Restorative Neurology and Neuroscience - Volume 24, issue 3

Authors: Byler, S.L. | Shaffer, M.C. | Barth, T.M.

Article Type: Research Article

Abstract: Purpose: To better understand the behavioral effects of pallidotomy as a treatment for a range of movement disorders, including Parkinson's disease, chorea, and ballismus. In some cases, pallidotomy increases movement whereas in others it decreases unwanted motor behavior. Method: The present study investigated the effects of unilateral pallidotomy in rats with an otherwise healthy nervous system. Pallidotomized and sham lesion rats were evaluated on a battery of tests that measure sensorimotor behavior. Results: …Compared to sham lesion controls, pallidotomized rats showed motor deficits (forelimb placing; bracing) and excesses (locomotor behavior) as well as sensorimotor asymmetries (ipsilateral adhesive patch bias; increased contralateral foot faults). Conclusion: Motor deficits observed after pallidotomy were similar to those reported in previous research from this and other laboratories following damage to the nigrostriatal pathway or sensorimotor cortex. Motor excesses after pallidotomy are consistent with current theories of globus pallidus function. Taken together, these data suggest hypokinetic effects of pallidotomy may be related to fibers of passage (i.e. internal capsule), while hyperkinetic effects may be related to damage of pallidal cell bodies. These data may have important clinical implications because they suggest that regardless of the state of existing pathology, pallidotomy may create unwanted behavioral side effects. Show more

Keywords: Pallidotomy, motor deficits, motor excesses, Parkinson's, chorea, entopeduncular nucleus, rats

Citation: Restorative Neurology and Neuroscience, vol. 24, no. 3, pp. 133-145, 2006

Authors: Moon, L.D.F. | Leasure, J.L. | Gage, F.H. | Bunge, M.B.

Article Type: Research Article

Abstract: Purpose: This study investigated whether enrichment improves hindlimb movement following complete spinal cord transection and transplantation of olfactory ensheathing glia (OEG), with or without a Schwann cell (SC) bridge. Methods: Motor activity was encouraged through provision of motor enrichment housing (MEH); a multi-level cage containing ramps, textured surfaces and rewards. Hindlimb joint movement was assessed weekly for 22 weeks starting one week post-surgery, comparing rats housed in MEH to those in basic …housing (BH). Transganglionic tracer was injected into the crushed right sciatic nerve three days prior to sacrifice, allowing sensory axons in the dorsal columns to be visualized by immunolabeling. Serotonergic axons and glial cells expressing low affinity nerve growth factor receptor were identified by immunolabeling. Results: All rats, having received transplants, recovered some hindlimb movement. Rats housed in BH progressively lost recovered hindlimb function whereas recovered hindlimb movements were sustained in most rats in MEH. In rats transplanted with SCs and OEG, effects of MEH were first significant 14 weeks after injury. In rats transplanted with OEG, a trend was seen from 14 weeks after injury, but this did not reach significance. In all rats, traced sensory axons died back from sites of transplantation and did not regenerate rostrally. Further, in no rat were serotonergic axons observed regenerating into, around or beyond transplants. Conclusions: Transection and transplantation of SC/OEG or OEG induced recovery of hindlimb function. This recovered hindlimb movement was sustained in rats housed in MEH but was progressively lost in rats housed in BH. Because benefits of MEH were not observed until 14 weeks after injury, long-term assessment of behavior is recommended. BH conditions are not conducive to maintenance of recovered hindlimb function, and MEH should be used in studies of recovery of function following spinal cord injury. Show more

Keywords: Motor enrichment, rehabilitation, spinal cord transection, injury, hindlimb movement, Schwann cells, olfactory ensheathing glia

Citation: Restorative Neurology and Neuroscience, vol. 24, no. 3, pp. 147-161, 2006

Authors: Bazarian, Jeffrey J. | Beck, Christopher | Blyth, Brian | von Ahsen, Nicolas | Hasselblatt, Martin

Article Type: Research Article

Abstract: Purpose: To validate a correction factor for the extracranial release of the astroglial protein, S-100B, based on concomitant creatine kinase (CK) levels. Methods: The CK- S-100B relationship in non-head injured marathon runners was used to derive a correction factor for the extracranial release of S-100B. This factor was then applied to a separate cohort of 96 mild traumatic brain injury (TBI) patients in whom both CK and S-100B levels were measured. Corrected S-100B was …compared to uncorrected S-100B for the prediction of initial head CT, three-month headache and three-month post concussive syndrome (PCS). Results: Corrected S-100B resulted in a statistically significant improvement in the prediction of 3-month headache (area under curve [AUC] 0.46 vs 0.52, p=0.02), but not PCS or initial head CT. Using a cutoff that maximizes sensitivity (⩾90%), corrected S-100B improved the prediction of initial head CT scan (negative predictive value from 75% [95% CI, 2.6%, 67.0%] to 96% [95% CI: 83.5%, 99.8%]). Conclusions: Although S-100B is overall poorly predictive of outcome, a correction factor using CK is a valid means of accounting for extracranial release. By increasing the proportion of mild TBI patients correctly categorized as low risk for abnormal head CT, CK-corrected S100-B can further reduce the number of unnecessary brain CT scans performed after this injury. Show more

Keywords: Mild traumatic brain injury, cerebral concussion, serum markers, post concussive syndrome

Citation: Restorative Neurology and Neuroscience, vol. 24, no. 3, pp. 163-172, 2006

Authors: Chung, Yi-Jung | Cho, Sang-Hyun | Lee, Young-Hee

Article Type: Research Article

Abstract: Purposes: This study tested the hypothesis that our method of knee-joint-tracking training for stroke patients induces significant motor learning effects, and the findings were compared with those of previous studies. Methods: Six stroke patients and six age-matched healthy controls were recruited. The tracking task involved following computer-generated sine waves of changing frequency (0.2, 0.3, or 0.4 Hz) for each repeating cycle with a plot of the knee-joint angle on a computer monitor …as closely as possible. The closed-kinetic chain set involved standing with both hands placed on a support table, with one foot placed on a wooden box and the other foot placed on a digital body-weight scale. The sessions in this study were performed in the following sequence: practice, pretest evaluation, 4 weeks of training, and posttraining evaluation. The tracking performance was evaluated with the accuracy index (AI) score. Results: Tracking training produced a significant improvement not only in the motor-function scores but also in the AI score of the stroke-patient group. The improvement in their AI did not differ significantly from that of the control group. Conclusions: Our tracking protocol exerted a significant training effect in stroke patients, and the AI improvement was greater than that induced by the most recent protocol. This training will enhance motor skill acquisition and possibly contribute to cortical reorganization. Show more

Keywords: Knee, joint tracking, biofeedback, stroke, hemiplegia, recovery, accuracy index

Citation: Restorative Neurology and Neuroscience, vol. 24, no. 3, pp. 173-180, 2006

Authors: Keune, Jason D. | Brenner, Michael J. | Schwetye, Katherine E. | Yu, Jeffery W. | Fox, Ida K. | Hunter, Daniel A. | Mackinnon, Susan E.

Article Type: Research Article

Abstract: Purpose: This study investigated nerve regeneration following nerve repair with longitudinally oriented sutures, with emphasis on timing. Prior work in rodents has shown that suture scaffolds are comparable to nerve grafting when assessments are made at late time points. However, rodents have exceptional regenerative capacity, making it difficult to detect key differences at late time points. This study therefore investigated regeneration across suture scaffolds both at early (4 week) and late (12 week) endpoints. …Methods: Rodents were randomized to nerve gap, transection and repair, nerve grafting, and suture scaffold groups. Nerve regeneration was evaluated at 4 and 12 weeks. Histomorphometry parameters were evaluated using binary image analysis of toluidine blue-stained nerve cross sections. Results: Compared to nerve grafts, suture scaffolds were associated with significantly decreased neural density (4208 ± 3546 vs. 193 ± 416, fibers/mm^2 , p<0.05) and fiber width (1.92 ± 1.21 vs. 0.75± 1.16, μm, p<0.05). At 12 weeks, differences between groups were no longer detectable. Conclusion: When evaluated at optimal time points for rodents, suture scaffolds fail to support regeneration comparable to the existing gold standard of nerve grafting. This finding raises significant concerns regarding the clinical application of suture scaffolds. Show more

Keywords: Nerve regeneration, peripheral nerve, polyglactin suture, absorbable suture, nerve graft

Citation: Restorative Neurology and Neuroscience, vol. 24, no. 3, pp. 181-190, 2006

Authors: Carey, James R. | Fregni, Felipe | Pascual-Leone, Alvaro

Article Type: Research Article

Abstract: Purpose. This study explored the effects of motor learning training combined with repetitive transcranial magnetic stimulation (rTMS) on motor performance in healthy subjects. Methods. Twenty-seven right-handed subjects were randomized to three groups: ipsilateral rTMS (IS group), contralateral rTMS (CS group), and sham rTMS (SS group). rTMS was applied for 10 minutes (1 Hz, 90% motor threshold) prior to training. Training involved 10 minutes of finger tracking with the right hand. Tracking performance was tested …before, during and after training. Results. Improvement in tracking performance over the posttests was not significantly different between the CS and SS groups, whereas it was significantly lower for the IS group compared to the SS group. No difference was found across groups at retention tests. Conclusion. These findings indicate that rTMS interfered with motor performance transiently when applied ipsilateral to the training hand and had no effect when applied contralaterally. These results invite further work to determine whether the disruptive effect of ipsilateral rTMS observed here in healthy subjects, with presumably balanced interhemispheric inhibition, might translate differently to subjects with abnormal interhemispheric inhibition (stroke patients) in a way that disinhibits the ipsilesional hemisphere and improves performance in the paretic hand. Show more

Keywords: Repetitive transcranial magnetic stimulation, motor cortex, motor learning, interhemispheric inhibition

Citation: Restorative Neurology and Neuroscience, vol. 24, no. 3, pp. 191-199, 2006