation approach for expedient translation to individuals with SCI and potentially other neurologic disorders.

Sensorimotor, Cognitive, and Affective Functions Contribute to the Prediction of Falls in Old Age and Neurologic Disorders: An Observational Study

ObjectiveTo determine whether impairments across cognitive and affective domains provide additional information to sensorimotor deficits for fall prediction among various populations. DesignWe pooled data from 5 studies for this observational analysis of prospective falls. SettingCommunity or low-level care facility. ParticipantsOlder people (N=1090; 74.0±9.4y; 579 female); 500 neurologically intact (NI) older people and 3 groups with neurologic disorders (cognitive impairment, n=174; multiple sclerosis (MS), n=111; Parkinson disease, n=305). InterventionsNone. Main Outcome MeasuresSensorimotor function was assessed with the Physiological Profile Assessment, cognitive function with tests of executive function, affect with questionnaires of depression, and concern about falling with falls efficacy questionnaires.These variables were associated with fall incidence rates, obtained prospectively over 6-12 months. ResultsPoorer sensorimotor function was associated with falls (incidence rate ratio [95% CI], 1.46 [1.28-1.66]). Impaired executive function was the strongest predictor of falls overall (2.91 [2.27-3.73]), followed by depressive symptoms (2.07 [1.56-2.75]) and concern about falling (2.02 [1.61-2.55]). Associations were similar among groups, except for a weaker relationship with executive impairment in NI persons and a stronger relationship with concern about falling in persons with MS. Multivariable analyses showed that executive impairment, poorer sensorimotor performance, depressive symptoms, and concern about falling were independently associated with falls. ConclusionsDeficits in cognition (executive function) and affect (depressive symptoms) and concern about falling are as important as sensorimotor function for fall prediction. These domains should be included in fall risk assessments for older people and clinical groups.

Extracorporeal Cardiopulmonary Resuscitation in a 36-Year-Old Man with Viral Myocarditis Who Survived Prolonged Cardiac Arrest and Bedside Decompressive Laparotomy Neurologically Intact

We report a case of prolonged cardiac arrest in a patient with viral myocarditis who was subsequently cannulated for veno-arterial extracorporeal membrane oxygenation (VA-ECMO) while in cardiac arrest. The patient developed bowel ischemia and abdominal compartment syndrome on ECMO and required a bedside decompressive laparotomy and hemicolectomy. This case demonstrates that prolonged downtime with high quality CPR and potential ischemic complications of VA-ECMO should not preclude ongoing resuscitation and treatment as favorable neurologic outcome is still possible.

Contribution of corticospinal drive to ankle plantar flexor muscle activation during gait in adults with cerebral palsy.

Impaired plantar flexor muscle activation during push-off in late stance contributes importantly to reduced gait ability in adults with cerebral palsy (CP). Here we used low-intensity transcranial magnetic stimulation (TMS) to suppress soleus EMG activity during push-off as an estimate of corticospinal drive in CP adults and neurologically intact (NI) adults. Ten CP adults (age 34years, SD 14.6, GMFCS I-II) and ten NI adults (age 33years, SD 9.8) walked on a treadmill at their preferred walking speed. TMS of the leg motor cortex was elicited just prior to push-off during gait at intensities below threshold for motor-evoked potentials. Soleus EMG from steps with and without TMS were averaged and compared. Control experiments were performed while standing and in NI adults during gait at slow speed. TMS induced a suppression at a latency of about 40ms. This suppression was similar in the two populations when differences in control EMG and gait speed were taken into account (CP 18%, NI 16%). The threshold of the suppression was higher in CP adults. The findings suggest that corticospinal drive to ankle plantar flexors at push-off is comparable in CP and NI adults. The higher threshold of the suppression in CP adults may reflect downregulation of cortical inhibition to facilitate corticospinal drive. Interventions aiming to facilitate excitability in cortical networks may contribute to maintain or even improve efficient gait in CP adults.

Full Activation Profiles and Integrity of Corticospinal Pathways in Adults With Bilateral Spastic Cerebral Palsy

Background. Dysfunction of corticospinal pathways has been implicated in motor impairments in people with bilateral spastic cerebral palsy (CP). While structural damage to corticospinal pathways in people with CP is known, its impact on the activation of these pathways is not. Objective. To provide the first, complete activation profile of corticospinal pathways in adults with CP using a full range of transcranial magnetic stimulation (TMS) intensities and voluntary contractions. Methods. TMS targeted the soleus muscle of 16 adults with bilateral spastic CP and 15 neurologically intact (NI) control participants. Activation profiles were generated using motor-evoked potentials (MEPs) produced by varying both stimulation intensity and degree of voluntary muscle activity. Anatomical integrity of corticospinal pathways was also measured with diffusion tractography. Results. Participants with CP had smaller MEPs produced by TMS at 1.2× active motor threshold during submaximal (20%) muscle activity and smaller maximal MEPs produced under any combination of stimulation intensity and voluntary muscle activity. At a fixed stimulation intensity, increasing voluntary muscle activity facilitated MEP amplitudes to a lesser degree in the participants with CP. Consistent differences in diffusion tractography suggested structural abnormalities in the corticospinal pathways of participants with CP that correlated with maximal MEPs. Conclusion. People with bilateral spastic CP have impaired activation of low and high-threshold corticospinal pathways to soleus motoneurons by TMS and reduced facilitation by voluntary activity that may be associated with structural damage to these pathways. These impairments likely contribute to impaired voluntary movement.

Effect of cervicolumbar coupling on spinal reflexes during cycling after incomplete spinal cord injury.

Spinal networks in the cervical and lumbar cord are actively coupled during locomotion to coordinate arm and leg activity. The goals of this project were to investigate the intersegmental cervicolumbar connectivity during cycling after incomplete spinal cord injury (iSCI) and to assess the effect of rehabilitation training on improving reflex modulation mediated by cervicolumbar pathways. Two studies were conducted. In the first, 22 neurologically intact (NI) people and 10 people with chronic iSCI were recruited. The change in H-reflex amplitude in flexor carpi radialis (FCR) during leg cycling and H-reflex amplitude in soleus (SOL) during arm cycling were investigated. In the second study, two groups of participants with chronic iSCI underwent 12 wk of cycling training: one performed combined arm and leg cycling (A&L) and the other legs only cycling (Leg). The effect of training paradigm on the amplitude of the SOL H-reflex was assessed. Significant reduction in the amplitude of both FCR and SOL H-reflexes during dynamic cycling of the opposite limbs was found in NI participants but not in participants with iSCI. Nonetheless, there was a significant reduction in the SOL H-reflex during dynamic arm cycling in iSCI participants after training. Substantial improvements in SOL H-reflex properties were found in the A&L group after training. The results demonstrate that cervicolumbar modulation during rhythmic movements is disrupted in people with chronic iSCI; however, this modulation is restored after cycling training. Furthermore, involvement of the arms simultaneously with the legs during training may better regulate the leg spinal reflexes. NEW & NOTEWORTHY This work systematically demonstrates the disruptive effect of incomplete spinal cord injury on cervicolumbar coupling during rhythmic locomotor movements. It also shows that the impaired cervicolumbar coupling could be significantly restored after cycling training. Actively engaging the arms in rehabilitation paradigms for the improvement of walking substantially regulates the excitability of the lumbar spinal networks. The resulting regulation may be better than that obtained by interventions that focus on training of the legs only.

Modulation of corticospinal input to the legs by arm and leg cycling in people with incomplete spinal cord injury.

The spinal cervico-lumbar interaction during rhythmic movements in humans has recently been studied; however, the role of arm movements in modulating the corticospinal drive to the legs is not well understood. The goals of this study were to investigate the effect of active rhythmic arm movements on the corticospinal drive to the legs (study 1) and assess the effect of simultaneous arm and leg training on the corticospinal pathway after incomplete spinal cord injury (iSCI) (study 2). In study 1, neurologically intact (NI) participants or participants with iSCI performed combinations of stationary and rhythmic cycling of the arms and legs while motor evoked potentials (MEPs) were recorded from the vastus lateralis (VL) muscle. In the NI group, arm cycling alone could facilitate the VL MEP amplitude, suggesting that dynamic arm movements strongly modulate the corticospinal pathway to the legs. No significant difference in VL MEP between conditions was found in participants with iSCI. In study 2, participants with iSCI underwent 12 wk of electrical stimulation-assisted cycling training: one group performed simultaneous arm and leg (A&L) cycling and the other legs-only cycling. MEPs in the tibialis anterior (TA) muscle were compared before and after training. After training, only the A&L group had a significantly larger TA MEP, suggesting increased excitability in the corticospinal pathway. The findings demonstrate the importance of arm movements in modulating the corticospinal drive to the legs and suggest that active engagement of the arms in lower limb rehabilitation may produce better neural regulation and restoration of function.NEW & NOTEWORTHY This study aimed to demonstrate the importance of arm movements in modulating the corticospinal drive to the legs. It provides direct evidence in humans that active movement of the arms could facilitate corticospinal transmission to the legs and, for the first time, shows that facilitation is absent after spinal cord injury. Active engagement of the arms in lower limb rehabilitation increased the excitability of the corticospinal pathway and may produce more effective improvement in leg function.

Rapid amyloid-β oligomer and protofibril accumulation in traumatic brain injury.

Deposition of amyloid-β (Aβ) is central to Alzheimer's disease (AD) pathogenesis and associated with progressive neurodegeneration in traumatic brain injury (TBI). We analyzed predisposing factors for Aβ deposition including monomeric Aβ40, Aβ42 and Aβ oligomers/protofibrils, Aβ species with pronounced neurotoxic properties, following human TBI. Highly selective ELISAs were used to analyze N-terminally intact and truncated Aβ40 and Aβ42, as well as Aβ oligomers/protofibrils, in human brain tissue, surgically resected from severe TBI patients (n = 12; mean age 49.5 ± 19 years) due to life-threatening brain swelling/hemorrhage within one week post-injury. The TBI tissues were compared to post-mortem AD brains (n = 5), to post-mortem tissue of neurologically intact (NI) subjects (n = 4) and to cortical biopsies obtained at surgery for idiopathic normal pressure hydrocephalus patients (iNPH; n = 4). The levels of Aβ40 and Aβ42 were not elevated by TBI. The levels of Aβ oligomers/protofibrils in TBI were similar to those in the significantly older AD patients and increased compared to NI and iNPH controls (P < 0.05). Moreover, TBI patients carrying the AD risk genotype Apolipoprotein E epsilon3/4 (APOE ε3/4; n = 4) had increased levels of Aβ oligomers/protofibrils (P < 0.05) and of both N-terminally intact and truncated Aβ42 (P < 0.05) compared to APOE ε3/4-negative TBI patients (n = 8). Neuropathological analysis showed insoluble Aβ aggregates (commonly referred to as Aβ plaques) in three TBI patients, all of whom were APOE ε3/4 carriers. We conclude that soluble intermediary Aβ aggregates form rapidly after TBI, especially among APOE ε3/4 carriers. Further research is needed to determine whether these aggregates aggravate the clinical short- and long-term outcome in TBI.

Spinal inhibition and motor function in adults with spastic cerebral palsy.

Abnormal activation of motoneurons in the spinal cord by sensory pathways is thought to contribute to impaired movement control and spasticity in individuals with cerebral palsy. Here we use single motor unit recordings to show how individual motoneurons in the spinal cord respond to sensory inputs in a group of participants with cerebral palsy having different degrees of motor dysfunction. In participants who had problems walking independently and required assistive devices such as wheelchairs, sensory pathways only excited motoneurons in the spinal cord. In contrast, in participants with cerebral palsy who walked independently for long distances, sensory inputs both inhibited and excited motoneurons in the spinal cord, similar to what we found in uninjured control participants. These findings demonstrate that in individuals with severe cerebral palsy, inhibitory control of motoneurons from sensory pathways is reduced and may contribute to motor dysfunction and spasticity. Reduced inhibition of spinal motoneurons by sensory pathways may contribute to heightened reflex activity, spasticity and impaired motor function in individuals with cerebral palsy (CP). To measure if the activation of inhibitory post-synaptic potentials (IPSPs) by sensory inputs is reduced in CP, the tonic discharge rate of single motor units from the soleus muscle was plotted time-locked to the occurrence of a sensory stimulation to produce peri-stimulus frequencygrams (PSFs). Stimulation to the medial arch of the foot was used to activate cutaneomuscular afferents in 17 adults with bilateral spastic CP and 15 neurologically intact (NI) peers. Evidence of IPSP activation from the PSF profiles, namely a marked pause or reduction in motor unit firing rates at the onset of the cutaneomuscular reflex, was found in all NI participants but in only half of participants with CP. In the other half of the participants with CP, stimulation of cutaneomuscular afferents produced a PSF profile indicative of a pure excitatory post-synaptic potential, with firing rates increasing above the mean pre-stimulus rate for 300ms or more. The amplitude of motoneuron inhibition during the period of IPSP activation, as measured from the surface EMG, was less in participants with poor motor function as evaluated with the Gross Motor Functional Classification System (r=0.72, P<0.001) and the Functional Mobility Scale (r=-0.82, P<0.001). These findings demonstrate that in individuals with CP, reduced activation of motoneuron IPSPs by sensory inputs is associated with reduced motor function and may contribute to enhanced reflexes and spasticity in CP.

Abstract 246: Reduced Prehospital Survival Rate After Out-of-Hospital Cardiac Arrest in Patients with Diabetes Mellitus Type 2: A Prospective Community-Based Study

Objectives: Out-of-hospital cardiac arrest (OHCA) remains a major cause of death. We aimed to determine whether diabetes mellitus type 2 (T2DM) is associated with survival to hospital admission and to hospital discharge after OHCA. Methods: We performed a community-based cohort study of 1549 OHCA patients with ECG-documented ventricular tachycardia/ventricular fibrillation (VT/VF). Survival to hospital admission and to hospital discharge was compared between patients with T2DM and non-DM patients using multivariate logistic regression analysis. Among discharged patients, we compared the proportions of neurologically intact (NI) survival. All analyses were stratified according to T2DM disease severity. Results: Patients with T2DM (n=275) had lower survival rates to hospital admission than non-DM patients (n=1274, 48.7% vs. 55.8%, P=0.032). Patients with severe T2DM had lower survival rates to admission than patients with mild T2DM (37.3% vs. 53.3%, P=0.034). Multivariate analysis revealed that T2DM was an independent determinant of survival to hospital admission (OR 0.75 [95% CI 0.58-0.98]). Survival rates to hospital discharge were also lower in patients with T2DM (n=134) than in non-DM patients (n=711, 40.3% vs. 57.7%, P&lt;0.001). Multivariate logistic regression analysis among patients admitted to hospital showed that T2DM was associated with lower survival to discharge (OR 0.57 [95% CI 0.38-0.84]). NI-status at discharge was high in both patients with T2DM and non-DM patients (94.4% vs. 94.6%, P=0.954) Conclusion: Patients with T2DM had lower survival rates to hospital admission and to hospital discharge after OHCA than non-DM patients. T2DM was an independent determinant of lower survival.

Short-segment fixation of thoracolumbar burst fractures using pedicle fixation at the level of fracture in patients with osteoporosis

To evaluate the curative effect of short-segment transpedicular fixation plus vertebra fracture fixation for thoracolumbar burst fractures in patients with osteoporosis. The clinical data of thoracolumbar burst fractures in 46 patients with osteoporosis, single segment fracture and neurological intactness were analyzed retrospectively from January 2008 to January 2012. There were 20 males and 26 females with a mean age of 64.5 (56-78) years. The mechanisms of injury were fall (n = 20), traffic accident (n = 12), high falling injury (n = 8) and heavy pound injury (n = 4). The involved vertebrae included T11 (n = 5); T12 (n = 17); L1 (n = 21); L2 (n = 3). Pedicle screw was inserted into injured vertebra and the height of collapsed vertebra fractures reduced with position and instrument. Visual analogue scale (VAS) and short form-36 scoring systems were used to evaluate pain level and quality of life. The height restoration and kyphotic correction rates of fracture level were measured radiologically. All patients underwent surgery safely without severe complications. The average follow-up period was 20.5 (9-48) months. There was significant difference (t = 20.057, P = 0.000; t = 24.287, P = 0.000) in VAS score between last follow-up (3.09 ± 1.01) and post-operation (2.35 ± 1.02) versus pre-operation (7.22 ± 1.05) respectively. And also there was significant difference (P < 0.05) in SF-36 score between last follow-up (126.5 ± 22.3) and post-operation (96.7 ± 17.5). The Cobb angle was corrected to (5.6 ± 1.9)° of post-operation and (7.8 ± 3.3)° of last follow-up. The loss rate of vertebral was (4.8 ± 5.2)% of post-operation and (7.6 ± 2.9) % of last follow-up. There was no loosening or breakage of internal fixations. The approach of short-segment transpedicular fixation plus vertebra fracture fixation is both safe and effective to maintain reduction and reduce the rate of correction loss and instrument failure.

Abstract 51: Demographics, Automated External Defibrillator Deployment and Neurologically Intact Survival of Out-of-Hospital Pediatric Cardiac Arrest in the Cardiac Arrest Registry to Enhance Survival Registry

Background: Since 2005, the American Heart Association has recommended that children in cardiopulmonary arrest (CA), greater than 1 year of age, receive an attempt at automated external defibrillator (AED) application and shock. However, little is known about whether these guidelines have reached the bystander response in the U.S. Objective: 1) To characterize survival and neurologically intact (NI) outcomes of pediatric out of hospital CA events 2) To determine the prevalence of bystander cardiopulmonary resuscitation (CPR) and AED, particularly in those victims under 8 years of age. Methods: We conducted a secondary analysis of prospectively collected data from 29 U.S. cities that participate in the Cardiac Arrest Registry to Enhance Survival (CARES). Patients were included if they were less than 18 years of age and had a documented resuscitation attempt from October 1, 2005 through December 31, 2009. Chi-squared tests were used to test for differences in AED and bystander CPR provision between age groups. Results: A total of 481 cases comprised our cohort. The overall survival was 5.6 % (95% CI: 3.7-8.1), and NI survival was 3.5% (95% CI: 2.0- 5.6). Across all age strata, asystole was the most common initial rhythm. Sixty-six (13.7 % (95% CI: 10.8-17.1) patients had a shockable rhythm with increasing percentages of shockable rhythms at older ages (&lt;30 days: 3.2% (n=2); 30 days-1 year old: 3.4% (n=7); 1-5 years old: 10.1% (n=7); 5-12 years old: 22.1% (n=13); 12-18 years old: 31.8% (n=27), p&lt;0.05). Bystander CPR and AED rates are shown in the table. Overall AED use for the sample was 70/481; 14.6% (95% CI: 11.5-18.0) while the provision of bystander CPR was 160/481; 33.3% (95% CI: 29.1-37.7). Conclusions: Despite a similar rate of bystander CPR and higher rate of AED use, pediatric CA have lower overall and NI survival as compared to the adult population. Future research will need to be conducted to determine the barriers to children receiving bystander CPR and having AEDs applied

Verbal and non-verbal working memory in aphasia: What three n-back tasks reveal

Background: Researchers have found that many individuals with aphasia (IWA) present with cognitive deficits that may impact their communication, and perhaps underlie their language-processing deficits (e.g., Erickson et al., 1996; Murray et al., 1997; Wright et al., 2003). However, many investigations of cognitive ability in aphasia have included measures that may be considered “language heavy”; they require overt lexical, semantic, and/or phonological processing to follow the task instructions and/or formulate a response. Few have considered the amount of linguistic processing required to perform the task. Subsequently, it is not clear if poorer performance by IWA on cognitive tasks compared to neurologically intact (NI) participants is due to a deficit in the respective cognitive domain or due to the inability of IWA to perform the task because of their language difficulties. Aims: The purpose of the current study was to explore the effect of varying linguistic processing demands in the context of a dynamic working memory task—an n-back task for participants with and without aphasia. Method & Procedures: This study compared differences on three different n-back tasks within and across groups for individuals with aphasia and NI matched peers. Participants completed three different n-back tasks; stimuli for the tasks varied in “linguistic load”. For each n-back task participants completed two levels of difficulty: 1-back and 2-back. Outcomes & Results: The aphasia group performed significantly worse than the NI participants across the n-back tasks. All participants performed significantly better with the stimuli that carried a higher linguistic load (i.e., the fruit), than with the fribbles (semi-linguistic) and blocks (non-linguistic). All participants performed significantly better on the 1-back than the 2-back working memory task. Unlike the NI participants, IWA performed equally poorly with the fribbles and the blocks in the 2-back task. Conclusions: Overall, the performance of individuals with aphasia on working memory tasks that varied in their linguistic load was similar to the control group but reduced. However, unlike the NI participants, IWA were less skilled at rapidly utilising linguistic knowledge to increase performance on the fribbles, demonstrating the further decrement in working memory that results from a decreased ability to utilise a linguistic strategy to increase performance on verbal working memory tasks. The results of this study indicate that language ability has a significant influence on performance on working memory tasks and should be considered when discussing cognitive deficits in aphasia.

The incidence and characterisation of hospitalised acute spinal trauma in Taiwan—A population-based study

The purpose of this study was to perform a cross-sectional population-based study of hospitalised cases due to acute spinal trauma in Taiwan, based on information from the nationwide National Health Insurance (NHI) database. To calculate the annual incidence of hospitalised acute spinal trauma, evaluate the distribution of neurological injury and its surgical intervention, and analyse the use of medical resources and related factors in Taiwan, the entire inpatient datasets were selected between 2000 and 2003 for use in the present study. There were 13,371, 13,800, 13,728 and 13,585 cases identified in 2000, 2001, 2002 and 2003, respectively, the average incidence of hospitalised acute spinal trauma in Taiwan was 61.61/100,000, and it was similar in both genders (rate ratio of male to female: 0.99). There was a significant trend of increased incidence with increasing age in both genders, particularly after the age of 60. The decreasing incidence rate ratios of neurological deficit to neurological intactness are 0.75, 0.58, 0.45, 0.26 and 0.16 in the age strata of 0-19, 20-39, 40-59, 60-79 and 80 or more years, respectively. In general, the operation rate is only 17.3% of all acute spinal injury cases, but it would be up to a significant 29.5% if the patients had spinal fractures with neurological insufficiency. There is an obvious decreasing trend of operation rate in spinal bony trauma with age, but a reverse trend is noted in the group with spinal nerve injury without spinal fracture. Finally, the enrolled subjects of acute spinal injuries spent $NT 43336.3+/-80270.2 (equal to US$ 1313+/-2432) and stayed for 8.5+/-8.9 days in hospital. The above two variables of hospitalised medical utilisation are significantly different when considering gender, neurological status, and surgical intervention or not. Noticeably, if operative treatment for acute spinal injury is necessary, the LOS would increase by two times and the medical cost by six times. In Taiwan, the annual incidence of hospitalised acute spinal injuries was higher but the direct cost was much lower. The characterisation of gender ratio, neurological condition, and surgical performance had been significantly effected by age.

Problem‐solving abilities of participants with and without diffuse neurologic involvement

Background: Impaired problem solving is a frequent consequence of brain trauma and other conditions that result in diffuse neurologic involvement. Information about how individuals with diffuse neurologic involvement solve problems is important to the development of strategies designed to help them achieve the highest degree of independent living despite neuropsychological compromise, and may aid clinical decision making in general. Aims: To examine and compare problem‐solving abilities of participants with and without diffuse neurologic involvement. Methods & Procedures: We used the Rapid Assessment of Problem Solving test (RAPS; Marshall, Karow, Morelli, Iden, & Dixon, 2003a), a modification of Mosher and Hornsby's (1966) 20 Question task, to examine the problem‐solving abilities of two groups of neurologically intact (NI) participants and three groups of participants with diffuse neurologic involvement (DNI). The RAPS is a clinical test of problem‐solving abilities in which the client asks yes/no questions to identify a “target picture” in a 32‐item array. The DNI groups included individuals with recent and chronic acquired traumatic brain injuries, and a third group of participants with severe mental illness. It was hypothesised that participants with DNI would perform less well on the RAPS than the NI participants, and that these differences would be reflected in lower scores on the RAPS and differences in the frequency with which certain types of questions were used to solve problems. Outcomes & Results: Findings revealed significant differences between NI groups and two of the three DNI groups on objective scores, types of questions asked, and the strategies used to solve problems on the RAPS. The NI participants used a more systematic, organised approach to solving problems, whereas participants with DNI were less organised, inconsistent, and sometimes inflexible in their use of problem‐solving strategies. Conclusions: Findings suggest the problem‐solving abilities of participants with and without DNI are distinguishable in terms of selected components of Scholnick and Friedman's (1993) developmental theory of planning. These include a decision to plan, strategy choice and execution, and monitoring effects of prior actions.