Joaquim P. Brasil-Neto

Injections of botulinum toxin type A produce pain alleviation in intractable trigeminal neuralgia

To report the effects of local injections of botulinum toxin type A regarding pain relief and long-term control in a patient with intractable trigeminal neuralgia. The patient was a 75-year-old man with trigeminal neuralgia in the left hemifacial region. His pain was unbearable and could not be controlled by carbamazepine, amitriptyline, or blocked by infiltration of a glycerol solution or phenol. The authors evaluated pain intensity, quality, and location using a Visual Analog Scale to establish the efficacy of botulinum toxin type A injections. Two units of botulinum toxin type A (Botox®) were subcutaneously injected once in eight points distributed along the territory of V1 and V2. Visual Analog Scores were measured at baseline and at 7, 30, 60, and 90 days after treatment. The authors also examined the patients general condition and daily life activities. The Visual Analog values were, respectively, 82, 54, 25, 25, and 45 mm at each follow-up examination. No side effects were observed on the site of injection and on the patients clinical state. The authors have been able to reduce trigeminal neuralgia pain with botulinum toxin type A injections in the V1, V2 territory during all the period of study, as well as to withdraw all medication. Interestingly, there was concomitant reduction of pain also in V3, which was not injected.

Neuromodulation approaches for the treatment of major depression: challenges and recommendations from a working group meeting

UNLABELLED The use of neuromodulation as a treatment for major depressive disorder (MDD) has recently attracted renewed interest due to development of other non-pharmacological therapies besides electroconvulsive therapy (ECT) such as transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), deep brain stimulation (DBS), and vagus nerve stimulation (VNS). METHOD We convened a working group of researchers to discuss the updates and key challenges of neuromodulation use for the treatment of MDD. RESULTS The state-of-art of neuromodulation techniques was reviewed and discussed in four sections: [1] epidemiology and pathophysiology of MDD; [2] a comprehensive overview of the neuromodulation techniques; [3] using neuromodulation techniques in MDD associated with non-psychiatric conditions; [4] the main challenges of neuromodulation research and alternatives to overcome them. DISCUSSION ECT is the first-line treatment for severe depression. TMS and tDCS are strategies with a relative benign profile of side effects; however, while TMS effects are comparable to antidepressant drugs for treating MDD; further research is needed to establish the role of tDCS. DBS and VNS are invasive strategies with a possible role in treatment-resistant depression. In summary, MDD is a chronic and incapacitating condition with a high prevalence; therefore clinicians should consider all the treatment options including invasive and non-invasive neuromodulation approaches.

Feeling Pain in the Rubber Hand: Integration of Visual, Proprioceptive, and Painful Stimuli:

The visual capture phenomenon has recently been explored, especially in the context of the rubber-hand illusion (RHI)—an illusion in which tactile sensations are referred to an illusory limb. We have induced the RHI with the difference that tactile-painful stimuli were added in order to verify the interaction between vision, touch, proprioception, and pain. Thirty volunteers were used. We found that tactile-painful stimuli could cause the same illusion as purely tactile stimuli. This result suggests that localisation of pain may also be distorted by spurious visual cues. The implications of this finding for distorted human proprioception (as in amputees with phantom pain or limbs) are discussed.

A Randomized, Double-Blind Trial of Repetitive Transcranial Magnetic Stimulation in Obsessive-Compulsive Disorder With Three-Month Follow-Up

Recent findings indicate that the motor and premotor cortices are hyperexcitable in obsessive-compulsive disorder (OCD). The authors have performed the first randomized, double-blind clinical trial of repetitive transcranial magnetic stimulation (rTMS) in OCD, with a 3-month follow-up. OCD patients (N=22) were assigned to either 2 weeks of active or sham rTMS to the supplementary motor area bilaterally. After 14 weeks, the response rate was 41% (7/12) with active and 10% (1/10) with sham treatment. At 14 weeks, patients receiving active rTMS showed, on average, a 35% reduction on the Y-BOCS, as compared with a 6.2% reduction in those receiving sham treatment.

Learning, Memory, and Transcranial Direct Current Stimulation

Transcranial direct current stimulation (tDCS) has been the subject of many studies concerning its possible cognitive effects. One of the proposed mechanisms of action for neuromodulatory techniques, such as transcranial magnetic stimulation and tDCS is induction of long-term potentiation (LTP) and long-term depression (LTD)-like phenomena. LTP and LTD are also among the most important neurobiological processes involved in memory and learning. This fact has led to an immediate interest in the study of possible effects of tDCS on memory consolidation, retrieval, or learning of various tasks. This review analyses published articles describing beneficial or disruptive effects of tDCS on memory and learning in normal subjects. The most likely mechanisms underlying these effects are discussed.

Experimental therapy of epilepsy with transcranial magnetic stimulation: lack of additional benefit with prolonged treatment

OBJECTIVE To investigate the effect of three months of low-frequency repetitive transcranial magnetic stimulation (rTMS) treatment in intractable epilepsy. METHODS Five patients (four males, one female; ages 6 to 50 years), were enrolled in the study; their epilepsy could not be controlled by medical treatment and surgery was not indicated. rTMS was performed twice a week for three months; patients kept records of seizure frequency for an equal period of time before, during, and after rTMS sessions. rTMS was delivered to the vertex with a round coil, at an intensity 5% below motor threshold. During rTMS sessions, 100 stimuli (five series of 20 stimuli, with one-minute intervals between series) were delivered at a frequency of 0.3 Hz. RESULTS Mean daily number of seizures (MDNS) decreased in three patients and increased in two during rTMS--one of these was treated for only one month; the best result was achieved in a patient with focal cortical dysplasia (reduction of 43.09% in MDNS). In the whole patient group, there was a significant (p<0.01) decrease in MDNS of 22.8%. CONCLUSION Although prolonged rTMS treatment is safe and moderately decreases MDNS in a group of patients with intractable epilepsy, individual patient responses were mostly subtle and clinical relevance of this method is probably low. Our data suggest, however, that patients with focal cortical lesions may indeed benefit from this novel treatment. Further studies should concentrate on that patient subgroup.

O uso da estimulação magnética transcraniana de baixa frequência no tratamento da depressão no Hospital Universitário de Brasília: achados preliminares

This paper reports the use of slow frequency transcranial magnetic stimulation of the right pre-frontal cortex in three patients with a diagnosis of major depressive episode according to the DSM-IV classification. There was a significant improvement in two patients, with a decrease of over 50% in the Hamilton Scale scores- 17 items. Possible indications and limitations of this therapeutic tool are discussed, as well as socio-economic aspects of this new treatment.

Lack of effect of botulinum toxin on cortical excitability in patients with cranial dystonia.

The aim of this study was to verify whether botulinum toxin (BTX)-induced clinical improvement of cranial dystonia is associated with changes in the cortical silent period (SP), a measure of cortical excitability. By transcranial magnetic stimulation (TMS), high-intensity stimuli were delivered with a round coil centered at the vertex during a maximal muscle contraction of the orbicularis oculi. Motor evoked potentials (MEPs) and SPs were obtained from surface electrodes placed over the orbicularis oculi muscle before and 2 to 3 weeks after BTX-A injection into the affected muscles in 10 patients with cranial dystonia and 8 age-matched control subjects. BTX injection improved blepharospasm in all patients. Facial muscle SPs were significantly shorter in patients than in control subjects and did not significantly change after treatment, at the time of maximal clinical improvement. We conclude that the clinical improvement induced by BTX in patients with cranial dystonia is largely symptomatic. It does not appear to result from modulation of abnormal aspects of intracortical excitability, although these may play a role in craniofacial dystonia.

Postexercise facilitation of motor evoked potentials elicited by ipsilateral voluntary contraction

Motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) increase in amplitude when obtained immediately after a period of exercise of the target muscle (postexercise facilitation). We studied postexercise facilitation of MEPs to TMS after periods of voluntary activation of either the ipsilateral or contralateral primary motor cortex (simple finger movements) or supplementary motor area (complex finger movements). Postexercise facilitation of the first dorsal interosseous MEPs occurred ipsilaterally even after simple, unilateral finger movements of the dominant hand. The findings are taken to suggest transcallosal transfer of excitability from the dominant to nondominant cerebral hemisphere, perhaps related to mechanisms involved in bimanual motor coordination.

[Transcranial Magnetic Stimulation in depression: results of bi-weekly treatment].

OBJECTIVE Transcranial Magnetic Stimulation (TMS) has been shown to be a useful therapy for depression. This paper evaluates the results of bi-weekly low-frequency TMS of 4 weeks duration, in 10 patients with depression who do not respond or are intolerant to antidepressive medication. METHODS This is a case series study. DMS-IV criteria were used to diagnose depression. In order to disclose possible improvements in depressive symptoms, the 17 items Hamilton scale was used at three different moments: at the beginning, middle and end of the treatment period. Results were analysed using Friedmans chi2 test. RESULTS Hamiltons scale score improvement was > 50% in five patients and > 75% in 3 of these. CONCLUSIONS TMS may be efficacious, safe and easily performed as an adjunct to medical treatment of depression. We cannot differentiate a potentiation of the effect of antidepressive medication from an intrinsic effect of TMS alone, since we did not treat any subjects without the concurrent use of medication.