Josep Maria Tormos

Low-frequency repetitive transcranial magnetic stimulation of the motor cortex in writer’s cramp

Objective: To study the short-term effects of slow repetitive transcranial magnetic stimulation (rTMS) of the motor cortex on cortical excitability and handwriting in patients with writer’s cramp. Background: Cortical excitability of the primary motor cortex is abnormally enhanced in patients with writer’s cramp. Therefore, reducing cortical excitability by low-frequency rTMS of the motor cortex might result in beneficial effects on handwriting in writer’s cramp. Design/Methods: We studied the effects of subthreshold 1-Hz rTMS on motor threshold and cortico-cortical excitability using the paired-pulse technique in seven patients and seven controls. In another 16 patients and 11 age-matched controls we evaluated changes in cortical excitability by measuring the stimulus-response curve and the postexcitatory silent period before and after subthreshold 1-Hz rTMS. In addition, we analyzed the handwriting before and 20 minutes after 1-Hz rTMS. Results: In the first experiment, low-frequency rTMS resulted in a normalization of the deficient cortico-cortical inhibition in the patients without affecting motor threshold. In the second experiment, 1-Hz rTMS resulted in a significant prolongation of the postexcitatory silent period without affecting the stimulus-response curve in the patient group. Moreover, the dystonic patients showed a significant reduction of mean writing pressure after subthreshold 1-Hz rTMS that was associated with clear but transient improvement in six patients. Conclusions: In some patients 1-Hz rTMS can reinforce deficient intracortical inhibition and may improve handwriting temporarily. Our data support the notion that reduced intracortical inhibition plays a part in the pathophysiology of focal dystonia.

Reorganization of human cortical motor output maps following traumatic forearm amputation

We report the results of serial transcranial magnetic stimulation mapping of cortical motor outputs to the face and upper extremity in a subject studied before and repeatedly after traumatic amputation of the right arm immediately below the elbow. The results of the mapping studies illustrate the time course of plastic changes in the motor cortical representation in humans following a traumatic amputation and allow the correlation of subjective perceptions of phantom limbs with the reorganization of cortical outputs.

Effectiveness of transcranial direct current stimulation and visual illusion on neuropathic pain in spinal cord injury

The aim of this study was to evaluate the analgesic effect of transcranial direct current stimulation of the motor cortex and techniques of visual illusion, applied isolated or combined, in patients with neuropathic pain following spinal cord injury. In a sham controlled, double-blind, parallel group design, 39 patients were randomized into four groups receiving transcranial direct current stimulation with walking visual illusion or with control illusion and sham stimulation with visual illusion or with control illusion. For transcranial direct current stimulation, the anode was placed over the primary motor cortex. Each patient received ten treatment sessions during two consecutive weeks. Clinical assessment was performed before, after the last day of treatment, after 2 and 4 weeks follow-up and after 12 weeks. Clinical assessment included overall pain intensity perception, Neuropathic Pain Symptom Inventory and Brief Pain Inventory. The combination of transcranial direct current stimulation and visual illusion reduced the intensity of neuropathic pain significantly more than any of the single interventions. Patients receiving transcranial direct current stimulation and visual illusion experienced a significant improvement in all pain subtypes, while patients in the transcranial direct current stimulation group showed improvement in continuous and paroxysmal pain, and those in the visual illusion group improved only in continuous pain and dysaesthesias. At 12 weeks after treatment, the combined treatment group still presented significant improvement on the overall pain intensity perception, whereas no improvements were reported in the other three groups. Our results demonstrate that transcranial direct current stimulation and visual illusion can be effective in the management of neuropathic pain following spinal cord injury, with minimal side effects and with good tolerability.

Prefrontal repetitive transcranial magnetic stimulation as add on treatment in depression

A growing number of studies report antidepressant effects of repetitive transcranial magnetic stimulation (rTMS) in patients with major depression. The hypothesis that high frequency (20 Hz) rTMS (HF-rTMS) may speed up and strengthen the therapeutic response to sertraline in MD was tested. Twenty eight patients who had not yet received medication for the present depressive episode (n=12) or had failed a single trial of an antidepressant medication (n=16) were started on sertraline and randomised to receive either real of sham HF-rTMS. HF-rTMS was applied to the left dorsolateral prefrontal area in daily sessions (30 trains of 2 s, 20–40 s intertrain interval, at 90% motor threshold) on 10 consecutive working days. The results suggest that in this patient population, HF-rTMS does not add efficacy over the use of standard antidepressant medication.

Reduction of Spasticity With Repetitive Transcranial Magnetic Stimulation in Patients With Spinal Cord Injury

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.

Upper limb portable motion analysis system based on inertial technology for neurorehabilitation purposes.

Here an inertial sensor-based monitoring system for measuring and analyzing upper limb movements is presented. The final goal is the integration of this motion-tracking device within a portable rehabilitation system for brain injury patients. A set of four inertial sensors mounted on a special garment worn by the patient provides the quaternions representing the patient upper limb’s orientation in space. A kinematic model is built to estimate 3D upper limb motion for accurate therapeutic evaluation. The human upper limb is represented as a kinematic chain of rigid bodies with three joints and six degrees of freedom. Validation of the system has been performed by co-registration of movements with a commercial optoelectronic tracking system. Successful results are shown that exhibit a high correlation among signals provided by both devices and obtained at the Institut Guttmann Neurorehabilitation Hospital.

The effects of transcranial direct current stimulation with visual illusion in neuropathic pain due to spinal cord injury: An evoked potentials and quantitative thermal testing study

Neuropathic pain (NP) is common in spinal cord injury (SCI) patients. One of its manifestations is a lowering of pain perception threshold in quantitative thermal testing (QTT) in dermatomes rostral to the injury level. Transcranial direct current stimulation (tDCS) combined with visual illusion (VI) improves pain in SCI patients. We studied whether pain relief with tDCS + VI intervention is accompanied by a change in contact heat‐ evoked potentials (CHEPs) or in QTT.

Motor and gait improvement in patients with incomplete spinal cord injury induced by high-frequency repetitive transcranial magnetic stimulation.

OBJECTIVE To assess the effect of high-frequency repetitive transcranial magnetic stimulation (rTMS) on lower extremities motor score (LEMS) and gait in patients with motor incomplete spinal cord injury (SCI). METHOD The prospective longitudinal randomized, double-blind study assessed 17 SCI patients ASIA D. We assessed LEMS, modified Ashworth Scale (MAS), 10-m walking test (10MWT), Walking Index for SCI (WISCI II) scale, step length, cadence, and Timed Up and Go (TUG) test at baseline, after the last of 15 daily sessions of rTMS and 2 weeks later. Patients were randomized to active rTMS or sham stimulation. Three patients from the initial group of 10 randomized to sham stimulation entered the active rTMS group after a 3-week washout period. Therefore a total of 10 patients completed each study condition. Both groups were homogeneous for age, gender, time since injury, etiology, and ASIA scale. Active rTMS consisted of 15 days of daily sessions of 20 trains of 40 pulses at 20 Hz and an intensity of 90% of resting motor threshold. rTMS was applied with a double cone coil to the leg motor area. RESULTS There was a significant improvement in LEMS in the active group (28.4 at baseline and 33.2 after stimulation; P = .004) but not in the sham group (29.6 at baseline, and 30.9 after stimulation; P = .6). The active group also showed significant improvements in the MAS, 10MWT, cadence, step length, and TUG, and these improvements were maintained 2 weeks later. Following sham stimulation, significant improvement was found only for step length and TUG. No significant changes were observed in the WISCI II scale in either group. CONCLUSION High-frequency rTMS over the leg motor area can improve LEMS, spasticity, and gait in patients with motor incomplete SCI.

RETRACTED: Effects of High-Frequency Repetitive Transcranial Magnetic Stimulation on Motor and Gait Improvement in Incomplete Spinal Cord Injury Patients:

Kumru H, Benito J, Murillo N, et al. Effects of high-frequency repetitive transcranial magnetic stimulation on motor and gait improvement in incomplete spinal cord injury patients. Neurorehabil & Neural Repair. 2013;27:421-429. Original DOI: 10.1177/1545968312471901. The above article has been retracted because of substantial overlap with a previously published article in another journal.

Evoked potentials and quantitative thermal testing in spinal cord injury patients with chronic neuropathic pain

OBJECTIVE Neuropathic pain (NP) is a common symptom following spinal cord injury (SCI). NP may be associated with altered processing of somatosensory pathways in dermatomes rostral to the injury level. To explore this possibility, the characteristics of contact heat evoked potentials (CHEPs) and quantitative thermal testing (QTT) were studied at and above the lesion level in SCI patients with NP. The goal was to determine processing abnormalities correlated with data from clinical evaluations. METHODS Thirty-two subjects with chronic NP, 22 subjects without NP and 16 healthy control subjects were studied. Warm and heat pain thresholds were determined both at and above SCI level. CHEPs were recorded above SCI level and subjects rated their perception of evoked heat pain using a numerical rating scale. RESULTS CHEPs were not different between the three groups. Evoked pain perception in SCI subjects with NP was significantly higher than in SCI subjects without NP and healthy controls. Heat pain threshold was significantly lower in subjects with NP in comparison to both groups. CONCLUSIONS Our findings indicate that processing of somatosensory inputs from dermatomes rostral to the injury level is abnormal in SCI subjects with NP. SIGNIFICANCE SCI somatosensory processing alteration may contribute to the understanding of the mechanisms underlying NP and secondary changes to NP in SCI.