Perspectives of Implementation of Closed-Loop Deep Brain Stimulation: From Neurological to Psychiatric Disorders.

BACKGROUND: Deep brain stimulation (DBS) is a highly efficient, evidence-based therapy to alleviate symptoms and improve quality of life in movement disorders such as Parkinson's disease, essential tremor, and dystonia, which is also being applied in several psychiatric disorders, such as obsessive-compulsive disorder and depression, when they are otherwise resistant to therapy. SUMMARY: At present, DBS is clinically applied in the so-called open-loop approach, with fixed stimulation parameters, irrespective of the patients' clinical state(s). This approach ignores the brain states or feedback from the central nervous system or peripheral recordings, thus potentially limiting its efficacy and inducing side effects by stimulation of the targeted networks below or above the therapeutic level. KEY MESSAGES: The currently emerging closed-loop (CL) approaches are designed to adapt stimulation parameters to the electrophysiological surrogates of disease symptoms and states. CL-DBS paves the way for adaptive personalized DBS protocols. This review elaborates on the perspectives of the CL technology and discusses its opportunities as well as its potential pitfalls for both clinical and research use in neuropsychiatric disorders.

Multi-centre analysis of networks and genes modulated by hypothalamic stimulation in patients with aggressive behaviours.

Deep brain stimulation targeting the posterior hypothalamus (pHyp-DBS) is being investigated as a treatment for refractory aggressive behavior, but its mechanisms of action remain elusive. We conducted an integrated imaging analysis of a large multi-centre dataset, incorporating volume of activated tissue modeling, probabilistic mapping, normative connectomics, and atlas-derived transcriptomics. Ninety-one percent of the patients responded positively to treatment, with a more striking improvement recorded in the pediatric population. Probabilistic mapping revealed an optimized surgical target within the posterior-inferior-lateral region of the posterior hypothalamic area. Normative connectomic analyses identified fiber tracts and functionally connected with brain areas associated with sensorimotor function, emotional regulation, and monoamine production. Functional connectivity between the target, periaqueductal gray and key limbic areas - together with patient age - were highly predictive of treatment outcome. Transcriptomic analysis showed that genes involved in mechanisms of aggressive behavior, neuronal communication, plasticity and neuroinflammation might underlie this functional network.

DNA Methylation Description of Hippocampus, Cortex, Amygdala, and Blood of Drug-Resistant Temporal Lobe Epilepsy.

Epigenetic changes such as DNA methylation were observed in drug-resistant temporal lobe epilepsy (DR-TLE), a disease that affects 25-30% of epilepsy patients. The main objective is to simultaneously describe DNA methylation patterns associated with DR-TLE in hippocampus, amygdala, surrounding cortex to the epileptogenic zone (SCEZ), and peripheral blood. An Illumina Infinium MethylationEPIC BeadChip array was performed in 19 DR-TLE patients and 10 postmortem non-epileptic controls. Overall, 32, 59, and 3210 differentially methylated probes (DMPs) were associated with DR-TLE in the hippocampus, amygdala, and SCEZ, respectively. These DMP-affected genes were involved in neurotrophic and calcium signaling in the hippocampus and voltage-gated channels in SCEZ, among others. One of the hippocampus DMPs (cg26834418 (CHORDC1)) showed a strong blood-brain correlation with BECon and IMAGE-CpG, suggesting that it could be a potential surrogate peripheral biomarker of DR-TLE. Moreover, in three of the top SCEZ's DMPs (SHANK3, SBF1, and MCF2L), methylation status was verified with methylation-specific qPCR. The differentially methylated CpGs were classified in DMRs: 2 in the hippocampus, 12 in the amygdala, and 531 in the SCEZ. We identified genes that had not been associated to DR-TLE so far such as TBX5, EXOC7, and WRHN. The area with more DMPs associated with DR-TLE was the SCEZ, some of them related to voltage-gated channels. The DMPs found in the amygdala were involved in inflammatory processes. We also found a potential surrogate peripheral biomarker of DR-TLE. Thus, these results provide new insights into epigenetic modifications involved in DR-TLE.

Neuronal and astrocytic tetraploidy is increased in drug-resistant epilepsy.

AIMS: Epilepsy is one of the most prevalent neurological diseases. A third of patients with epilepsy remain drug-resistant. The exact aetiology of drug-resistant epilepsy (DRE) is still unknown. Neuronal tetraploidy has been associated with neuropathology. The aim of this study was to assess the presence of tetraploid neurons and astrocytes in DRE. METHODS: For that purpose, cortex, hippocampus and amygdala samples were obtained from patients subjected to surgical resection of the epileptogenic zone. Post-mortem brain tissue of subjects without previous records of neurological, neurodegenerative or psychiatric diseases was used as control. RESULTS: The percentage of tetraploid cells was measured by immunostaining of neurons (NeuN) or astrocytes (S100ß) followed by flow cytometry analysis. The results were confirmed by image cytometry (ImageStream X Amnis System Cytometer) and with an alternative astrocyte biomarker (NDRG2). Statistical comparison was performed using univariate tests. A total of 22 patients and 10 controls were included. Tetraploid neurons and astrocytes were found both in healthy individuals and DRE patients in the three brain areas analysed: cortex, hippocampus and amygdala. DRE patients presented a higher number of tetraploid neurons (p = 0.020) and astrocytes (p = 0.002) in the hippocampus than controls. These results were validated by image cytometry. CONCLUSIONS: We demonstrated the presence of both tetraploid neurons and astrocytes in healthy subjects as well as increased levels of both cell populations in DRE patients. Herein, we describe for the first time the presence of tetraploid astrocytes in healthy subjects. Furthermore, these results provide new insights into epilepsy, opening new avenues for future treatment.

Surgery of autism: Is it possible?

Autism spectrum disorder (ASD) is a developmental disability of the brain that can be associated to severe conductual alterations, such as self or heteroaggression and obsessive and compulsive behavior. Many of these patients do not improve with any pharmacological or behavioral therapy and represent a major social problem. We describe the outcome of patients with ASD, treated with radiofrequency brain lesions combined with Gamma Knife radiosurgery for therapy-resistant aggressiveness, obsessive thoughts, and compulsions. The ASD adapted YBOCS, PCQ and EAE scales assessed the therapeutic effect on symptoms. All patients had a significant reduction of their symptoms (YBOCS:34 and 22 PCQ 42 and 35, EAE 11 and 5.5, respectively), although all needed more than one treatment to maintain this improvement. The treatments resulted very safe for the patients and their neurological status has not change. We conclude that in these patients after surgery, there is a marked improvement in behavior, quality of life and relationship with the environment, with no evidence of secondary damage. Changes in connectivity might mediate the clinical improvement, although it is necessary to confirm these results with further studies.

Modern Gamma Knife radiosurgery for management of psychiatric disorders.

Psychiatric disorders result in great suffering of affected patients, who often have rather limited treatment options. In cases refractory to standard medical and behavioral therapy, interventional procedures may be the only feasible solution. The authors experience with Gamma Knife bilateral cingulotomy for treatment-resistant major depression disorder (5 cases) and anorexia nervosa (6 cases), and bilateral anterior capsulotomy for severe obsessive-compulsive disorder (10 cases) shows that such radiosurgical techniques may be applied both effectively and safely. During post-treatment follow-up, the vast majority of patients demonstrated gradual reduction of psychiatric symptoms and improvement of the quality of life, which was confirmed by results of regular neuropsychological testing and imaging examinations. No major side effect was observed in any case. More active application of radiosurgery (using standardized technique) for management of mental illnesses in various Gamma Knife centers worldwide should be encouraged.

Deep Brain Stimulation of the Nucleus Accumbens, Ventral Striatum, or Internal Capsule Targets for Medication-Resistant Obsessive-Compulsive Disorder: A Multicenter Study.

BACKGROUND: Deep brain stimulation of the nucleus accumbens, ventral striatum, or internal capsule region has shown a 45%-60% response rate in adults with severe treatment-refractory obsessive-compulsive disorder, regardless of which target is used. We sought to improve the effectiveness of deep brain stimulation by placing the electrode along a trajectory including these 3 targets, enabling a change of stimulation site depending on the patient's response. METHODS: This study used the medical records of 14 patients from 4 different Spanish institutions: 7 from the Hospital Universitario La Princesa, 3 from the Hospital Universitario Central de Asturias, 2 from Hospital Universitario Fundación Jiménez Díaz, and 2 from Hospital Universitari Son Espases. All patients were operated on under the same protocol. Qualitative and quantitative data were collected. RESULTS: Of 14 patients, 11 showed significant improvement in obsessive-compulsive disorder symptoms, as evident in a reduction ≥35% in Yale-Brown Obsessive Compulsive Scale scores following stimulation relative to preoperative scores. Seven patients responded to stimulation at the nucleus accumbens (the first area we set for stimulation), whereas 4 patients needed to have the active contact switched to the internal capsule to benefit from stimulation. CONCLUSIONS: Deep brain stimulation of the nucleus accumbens, internal capsule, and ventral striatum significantly benefited our cohort of patients with medication-resistant obsessive-compulsive disorder. Electrode insertion through the 3 main targets might confer additional therapeutic efficacy.

Cognitive deficits and clinical symptoms in patients with treatment-refractory obsessive-compulsive disorder: The role of slowness in information processing.

Patients with Obsessive-Compulsive Disorder (OCD) present neuropsychological deficits across different cognitive domains, especially in executive functioning and information processing speed. Some studies have even suggested that speed deficits may underlie poor neuropsychological performance. However, this hypothesis remains unanswered in both OCD general population and OCD refractory subgroup. In addition, it is not clear whether such deficits are secondary to the clinical symptoms or may constitute a primary deficit. The aim of this study was to explore the speed of processing hypothesis in treatment-refractory OCD patients, and to clarify to what extent slowness is related to psychopathological symptoms. Both clinical and neuropsychological examination was conducted to assess 39 OCD refractory patients candidates for neurosurgery and 39 healthy matched individuals. Principal component analysis revealed a three-component structure in the neuropsychological battery being used, including a speed of processing, working memory, and conflict monitoring components. Group comparisons revealed that OCD patients performed significantly worse than healthy individuals in speed measures, but no differences were found in executive tests not influenced by time. Correlation analyses revealed a lack of association between neuropsychological and clinical measures. The results suggest that treatment-refractory OCD patients exhibit a primary deficit in information processing speed independent of clinical symptoms.

Network Substrates of Centromedian Nucleus Deep Brain Stimulation in Generalized Pharmacoresistant Epilepsy.

Deep brain stimulation (DBS), specifically thalamic DBS, has achieved promising results to reduce seizure severity and frequency in pharmacoresistant epilepsies, thereby establishing it for clinical use. The mechanisms of action are, however, still unknown. We evidenced the brain networks directly modulated by centromedian (CM) nucleus-DBS and responsible for clinical outcomes in a cohort of patients uniquely diagnosed with generalized pharmacoresistant epilepsy. Preoperative imaging and long-term (2-11 years) clinical data from ten generalized pharmacoresistant epilepsy patients (mean age at surgery = 30.8 ± 5.9 years, 4 female) were evaluated. Volume of tissue activated (VTA) was included as seeds to reconstruct the targeted network to thalamic DBS from diffusion and functional imaging data. CM-DBS clinical outcome improvement (> 50%) appeared in 80% of patients and was tightly related to VTAs interconnected with a reticular system network encompassing sensorimotor and supplementary motor cortices, together with cerebellum/brainstem. Despite methodological differences, both structural and functional connectomes revealed the same targeted network. Our results demonstrate that CM-DBS outcome in generalized pharmacoresistant epilepsy is highly dependent on the individual connectivity profile, involving the cerebello-thalamo-cortical circuits. The proposed framework could be implemented in future studies to refine stereotactic implantation or the parameters for individualized neuromodulation.

Prediction of Memory Impairment in Epilepsy Surgery by White Matter Diffusion.

OBJECTIVE: To analyze the relationship between cognitive performance and white matter integrity in patients with temporal lobe epilepsy (TLE) to establish radiologic criteria to help with patient selection for surgery. METHODS: The study included 19 adults with temporal lobe epilepsy. A tractography analysis of fractional anisotropy and mean diffusivity (MD) of the following fascicles was performed: arcuate fascicle, cingulum, fornix, inferior fronto-occipital fascicle, inferior longitudinal fascicle, parahippocampal fibers of the cingulum, and uncinate fascicle. The Wechsler Memory Scale-Third Edition neuropsychological test was performed to evaluate short- and long-term verbal (Logical Memory I and II subtests) and nonverbal (Visual Reproduction I and II subtests) memory. Relationships between memory scores and diffusion were calculated. RESULTS: Lower Logical Memory I subtest scores were correlated with lower MD of the right inferior fronto-occipital fascicle, while lower Logical Memory II subtest scores were related to higher values of fractional anisotropy in bilateral cingulum, right uncinate, and right parahippocampal fibers of the cingulum and lower MD in left cingulum fascicle. Finally, lower values in Visual Reproduction I subtest scores were associated with lower values in MD in right cingulum and inferior fronto-occipital fascicles. CONCLUSIONS: Structural changes of some white matter tracts were associated with deterioration of both short- and long-term memory. These alterations were more associated with verbal memory than with nonverbal memory. These changes mainly consist of an increase in fractional anisotropy and a decrease in MD, which could be interpreted as reorganization phenomena. Diffusion tensor imaging could be a useful tool for cognitive assessment in surgical candidates with temporal lobe epilepsy who are not suitable for neuropsychological testing or in whom their results do not lead to definitive conclusions.

Radiofrequency Lesions through Deep Brain Stimulation Electrodes in Movement Disorders: Case Report and Review of the Literature.

BACKGROUND: Although there are few reports of radiofrequency lesions performed through deep brain stimulation (DBS) electrodes in patients with movement disorders, experience with this method is scarce. METHODS: We present 2 patients who had been previously treated with DBS of subthalamic nuclei (STN) and the ventral intermediate (VIM) nucleus of the thalamus for Parkinson's disease and essential tremor, respectively, and underwent a radiofrequency lesion through their DBS electrodes after developing a hardware infection. The authors conduct a review of the literature regarding this method. RESULTS: Both patients had a good clinical outcome after 20 and 8 months, respectively, as assessed by a reduction in Fahn-Tolosa-Marin Scale and Unified Parkinson's Disease Rating Scale scores. The second patient underwent a second DBS system implantation surgery after his radiofrequency treatment to optimize his management, achieving optimal clinical control with lower current and drug requirements than before the radiofrequency intervention. No adverse effects were observed. CONCLUSIONS: Radiofrequency lesions through DBS electrodes allow the creation of small and localized lesions. Its effectiveness and low-risk profile, in addition to its low cost, make this procedure suitable and a possible alternative in the therapeutic repertoire for the surgical treatment of movement disorders.

[Not Available]. / Tratamiento quirúrgico de la anorexia nerviosa resistente al tratamiento médico.

Gracias a los avances técnicos en técnicas neuroquirúrgicas, y debido a que el diagnóstico y la clasificación de las enfermedades psiquiátricas han evolucionado significativamente a lo largo de las últimas décadas, se están desarrollando tratamientos a nivel experimental para aquellos pacientes resistentes al manejo conservador.La anorexia nerviosa es una enfermedad de prevalencia creciente, con la tasa de mortalidad más elevada dentro de los trastornos psiquiátricos, y con aproximadamente un 20% de pacientes que presentan una evolución tórpida. Para estos pacientes que no responden a manejo conservador, la estimulación cerebral profunda ha surgido como una alternativa terapéutica, si bien la literatura especializada al respecto es escasa.A continuación presentamos una revisión de la fisiopatología de la anorexia nerviosa, así como de los distintos tratamientos neuroquirúrgicos realizados a lo largo de la historia. Se detalla la perspectiva de tratamiento quirúrgico actual, así como los aspectos éticos que se han de considerar en relación con el surgimiento de estas nuevas terapias.

Bilateral pallidal stimulation for x-linked dystonia parkinsonism.

OBJECTIVE: To report the clinical benefits of bilateral deep brain stimulation (DBS) of the globus pallidus internus (GPi) in a patient with X-linked dystonia parkinsonism (XDP). DESIGN: Case report. SETTING: Tertiary referral center. Patient A 40-year-old Filipino man with genetically confirmed XDP and severely disabling generalized dystonia. Intervention Bilateral GPi DBS. MAIN OUTCOME MEASURES: The primary outcome measures were the Burke-Fahn-Marsden Dystonia Scale (BFMDS) severity and disability scores, and the secondary outcome measure was the Unified Parkinson Disease Rating Scores. RESULTS: At the 1-year postoperative follow-up, there was 80.4% improvement in the BFMDS severity score and 66.7% improvement in the BFMDS disability score. CONCLUSION: Bilateral GPi DBS seems to be very effective in improving dystonia in XDP.