Kumru H.,Instituto Guttmann |
Vidal J.,Instituto Guttmann |
Kofler M.,Instituto Guttmann |
Portell E.,Instituto Guttmann |
Valls-Sole J.,Unitat dEmg
Journal of Neurotrauma | Year: 2010
Reorganization of the central nervous system following spinal cord injury (SCI) involves changes not only at the cortical level, but also at the level of the brainstem. To further understand changes in excitatory and inhibitory brainstem interneuronal circuits following SCI, we studied recovery curves of the blink reflex (BR) to paired suprathreshold stimuli at various intervals (160, 300, 500, and 1000 msec), and prepulse inhibition of the BR following right index finger stimulation 100 msec prior to supraorbital nerve stimulation. Both parameters were studied in patients with SCI without baclofen treatment (n = 19), in patients with continuous intrathecal baclofen (CITB) (n = 9), and in healthy controls (n = 13). R2 recovery, expressed as the ratio of R2 area following the second stimulus divided by the R2 area following the first stimulus, was significantly greater in SCI patients without baclofen compared to controls and patients with CITB at all intervals, while there was no difference between patients with CITB and controls. Prepulse inhibition of R2 was significantly less in patients without baclofen compared to patients with CITB and healthy controls. Our findings indicate enhanced excitability and reduced inhibition of brainstem interneuronal circuits in patients with SCI, that are restored in the presence of baclofen to levels comparable to controls. In conclusion, SCI patients show more extended alterations in brainstem circuitry than previously thought. Decreased GABAergic mechanisms seem to be related to both excitatory and inhibitory brainstem circuit alterations. Baclofen appears to effectively restore this decreased GABAeregic activity. © 2010, Mary Ann Liebert, Inc.
Kumru H.,Institute Guttmann |
Murillo N.,Institute Guttmann |
Vidal Samso J.,Institute Guttmann |
Valls-Sole J.,Unitat dEmg |
And 8 more authors.
Neurorehabilitation and Neural Repair | Year: 2010
Objective. Spasticity with increased tone and spasms is frequent in patients after spinal cord injury (SCI). Damage to descending corticospinal pathways that normally exert spinal segmental control is thought to play an important causal role in spasticity. The authors examined whether the modulation of excitability of the primary motor cortex with high-frequency repetitive transcranial magnetic stimulation (rTMS) could modify lower limb spasticity in patients with incomplete SCI. Methods. Patients were assessed by the Modified Ashworth Scale, Visual Analogue Scale, and the Spinal Cord Injury Spasticity Evaluation Tool (SCI-SET) and neurophysiologically with measures of corticospinal and segmental excitability by the Hmax/Mmax, T reflex, and withdrawal reflex. Fifteen patients received 5 days of daily sessions of active (n = 14) or sham (n = 7) rTMS to the leg motor area (20 trains of 40 pulses at 20 Hz and an intensity of 90% of resting motor threshold for the biceps brachii muscle). Result. A significant clinical improvement in lower limb spasticity was observed in patients following active rTMS but not after sham stimulation.This improvement lasted for at least 1 week following the intervention. Neurophysiological studies did not change. Conclusions. High-frequency rTMS over the leg motor area can improve aspects of spasticity in patients with incomplete SCI. © 2010 The Author(s).
Murillo N.,Autonomous University of Barcelona |
Kumru H.,Autonomous University of Barcelona |
Vidal-Samso J.,Autonomous University of Barcelona |
Benito J.,Autonomous University of Barcelona |
And 3 more authors.
Clinical Neurophysiology | Year: 2011
Objective: Spasticity is common after spinal cord injury (SCI). Exaggerated tendon jerks, clonus, and spasms are key features of spasticity that result from hyperexcitability of the stretch reflex circuit. Here we studied the effects of vibration on the rectus femoris muscle (RF) on clinical and electrophysiological measures of spasticity in the leg. Methods: Nineteen SCI patients with spasticity and nine healthy subjects were studied at baseline and under stimulation (vibration at 50. Hz during 10. min on the thigh). Neurophysiological studies included evaluation of the soleus T wave and Hmax/Mmax ratio. Clinical measurements of spasticity were the score in the Modified Ashworth Scale (MAS), range of motion (ROM), and duration and frequency of clonus. Results: Patients with incomplete SCI (iSCI) presented higher number of cycles and longer duration of clonus than patients with complete SCI (cSCI). The Hmax/Mmax ratio and T wave amplitude at baseline were significantly larger in iSCI patients than in cSCI or healthy subjects. During vibration, we found a significant reduction of MAS and duration of clonus, and an increase in ROM, in all patients as a group. The Hmax/Mmax ratio and the T wave amplitude decreased significantly in both, patients and controls. Conclusions: Prolonged vibration on proximal lower extremity muscles decreased limb spasticity in patients with spinal cord injury, regardless of whether the lesion is complete or incomplete. Significance: Muscle vibration may be useful for physical therapy, by facilitating passive and active movements of the extremities in spastic SCI patients. © 2010 International Federation of Clinical Neurophysiology.
Queralt A.,Institute Salud Carlos III |
Queralt A.,University of Valencia |
Valls-Sole J.,Unitat dEmg |
Valls-Sole J.,CIBER ISCIII |
And 2 more authors.
Gait and Posture | Year: 2010
Human gait involves a repetitive leg motor pattern that emerges after gait initiation. While the automatic maintenance of the gait-pattern may be under the control of subcortical motor centres, gait initiation requires the voluntary launching of a different motor program. In this study, we sought to examine how the two motor programmes respond to an experimental manipulation of the timing of gait initiation. Subjects were instructed to start walking as soon as possible at the perception of an imperative signal (IS) that, in some interspersed trials was accompanied by a startling auditory stimulus (SAS). This method is known to shorten the latency for execution of the motor task under preparation. We reasoned that, if the two motor programmes were launched together, the gait-pattern sequence would respond to SAS in the same way as gait initiation. We recorded the gait phases and the electromyographic (EMG) activity of four muscles from the leg that initiates gait. In trials with SAS, latency of all gait initiation-related events showed a significant shortening and the bursts of EMG activity had higher amplitude and shorter duration than in trials without SAS. The events related to gait-pattern were also advanced but otherwise unchanged. The fact that all the effects of SAS were limited to gait initiation suggests that startle selectively can affect the neural structures involved in gait initiation. Additionally, the proportional advancement of the gait-pattern sequence to the end of gait initiation supports the view that gait initiation may actually trigger the inputs necessary for generating the gait-pattern sequence. © 2009 Elsevier B.V. All rights reserved.
Casanova-Molla J.,Unitat dEmg |
Leon L.,Servei de Neurologia |
Castillo C.D.,Unitat dEmg |
Valls-Sole J.,Unitat dEmg
Muscle and Nerve | Year: 2011
Introduction: Reinnervation activity is triggered after complete unilateral peripheral facial palsy (PFP). Methods: In 27 patients with PFP we recorded electromyographic activity with a concentric needle electrode inserted 1 cm lateral to the oral commissure of the affected side. We applied electrical stimuli to the unaffected (contralateral) facial nerve from the tragus to the mid-lower lip and measured the response latency variability and segmental conduction velocity. Results: Responses to electrical stimulation of the unaffected facial nerve were found in all patients. Mean conduction velocity was 49.6 ± 6.2 m/s between tragus and oral commissure, and 6.0 ± 1.9 m/s between oral commissure and mid-lower lip. Latency variability was 0.27 ms to facial nerve stimulation and 0.08 ms to oral commissure stimulation. Conclusion: Short distance sprouting of axons that innervate muscle fibers, which originate from the unaffected facial nerve, results in propagation of impulses to muscle fibers in the midline. © 2011 Wiley Periodicals, Inc.