Segment Of Nerve Research Articles

Aurora Kinase A Is Overexpressed in Human Retinoblastoma and Correlates with Histopathologic High-Risk Factors: Implications for Targeted Therapy

Retinoblastoma (RB) is an intraocular malignancy initiated by loss of RB1 function and/or dysregulation of MYCN oncogene. RB is primarily treated with chemotherapy; however, systemic toxicity and long-term side effects remain a significant challenge necessitating the identification of specific molecular targets. Aurora kinase A (AURKA), a critical cell cycle regulator, contributes to cancer pathogenesis especially in RB1-deficient and MYCN dysregulated tumors. Our immunohistochemistry study in patient specimens (n=67) discovered that AURKA is overexpressed in RB and elevated expression correlates with one or more histopathological high-risk factors such as tumor involvement of the optic nerve, choroid, sclera and/or anterior segment. More specifically, AURKA is ubiquitously expressed in majority of the advanced-stage RB tumors that show a sub-optimal response to chemotherapy. shRNA-mediated depletion/pharmacological inhibition studies in cell lines, patient-derived cells, in-vivo xenografts, and enucleated patient specimens confirm that RB cells are highly sensitive to a lack of functional AURKA. In addition, we deciphered that AURKA and MYCN associate with each other to regulate their levels in RB cells. Overall, our results demonstrate a previously unknown upregulation of AURKA in RB, facilitated by its crosstalk with MYCN, and elevated levels of this kinase may indicate unfavorable prognosis in tumors refractory to chemotherapy. This study provides a rationale and confirms that therapeutic targeting of elevated AURKA in RB could be a potential treatment approach.

Establishment of Facial Nerve Injury Rat Model for Idiopathic Facial Paralysis Research.

Idiopathic facial paralysis is the most common type of facial nerve injury, accounting for approximately 70% of peripheral facial paralysis cases. This disease can not only lead to a change in facial expression but also greatly impact the psychology of patients. In severe cases, it can affect the normal work and life of patients. Therefore, the research on facial nerve injury repair has important clinical significance. In order to study the mechanism of this disease, it is necessary to carry out relevant animal experiments, among which the most important task is to establish an animal model with the same pathogenesis as human disease. The compression of the facial nerve within the petrous bone, especially the nerve trunk at the junction of the distal end of the internal auditory canal and the labyrinthine segment, is the pathogenesis of idiopathic facial paralysis. In order to simulate this common disease, a compression injury model of the main extracranial segment of the facial nerve was established in this study. The neurological damage was evaluated by behavioral, neuroelectrophysiological, and histological examination. Finally, 50 g constant force and 90 s clamp injury were selected as the injury parameters to construct a stable idiopathic facial paralysis model.

P.103 Automated pituitary adenoma segmentation for radiosurgery with deep learning-based model

Background: Pituitary adenomas are treated with endoscopic surgery, while stereotactic radiosurgery addresses complex cases. Our study highlights AI’s role in accurate segmentation, improving treatment planning workflow efficiency Methods: In a retrospective study at Na Homolce Hospital (January 2010 to October 2022), SRS for pituitary adenomas was analyzed. Data were split 80:20 for training and validation. Using nnU-net, a medical image segmentation tool, a model predicted precise tumor, optic nerve, and pituitary gland segmentation. Accuracy was evaluated quantitatively with Dice similarity coefficient and qualitatively by human experts. The study explored the impact of tumor volume and hormonal activity status on segmentation accuracy. Results: The study comprised 582 and 146 patients in training and validation sets, respectively. The model achieved Dice similarity coefficients of 83.1% (tumor), 62.9% (normal gland), and 78.0% (optic nerve). Expert assessments deemed 41% directly applicable, 31.5% needing minor adjustments, and 27.4% unsuitable for clinical use. Larger tumor volume and non-functioning adenomas correlated with higher accuracy. Including T2 weighted scans improved DSC for optic nerve and normal gland. Conclusions: The study showcases deep learning’s potential in automating pituitary adenoma segmentation from MRI data, particularly excelling in large, hormonally inactive macroadenomas. Encourages collaborative use with clinicians for improved neurosurgical patient care.

The endoscopic transcanal approach to the internal auditory canal: an anatomic study.

The internal auditory canal (IAC) plays a key role in lateral skull base surgery. Although several approaches to the IAC have been proposed, endoscope-assisted transcanal corridors to the IAC have rarely been studied. We sought to provide a step-by-step description of the transcanal transpromontorial approach to the IAC and analyze anatomic relationships that might enhance predictability and safety of this approach. Ten cadaveric specimens were dissected and the extended transcanal transpromontorial approach to the IAC was established. Various morphometric measurements and anatomic landmarks were reviewed and analyzed. The proposed technique proved feasible and safe in all specimens. There was no inadvertent injury to the jugular bulb or internal carotid artery. The chorda tympani, a key landmark for the mastoid segment of the facial nerve, was identified in all dissections. The spherical recess of the vestibule and middle turn of cochlea are important landmarks for identification of the labyrinthine segment of the facial nerve. Identification of all boundaries of the working area is also essential for safe access. Among various morphometric measurements, the modiolus-IAC angle (≈150°) proved particularly consistent; given its ease of use and low variability, we believe it could serve as a landmark for identification and subsequent dissection of the IAC. The extended transcanal transpromontorial approach to the IAC is feasible and safe. Relying on anatomic landmarks to ensure preservation of the involved neurovascular structures is essential for a successful approach. The modiolus-IAC angle is a consistent, reproducible landmark for IAC identification and dissection.

Simulated Injuries of the Sheep Ossicular Chain: Correlations With Their Radiological Images.

Hypothesis We hypothesized that a sheep temporal bone would be a suitable model to study correlations between simulated middle ear injuries and their radiological appearances. Simulated ossicular chain injuries correlate well with their radiological images, and post-processing techniques provide optimal visualization of the sheep ossicles. Background The subtle ossicular trauma may be difficult to assess due to the small size of the structures. The precise radiological and clinical correlations of the ossicular injuries are not well documented. Methods The most common traumatic ossicular chain injuries were systematically simulated in the sheep temporal bone model. The images of the temporal bones were obtained with a high-resolution computed tomography scanner. The values of the dislocations were measured from the obtained images as well as in the temporal bones using calipers. Two observers independently evaluated the fine structures of the auditory ossicles using oblique multiplanar reconstructions (MPRs) and maximum intensity projections (MIPs). All segments of the facial nerve were also visualized. Results Optimal visualization planes of the sheep's middle ear joints have been obtained. The coincidence of simulated ossicular injuries in the specimens and MIPs was 40%. All structures of the ossicular chain were clearly distinguished except for the stapes footplate. Evaluation of the traumatic changes of the incudostapedial joint was challenging. Conclusions The sheep temporal bone is a suitable model for studying the correlations between pathological alterations in the ossicular chain and their radiological appearances. The post-processing MIP technique provides a more accurate and easier diagnosis of traumatic ossicular chain injuries than MPRs alone.

MR Imaging of Adverse Effects and Ocular Growth Decline after Selective Intra-Arterial Chemotherapy for Retinoblastoma.

This retrospective multicenter study examines therapy-induced orbital and ocular MRI findings in retinoblastoma patients following selective intra-arterial chemotherapy (SIAC) and quantifies the impact of SIAC on ocular and optic nerve growth. Patients were selected based on medical chart review, with inclusion criteria requiring the availability of posttreatment MR imaging encompassing T2-weighted and T1-weighted images (pre- and post-intravenous gadolinium administration). Qualitative features and quantitative measurements were independently scored by experienced radiologists, with deep learning segmentation aiding total eye volume assessment. Eyes were categorized into three groups: eyes receiving SIAC (Rb-SIAC), eyes treated with other eye-saving methods (Rb-control), and healthy eyes. The most prevalent adverse effects post-SIAC were inflammatory and vascular features, with therapy-induced contrast enhancement observed in the intraorbital optic nerve segment in 6% of patients. Quantitative analysis revealed significant growth arrest in Rb-SIAC eyes, particularly when treatment commenced ≤ 12 months of age. Optic nerve atrophy was a significant complication in Rb-SIAC eyes. In conclusion, this study highlights the vascular and inflammatory adverse effects observed post-SIAC in retinoblastoma patients and demonstrates a negative impact on eye and optic nerve growth, particularly in children treated ≤ 12 months of age, providing crucial insights for clinical management and future research.

Predicting long-term outcomes in patients with classical trigeminal neuralgia following microvascular decompression with an MRI-based radiomics nomogram: a multicentre study.

This study aimed to develop a clinical-radiomics nomogram to predict the long-term outcomes of patients with classical trigeminal neuralgia (CTN) following microvascular decompression (MVD). This retrospective study included 455 patients with CTN who underwent MVD from three independent institutions A total of 2030 radiomics features from the cistern segment of the trigeminal nerve were extracted computationally from the three-dimensional steady-state free precession and three-dimensional time-of-flight magnetic resonance angiography sequences. Using the least absolute shrinkage and selection operator regression, 16 features were chosen to develop radiomics signatures. A clinical-radiomics nomogram was subsequently developed in the development cohort of 279 patients via multivariate Cox regression. The predictive performance and clinical application of the nomogram were assessed in an external cohort consisting of 176 patients. Sixteen highly outcome-related radiomics features extracted from multisequence images were used to construct the radiomics model, with concordance indices (C-index) of 0.804 and 0.796 in the development and test cohorts, respectively. Additionally, a clinical-radiomics nomogram was developed by incorporating both radiomics features and clinical characteristics (i.e., pain type and degree of neurovascular compression) and yielded higher C-indices of 0.865 and 0.834 in the development and test cohorts, respectively. K‒M survival analysis indicated that the nomogram successfully stratified patients with CTN into high-risk and low-risk groups for poor outcomes (hazard ratio: 37.18, p < 0.001). Our study findings indicated that the clinical-radiomics nomogram exhibited promising performance in accurately predicting long-term pain outcomes following MVD. This model had the potential to aid clinicians in making well-informed decisions regarding the treatment of patients with CTN. Trigeminal neuralgia recurs in about one-third of patients after undergoing MVD. The clinical-radiomics nomogram stratified patients into high- and low-risk groups for poor surgical outcomes. Using this nomogram could better inform patients of recurrence risk and allow for discussion of alternative treatments.

Whole-body magnetic resonance neurography in patients with chronic inflammatory demyelinating polyneuropathy.

Whole-body magnetic resonance neurography (MRN) is an imaging modality that shows peripheral nerve signal change in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). We aimed to explore the diagnostic potential of whole-body MRN and its potential as a monitoring tool after immunotherapy in treatment-naïve CIDP patients. Whole-body MRN using coronal 3-dimensional short tau inversion recovery (STIR) sampling perfection with application-optimized contrasts by using different flip angle evolution (SPACE) techniques was performed in patients being investigated for CIDP and in healthy controls. Baseline clinical neuropathy scales and electrophysiologic parameters were collected, and MRN findings were compared before and after CIDP treatment. We found highly concordant symmetrical thickening and increased T2 signal intensities in the brachial/lumbosacral plexus, femoral, or sciatic nerves in five of the eight patients with a final diagnosis of CIDP and none of the healthy controls. There were no treatment-related imaging changes in five patients with CIDP who completed a follow-up study. Diffuse, symmetrical thickening, and increased T2 signal in root, plexus, and peripheral nerves were found in two patients ultimately excluded due to a diagnosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) syndrome in addition to signal changes in the muscles, bony lesions, organomegaly, and lymphadenopathy. Whole-body MRN imaging shows promise in detecting abnormalities in proximal nerve segments in patients with CIDP. Future studies evaluating the role of MRN in assessing treatment response should consider follow-up scans after treatment durations of more than 4 months.

Biomimetic Peripheral Nerve Stimulation Promotes the Rat Hindlimb Motion Modulation in Stepping: An Experimental Analysis.

Peripheral nerve stimulation is an effective neuromodulation method in patients with lower extremity movement disorders caused by stroke, spinal cord injury, or other diseases. However, most current studies on rehabilitation using sciatic nerve stimulation focus solely on ankle motor regulation through stimulation of common peroneal and tibial nerves. Using the electrical nerve stimulation method, we here achieved muscle control via different sciatic nerve branches to facilitate the regulation of lower limb movements during stepping and standing. A map of relationships between muscles and nerve segments was established to artificially activate specific nerve fibers with the biomimetic stimulation waveform. Then, characteristic curves depicting the relationship between neural electrical stimulation intensity and joint control were established. Finally, by testing the selected stimulation parameters in anesthetized rats, we confirmed that single-cathode extraneural electrical stimulation could activate combined movements to promote lower limb movements. Thus, this method is effective and reliable for use in treatment for improving and rehabilitating lower limb motor dysfunction.

Peripheral Nerve Crush in Drosophila Larvae.

The long length of axons makes them vulnerable to damage; hence, it is logical that nervous systems have evolved adaptive mechanisms for responding to axon damage. Studies in Drosophila melanogaster have identified evolutionarily conserved molecular pathways that enable axonal degeneration and regeneration of damaged axons and/or dendrites. This protocol describes a simple method for inducing nerve crush injury to motoneuron and sensory neuron axons in the peripheral (segmental) nerves in second- or early third-instar larvae. Small forceps are used to pinch the cuticle at a location that overlays the segmental nerves. Although the connective tissue of the nerves remains intact and the larva survives the injury, single motoneuron and sensory neuron axons incur a break in continuity at the damage site and then undergo Wallerian degeneration distal to the break. This degeneration includes the dismantling of neuromuscular junction (NMJ) synapses formed by the axons that incurred damage. With stereotyped anatomy and accessibility to structural and electrophysiological studies, the larval NMJ is a good model to characterize the cellular changes that occur in synapses undergoing degeneration and to identify conditions that can protect axons and synapses from degeneration.

Immobilizing Second-Instar Drosophila Larvae for Imaging and Surgery Using the Larva Chip.

The simple body plan and semitranslucent cuticle of the Drosophila larva allow for imaging of structures close to the body wall within intact animals. These include sensory neurons, muscles, neuromuscular junctions, and some regions of the segmental nerve. However, imaging within an intact larva requires a strategy to immobilize the animal in a position that presents the structures within the working distance of the microscope objective. Although various methods have been implemented for Drosophila larvae, this protocol describes a simple and noninvasive method that makes use of the polydimethylsiloxane (PDMS) larva chip. This larva chip immobilizes animals without the use of anesthetics or changes in temperature, which alter neuronal physiology, making it suitable for calcium imaging of endogenous activity in live animals. The membrane is air-permeable. Animals robustly survive short periods of immobilization (up to 30 min) and can even survive longer time periods. Since animals recover well after the procedure, the same animal can be reimaged multiple times. This makes the method amenable to manipulations such as laser microsurgery, photobleaching, and photoconversion followed by imaging of outcomes of these manipulations over time.

Study of Axonal Injury and Degeneration in Drosophila.

A fundamental feature of nervous systems is a highly specified synaptic connectivity between cells and the ability to adaptively change this connectivity through plasticity mechanisms. Plasticity mechanisms are highly relevant for responding to nervous system damage, and studies using nervous system injury paradigms in Drosophila (as well as other model organisms) have revealed conserved molecular pathways that are triggered by axon damage. Simple assays that introduce injuries to axons in either adult flies or larvae have proven to be particularly powerful for uncovering mechanisms of axonal degeneration and clearance. They have also been used to reveal requirements for regrowth of axons and dendrites, as well as signaling pathways that regulate cellular responses to nerve injury. Here we review commonly used and simple to carry out techniques that enable experimenters to study responses to axonal damage in either adult flies (following antennal transection) or larvae (following nerve crush to segmental nerves). Because axons and dendrites in the larval peripheral nervous system can be readily visualized through the translucent cuticle, another versatile method to probe injury responses is to focus high-energy laser light to a small and specific location in the animal. We therefore discuss a method for immobilizing intact larvae for imaging through the cuticle to carry out injury by pulse dye laser, which can be used to generate many different kinds of injuries and directed ablations within intact larvae. These techniques, combined with powerful genetic tools in Drosophila, make the fruit fly an excellent model system for studying the effects of injury and the mechanisms of axon degeneration, synapse plasticity, and immune response.

Clinical features of COVID-19-related optic neuritis: a retrospective study.

This retrospective study aimed to investigate the clinical features of optic neuritis associated with COVID-19 (COVID-19 ON), comparing them with neuromyelitis optica-associated optic neuritis (NMO-ON), myelin oligodendrocyte glycoprotein-associated optic neuritis (MOG-ON), and antibody-negative optic neuritis (antibody-negative ON). Data from 117 patients (145 eyes) with optic neuritis at the Shantou International Eye Center (March 2020-June 2023) were categorized into four groups based on etiology: Group 1 (neuromyelitis optica-related optic neuritis, NMO-ON), Group 2 (myelin oligodendrocyte glycoprotein optic neuritis, MOG-ON), Group 3 (antibody-negative optic neuritis, antibody-negative ON), and Group 4 (optic neuritis associated with COVID-19, COVID-19 ON). Characteristics of T2 and enhancement in orbital magnetic resonance imaging (MRI) were assessed. Best-corrected visual acuity (BCVA) was compared before treatment, at a short-term follow-up (14 days), and at the last follow-up after treatment. The COVID-19-associated optic neuritis (COVID-19 ON) group exhibited 100% bilateral involvement, significantly surpassing other groups (P < 0.001). Optic disk edema was observed in 100% of COVID-19 ON cases, markedly differing from neuromyelitis optica-related optic neuritis (NMO-ON) (P = 0.023). Orbital magnetic resonance imaging (MRI) revealed distinctive long-segment lesions without intracranial involvement in T1-enhanced sequences for the COVID-19 ON group compared to the other three groups (P < 0.001). Discrepancies in optic nerve sheath involvement were noted between the COVID-19 ON group and both NMO-ON and antibody-negative optic neuritis (antibody-negative ON) groups (P = 0.028). Before treatment, no significant difference in best-corrected visual acuity (BCVA) existed between the COVID-19 ON group and other groups. At the 14-day follow-up, BCVA in the COVID-19 ON group outperformed the NMO-ON (P < 0.001) and antibody-negative ON (P = 0.028) groups, with no significant difference observed compared to the myelin oligodendrocyte glycoprotein optic neuritis (MOG-ON) group. At the last follow-up after treatment, BCVA in the COVID-19 ON group significantly differed from the NMO-ON group (P < 0.001). Optic neuritis associated with COVID-19 (COVID-19 ON) predominantly presents with bilateral onset and optic disk edema. Orbital magnetic resonance imaging (MRI) demonstrates that COVID-19 ON presents as long-segment enhancement without the involvement of the intracranial segment of the optic nerve in T1-enhanced images. Glucocorticoid therapy showed positive outcomes.

A Novel In Vitro Pathological Model for Studying Neural Invasion in Non-Melanoma Skin Cancer.

Neural Invasion (NI) is a key pathological feature of cancer in the colonization of distant tissues, and its underlying biological mechanisms are still scarcely known. The complex interactions between nerve and tumor cells, along with the stroma, make it difficult to reproduce this pathology in effective study models, which in turn has limited the understanding of NI pathogenesis. In this study, we have designed a three-dimensional model of NI squamous cell carcinoma combining human epidermoid carcinoma cells (hECCs) with a complete peripheral nerve segment encapsulated in a fibrine-agarose hydrogel. We recreated two vital processes of NI: a pre-invasive NI model in which hECCs were seeded on the top of the nerve-enriched stroma, and an invasive NI model in which cancer cells were immersed with the nerve in the hydrogel. Histological, histochemical and immunohistochemical analyses were performed to validate the model. Results showed that the integration of fibrin-agarose advanced hydrogel with a complete nerve structure and hECCs successfully generated an environment in which tumor cells and nerve components coexisted. Moreover, this model correctly preserved components of the neural extracellular matrix as well as allowing the proliferation and migration of cells embedded in hydrogel. All these results suggest the suitability of the model for the study of the mechanisms underlaying NI.

Nerve Detection and Visualization Using Hyperspectral Imaging for Surgical Guidance.

During surgery of delicate regions, differentiation between nerve and surrounding tissue is crucial. Hyperspectral imaging (HSI) techniques can enhance the contrast between types of tissue beyond what the human eye can differentiate. Whereas an RGB image captures 3 bands within the visible light range (e.g., 400 nm to 700 nm), HSI can acquire many bands in wavelength increments that highlight regions of an image across a wavelength spectrum. We developed a workflow to identify nerve tissues from other similar tissues such as fat, bone, and muscle. Our workflow uses spectral angle mapper (SAM) and endmember selection. The method is robust for different types of environment and lighting conditions. We validated our workflow on two samples of human tissues. We used a compact HSI system that can image from 400 to 1700 nm to produce HSI of the samples. On these two samples, we achieved an intersection-over-union (IoU) segmentation score of 84.15% and 76.73%, respectively. We showed that our workflow identifies nerve segments that are not easily seen in RGB images. This method is fast, does not rely on special hardware, and can be applied in real time. The hyperspectral imaging and nerve detection approach may provide a powerful tool for image-guided surgery.

Zoster-associated Limb Paralysis: Clinical and Electrophysiological Data of 15 Cases with Segmental Zoster Paresis with the Literature Review

ABSTRACT Background: Herpes zoster (HZ) is a viral disease characterized by skin eruptions and pain in specific dermatomes. Focal motor weakness that appears in the segment of skin eruptions is a rare complication of this infection. Because of the difficulty in clinically diagnosing thoracic or upper cervical motor weakness and due to the pain that causes overlooking of weakness, the true incidence of this complication is not known. In this study, we want to review the clinical presentation of segmental zoster paresis and also discuss electrophysiological findings with the involvement of nerve, plexus parts, or spinal roots. Methods: Electromyography records were examined retrospectively from 2010 to 2023 for patients who had HZ-associated limb paresis. Clinical data were reviewed and abstracted, and patients whose clinical limb weakness and sensory deficits conformed to the distribution of peripheral nerve (s) or spinal root and whose electrodiagnostic evaluation corroborated the localization, were included in the series. Results: Fifteen patients were included in our study. Ten of them were men and five of them were women. Paresis and neuropathic pain are the main complaints. In all patients, the distribution of paresis was consistent with the area of skin eruptions. C8–T1 in the upper extremity and L5–S1 in the lower extremity are the most commonly involved segments. Electrophysiological findings showed radicular involvement in three cases, brachial plexus in six cases, ulnar nerve in one case, sciatic nerve in two cases, and fibular nerve in three cases. Axonopathy is the main detected pathology in all cases. Conclusion: Segmental zoster paresis is a rare complication of cutaneous zona zoster and it affects different nerve segments. Clinicians should be aware of clinical and electrophysiological findings of this disease for the appropriate management of the patients.

128 The Sagittal Angle of the Trigeminal Nerve at the Porus Trigeminus is a Radiologic Predictor of Surgical Outcome in Microvascular Decompression for Classical Trigeminal Neuralgia

INTRODUCTION: Classical Trigeminal Neuralgia (cTN) is a facial pain syndrome with specific diagnostic criteria, including paroxysms that last 1-120 seconds, are sharp, stabbing, or electric in character, and are induced by innocuous stimuli. The most commonly accepted cause of cTN is neurovascular compression (NVC) of the proximal cisternal segment of the trigeminal nerve by an adjacent artery. Microvascular decompression surgery (MVD) provides immediate and durable relief in many patients. METHODS: Pre-operative MRIs from 300 patients with cTN who underwent MVD were analyzed to identify patients with a hyperacute SATNaPT (defined as less than 3 standard deviations below the mean). The rate of surgical success (pain-free after at least 12 months) was compared between patients with a hyperacute SATNaPT and all other patients. RESULTS: Patients without a hyperacute SATNaPT had an 82% likelihood of surgical success, whereas patients with a hyperacute SATNaPT had a 58% likelihood of surgical success (p &lt; 0.05). Patients with a hyperacute SATNaPT who also had no evidence of vascular compression on preoperative MRI had an even lower likelihood of success (29%, p &lt; 0.05). CONCLUSIONS: In patients with cTN being considered for MVD, a hyperacute SATNaPT is a negative prognostic biomarker that predicts a higher likelihood of surgical failure. Patients with a hyperacute SATNaPT, particularly those without MRI evidence of vascular compression, may benefit from other surgical treatments or a modification of MVD to adequately address the underlying cause of cTN.

Secondary Trigeminal Neuralgia Caused by Cerebellopontine Angle Arachnoid Cyst in A 27-Year-Old Female: A Case Report

Purpose: Secondary (TN) caused by an arachnoid cyst in the (CPA) region is a rare finding. Based on the reported literature, there are only 5 cases of secondary trigeminal neuralgia caused by an arachnoid cyst in the cerebellopontine angle region. Case report: A 27-year-old female presented to our neurosurgery clinic with a 2-year history of brief episodes of paroxysm pain in the left cheek. The pain was described as an electric shock-like pain triggered by simple stimuli. The magnetic resonance imaging (MRI) showed a well-confined cystic lesion in the left CPA, which compresses the left pons and the cisternal segment of the left trigeminal nerve. The patient was managed operatively to fenestrate the cyst and decompress the trigeminal nerve. The histopathological result of the cyst wall was consistent with an arachnoid cyst. Six months after surgery, the patient is in good health condition and symptom-free without medication. Conclusion: Arachnoid cyst in the CPA region is one of the rare causes of secondary TN. Preoperative imaging with MRI is important to provide better results to differentiate the pathology. Surgical treatment to fenestrate the arachnoid cyst and decompress the trigeminal nerve have a good result and can improve the patient’s quality of life.

Sporadic Optic Nerve Glioma Causing Bitemporal Hemianopia

Abstract Primary tumours of the optic nerve are relatively rare. Optic nerve gliomas are usually seen in children under the age of 10 and present with gradual vision loss followed by proptosis. A 19-year-old female presented to our neuro-ophthalmology clinic with chief complaints of disturbances in vision in both eyes and headache. Ocular examination showed best corrected visual acuity (BCVA) of 6/6 in both eyes and visual field analysis revealed bitemporal hemianopia. Urgent neuroimaging was advised and her MRI brain revealed optic pathway glioma involving the intracranial segment of right optic nerve and optic chiasma. Improvement in vision was noted during post-surgical follow-up. We present this case to highlight the importance of visual field examination in a young patient with headache, even with a BCVA of 6/6.

Comparison of the activation level in the sensorimotor cortex between motor point and proximal nerve bundle electrical stimulation

Objective. Neuromuscular electrical stimulation (NMES) is widely used for motor function rehabilitation in stroke survivors. Compared with the conventional motor point (MP) stimulation, the stimulation at the proximal segment of the peripheral nerve (PN) bundles has been demonstrated to have multiple advantages. However, it is not known yet whether the PN stimulation can increase the cortical activation level, which is crucial for motor function rehabilitation. Approach. The current stimuli were delivered transcutaneously at the muscle belly of the finger flexors and the proximal segment of the median and ulnar nerves, respectively for the MP and PN stimulation. The stimulation intensity was determined to elicit the same contraction levels between the two stimulation methods in 18 healthy individuals and a stroke patient. The functional near-infrared spectroscopy and the electromyogram were recorded to compare the activation pattern of the sensorimotor regions and the target muscles. Main Results. For the healthy subjects, the PN stimulation induced significantly increased concentration of the oxygenated hemoglobin in the contralateral sensorimotor areas, and enhanced the functional connectivity between brain regions compared with the MP stimulation. Meanwhile, the compound action potentials had a smaller amplitude and the H-reflex became stronger under the PN stimulation, indicating that more sensory axons were activated in the PN stimulation. For the stroke patient, the PN stimulation can elicit finger forces and induce activation of both the contralateral and ipsilateral motor cortex. Conclusions. Compared with the MP stimulation, the PN stimulation can induce more cortical activation in the contralateral sensorimotor areas possibly via involving more activities in the central pathway. Significance. This study demonstrated the potential of the PN stimulation to facilitate functional recovery via increasing the cortical activation level, which may help to improve the outcome of the NMES-based rehabilitation for motor function recovery after stroke.