Anterior Limb Of The Internal Capsule Research Articles

Image Findings as Predictors of Fall Risk in Patients with Cerebrovascular Disease.

This study examined computed tomography findings in patients with cerebrovascular disease and determined predictors for falls. Images of the head were divided into 13 regions, and the relationships between computed tomography findings and the presence or absence of falls were investigated. A total of 138 patients with cerebrovascular disease (66% men, aged 73.8 ± 9.6 years) were included. A comparison between the fall and non-fall groups revealed a significant difference in the total functional independence measure scores and imaging findings at admission. Logistic regression analysis showed that the thalamus (p < 0.001), periventricular lucency (p < 0.001), lateral hemisphere room enlargement (p < 0.05), and age (p < 0.05) were related to the presence or absence of falls. For the 42 patients with cerebral hemorrhage, the thalamus (p < 0.01), periventricular lucency (p < 0.05), lateral ventricle vicinity (p < 0.05), and posterior limb of the internal capsule (p < 0.05) were extracted as factors related to the presence or absence of falls. For the 96 patients with cerebral infarction, the thalamus (p < 0.001), periventricular lucency (p < 0.01), and anterior limb of the internal capsule (p < 0.05) were extracted as factors related to the presence or absence of falls. This study found a relationship between the thalamus, lateral ventricle enlargement, periventricular lucency, and falls. Fall prognosis can potentially be predicted from computed tomography findings at admission.

Bilateral basal ganglia hemorrhage in a 2-year-old child

Background: Basal ganglia hemorrhage (BGH) is an intracerebral subtype of hemorrhage located in the caudate nucleus, putamen, globus pallidus, or adjacent structures such as the thalamus or internal capsule. Bilateral involvement of both basal ganglia is exceedingly infrequent. Herein, we report a case of a 2-year-old female who was discovered to have spontaneous bilateral BGH with a unique hemorrhagic extension. Case Description: A 2-year-old female child who presented with a decreased level of consciousness, seizure, and fever was discovered to have bilateral BGH during imaging evaluation that extended from the head of the caudate to involve the putamen, globus pallidus, and anterior limb of the internal capsule. Conclusion: Bilateral BGH is extremely rare, and to the best of our knowledge, this is the first case report in pediatric age groups.

Use of Connectomes in Deep Brain Stimulation for the Treatment of Obsessive-Compulsive Disorder

AbstractObsessive-compulsive disorder (OCD) is a psychiatric disorder characterized by the performance of repetitive behaviors in response to an obsession, which currently ranks as the tenth cause of disability in the world. Patients who are refractory to conventional treatment are candidates for the neurosurgical treatment of deep brain stimulation (DBS). In this procedure, electrodes are implanted in specific anatomical brain targets. The present systematic literature review aimed to describe the main connectomes and associate them with their respective targets involved in DBS for the treatment of OCD, to understand the connectomes related to OCD and their contributions to DBS, and to describe the main targets used in DBS surgery for OCD. Based on the present results, the stimulated targets that showed better clinical outcomes were the anterior limb of the internal capsule, the nucleus accumbens, the subthalamic nucleus, and the ventral capsule/striatal capsule. The target associated with the worst clinical results was the posterior limb of the anterior commissure. The variable stimulation of certain regions of the brain determines different clinical results. However, an individualized investigation of the OCD patient is essential for choosing the best target for DBS.

Anterior Capsulotomy for Refractory Obsessive-Compulsive Disorder: A Tractography and Lesion Geometry study

Introduction: A bilateral anterior capsulotomy effectively treats refractory obsessive-compulsive disorder (OCD). We investigated the geometry of lesions and disruption of white matter pathways within the anterior limb of the internal capsule (ALIC) in patients with different outcomes. Methods: In this retrospective study, we analyzed data from 18 patients with refractory OCD who underwent capsulotomies. Patients were grouped into “responders” and “nonresponders” based on the percentage of decrease in the Yale-Brown Obsessive-Compulsive Scale (YBOCS) after surgery. We investigated neurobehavioral adverse effects and analyzed the overlap between lesions and the ventromedial prefrontal (vmPFC) and dorsolateral prefrontal (dlPFC) pathways. Probabilistic maps were constructed to investigate the relationship between lesion location and clinical outcomes. Results: Of the 18 patients who underwent capsulotomies, 12 were responders (>35% improvement in YBOCS), and six were nonresponders. The vmPFC pathway was more involved than the dlPFC pathway in responders (p = 0.01), but no significant difference was observed in nonresponders (p = 0.10). The probabilistic voxel-wise efficacy map showed a relationship between ventral voxels within the ALIC with symptom improvement. Weight gains occurred in 11/18 (61%) patients and could be associated with medial voxels within the ALIC. Conclusion: The optimal outcome after capsulotomy in refractory OCD is linked to vmPFC disruption in the ALIC. Medial voxels within the ALIC could be associated with weight gains following capsulotomy.

Use of differential stimulation of the nucleus accumbens and anterior limb of the internal capsule to improve outcomes of obsessive-compulsive disorder.

Personalized stimulation is key to optimizing the outcomes of deep brain stimulation (DBS) for refractory obsessive-compulsive disorder (OCD). However, the contacts in a single conventional electrode cannot be programmed independently, which may affect the therapeutic efficacy of DBS for OCD. Therefore, a novel designed electrode and implantable pulse generator (IPG) that could achieve differential stimulation parameters for different contacts was implanted into the nucleus accumbens (NAc) and anterior limb of the internal capsule (ALIC) of a cohort of patients with OCD. Thirteen consecutive patients underwent bilateral DBS of the NAc-ALIC between January 2016 and May 2021. Differential stimulation of the NAc-ALIC was applied at initial activation. Primary effectiveness was assessed on the basis of change in scores on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) from baseline to 6-month follow-up. Full-response was defined as a 35% decrease in Y-BOCS score. Secondary effectiveness measures were the Hamilton Anxiety Rating Scale (HAMA) and Hamilton Depression Rating Scale (HAMD). The local field potential of bilateral NAc-ALIC was recorded in 4 patients who were reimplanted with a sensing IPG after battery depletion of the previous IPG. The Y-BOCS, HAMA, and HAMD scores decreased remarkably during the first 6 months of DBS. Ten of 13 patients were categorized as responders (76.9%). Differential stimulation of the NAc-ALIC was favorable to optimization of the stimulation parameters by increasing the parameter configurations. Power spectral density analysis revealed pronounced delta-alpha frequency activity in the NAc-ALIC. Phase-amplitude coupling of the NAc-ALIC showed that strong coupling is present between the phase of delta-theta and broadband gamma amplitude. These preliminary findings indicate that differential stimulation of the NAc-ALIC can improve the efficacy of DBS for OCD. Clinical trial registration no.: NCT02398318 (ClinicalTrials.gov).

Intraoperative valence testing to adjudicate between ventral capsule/ventral striatum and bed nucleus of the stria terminalis target selection in deep brain stimulation for obsessive-compulsive disorder.

Deep brain stimulation (DBS) is an accepted therapy for severe, treatment-refractory obsessive-compulsive disorder (trOCD). The optimal DBS target location within the anterior limb of the internal capsule, particularly along the anterior-posterior axis, remains elusive. Empirical evidence from several studies in the past decade has suggested that the ideal target lies in the vicinity of the anterior commissure (AC), either just anterior to the AC, above the ventral striatum (VS), or just posterior to the AC, above the bed nucleus of the stria terminalis (BNST). Various methods have been utilized to optimize target selection for trOCD DBS. The authors describe their practice of planning trajectories to both the VS and BNST and adjudicating between them with awake intraoperative valence testing to individualize permanent target selection. Eight patients with trOCD underwent awake DBS with trajectories planned for both VS and BNST targets bilaterally. The authors intraoperatively assessed the acute effects of stimulation on mood, energy, and anxiety and implanted the trajectory with the most reliable positive valence responses and least stimulation-induced side effects. The method of intraoperative target adjudication is described, and the OCD outcome at last follow-up is reported. The mean patient age at surgery was 41.25 ± 15.1 years, and the mean disease duration was 22.75 ± 10.2 years. The median preoperative Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score was 39 (range 34-40). Two patients had previously undergone capsulotomy, with insufficient response. Seven (44%) of 16 leads were moved to the second target based on intraoperative stimulation findings, 4 of them to avoid strong negative valence effects. Three patients had an asymmetric implant (1 lead in each target). All 8 patients (100%) met full response criteria, and the mean Y-BOCS score reduction across the full cohort was 51.2% ± 12.8%. Planning and intraoperatively testing trajectories flanking the AC-superjacent to the VS anteriorly and to the BNST posteriorly-allowed identification of positive valence responses and acute adverse effects. Awake testing helped to select between possible trajectories and identify individually optimized targets in DBS for trOCD.

Sleep disorders and white matter integrity in patients with sporadic amyotrophic lateral sclerosis

This study aimed to explore the characteristics of sleep disorders and their relationship with abnormal white-matter integrity in patients with sporadic amyotrophic lateral sclerosis. One hundred and thirty-six patients and 80 healthy controls were screened consecutively, and 56 patients and 43 healthy controls were ultimately analyzed. Sleep disorders were confirmed using the Pittsburgh sleep quality index, the Epworth sleepiness scale, and polysomnography; patients were classified into those with poor and good sleep quality. White-matter integrity was assessed using diffusion tensor imaging and compared between groups to identify the white-matter tracts associated with sleep disorders. The relationship between scores on the Pittsburgh sleep quality index and impaired white-matter tracts was analyzed using multiple regression. Poor sleep quality was more common in patients (adjusted odds ratio, 4.26; p = 0.005). Compared to patients with good sleep quality (n = 30), patients with poor sleep quality (n = 26; 46.4%) showed decreased fractional anisotropy, increased mean diffusivity, and increased radial diffusivity of projection and commissural fibers, and increased radial diffusivity of the right thalamus. The Pittsburgh score showed the best fit with the mean fractional anisotropy of the right anterior limb of the internal capsule (r = - 0.355, p = 0.011) and the mean radial diffusivity of the right thalamus (r = 0.309, p = 0.028). We conclude that sleep disorders are common in patients with sporadic amyotrophic lateral sclerosis and are associated with reduced white-matter integrity. The pathophysiology of amyotrophic lateral sclerosis may contribute directly to sleep disorders.

Deep brain stimulation for autism spectrum disorder.

Deep brain stimulation (DBS) is a medical treatment that aims to obtain therapeutic effects by applying chronic electrical impulses in specific brain structures and neurological circuits. Over the years, DBS has been studied for the treatment of many psychiatric disorders. Scientific research on the use of DBS in people with autism has focused this interest mainly on treatment-resistant obsessive-compulsive disorder, drug-resistant epilepsy, self-injurious behaviors (SIB), and aggressive behaviors toward the self. Autism spectrum disorder (ASD) includes a group of developmental disabilities characterized by patterns of delay and deviance in the development of social, communicative, and cognitive skills and the presence of repetitive and stereotyped behaviors as well as restricted interests. People with autism often have numerous medical and psychiatric comorbidities that worsen the quality of life of patients and their caregivers. Obsessive-compulsive symptoms can be found in up to 81.3% of people with autism. They are often severe, refractory to treatment, and particularly difficult to treat. SIB has a high prevalence in severely retarded individuals and is often associated with autism. Drug treatment of both autism and SIB presents a therapeutic challenge. To describe the current state of the art regarding the efficacy of DBS in people with ASD, a literature search was conducted for relevant studies using the PubMed database. Thirteen studies have been considered in this paper. Up to date, DBS has been used for the stimulation of the nucleus accumbens, globus pallidus internus, anterior limb of the internal capsule, ventral anterior limb of the internal capsule, basolateral amygdala, ventral capsule and ventral striatum, medial forebrain bundle, and posterior hypothalamus. In the total sample of 16 patients, 4 were adolescents, and 12 were adults. All patients had symptoms resistant to multiple drug therapy. Many patients taken into consideration by the studies showed clinical improvements as evidenced by the scores of the psychopathological scales used. In some cases, clinical improvements have varied over time, which may require further investigation. Among the new therapeutic perspectives, DBS could be a valid option. However, further, and more in-depth research is needed in this field.

Treating Obsessive-Compulsive Disorder by Invasively Modulating Thoughts, Feelings, or Both

The defining characteristic of pathological compulsions is that they are carried out to reduce momentary distress, even though performing the compulsive act or thought is rationally not in the individual’s true best interest. This inability to flexibly adapt is a prominent component of obsessive-compulsive disorder (OCD) and closely related illnesses such as Tourette syndrome and is also observed in substance use disorders ( 1 Figee M. Pattij T. Willuhn I. Luigjes J. van den Brink W. Goudriaan A. et al. Compulsivity in obsessive-compulsive disorder and addictions. Eur Neuropsychopharmacol. 2016; 26: 856-868 Crossref PubMed Scopus (111) Google Scholar ). Following the 20th century experience with ablative procedures such as capsulotomy, deep brain stimulation (DBS) was applied to the treatment of OCD. Electrodes are most commonly placed within the anterior limb of the internal capsule (ALIC), modulating cortico-basal ganglia-thalamo-cortical parallel white matter loops relevant to limbic, associative, and motor functions, respectively. ALIC stimulation has proven to be a highly effective treatment for severe OCD ( 2 Smith AH, Mayberg HS, Figee M (in press): Neuromodulation and psychiatric disorders. In: Nestler EJ, Charney DS, editors. Neurobiology of Mental Illness, 6th ed. New York: Oxford University Press. Google Scholar ). DBS to a different anatomical location, the subthalamic nucleus (STN), was initially developed for Parkinson’s disease, but positive early experience in patients with comorbid Parkinson’s disease and OCD led to research establishing high-frequency stimulation straight to the STN as clinically efficacious for OCD ( 3 Mallet L. Polosan M. Jaafari N. Baup N. Welter M.L. Fontaine D. et al. Subthalamic nucleus stimulation in severe obsessive-compulsive disorder. N Engl J Med. 2008; 359: 2121-2134 Crossref PubMed Scopus (687) Google Scholar ). In a similar manner, promising early pilot studies led to further exploration of other targets. These include the bed nucleus of the stria terminalis, the “extended amygdala” located between the ALIC and STN targets ( 4 Mosley P.E. Windels F. Morris J. Coyne T. Marsh R. Giorni A. et al. A randomised, double-blind, sham-controlled trial of deep brain stimulation of the bed nucleus of the stria terminalis for treatment-resistant obsessive-compulsive disorder. Transl Psychiatry. 2021; 11: 190 Crossref PubMed Scopus (38) Google Scholar ). More recently, evidence has emerged for the effectiveness of stimulation delivered deeper in the midbrain than the STN, adjacent to the ventral tegmental area (VTA)—a source of dopaminergic projections to the cortex (via the medial forebrain bundle [MFB]) and a recipient of proposed regulatory projections back from the cortex (via the “supralateral MFB”) ( 5 Meyer D.M. Spanier S. Kilian H.M. Reisert M. Urbach H. Sajonz B.E. et al. Efficacy of superolateral medial forebrain bundle deep brain stimulation in obsessive-compulsive disorder. Brain Stimul. 2022; 15: 582-585 Abstract Full Text Full Text PDF Scopus (3) Google Scholar ). SEE CORRESPONDING ARTICLE ON PAGE 1010 SEE CORRESPONDING ARTICLE ON PAGE 1010 The Rostral Zona Incerta: A Subcortical Integrative Hub and Potential Deep Brain Stimulation Target for Obsessive-Compulsive DisorderBiological PsychiatryVol. 93Issue 11PreviewThe zona incerta (ZI) is involved in mediating survival behaviors and is connected to a wide range of cortical and subcortical structures, including key basal ganglia nuclei. Based on these connections and their links to behavioral modulation, we propose that the ZI is a connectional hub for mediating between top-down and bottom-up control and a possible target for deep brain stimulation for obsessive-compulsive disorder. Full-Text PDF

Improved Myelination following Camp Leg Power, a Selective Motor Control Intervention for Children with Spastic Bilateral Cerebral Palsy: A Diffusion Tensor MRI Study.

Children with spastic cerebral palsy have motor deficits associated with periventricular leukomalacia indicating WM damage to the corticospinal tracts. We investigated whether practice of skilled lower extremity selective motor control movements would elicit neuroplasticity. Twelve children with spastic bilateral cerebral palsy and periventricular leukomalacia born preterm (mean age, 11.5 years; age range, 7.3-16.6 years) participated in a lower extremity selective motor control intervention, Camp Leg Power. Activities promoted isolated joint movement including isokinetic knee exercises, ankle-controlled gaming, gait training, and sensorimotor activities (3 hours/day, 15 sessions, 1 month). DWI scans were collected pre- and postintervention. Tract-Based Spatial Statistics was used to analyze changes in fractional anisotropy, radial diffusivity, axial diffusivity, and mean diffusivity. Significantly reduced radial diffusivity (P < . 05) was found within corticospinal tract ROIs, including 28.4% of the left and 3.6% of the right posterior limb of the internal capsule and 14.1% of the left superior corona radiata. Reduced mean diffusivity was found within the same ROIs (13.3%, 11.6%, and 6.6%, respectively). Additionally, decreased radial diffusivity was observed in the left primary motor cortex. Additional WM tracts had decreased radial diffusivity and mean diffusivity, including the anterior limb of the internal capsule, external capsule, anterior corona radiata, and corpus callosum body and genu. Myelination of the corticospinal tracts improved following Camp Leg Power. Neighboring WM changes suggest recruitment of additional tracts involved in regulating neuroplasticity of the motor regions. Intensive practice of skilled lower extremity selective motor control movements promotes neuroplasticity in children with spastic bilateral cerebral palsy.

Gamma knife capsulotomy for intractable OCD: Neuroimage analysis of lesion size, location, and clinical response

Obsessive-compulsive disorder (OCD) affects 2–3% of the population. One-third of patients are poorly responsive to conventional therapies, and for a subgroup, gamma knife capsulotomy (GKC) is an option. We examined lesion characteristics in patients previously treated with GKC through well-established programs in Providence, RI (Butler Hospital/Rhode Island Hospital/Alpert Medical School of Brown University) and São Paulo, Brazil (University of São Paolo). Lesions were traced on T1 images from 26 patients who had received GKC targeting the ventral half of the anterior limb of the internal capsule (ALIC), and the masks were transformed into MNI space. Voxel-wise lesion-symptom mapping was performed to assess the influence of lesion location on Y-BOCS ratings. General linear models were built to compare the relationship between lesion size/location along different axes of the ALIC and above or below-average change in Y-BOCS ratings. Sixty-nine percent of this sample were full responders (≥35% improvement in OCD). Lesion occurrence anywhere within the targeted region was associated with clinical improvement, but modeling results demonstrated that lesions occurring posteriorly (closer to the anterior commissure) and dorsally (closer to the mid-ALIC) were associated with the greatest Y-BOCS reduction. No association was found between Y-BOCS reduction and overall lesion volume. GKC remains an effective treatment for refractory OCD. Our data suggest that continuing to target the bottom half of the ALIC in the coronal plane is likely to provide the dorsal–ventral height required to achieve optimal outcomes, as it will cover the white matter pathways relevant to change. Further analysis of individual variability will be essential for improving targeting and clinical outcomes, and potentially further reducing the lesion size necessary for beneficial outcomes.

Deep brain stimulation normalizes amygdala responsivity in treatment-resistant depression.

Deep brain stimulation (DBS) of the ventral anterior limb of the internal capsule (vALIC) is a promising intervention for treatment-resistant depression (TRD). However, the working mechanisms of vALIC DBS in TRD remain largely unexplored. As major depressive disorder has been associated with aberrant amygdala functioning, we investigated whether vALIC DBS affects amygdala responsivity and functional connectivity. To investigate the long-term effects of DBS, eleven patients with TRD performed an implicit emotional face-viewing paradigm during functional magnetic resonance imaging (fMRI) before DBS surgery and after DBS parameter optimization. Sixteen matched healthy controls performed the fMRI paradigm at two-time points to control for test-retest effects. To investigate the short-term effects of DBS de-activation after parameter optimization, thirteen patients additionally performed the fMRI paradigm after double-blind periods of active and sham stimulation. Results showed that TRD patients had decreased right amygdala responsivity compared to healthy controls at baseline. Long-term vALIC DBS normalized right amygdala responsivity, which was associated with faster reaction times. This effect was not dependent on emotional valence. Furthermore, active compared to sham DBS increased amygdala connectivity with sensorimotor and cingulate cortices, which was not significantly different between responders and non-responders. These results suggest that vALIC DBS restores amygdala responsivity and behavioral vigilance in TRD, which may contribute to the DBS-induced antidepressant effect.

Efficacy of deep brain stimulation for the treatment of anorexia nervosa: a systematic review and network meta-analysis of patient-level data.

Deep brain stimulation (DBS) has been approved as a therapy for movement disorders and obsessive-compulsive disorder. Recently, DBS has been studied in patients with anorexia nervosa (AN), which is a debilitating and life-threatening psychiatric disorder. Several stimulation locations have been tested without a clear indication of the best region. In this systematic review and network meta-analysis, the authors used patient-level data to identify stimulation targets with the greatest evidence for efficacy in increasing body mass index (BMI). A systematic search was performed on or before August 4, 2022, using PubMed/MEDLINE, Ovid, and Scopus. Articles were included if patient-level data were presented, patients were diagnosed with AN and treated with DBS, and 6 months or more of postoperative follow-up data were reported. Quality and risk of bias were assessed with the NIH assessment tools. Patient data were collected and stratified by stimulation location. A network meta-analysis was performed. This review was written in accordance with PRISMA guidelines for systematic reviews. Eleven studies consisting of 36 patients were included. The mean age and BMI at the time of surgery were 38.07 (SD 11.64) years and 12.58 (SD 1.4) kg/m2, respectively. After 6 months of DBS, a significant difference in percentage change in BMI was found between the nucleus accumbens and subcallosal cingulate cortex (SCC) (SMD 0.78; 95% CI 0.10, 1.45) and between the SCC and ventral anterior limb of the internal capsule (SMD -1.51; 95% CI -2.39, -0.62). Similarly, at 9-12 months, a significant difference in percentage change in BMI was found between the SCC and ventral anterior limb of the internal capsule (SMD -1.18; 95% CI -2.21, -0.15). With hierarchical ranking, this study identified SCC as the most supported stimulation location for BMI change at 6 and 9-12 months (P-scores 0.9449 and 0.9771, respectively). Several DBS targets have been tested for AN, and this study identified the SCC as the most supported region for BMI change. However, further studies with blinded on/off periods are necessary to confirm this finding.

Acute effects of deep brain stimulation on brain function in obsessive–compulsive disorder

ObjectiveDeep brain stimulation (DBS) is an effective treatment for refractory obsessive–compulsive disorder (OCD) yet neural markers of optimized stimulation parameters are largely unknown. We aimed to describe (sub-)cortical electrophysiological responses to acute DBS at various voltages in OCD. MethodsWe explored how DBS doses between 3–5 V delivered to the ventral anterior limb of the internal capsule of five OCD patients affected electroencephalograms and intracranial local field potentials (LFPs). We focused on theta power/ phase-stability, given their previously established role in DBS for OCD. ResultsCortical theta power and theta phase-stability did not increase significantly with DBS voltage. DBS-induced theta power peaks were seen at the previously defined individualized therapeutic voltage. Although LFP power generally increased with DBS voltages, this occurred mostly in frequency peaks that overlapped with stimulation artifacts limiting its interpretability. Though highly idiosyncratic, three subjects showed significant acute DBS effects on electroencephalogram theta power and four subjects showed significant carry-over effects (pre-vs post DBS, unstimulated) on LFP and electroencephalogram theta power. ConclusionsOur findings challenge the presence of a consistent dose–response relationship between stimulation voltage and brain activity. SignificanceTheta power may be investigated further as a neurophysiological marker to aid personalized DBS voltage optimization in OCD.

Identification of a personalized intracranial biomarker of depression and response to DBS therapy

Abstract Deep brain stimulation (DBS) of the anterior limb of the internal capsule (ALIC) has shown promise as a therapy for refractory obsessive-compulsive disorder (OCD) and major depressive disorder (MDD). DBS currently is ‘open-loop’ with stimulation parameters remaining fixed over time. In contrast, ‘closed-loop’ DBS delivers stimulation only when a biomarker of the target symptom state indicates it is needed. One challenge to the development of closed-loop DBS for psychiatric indications is the dearth of biomarkers of symptom state. Here, we report identification of an electrophysiological depression biomarker in a patient receiving DBS in the ALIC and nearby bed nucleus of the stria terminalis (BNST) for refractory OCD. Research Category and Technology and Methods Translational Research: 1. Deep Brain Stimulation (DBS) Keywords: Closed-loop, Biomarker, OCD, DBS

Diffusion Tensor Imaging in Parenchymal Neuro-Behçet's Disease.

Parenchymal Neuro-Behçet's disease (p-NBD) usually presents with a characteristic lesion in the mesodiencephalic region. However, there is a lack of information regarding the axonal integrity of normal-appearing white matter in p-NBD. Diffusion tensor imaging (DTI) is based on the properties of diffusivity and anisotropy that indicate the integrity of axons. The primary objective of the study was to compare p-NBD patients to healthy controls using diffusion tensor magnetic resonance imaging (DTI-MRI). The study enrolled parenchymal p-NBD patients who maintained stable disease status for 12 months. Healthy controls were chosen from a population with a similar age and gender distribution. Axial DTI was acquired using single-shot echo-planar imaging. Group analyses were carried out using the track-based spatial statistics tool of FMRIB software library (FSL). Correlations between DTI parameters and clinical outcomes were analyzed in the patient group. We recruited 12 patients with p-NBD and 12 healthy individuals. We found significant fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD) differences in the superior longitudinal fasciculus, superior corona radiata, anterior corona radiata, body and genu of the corpus callosum, external capsule, and anterior limb of the internal capsule, mainly in the frontal white matter. Patients with p-NBD exhibit significant DTI alterations in the otherwise normal-appearing frontal association tracts. This study may contribute to a better understanding of the neuropsychological impairment pattern in patients with p-NBD, which is often associated with frontal cognitive networks.

Cyclic versus continuous deep brain stimulation in patients with obsessive compulsive disorder: A randomized controlled trial

BackgroundDeep brain stimulation (DBS) of the ventral anterior limb of the internal capsule (vALIC) is effective for refractory obsessive-compulsive disorder (OCD), but patients typically require high stimulation voltages and DBS comes with a risk for adverse events (AE). ObjectiveThe aim of the present study was to advance DBS for OCD by optimizing energy efficiency and minimize adverse events using a cyclic form of stimulation MethodsThis double blind, randomized crossover trial compares 2 weeks of continuous versus cyclic DBS (0.1 s ON, 0.2 s OFF) in 16 patients with OCD. We compared OCD symptoms (Yale-Brown Obsessive-Compulsive Scale, Y-BOCS), Hamilton Depression Rating Scale (HAM-D), Hamilton Anxiety Scale (HAM-A), AEs, battery life, cognitive performance and quality of life. ResultsAverage Y-BOCS scores at baseline increased significantly with 5.5 points (p = 0.006) in the cyclic condition. Average HAM-D and HAM-A scores increased with 2.2 (p = 0.088) and 2.8 points (p = 0.018). The overall health scale of quality of life worsened during cyclic DBS (p = 0.044). Patients reported on average 3.3 AEs during continuous stimulation and 4.4 AEs during cyclic stimulation (p = 0.175), though stimulation-related AEs such as headache and concentration problems reduced during cyclic DBS. Battery usage during continuous DBS was 0.021 V per hour compared to 0.008 V per hour during cyclic DBS. ConclusionThough specific stimulation-related AEs improved, cyclic stimulation (0.1 s ON, 0.2 s OFF) comes with a high relapse risk in patients with DBS for OCD. Cyclic DBS is no alternative for standard DBS treatment, but applicable in case of debilitating AEs.

White Matter Microstructure Associated with the Antidepressant Effects of Deep Brain Stimulation in Treatment-Resistant Depression: A Review of Diffusion Tensor Imaging Studies

Treatment-resistant depression (TRD) is a severe disorder characterized by high relapse rates and decreased quality of life. An effective strategy in the management of TRD is deep brain stimulation (DBS), a technique consisting of the implantation of electrodes that receive a stimulation via a pacemaker-like stimulator into specific brain areas, detected through neuroimaging investigations, which include the subgenual cingulate cortex (sgCC), basal ganglia, and forebrain bundles. In this context, to improve our understanding of the mechanism underlying the antidepressant effects of DBS in TRD, we collected the results of diffusion tensor imaging (DTI) studies exploring how WM microstructure is associated with the therapeutic effects of DBS in TRD. A search on PubMed, Web of Science, and Scopus identified 11 investigations assessing WM microstructure in responders and non-responders to DBS. Altered WM microstructure, particularly in the sgCC, medial forebrain bundle, cingulum bundle, forceps minor, and uncinate fasciculus, was associated with the antidepressant effect of DBS in TRD. Overall, the results show that DBS targeting selective brain regions, including the sgCC, forebrain bundle, cingulum bundle, rectus gyrus, anterior limb of the internal capsule, forceps minor, and uncinate fasciculus, seem to be effective for the treatment of TRD.

White matter integrity as a mediator between socioeconomic status and executive function.

Lower socioeconomic status (SES) is associated with poorer executive function, but the neural mechanisms of this association remain unclear. As healthy brain communication is essential to our cognitive abilities, white matter integrity may be key to understanding socioeconomic disparities. Participants were 201 African American and White adults (ages 33-72) from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) SCAN study. Diffusion tensor imaging was used to estimate regional fractional anisotropy as a measure of white matter integrity. Adjusting for age, analyses examined if integrity of the anterior limb of the internal capsule (ALIC), external capsule (EC), superior longitudinal fasciculus (SLF), and cingulum mediated SES-executive function relations. Lower SES was related to poorer cognitive performance and white matter integrity. Lower Trails B performance was related to poorer integrity of the ALIC, EC, and SLF, and lower Stroop performance was associated with poorer integrity of the ALIC and EC. ALIC mediated the SES-Trails B relation, and EC mediated the SES-Trails B and SES-Stroop relations. Sensitivity analyses revealed that (1) adjustment for race rendered the EC mediations non-significant, (2) when using poverty status and continuous education as predictors, results were largely the same, (3) at least some of the study's findings may generalize to processing speed, (4) mediations are not age-dependent in our sample, and (5) more research is needed to understand the role of cardiovascular risk factors in these models. Findings demonstrate that poorer white matter integrity helps explain SES disparities in executive function and highlight the need for further clarification of the biopsychosocial mechanisms of the SES-cognition association.

Increased White Matter Coherence Following Three and Six Months of Medical Cannabis Treatment.

Background: Previous studies have demonstrated abnormal white matter (WM) microstructure in recreational cannabis consumers; however, the long-term impact of medical cannabis (MC) use on WM coherence is unknown. Accordingly, this study assessed the longitudinal impact of MC treatment on WM coherence. Given results from preclinical studies, we hypothesized that MC treatment would be associated with increased fractional anisotropy (FA) and reduced mean diffusivity (MD). Methods: As part of a larger, longitudinal investigation, patients interested in treating at least one medical condition with commercially available MC products of their choosing were assessed before initiating MC use (baseline n=37; female=25, male=12) and following three (n=31) and six (n=22) months of treatment. WM coherence was assessed via diffusion tensor imaging for bilateral regions of interest including the genu of the corpus callosum, anterior limb of the internal capsule, external capsule, and anterior corona radiata, as well as an occipital control region not expected to change over time. Results: In MC patients, FA values significantly increased bilaterally in several callosal regions relative to baseline following both 3 and 6 months of treatment; MD values significantly decreased in all callosal regions but only following 6 months of treatment. No significant changes in WM coherence were observed in the control region or in a pilot sample of treatment-as-usual patients (baseline n=14), suggesting that increased WM coherence observed in MC patients may be attributed to MC treatment as opposed to confounding factors. Interestingly, significant reductions in MD values correlated with higher cannabidiol (CBD) exposure but not Δ-9-tetrahydrocannabinol exposure. Conclusions: Overall, MC treatment was associated with increased WM coherence, which contrasts with prior research examining recreational cannabis consumers, likely related to inherent differences between recreational consumers and MC patients (e.g., product choice, age of onset). In addition, increased CBD exposure was associated with reduced MD following 6 months of treatment, extending evidence from preclinical research indicating that CBD may be neuroprotective against demyelination. However, additional research is needed to elucidate the clinical efficacy of MC treatment and the risks and benefits of long-term MC use.