Search

Obsessive-compulsive disorder is a chronic and severe psychiatric disorder with a high prevalence (2-3%) worldwide, of which 30% will be refractory to conventional treatment. Surgical treatment with deep brain stimulation, approved by the U.S. Food and Drug Administration in 2009, seems to be effective in symptomatic control, with response rates exceeding 50% in severely affected patients. However, despite the efficacy indicated in the different studies, surgical treatments for psychiatric disorders are still controversial, and deep brain stimulation for obsessivecompulsive disorder is not yet considered a standard therapy. Since 2009, a wide variety of targets have been suggested for the treatment of obsessive-compulsive disorder; however, to date, there is still no consensus on which target might be optimal for the treatment of obsessivecompulsive disorder. On one hand, authors are trying to find the best target based on each patient and the variability of their symptoms, in an attempt to personalize the treatment. In parallel, there has been a shift in the paradigm of functional neurosurgery from the belief in stimulation focusing on a single target to the modulation of brain circuits or connectomes. With this in mind, it may be possible that many of the targets used in obsessive-compulsive disorder could modulate the same brain network and thus produce an improvement in patients' symptomatology. This study aims to review the evolution of this treatment up to the present time; as well as to make a comparison between these two lines of thought, thus exposing the current state of deep brain stimulation for obsessive-compulsive disorder. [ABSTRACT FROM AUTHOR]

Deep brain stimulation (DBS) requires precise localization, which is especially difficult at the thalamus, and even more difficult in anesthetized patients. We aimed to characterize the neurophysiological properties of the ventral intermediate (V.im), ventral caudal (V.c), and centromedian parvo (Ce.pc) and the magnocellular (Ce.mc) thalamic nuclei. We obtained microelectrode recordings from five patients with refractory epilepsy under general anesthesia. Somatosensory evoked potentials recorded by microelectrodes were used to identify the V.c nucleus. Trajectories were reconstructed off-line to identify the nucleus recorded, and the amplitude of the action potential (AP) and the tonic (i.e., mean frequency, density, probability of interspike interval) and phasic (i.e., burst index, pause index, and pause ratio) properties of the pattern discharges were analyzed. The Mahalanobis metric was used to evaluate the similarity of the patterns. The mean AP amplitude was higher for the V.im nucleus (172.7 ± 7.6 µV) than for the other nuclei, and the mean frequency was lower for the Ce.pc nucleus (7.2 ± 0.8 Hz) and higher for the V.c nucleus (11.9 ± 0.8 Hz) than for the other nuclei. The phasic properties showed a bursting pattern for the V.c nucleus and a tonic pattern for the centromedian and V.im nuclei. The Mahalanobis distance was the shortest for the V.im/V.c and Ce.mp/Ce.pc pairs. Therefore, the different properties of the thalamic nuclei, even for patients under general anesthesia, can be used to positively define the recorded structure, improving the exactness of electrode placement in DBS. [ABSTRACT FROM AUTHOR]

Objective: Language lateralization is a major concern in some patients with pharmacoresistant epilepsy who will face surgery; in these patients, hemispheric dominance testing is essential to avoid further complications. The Wada test is considered the gold standard examination for language localization, but is invasive and requires many human and material resources. Functional MRI and tractography with diffusion tensor imaging (DTI) have demonstrated that they could be useful for locating language in epilepsy surgery, but there is no evidence of the correlation between the Wada test and DTI MRI in language dominance., Methods: The authors performed a retrospective review of patients who underwent a Wada test before epilepsy surgery at their institution from 2012 to 2017. The authors retrospectively analyzed fractional anisotropy (FA), number and length of fibers, and volume of the arcuate fasciculus and uncinate fasciculus, comparing dominant and nondominant hemispheres., Results: Ten patients with temporal lobe epilepsy were reviewed. Statistical analysis showed that the mean FA of the arcuate fasciculus in the dominant hemisphere was higher than in the nondominant hemisphere (0.369 vs 0.329, p = 0.049). Also, the number of fibers in the arcuate fasciculus was greater in the dominant hemisphere (881.5 vs 305.4, p = 0.003). However, no differences were found in the FA of the uncinate fasciculus or number of fibers between hemispheres. The length of fibers of the uncinate fasciculus was longer in the dominant side (74.4 vs 50.1 mm, p = 0.05). Volume in both bundles was more prominent in the dominant hemisphere (12.12 vs 6.48 cm3, p = 0.004, in the arcuate fasciculus, and 8.41 vs 4.16 cm3, p = 0.018, in the uncinate fasciculus). Finally, these parameters were compared in patients in whom the seizure focus was situated in the dominant hemisphere: FA (0.37 vs 0.30, p = 0.05), number of fibers (114.4 vs 315.6, p = 0.014), and volume (12.58 vs 5.88 cm3, p = 0.035) in the arcuate fasciculus were found to be statistically significantly higher in the dominant hemispheres. Linear discriminant analysis of FA, number of fibers, and volume of the arcuate fasciculus showed a correct discrimination in 80% of patients (p = 0.024)., Conclusions: The analysis of the arcuate fasciculus and other tract bundles by DTI could be a useful tool for language location testing in the preoperative study of patients with refractory epilepsy.

Objective: Initial studies applying deep brain stimulation (DBS) of the posteromedial hypothalamus (PMH) to patients with pathological aggressiveness have yielded encouraging results. However, the anatomical structures involved in its therapeutic effect have not been precisely identified. The authors' objective was to describe the long-term outcome in their 7-patient series, and the tractography analysis of the volumes of tissue activated in 2 of the responders., Methods: This was a retrospective study of 7 subjects with pathological aggressiveness. The findings on MRI with diffusion tensor imaging (DTI) in 2 of the responders were analyzed. The authors generated volumes of tissue activated according to the parameters used, and selected those volumes as regions of interest to delineate the tracts affected by stimulation., Results: The series consisted of 5 men and 2 women. Of the 7 patients, 5 significantly improved with stimulation. The PMH, ventral tegmental area, dorsal longitudinal fasciculus, and medial forebrain bundle seem to be involved in the stimulation field., Conclusions: In this series, 5 of 7 medication-resistant patients with severe aggressiveness who were treated with bilateral PMH DBS showed a significant long-lasting improvement. The PMH, ventral tegmental area, dorsal longitudinal fasciculus, and medial forebrain bundle seem to be in the stimulation field and might be responsible for the therapeutic effect of DBS.

Introduction: Intracranial angioleiomyomas are extremely rare lesions. Only 22 intracranial angioleiomyomas have been described in the literature and only three were infratentorial., Case Report: We report a case of an infratentorial angioleiomyoma in a 43 year-old-man, who underwent a brain computer tomography because of hearing loss. The MRI showed a 1.4 cm tumor, initially described as a meningioma, with progressive enhancement after gadolinium injection, an augmented apparent diffusion coefficient and a generalized metabolite decreased in the spectroscopy. The lesion was surgically removed through a suboccipital approach with a good evolution and without postoperative complications. In the immunohistological study, the lesion was mainly composed of multiple vessels and the immunohistochemistry was positive for actin and caldesmon. Two years after surgery, no recurrence has been found in the MRI., Conclusion: Angioleiomyomas diagnostic may be complex, but some radiological features could help in the differential diagnostic. Angioleiomyomas are benign tumors associated with favorable outcomes after total resection, that in our case, did not show a significant bleeding risk.

Introduction: Ring chromosome 20 syndrome is a rare genetic disorder, with a late diagnosis., Case Report: A 43-year-old woman who had had refractory epilepsy since the age of six years, for which she was treated with deep brain stimulation of the centromedian nucleus, and also a ring chromosome 20., Conclusions: From the findings of the study it can be concluded that deep brain stimulation of the centromedian nucleus is ineffective in patients with ring chromosome, but note must be taken of the importance of genetic characterisation for the management of refractory epilepsy.

Introduction: Occipital nerve stimulation (ONS) is an emerging and promising preventive treatment for refractory chronic migraine., Aim: To evaluate the mechanisms of actions, clinical studies, implantation techniques and inclusion criteria of the ONS as a preventive treatment for migraine., Development: This work includes a non-systematic review of the literature on the above-mentioned aspects of ONS as a treatment for refractory chronic migraine. This disease affects approximately 2% of the population and results in a significant impairment in quality of life, economic burden and interference with labor and social activities. ONS is an emerging and promising therapy for the treatment of chronic migraine with greater than 50% pain reduction in most of open-label studies and published clinical trials. Although the mechanisms of action remain unknown, there seem to be a neuromodulation of the transmitted nociceptive trigeminal information in the trigeminal caudal nucleus, what could be explained by means of the Melzack and Wall pain gate theory. ONS is a safe and well tolerated treatment, and its most frequent side effects are usually local such as electrodes displacement or infections of the surgical incision. These complications do not usually require the electrodes withdrawal., Conclusions: ONS is an effective, well tolerated and safe treatment for the prevention of chronic migraine and could emerge as a useful option for those patients with medically refractory chronic migraine.

Introduction: Intraoperative monitoring of functional language and motor areas is a commonly used technique which makes it possible to minimise the post-operative sequelae and to perform an optimal resection of lesions in these areas. Monitoring of the visual cortex, however, is not usually carried out nowadays. The scarce spatial resolution and its sensitivity to anaesthesia are some of the technical difficulties that reduce its clinical usefulness. The study reports a case of resection of an occipital lesion under general anaesthetic, with intraoperative monitoring of the cortical visual evoked potentials (VEP) by means of subdural electrodes., Case Report: A 50-year-old female who underwent surgery involving the resection of an occipital lesion that was suggestive of radionecrosis. The VEP were monitored by administering flashing light at 4.1 Hz and recording with subdural strip electrodes on the occipital cortex. During the operation, a progressive lowering of the amplitude of the cortical VEP was observed when 50% of the baseline amplitude was exceeded, and thus the resection was finished. The increase in latency was below 10% of the baseline value. The patient recovered well during the post-operative period and her sight did not present any changes with respect to the baseline values., Conclusions: In our case, monitoring the cortical VEP by cortical recordings produced stable recordings with a good correlation with the post-operative visual function. Cortical recordings performed either directly or by means of subdural electrodes make it possible to achieve adequate spatial resolution and response intensity. Further studies need to be conducted with a greater number of patients in order to obtain decisive conclusions.

Neuromodulation for treating pain goes back to the times of the ancient Egyptians, who applied natural electric currents to modulate the painful sensation. Since then, this concept has been developed in parallel with the scientific and technological development, and various forms of neuromodulation with different indications and characteristics have originated. Chronic pain may produce significant disability, which leads to important physical, social and psychological consequences. Peripheral nerve, spinal cord, deep brain and motor cortex stimulation are safe and effective techniques that control pain and improve quality of life in selected patients.

Epilepsy is a neurological disorder that affects 1-2% of the population. Despite the available treatments (drug therapy, resective surgery, vagus nerve stimulation), there is a significant subgroup of patients that continues to have disabling seizures. The indications of deep brain stimulation are exponentially growing, and there is a wide experience with deep brain stimulation (DBS) for the treatment of abnormal movements. DBS for epilepsy may be a new therapy for the subgroup of patients that remain disabled despite other treatments. Experiments with animal models, and the new advances in our knowledge about the neurophysiological processes that govern the genesis of epilepsy, have led to the selection of various brain targets for stimulation. The thalamus is a fundamental relay centre in the corticothalamic and corticostriatal thalamocortical circuits, and it has been studied with this purpose. Studies on epileptic patients have shown various degrees of effectiveness; however, controlled studies do not permit definitive conclusions about the role of DBS in the treatment of epilepsy. Probably a better patient selection would lead to more decisive conclusions. Further randomised studies are needed to draw reliable conclusions and scientific evidence on the effectiveness of DBS for refractory epilepsy.