Connectivity-based parcellation of the amygdala and identification of its main white matter connections.

The amygdala plays a role in emotion, learning, and memory and has been implicated in behavioral disorders. Better understanding of the amygdala circuitry is crucial to develop new therapies for these disorders. We used data from 200 healthy-subjects from the human connectome project. Using probabilistic tractography, we created population statistical maps of amygdala connectivity to brain regions involved in limbic, associative, memory, and reward circuits. Based on the amygdala connectivity with these regions, we applied k-means clustering to parcellate the amygdala into three clusters. The resultant clusters were averaged across all subjects and the main white-matter pathways of the amygdala from each averaged cluster were generated. Amygdala parcellation into three clusters showed a medial-to-lateral pattern. The medial cluster corresponded with the centromedial and cortical nuclei, the basal cluster with the basal nuclei and the lateral cluster with the lateral nuclei. The connectivity analysis revealed different white-matter pathways consistent with the anatomy of the amygdala circuit. This in vivo connectivity-based parcellation of the amygdala delineates three clusters of the amygdala in a mediolateral pattern based on its connectivity with brain areas involved in cognition, memory, emotion, and reward. The human amygdala circuit presented in this work provides the first step for personalized amygdala circuit mapping for patients with behavioral disorders.

Deep brain stimulation of thalamic nuclei for the treatment of drug-resistant epilepsy: Are we confident with the precise surgical target?

Deep brain stimulation (DBS) of the thalamic nuclei for the treatment of drug-resistant epilepsy (DRE) has been investigated for decades. In recent years, DBS targeting the anterior nucleus of the thalamus (ANT) was approved by CE and FDA for the treatment of focal-onset DRE in light of the results from the multicentric randomized controlled SANTE trial. However, stereotactic targeting of thalamic nuclei is not straightforward because of the low contrast definition among thalamic nuclei on the current MRI sequences. When the FGATIR sequence is added to the preoperative MRI protocol, the mammillothalamic tract can be identified and used as a visible landmark to directly target ANT. According to the current evidence, the trans-ventricular trajectory allows the placement of stimulating contact into the nucleus more frequently than the trans-cortical trajectory. Another thalamic nucleus whose stimulation for the treatment of generalized DRE is receiving increasing attention is the centromedian nucleus (CM). CM-DBS seems to be particularly efficacious in patients suffering from Lennox-Gastault syndrome (LGS) and the recent monocentric randomized controlled ESTEL trial also described a beneficial "sweet-spot". However, CM targeting is still based on indirect stereotactic coordinates, since acquisition times and post-processing techniques of the actual MRI sequences are not applicable in clinical practice. Moreover, the results of the ESTEL trial await confirmation from similar studies accounting for epileptic syndromes other than LGS. Therefore, novel neuroimaging approaches are advisable to improve the surgical targeting of CM and potentially tailor the stimulation based on the patient's specific epileptic phenotype.

Vagus nerve stimulation using a miniaturized wirelessly powered stimulator in pigs.

Neuromodulation of peripheral nerves has been clinically used for a wide range of indications. Wireless and batteryless stimulators offer important capabilities such as no need for reoperation, and extended life compared to their wired counterparts. However, there are challenging trade-offs between the device size and its operating range, which can limit their use. This study aimed to examine the functionality of newly designed wirelessly powered and controlled implants in vagus nerve stimulation for pigs. The implant used near field inductive coupling at 13.56 MHz industrial, scientific, and medical band to harvest power from an external coil. The circular implant had a diameter of 13 mm and weighed 483 mg with cuff electrodes. The efficiency of the inductive link and robustness to distance and misalignment were optimized. As a result, the specific absorption rate was orders of magnitude lower than the safety limit, and the stimulation can be performed using only 0.1 W of external power. For the first time, wireless and batteryless VNS with more than 5 cm operation range was demonstrated in pigs. A total of 84 vagus nerve stimulations (10 s each) have been performed in three adult pigs. In a quantitative comparison of the effectiveness of VNS devices, the efficiency of systems on reducing heart rate was similar in both conventional (75%) and wireless (78.5%) systems. The pulse width and frequency of the stimulation were swept on both systems, and the response for physiological markers was drawn. The results were easily reproducible, and methods used in this study can serve as a basis for future wirelessly powered implants.

Telemetric Intracranial Pressure Monitoring: A Systematic Review.

Telemetric intracranial pressure (ICP) monitoring is a new method of measuring ICP which eliminates some of the shortcomings of previous methods. However, there are limited data on specific characteristics, including the advantages and disadvantages of this method. The main aim of this study was to demonstrate the indications, benefits, and complications of telemetric ICP monitoring. PubMed, MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for relevant studies without language or date restriction in May 2019. Human studies in which telemetric ICP monitoring was the main subject of the study were included. Our initial search resulted in 1650 articles from which 50 studies were included. There were no randomized controlled trials. The majority of the studies were case reports or case series (68%). The most common aim of studies was testing of the device (52%), and monitoring the disease progression or recovery (46%). The most common indications for telemetric ICP monitoring in these studies were testing cerebrospinal fluid shunt function (46%), ICP control after the procedure (36%), and diagnosing intracranial hypertension (22%) and hydrocephalus (12%). In total, 1423 brain disease patients had been monitored in studies. The possibility of long-term ICP monitoring as the main benefit was reported in 38 (76%) studies. The associated complication rate was 7.1%. Despite the increasing application of telemetric monitoring devices, studies to evaluate specific characteristics of this method have been infrequent and inadequate. Future research using a higher level of scientific methods is needed to evaluate advantage and disadvantages.

Meningothelial meningioma of the oculomotor nerve: A case report and review of the literature.

BACKGROUND: The origin of meningioma tumors is known as the meningothelial or arachnoid cap cells. The arachnoid granulations or villi are concentrated along with the dural venous sinuses in the cerebral convexity, parasagittally, and sphenoid wing regions. The majority of meningiomas are found in these locations with dural attachment. Infrequently, meningiomas develop without dural attachment but in dural adjacent. There are numerous reports of patients with cranial nerve involvement as a result of the compressive effect of the sinus cavernous or adjacent structures meningioma tumor on the cranial nerve. CASE DESCRIPTION: In this study, we reviewed all reports of patients with third nerve involvement as a result of meningioma tumors in addition to the introduction of a new case. We present a 47-year-old woman presented with headache, diplopia, and ptosis. A gadolinium-enhanced mass on anterolateral of the left cerebral peduncle with no dural attachment was suggesting for Schwannoma at preoperative imaging. An adhesive 10 × 5 × 4 mm meningothelial meningioma arising from the oculomotor nerve was resected. CONCLUSION: The findings of this review suggest that there may be other mechanisms as the origin of meningiomas tumors. It is crucial to take into account origination mechanisms of meningioma using ectopic meningiomas due to the increasing prevalence of meningioma.

Health-related quality of life after epilepsy surgery: A prospective, controlled follow-up on the Iranian population.

Quality of life is affected by factors such as regional differences in access to treatment choices, and rehabilitation. This study aims to assess the result of epilepsy surgery and its impact on QoL in Iran. The data for 60 patients who underwent epilepsy surgery in Loghman-Hakim hospital between 2003 to 2017 were analyzed prospectively through clinical observation. Clinical variables of interest and the WHOQOL-BREF scale to assess QoL were applied. Scores of operated patients were compared to their preoperative scores as well as epileptic patients controlled with antiepileptic drugs (AEDs) and healthy individuals. The mean age of surgery group patients was 33.78 (34 male; 26 female). Twenty seven patients underwent temporal mesial lobectomy, 20 anterior callosotomy, and 13 neocortical resections. The average QoL score in healthy group was 72.48, in AEDs controls was 56.16, and in operated patients was 65.61. In addition, analysis showed a significant increase in postoperative QoL of the surgical group compared to the AEDs controls. Epilepsy surgery could be the best approach in patients suffering from drug-resistant epilepsy even in developing countries, which can result in seizure relief and a reduction in the frequency of disabling seizures.

Nerve-Sheath-Risen Neuroglial Cyst: Case Report and Review of the Literature.

BACKGROUND: Neuroglial cysts are rare intracranial lesions that are believed to originate from the sequestration of neural tube lining during embryogenesis. They can present anywhere within the neuraxis; however, their most common location is the frontal lobe. Cerebellopontine angle (CPA) neuroglial cysts are extremely rare and, to the best of our knowledge, there are no previous reports of a neuroglial cyst arising from cranial nerves. CASE DESCRIPTION: The current study presented a male adolescent with the reoccurrence of an intracranial cyst with symptoms of diplopia and facial numbness primarily treated as CPA arachnoid cyst with fenestration of the cyst 12 months prior to admission to our center. Different magnetic resonance imaging sequences showed a thin-walled extra-axial cyst at the right CPA without gadolinium enhancement. Direct visualization of the lesion revealed a cyst arising from the fifth cranial nerve sheath compressing the surrounding structures. The cyst was fenestrated, and a biopsy was taken from the cyst wall. The pathological analysis, along with specified histological markers, indicated the neuroglial nature of the cyst. CONCLUSIONS: The rising of a neuroglial cyst from the nerve sheath is a finding that brings other possible origins of neuroglial cysts into consideration.

Frequently asked questions of individuals with spinal cord injuries: results of a web-based consultation service in Iran.

STUDY DESIGN: Descriptive study of the results of a web-based consultation service for individuals with spinal cord injury (SCI). OBJECTIVES: To review frequently asked questions (FAQ) among individuals with SCI and determine the most important topics. SETTING: Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. METHODS: A cross-sectional study reviewing questions from patients with SCI that were collected from the Health and Safety Consultant Center (HSCC) between January and December 2015. The HSCC is a web-based medical consultation service that provides patients with information and counseling pertaining to SCI. RESULTS: A total of 113 questions were collected from 99 individuals. The mean age was 32.02 ± 13.28 years with a range of 3-70 years. Men accounted for 81.7% of the questions, while women accounted for 18.3%. The most common site of SCI was thoracic (40.6%), followed by lumbar (31.3%), and cervical (28.1%). Recovery potential (38.1%), sexual and reproductive issues (26.5%), urinary (10.6%), and motor (10.6%) problems were among the most commonly reviewed topics. CONCLUSIONS: FAQ provide insight on areas of concerns for individuals with SCI and help guide providers to determine high-yield topics. Discerning the specific areas of need or concern for patients is instrumental in developing pertinent educational materials and programs, in addition to efficiently counseling patients and caregivers on the aftercare of SCI.

Congenital Absence of the Posterior Element of C1, C2, and C3 Along with Bilateral Absence of C4 Pedicles: Case Report and Review of the Literature.

BACKGROUND: Abnormalities of the posterior arch of vertebrae are rare conditions that may incidentally be found on neck radiographs. We report a case and present a comprehensive review of the literature. CASE DESCRIPTION: A 10-year-old boy presented with intermittent paresthesia in the lower extremities, mild neck pain, and episodes of drop attacks following neck flexion. Radiologic investigations depicted a complete absence of the posterior element of C1, C2, and C3 along with bilateral absence of C4 pedicles. CONCLUSIONS: The diagnosis of posterior arch abnormalities is of high-level of importance because of resultant neurologic defects. To the best of our knowledge, no case of this type has been reported in literature thus far.

Childhood Epilepsy; Prognostic Factors in Predicting the Treatment Failure.

OBJECTIVE: We aimed to find the prognostic factors to detect the patients who fail the treatment of epilepsy, in the early stages of the disease. MATERIALS &METHODS: This study was done on the epileptic patients attending the Neurology Clinic of Mofid Children's Hospital, Tehran, Iran from September 2013 to October 2014. After defining the criteria for exclusion and inclusion, the patients were divided to two groups based on responding to the medical treatment for their epilepsy and indices were recorded for all the patients to be used in the statistical analyses. RESULTS: The patients' age ranged from 1 to 15 yr. There was 188 patients with refractory seizure in group 1 (experimental group) and 178 patient with well controlled seizure in group 2(control group).There was a significant different between serum drug level in both groups and patients with refractory seizure group had a lower serum drug level than control group. In both groups tonic-clonic was the most common type of seizure. Also the prevalence of brain imaging Abnormalityand other neurologic disorders was significantly higher in patients with refractory seizure in compare with control group. CONCLUSION: Children with seizure who suffer from refractory epilepsy need more attention and exact observation by the medical staff.

Persian version of frontal assessment battery: Correlations with formal measures of executive functioning and providing normative data for Persian population.

BACKGROUND: Cognitive impairment in patients with Parkinson's disease (PD) mainly involves executive function (EF). The frontal assessment battery (FAB) is an efficient tool for the assessment of EFs. The aims of this study were to determine the validity and reliability of the psychometric properties of the Persian version of FAB and assess its correlation with formal measures of EFs to provide normative data for the Persian version of FAB in patients with PD. METHODS: The study recruited 149 healthy participants and 49 patients with idiopathic PD. In PD patients, FAB results were compared to their performance on EF tests. Reliability analysis involved test-retest reliability and internal consistency, whereas validity analysis involved convergent validity approach. FAB scores compared in normal controls and in PD patients matched for age, education, and Mini-Mental State Examination (MMSE) score. RESULTS: In PD patients, FAB scores were significantly decreased compared to normal controls, and correlated with Stroop test and Wisconsin Card Sorting Test (WCST). In healthy subjects, FAB scores varied according to the age, education, and MMSE. In the FAB subtest analysis, the performances of PD patients were worse than the healthy participants on similarities, fluency tasks, and Luria's motor series. CONCLUSION: Persian version of FAB could be used as a reliable scale for the assessment of frontal lobe functions in Iranian patients with PD. Furthermore, normative data provided for the Persian version of this test improve the accuracy and confidence in the clinical application of the FAB.

A new perspective on word order preferences: the availability of a lexicon triggers the use of SVO word order.

Word orders are not distributed equally: SOV and SVO are the most prevalent among the world's languages. While there is a consensus that SOV might be the "default" order in human languages, the factors that trigger the preference for SVO are still a matter of debate. Here we provide a new perspective on word order preferences that emphasizes the role of a lexicon. We propose that while there is a tendency to favor SOV in the case of improvised communication, the exposure to a shared lexicon makes it possible to liberate sufficient cognitive resources to use syntax. Consequently SVO, the more efficient word order to express syntactic relations, emerges. To test this hypothesis, we taught Italian (SVO) and Persian (SOV) speakers a set of gestures and later asked them to describe simple events. Confirming our prediction, results showed that in both groups a consistent use of SVO emerged after acquiring a stable gesture repertoire.