scholarly journals Clinical Effects of Theophylline on Inspiratory Muscle Drive in Tetraplegia

1999 ◽  
Vol 13 (3) ◽  
pp. 191-197 ◽  
Author(s):  
Gary T. Ferguson ◽  
Narendra Khanchandani ◽  
Chris D. Lattin ◽  
Harry G. Goshgarian
Keyword(s):  
Spinal Cord ◽  
Muscle Function ◽  
Muscle Force ◽  
Cervical Spinal Cord ◽  
Inspiratory Muscle ◽  
Emg Activity ◽  
Neural Activation ◽  
Clinical Effects ◽  
Respiratory Drive ◽  
Before And After

Theophylline has been shown to restore diaphragmatic function in animals following cervical spinal cord hemisection, which induces hemidiaphragm paralysis. Although theophylline had been used clinically in the treatment of various pulmonary diseases, its effects on respiratory muscle function in cervical spinal cord injured tetraplegics has not been studied. In the present case study, we evaluated a patient injured in 1979 with a chronic asymmetric C5-7 tetraplegia (left C5-6, right C6-7) before and after receiving theophylline chronically by mouth for three weeks and again before and after receiving acute intravenous (IV) aminophylline after the effects of the chronic drug administration wore off. Neural activation to inspiratory muscles was assessed by right and left parasternal intercostal and diaphragm EMGs during quiet breathing and max imal inspiratory efforts. Global respiratory drive was assessed by P100, and inspiratory muscle force was assessed by maximal inspiratory pressures and vital capacity. Both long-term orally administered and acute IV theophylline increased neural activation to the diaphragm, especially on the more affected left side. Theophylline treatment was also associated with an increase in global central respiratory drive and inspiratory muscle force, without changing expiratory airflows. Left diaphragm EMG activity was markedly increased following the administration of theophylline. Of interest, upper parasternal intercostal EMG activity was also recruited on the left in spite of being below the level of cervical injury. We speculate that the administration of theophylline in selected patients with an asymmetric cervical spinal cord injury may activate la tent bulbospinal respiratory pathways and improve inspiratory muscle function, re ducing the likelihood of associated respiratory failure.

Neural factors account for strength decrements observed after short-term muscle unloading

2002 ◽  
Vol 282 (2) ◽  
pp. R578-R583 ◽  
Author(s):  
Michael R. Deschenes ◽  
Jennifer A. Giles ◽  
Raymond W. McCoy ◽  
Jeff S. Volek ◽  
Ana L. Gomez ◽  
...  
Keyword(s):  
Muscle Function ◽  
Fiber Type ◽  
Peak Torque ◽  
Knee Extensors ◽  
Emg Activity ◽  
Neural Activation ◽  
Before And After ◽  
Fiber Type Distribution ◽  
Neural Factors ◽  
Muscle Unloading

Strength decrements observed after extended (4–6 wk) periods of muscle unloading are associated with significant atrophy. Because early (up to 2 wk) strength gains from resistance exercise are related to improved neural recruitment, we hypothesized that the loss of strength resulting from 2 wk of muscle unloading [unilateral lower limb suspension (ULLS)] was due to impaired neural activation of the affected muscle. Blood samples, muscle biopsy specimens, muscle function data, and electromyography (EMG) recordings were analyzed before and after 14 days of muscle unloading. Pre- to postunloading data showed significant ( P ≤ 0.05) decrements in peak torque and total work performed by knee extensors and flexors. This was coupled with decreased EMG activity, but no change in neuromuscular efficiency (total torque/EMG). Resistance to muscle fatigue was enhanced after ULLS. The 14-day intervention failed to alter the size or fiber type distribution of muscle samples. However, resting plasma cortisol levels were significantly increased after muscle unloading, suggesting an endocrine environment favorable to muscle atrophy. Our data confirm that the diminution in muscle function displayed after 2 wk of unloading is mainly due to neural, rather than contractile, disturbances.

5-Hydroxytryptophan-induced respiratory recovery after cervical spinal cord hemisection in rats

2000 ◽  
Vol 89 (4) ◽  
pp. 1528-1536 ◽  
Author(s):  
Shi-Yi Zhou ◽  
Harry G. Goshgarian
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Phrenic Nerve ◽  
Serotonin Receptor ◽  
Cervical Spinal Cord ◽  
Respiratory Drive ◽  
Respiratory Pathway ◽  
Cord Injury ◽  
Respiratory Recovery ◽  
Spinal Cord Hemisection

The present study investigates the role of serotonin in respiratory recovery after spinal cord injury. Experiments were conducted on C2 spinal cord hemisected, anesthetized, vagotomized, paralyzed, and artificially ventilated rats in which end-tidal CO2 was monitored and maintained. Before drug administration, the phrenic nerve ipsilateral to hemisection showed no respiratory-related activity due to the disruption of the descending bulbospinal respiratory pathways by spinal cord hemisection. 5-Hydroxytryptophan (5-HTP), a serotonin precursor, was administrated intravenously. 5-HTP induced time- and dose-dependent increases in respiratory recovery in the phrenic nerve ipsilateral to hemisection. Although the 5-HTP-induced recovery was initially accompanied by an increase in activity in the contralateral phrenic nerve, suggesting an increase in descending respiratory drive, the recovery persisted well after activity in the contralateral nerve returned to predrug levels. 5-HTP-induced effects were reversed by a serotonin receptor antagonist, methysergide. Because experiments were conducted on animals subjected to C2 spinal cord hemisection, the recovery was most likely mediated by the activation of a latent respiratory pathway spared by the spinal cord injury. The results suggest that serotonin is an important neuromodulator in the unmasking of the latent respiratory pathway after spinal cord injury. In addition, the results also suggest that the maintenance of 5-HTP-induced respiratory recovery may not require a continuous enhancement of central respiratory drive.

scholarly journals Altered modulation of sensorimotor rhythms with chronic paralysis

2017 ◽  
Vol 118 (4) ◽  
pp. 2412-2420 ◽  
Author(s):  
Stephen T. Foldes ◽  
Douglas J. Weber ◽  
Jennifer L. Collinger
Keyword(s):  
Spinal Cord ◽  
Motor Imagery ◽  
Muscle Activity ◽  
Cervical Spinal Cord ◽  
The Other ◽  
Emg Activity ◽  
Cortical Oscillations ◽  
Cord Injury ◽  
Intact Muscle ◽  
Sensorimotor Rhythms

After paralysis, the disconnection between the cortex and its peripheral targets leads to neuroplasticity throughout the nervous system. However, it is unclear how chronic paralysis specifically impacts cortical oscillations associated with attempted movement of impaired limbs. We hypothesized that μ- (8–13 Hz) and β- (15–30 Hz) event-related desynchronization (ERD) would be less modulated for individuals with hand paralysis due to cervical spinal cord injury (SCI). To test this, we compared the modulation of ERD from magnetoencephalography (MEG) during attempted and imagined grasping performed by participants with cervical SCI ( n = 12) and able-bodied controls ( n = 13). Seven participants with tetraplegia were able to generate some electromyography (EMG) activity during attempted grasping, whereas the other five were not. The peak and area of ERD were significantly decreased for individuals without volitional muscle activity when they attempted to grasp compared with able-bodied subjects and participants with SCI,with some residual EMG activity. However, no significant differences were found between subject groups during mentally simulated tasks (i.e., motor imagery) where no muscle activity or somatosensory consequences were expected. These findings suggest that individuals who are unable to produce muscle activity are capable of generating ERD when attempting to move, but the characteristics of this ERD are altered. However, for people who maintain volitional muscle activity after SCI, there are no significant differences in ERD characteristics compared with able-bodied controls. These results provide evidence that ERD is dependent on the level of intact muscle activity after SCI. NEW & NOTEWORTHY Source space MEG was used to investigate sensorimotor cortical oscillations in individuals with SCI. This study provides evidence that individuals with cervical SCI exhibit decreased ERD when they attempt to grasp if they are incapable of generating muscle activity. However, there were no significant differences in ERD between paralyzed and able-bodied participants during motor imagery. These results have important implications for the design and evaluation of new therapies, such as motor imagery and neurofeedback interventions.

Resistive inspiratory muscle training in subjects with chronic cervical spinal cord injury

1998 ◽  
Vol 79 (3) ◽  
pp. 293-297 ◽  
Author(s):  
Alyssa Rutchik ◽  
Ann R. Weissman ◽  
Peter L. Almenoff ◽  
Ann M. Spungen ◽  
William A. Bauman ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cervical Spinal Cord ◽  
Cervical Spinal Cord Injury ◽  
Inspiratory Muscle ◽  
Inspiratory Muscle Training ◽  
Muscle Training ◽  
Cord Injury

What Does EMC Tell Us about Muscle Function?

Motor Control ◽  
1999 ◽  
Vol 3 (1) ◽  
pp. 9-11 ◽  
Author(s):  
Stan C.A.M. Gielen
Keyword(s):  
Muscle Function ◽  
Muscle Force ◽  
Motor Units ◽  
Contractile Properties ◽  
Emg Activity ◽  
Motor Tasks ◽  
Muscle Properties

EMG recordings are frequently used to obtain a better understanding in the coordination of movements. However, EMG activity is made up by the weighted summation of activity of many motor units with different contractile properties. Recent studies have revealed that different motor units contribute to muscle force in different motor tasks. The flexible recruitment of motor units with various contractile properties allows a flexible tuning of muscle properties, but also complicates the interpretation of EMG activity.

scholarly journals The “presyrinx” state: is there a reversible myelopathic condition that may precede syringomyelia?

2000 ◽  
Vol 8 (3) ◽  
pp. 1-13 ◽  
Author(s):  
Nancy J. Fischbein ◽  
William P. Dillon ◽  
Charles Cobbs ◽  
Philip R. Weinstein
Keyword(s):  
Spinal Cord ◽  
Mr Imaging ◽  
Clinical Evidence ◽  
Cervical Spinal Cord ◽  
Central Canal ◽  
Intramedullary Tumor ◽  
Csf Flow ◽  
Before And After ◽  
Late Evolution ◽  
History Of

Object Alteration of cerebrospinal fluid (CSF) flow has been proposed as an important mechanism leading to the development of syringomyelia. We hypothesize that a “presyrinx” condition due to potentially reversible alteration in normal CSF flow exists and that its appearance may be due to variations in the competence of the central canal of the spinal cord. Methods Five patients with clinical evidence of myelopathy, no history of spinal cord trauma, enlargement of the cervical spinal cord with T1 and T2 prolongation but no cavitation, evidence for altered or obstructed CSF flow, and no evidence of intramedullary tumor or a spinal vascular event underwent MR imaging before and after intervention that alleviated obstruction to CSF flow. Results Preoperatively, all patients demonstrated enlarged spinal cords and parenchymal T1 and T2 prolongation without cavitation. Results of magnetic resonance (MR) imaging examinations following intervention in all patients showed resolution of cord enlargement and normalization or improvement of cord signal abnormalities. In one patient with severe arachnoid adhesions who initially improved following decompression, late evolution into syringomyelia occurred in association with continued CSF obstruction. Conclusion Nontraumatic obstruction of the CSF pathways in the spine may result in spinal cord parenchymal T2 prolongation that is reversible following restoration of patency of CSF pathways. We refer to this MR appearance as the “presyrinx” state and stress the importance of timely intervention to limit progression to syringomyelia.

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