Pontomedullary Junction Research Articles

Super-Resolution in Clinically Available Spinal Cord MRIs Enables Automated Atrophy Analysis.

Measurement of the mean upper cervical cord area (MUCCA) is an important biomarker in the study of neurodegeneration. However, dedicated high-resolution scans of the cervical spinal cord are rare in standard-of-care imaging due to timing and clinical usability. Most clinical cervical spinal cord imaging is sagittally acquired in 2D with thick slices and anisotropic voxels. As a solution, previous work describes high-resolution T1-weighted brain imaging for measuring the upper cord area, but this is still not common in clinical care. We propose using a zero-shot super-resolution technique, SMORE, already validated in the brain, to enhance the resolution of 2D-acquired scans for upper cord area calculations. To incorporate super-resolution in spinal cord analysis, we validate SMORE against high-resolution research imaging and in a real-world longitudinal data analysis. Super-resolved images reconstructed using SMORE showed significantly greater similarity to the ground truth than low-resolution images across all tested resolutions (p<0.001 for all resolutions in PSNR and MSSIM). MUCCA results from super-resolved scans demonstrate excellent correlation with high-resolution scans (r>0.973 for all resolutions) compared to low-resolution scans. Additionally, super-resolved scans are consistent between resolutions (r>0.969), an essential factor in longitudinal analysis. Compared to clinical outcomes such as walking speed or disease severity, MUCCA values from low-resolution scans have significantly lower correlations than those from high-resolution scans. Super-resolved results have no significant difference. In a longitudinal real-world dataset, we show that these super-resolved volumes can be used in conjunction with T1-weighted brain scans to show a significant rate of atrophy (-0.790, p=0.020 vs. -0.438, p=0.301 with low-resolution). Super-resolution is a valuable tool for enabling large-scale studies of cord atrophy, as low-resolution images acquired in clinical practice are common and available. MS=multiple sclerosis; MUCCA=mean upper cervical cord; HR=high-resolution; LR=low-resolution; SR=superresolved; CSC=cervical spinal cord; PMJ=pontomedullary junction; MSSIM=mean structural similarity; PSNR=peak signal-to-noise ratio; EDSS=expanded disability status scale.

DIPG-25. RELATIONSHIP BETWEEN MOLECULAR CLASSIFICATION, ORIGIN AND PROGNOSIS IN DIFFUSE MALIGNANT GLIOMA IN CHILDREN

Abstract INTRODUCTION Diffuse malignant gliomas that occurs in childhood is recognized as a biologically different disease from that in adults. Furthermore, with the recent development of molecular diagnostics, diffuse midline glioma (DMG), which occurs mainly in the thalamus and brainstem, frequently occurs in childhood and have poor prognosis. We report the relationship between imaging findings, origin, and prognosis of diffuse malignant glioma in children or young adult based on our case series. PATIENTS AND METHODS 43 cases of malignant glioma that occurred from childhood to young adult (below 30 years old) and were treated at our hospital since 2004 were registered in the analysis. Of the 42 cases, 24 cases were in brain stem, 11 cases in cerebral hemisphere, 6 cases in thalamus, and 1 case in cerebellar hemisphere. Histological diagnosis was possible in 31 cases, but without histological verification in 11 brain stem lesions. Histological diagnosis included 13 high-grade glioma (GBM, including NOS and G34R mutations), 11 DMG, and 7 anaplastic astrocytoma. RESULTS Of 13 cases of hemispheric high-grade gliomas, 2 cases had long-term survival (both cases received WT1 peptide vaccination), and 1 case survived for more than 5 years (total resection, MGMT methylation). Among the DMGs, 7 cases were found in brain stem (5 pons, 2 pontomedullary junction, 1 cerebellar peduncle, and 1 midbrain), 3 cases in the thalamus. Two cases of onset at the pontomedullary junction were found incidentally, and the symptoms gradually increased during follow-up, and multidisciplinary treatment was performed. Bilateral thalamus DMG with HIST1H3B mutation showed slowly growing and invasion. SUMMARY There were cases of pediatric hemisphere glioblastoma with long-term survival. In addition, the origin and imaging findings of DMG were various, and tumors that originate at the pontomedullary junction may be relatively favorable.

Swallowing-like activity elicited in neonatal rat medullary slice preparation

Swallowing is induced by a central pattern generator in the nucleus tractus solitarius (NTS). We aimed to create a medullary slice preparation to elucidate the neural architecture of the central pattern generator of swallowing (Sw-CPG) and record its neural activities. Experiments were conducted on 2-day-old Sprague–Dawley rats (n = 46). The brainstem-spinal cord was transected at the pontomedullary and cervicothoracic junctions; the medulla was sliced transversely at thicknesses of 600, 700, or 800 μm. The rostral end of the slice was 100 μm rostral to the vagus nerve. We recorded hypoglossal nerve activity and electrically stimulated the vagus nerve or microinjected bicuculline methiodide (BIC) into the NTS. The 800-μm slices generated both rhythmic respiratory activity and electrically elicited neural activity. The 700-μm slices generated only respiratory activity, while the 600-μm slices did not generate any neural activity. BIC microinjection into the NTS in 800-μm slices resulted in the typical activity that closely resembled the swallowing activity reported in other experiments. This swallowing-like activity consistently lengthened the respiratory interval. Despite complete inhibition of respiratory activity, weak swallowing-like activity was observed under bath application of a non-NMDA receptor antagonist. Contrastingly, bath application of NMDA receptor antagonists resulted in a complete loss of swallowing-like activity and no change in respiratory activity. These results suggest that the 800-μm medullary slice preparation contains both afferent and efferent neural circuits and pattern generators of swallowing activity. Additionally, NMDA receptors may be necessary for generating swallowing activity. This medullary slice preparation can therefore elucidate Sw-CPG neural networks.

Somatosensory evoked potentials recorded from DBS electrodes: the origin of subcortical N18.

The different peaks of somatosensory-evoked potentials (SEP) originate from a variety of anatomical sites in the central nervous system. The origin of the median nerve subcortical N18 SEP has been studied under various conditions, but the exact site of its generation is still unclear. While it has been claimed to be located in the thalamic region, other studies indicated its possible origin below the pontomedullary junction. Here, we scrutinized and compared SEP recordings from median nerve stimulation through deep brain stimulation (DBS) electrodes implanted in various subcortical targets. We studied 24 patients with dystonia, Parkinson's disease, and chronic pain who underwent quadripolar electrode implantation for chronic DBS and recorded median nerve SEPs from globus pallidus internus (GPi), subthalamic nucleus (STN), thalamic ventral intermediate nucleus (Vim), and ventral posterolateral nucleus (VPL) and the centromedian-parafascicular complex (CM-Pf). The largest amplitude of the triphasic potential of the N18 complex was recorded in Vim. Bipolar recordings confirmed the origin to be close to Vim electrodes (and VPL/CM-Pf) and less close to STN electrodes. GPi recorded only far-field potentials in unipolar derivation. Recordings from DBS electrodes located in different subcortical areas allow determining the origin of certain subcortical SEP waves more precisely. The subcortical N18 of the median nerve SEP-to its largest extent-is generated ventral to the Vim in the region of the prelemniscal radiation/ zona incerta.

The Anterior Inferior Cerebral Artery Variability in the Context of Neurovascular Compression Syndromes: A Narrative Review.

The anterior inferior cerebellar artery (AICA) is situated within the posterior cranial fossa and typically arises from the basilar artery, usually at the pontomedullary junction. AICA is implicated in various clinical conditions, encompassing the development of aneurysms, thrombus formation, and the manifestation of lateral pontine syndrome. Furthermore, owing to its close proximity to cranial nerves within the middle cerebellopontine angle, AICA's pulsatile compression at the root entry/exit zone of cranial nerves may give rise to specific neurovascular compression syndromes (NVCs), including hemifacial spasm (HFS) and geniculate neuralgia concurrent with HFS. In this narrative review, we undertake an examination of the influence of anatomical variations in AICA on the occurrence of NVCs. Significant methodological disparities between cadaveric and radiological studies (CTA, MRA, and DSA) were found, particularly in diagnosing AICA's absence, which was more common in radiological studies (up to 36.1%) compared to cadaver studies (less than 5%). Other observed variations included atypical origins from the vertebral artery and basilar-vertebral junction, as well as the AICA-and-PICA common trunk. Single cases of arterial triplication or fenestration have also been documented. Specifically, in relation to HFS, AICA variants that compress the facial nerve at its root entry/exit zone include parabola-shaped loops, dominant segments proximal to the REZ, and anchor-shaped bifurcations impacting the nerve's cisternal portion.

뇌교 및 연수 해면상혈관종에 대한 telovelar 접근법의 수술 결과 및 뉘앙스

Background: Brainstem cavernous malformations (CMs) are characterized by dilated sinusoidal channels related to capillary telangiectasia and developmental venous anomalies. Brainstem CM hemorrhages present with focal neurological symptoms, according to their invasive lesions. Surgical removal should be considered for symptomatic and recurrent bleeding of brainstem CMs. Despite the risk of surgery with highly eloquent tissue, surgical removal should be performed to protect patients from stepwise decline due to recurrent hemorrhage. The approaches for treating brainstem CMs are retrosigmoid, far lateral, midline suboccipital with or without telovelar, orbitozygomatic, and supracerebellar-infratentorial. Pontine and medullary CMs are approached via retrosigmoid, far lateral, and suboccipital craniotomies, with or without the telovelar approach. &#x0D; Materials and Methods: The telovelar approach is the standard approach used for pontine brain-stem CMs. Patients with brainstem CMs treated using the telovelar approach were enrolled from three institutions. &#x0D; Results: All three patients had no further neurological deficits after surgery. &#x0D; Conclusions: The surgical results suggest that the telovelar approach for pons and pontomedul-lary junction brainstem CMs is safe and effective.

The Effect of Posterior Fossa Decompression Surgery on Brainstem and Cervical Spinal Cord Dimensions in Adults with Chiari Malformation Type 1

Posterior fossa decompression (PFD) surgery creates more space at the skull base, reduces the resistance to the cerebrospinal fluid motion, and alters craniocervical biomechanics. In this paper, we retrospectively examined the changes in neural tissue dimensions following PFD surgery on Chiari malformation type 1 adults. Measurements were performed on T2-weighted brain magnetic resonance images acquired before and 4months after surgery. Measurements were conducted for neural tissue volume and spinal cord/brainstem width at 4 different locations; 2 width measurements were made on the brainstem and 2 on the spinal cord in the midsagittal plane. Cerebellar tonsillar position (CTP) was also measured before and after surgery. Twenty-five adult patients, with a mean age of 38.9±8.8years, were included in the study. The cervical cord volume increased by an average of 2.3 ± 3.3% (P= 0.002). The width at the pontomedullary junction increased by 2.2 ± 3.5% (P < 0.01), while the width 10mm caudal to this junction increased by 4.2 ± 3.9% (P < 0.0001). The spinal cord width at the base of second cervical vertebra and third cervical vertebra did not significantly change after surgery. The CTP decreased by 60 ± 37% (P < 0.0001) after surgery, but no correlation was found between CTP change and dimension change. The brainstem width and cervical cord volume showed a modest increase after PFD surgery, although standard deviations were large. A reduction in compression after PFD surgery may allow for an increase in neural tissue dimension. However, clinical relevance is unclear and should be assessed in future studies with high-resolution imaging.

A brainstem circuit for the expression of defensive facial reactions in rat

The brainstem houses neuronal circuits that control homeostasis of vital functions. These include the depth and rate of breathing1,2 and, critically, apnea, a transient cessation of breathing that prevents noxious vapors from entering further into the respiratory tract. Current thinking is that this reflex is mediated by two sensory pathways. One known pathway involves vagal and glossopharyngeal afferents that project to the nucleus of the solitary tract.3,4,5 Yet, apnea induced by electrical stimulation of the nasal epithelium or delivery of ammonia vapors to the nose persists after brainstem transection at the pontomedullary junction, indicating that the circuitry that mediates this reflex is intrinsic to the medulla.6 A second potential pathway, consistent with this observation, involves trigeminal afferents from the nasal cavity that project to the muralis subnucleus of the spinal trigeminal complex.7,8 Notably, the apneic reflex is not dependent on olfaction as it can be initiated even after disruption of olfactory pathways.9 We investigated how subnucleus muralis cells mediate apnea in rat. By means of electrophysiological recordings and lesions in anesthetized rats, we identified a pathway from chemosensors in the nostrils through the muralis subnucleus and onto both the preBötzinger and facial motor nuclei. We then monitored breathing and orofacial reactions upon ammonia delivery near the nostril of alert, head-restrained rats. The apneic reaction was associated with a grimace, characterized by vibrissa protraction, wrinkling of the nose, and squinting of the eyes. Our results show that a brainstem circuit can control facial expressions for nocifensive and potentially pain-inducing stimuli.

Pontomedullary junction as a reference for spinal cord cross-sectional area: validation across neck positions

Spinal cord cross-sectional area (CSA) is an important MRI biomarker to assess spinal cord atrophy in various neurodegenerative and traumatic spinal cord diseases. However, the conventional method of computing CSA based on vertebral levels is inherently flawed, as the prediction of spinal levels from vertebral levels lacks reliability, leading to considerable variability in CSA measurements. Computing CSA from an intrinsic neuroanatomical reference, the pontomedullary junction (PMJ), has been proposed in previous work to overcome limitations associated with using a vertebral reference. However, the validation of this alternative approach, along with its variability across and within participants under variable neck extensions, remains unexplored. The goal of this study was to determine if the variability of CSA across neck flexions/extensions is reduced when using the PMJ, compared to vertebral levels. Ten participants underwent a 3T MRI T2w isotropic scan at 0.6 mm3 for 3 neck positions: extension, neutral and flexion. Spinal cord segmentation, vertebral labeling, PMJ labeling, and CSA were computed automatically while spinal segments were labeled manually. Mean coefficient of variation for CSA across neck positions was 3.99 ± 2.96% for the PMJ method vs. 4.02 ± 3.01% for manual spinal segment method vs. 4.46 ± 3.10% for the disc method. These differences were not statistically significant. The PMJ method was slightly more reliable than the disc-based method to compute CSA at specific spinal segments, although the difference was not statistically significant. This suggests that the PMJ can serve as a valuable alternative and reliable method for estimating CSA when a disc-based approach is challenging or not feasible, such as in cases involving fused discs in individuals with spinal cord injuries.

Accuracy of Measurements of the Structural Reserve for Upper Limb Function in Patients With Moderate-to-Severe Stroke.

The structural integrity of the corticospinal tract (CST) is an important biomarker of poststroke upper limb recovery. Injured CST undergoes Wallerian degeneration rostrocaudally during the first few months. However, there is no standardized measurement of the structural integrity of the CST. This study aimed to determine the measurement accuracy of the structural integrity of the CST. This cross-sectional study included 50 consecutive patients with middle cerebral artery stroke who underwent diffusion tensor imaging upon transfer from the acute stroke unit to the inpatient rehabilitation facility (2018-2022). We evaluated hemiplegic upper limb function using Shoulder Abduction and Finger Extension (SAFE) scores. Fractional anisotropy values representing the structural integrity of the CST were evaluated using 4 region of interest-based and 2 tract-based measurements, including the posterior limb of internal capsule, cerebral peduncle, pons, pontomedullary junction, entire CST, and CST in the brainstem. Multivariate linear regression models and the area under the curve (AUC) were used to determine measurement accuracy for hemiplegic upper limb function. The structural integrity of the CST at the pontomedullary junction showed the highest explanatory power, followed by the entire CST, in the multivariate linear regression models (adjusted R2=0.459 and 0.425, respectively). The structural integrity of the CST at the pontomedullary junction also showed the highest AUC, followed by the entire CST, in discriminating patients with a SAFE score of <8 or 5 from those with SAFE ≥8 or 5 (SAFE <8: AUC, 0.90 [95% CI, 0.80-1.00]; AUC, 0.83 [0.66-0.99]; SAFE <5: AUC, 0.87 [0.77-0.96]; AUC, 0.83, [0.72-0.95], respectively). The structural integrity of the CST measured at the pontomedullary junction or entire CST demonstrated the highest accuracy for hemiplegic upper limb function in the subacute phase of stroke.

Comparison of the Retrosigmoid Suprameatal and Anterior Subtemporal Transpetrosal Approaches After Full Exposure of the Internal Acoustic Meatus.

Surgical approaches to the ventral brainstem and petroclival regions are complex, and standard retrosigmoid and subtemporal approaches are often inadequate. Retrosigmoid suprameatal tubercle (RSMTA) and anterior subtemporal transpetrosal (ASTA) approaches may provide extended surgical exposure with less brain retraction. The objective of this study was to evaluate advantages and disadvantages of RSMTA vs ASTA, and illustrate the surgical corridors and 3-dimensional microsurgical anatomy of the related structures. Four silicone-injected adult cadaver heads (8 sides) were dissected to evaluate the accessibility of lesions located at the petrous apex, ventral brainstem, and pontomedullary region using ASTA and RSTMA. Both ASTA and RSMTA provide access from the petrous apex to the ventral lower pons and pontomedullary junction. A greater extent of safely resected bone was found in ASTA vs RSMTA. ASTA provides a larger surgical view to the ventrolateral midpons, peritrigeminal region, superior neurovascular complex, pontomesencephalic junction, and posterior cavernous sinus. Meanwhile, through cranial nerve V mobilization, RSMTA provides a larger surgical view to the lower half part of the pons, ventrolateral part of the pontomedullary junction, and middle and lower neurovascular structures. The choice of surgical approach is determined by considering the area where the lesion originates, lesion size, the anatomic structures to which it extends, and evaluation of the area that can be surgically exposed. Our study highlights the differences between these approaches and important surgical anatomic considerations.

Posterolateral Routes to the Skull Base, Craniocervical Junction, and Jugular Foramen-The Far Lateral Transcondylar Approach and Combined Transpetrosal Transcervical Approaches.

The far lateral approach provides wide surgical access to the lower third of the clivus, pontomedullary junction, and anterolateral foramen magnum and rarely requires craniovertebral fusion. The most common indications for this approach are posterior inferior cerebellar artery and vertebral arteryaneurysms, brainstem cavernous malformations, and tumors anterior to the lower pons and medulla, including meningiomas of the anterior foramen magnum, schwannomas of the lower cranial nerves, and intramedullary tumors at the craniocervical junction. We provide a stepwise description of how we perform the far lateral approach, as well as how to combine the far lateral approach with other skull base approaches, including the subtemporal transtentorial approach, for lesions involving the upper clivus; the posterior transpetrosal approach, for lesions involving the cerebellopontine angle and/or petroclival region; and/or lateral cervical approaches, for lesions involving the jugular foramen or carotid sheath regions.

Cavernous Malformations: What They Have Taught Us.

Cavernous Malformations: What They Have Taught Us.

Abstract Number ‐ 234: Bilateral Non‐Painful Stimulus‐Induced Decerebrated Posturing In A Bilateral Pontine Ischemic Stroke: A Case Report

Introduction A 38 year‐old right‐handed female is a fully functional teacher with past medical history of hypertension, type II Diabetes Mellitus, polycystic ovarian syndrome, and infertility. She presented to our emergency department (ER) on the same day she was discharged twice from a local ER for acute onset persistent non‐fluctuating left‐sided weakness and painful bilateral leg spasms that woke her from sleep. Patient had pertinent exam findings of moderate pharyngeal dysarthria, mild right nasolabial flattening, mild weakness of left upper extremity (LUE), and stereotyped, painful tonic extensor posturing of the bilateral lower extremities associated with back arching and extensor response of bilateral toes. NIH Stroke Scale was 10. Methods We conducted a review of patient clinical documentation. Results MRI Brain showed anterior asymmetric bilateral pontine ischemic strokes at the ventral pontomedullary junction. MRA brain with black blood sequencing revealed multifocal vasculopathy at the right V4, mid‐basilar and left M1 segments. An angiogram showed Moya‐moya type collaterals. Tonic posturing and spasms persisted for several hours requiring muscle relaxants and benzodiazepines for symptomatic management. Unfortunately, the patient had worsening LUE weakness, inability to swallow and was found to have total vocal cord paralysis. She was intubated for airway protection and after failing extubation required tracheostomy and percutaneous gastrostomy placement. Initial workup revealed poorly controlled hyperlipidemia (LDL 162) and diabetes (A1c 8.7%), CRP 7–9, hypercoagulable panel and transthoracic echocardiogram were unremarkable. Lumbar puncture was also unremarkable (CSF TNC 2, RBC 3, glucose 116, protein 35, Enterovirus and HSV 1,2 PCR, Streptococcus antigen and VDRL were negative). Anticoagulation was started for an incidental right lower lobe subsegmental pulmonary embolism. Ultimately, the patient was discharged to inpatient rehabilitation (IPR) with a Modified Rankin Scale (mRS) of 4, on day 19th of hospitalization with some improvement in oral intake and decannulation of tracheostomy. Conclusions Movement disorders caused by strokes have been described in the literature. In their majority, they are secondary to a supratentorial injury. There have been some cases published of infratentorial, unilateral lesions that have caused different types of involuntary movements. More specifically, two papers described tonic spasms seen in pontine strokes. To our knowledge, this is a novel description of a case of bilateral pontine ischemic stroke that causes painful tonic spasms associated with decerebrate rigidity or posturing. Our hypothesis is that given the localization of the strokes in the anterior area of the inferior segment of the pons there may be involvement of the corticospinal, corticobulbar, and rubrospinal tracts which may be responsible for this presentation. Posterior circulation strokes can be missed about 9–14% of the time, possibly due to atypical presentations. We believe that presenting this case can help to improve the current available literature on this topic.

Automatic measure and normalization of spinal cord cross-sectional area using the pontomedullary junction.

Spinal cord cross-sectional area (CSA) is a relevant biomarker to assess spinal cord atrophy in neurodegenerative diseases. However, the considerable inter-subject variability among healthy participants currently limits its usage. Previous studies explored factors contributing to the variability, yet the normalization models required manual intervention and used vertebral levels as a reference, which is an imprecise prediction of the spinal levels. In this study we implemented a method to measure CSA automatically from a spatial reference based on the central nervous system (the pontomedullary junction, PMJ), we investigated factors to explain variability, and developed normalization strategies on a large cohort (N = 804). Following automatic spinal cord segmentation, vertebral labeling and PMJ labeling, the spinal cord CSA was computed on T1w MRI scans from the UK Biobank database. The CSA was computed using two methods. For the first method, the CSA was computed at the level of the C2-C3 intervertebral disc. For the second method, the CSA was computed at 64 mm caudally from the PMJ, this distance corresponding to the average distance between the PMJ and the C2-C3 disc across all participants. The effect of various demographic and anatomical factors was explored, and a stepwise regression found significant predictors; the coefficients of the best fit model were used to normalize CSA. CSA measured at C2-C3 disc and using the PMJ differed significantly (paired t-test, p-value = 0.0002). The best normalization model included thalamus, brain volume, sex and the interaction between brain volume and sex. The coefficient of variation went down for PMJ CSA from 10.09 (without normalization) to 8.59%, a reduction of 14.85%. For CSA at C2-C3, it went down from 9.96 to 8.42%, a reduction of 15.13 %. This study introduces an end-to-end automatic pipeline to measure and normalize cord CSA from a neurological reference. This approach requires further validation to assess atrophy in longitudinal studies. The inter-subject variability of CSA can be partly accounted for by demographics and anatomical factors.

Cerebro-cerebellar motor networks in clinical subtypes of Parkinson’s disease

Parkinson’s disease (PD) patients can be classified in tremor-dominant (TD) and postural-instability-and-gait-disorder (PIGD) motor subtypes. PIGD represents a more aggressive form of the disease that TD patients have a potentiality of converting into. This study investigated functional alterations within the cerebro-cerebellar system in PD-TD and PD-PIGD patients using stepwise functional connectivity (SFC) analysis and identified neuroimaging features that predict TD to PIGD conversion. Thirty-two PD-TD, 26 PD-PIGD patients and 60 healthy controls performed clinical/cognitive evaluations and resting-state functional MRI (fMRI). Four-year clinical follow-up data were available for 28 PD-TD patients, who were classified in 10 converters (cTD-PD) and 18 non-converters (ncTD-PD) to PIGD. The cerebellar seed-region was identified using a fMRI motor task. SFC analysis, characterizing regions that connect brain areas to the cerebellar seed at different levels of link-step distances, evaluated similar and divergent alterations in PD-TD and PD-PIGD. The discriminatory power of clinical data and/or SFC in distinguishing cPD-TD from ncPD-TD patients was assessed using ROC curve analysis. Compared to PD-TD, PD-PIGD patients showed decreased SFC in temporal lobe and occipital lobes and increased SFC in cerebellar cortex and ponto-medullary junction. Considering the subtype-conversion analysis, cPD-TD patients were characterized by increased SFC in temporal and occipital lobes and in cerebellum and ponto-medullary junction relative to ncPD-TD group. Combining clinical and SFC data, ROC curves provided the highest classification power to identify conversion to PIGD. These findings provide novel insights into the pathophysiology underlying different PD motor phenotypes and a potential tool for early characterization of PD-TD patients at risk of conversion to PIGD.

A-2 Neuropsychological and Neuropsychiatric Symptoms Following Hypertrophic Olivary Degeneration

Abstract Objective: Hypertrophic Olivary Degeneration (HOD) is a rare neurological condition causing hypertrophy and eventual degeneration of the inferior olivary nucleus via transneuronal degeneration in the dentato-rubro-olivary pathway (DROP), or Guillain–Mollaret triangle. HOD is considered unique because the olive initially becomes hypertrophic rather than atrophic. Etiology is often cerebral vascular insult, cavernous malformation, surgical resection, and neurological disease, albeit cause may be unclear. While the neurologic and imaging findings have been well delineated in the literature, few studies investigate the neuropsychological impact. Methods: With consent, a review of the medical chart was conducted of a 39-year-old female with hypertension referred for assessment due to progressive cognitive, motor, and psychiatric symptoms. Results: Physical symptoms included progressive limb and trunk ataxia, palatal tremor, and opsoclonus myoclonus that plateaued within 4 years. Initial Magnetic Resonance Imaging (MRI) revealed bilateral, nonenhancing hyperintensity of the pontomedullary junction and enlargement of the inferior olive. Subsequent MRI displayed cerebellar atrophy. Cognitive assessment documented significant executive, language, spatial and fine motor dexterity deficits, alongside depression, anxiety, emotional blunting, and passive suicidality. She reported believing her neighbors were listening and following her in public. She remained semi-independent in daily living. Conclusions: This is the first case study that captures the neurocognitive profile associated with HOD and associated degeneration of DROP. This case highlights the potential for Cognitive Cerebellar Affective Syndrome (CCAS) to arise from damage to adjacent cerebellar pathways via transneuronal degeneration of brainstem circuits. It also provides evidence for the presence of delusions within CCAS as dysmetria of thought.

Pearls & Oy-sters: Vertical Diplopia and Ocular Torsion: Peripheral vs Central Localization.

We describe a case with torsional deviation of the eyes from a brainstem lesion. Torsional eye movement refers to changes in the position of the eyes in the roll plane around the visual axis. When the head is tilted laterally (that is, rolled toward the shoulder), the eyes roll in the opposite direction as part of the torsional vestibulo-ocular reflex known as the ocular counter-roll. Pathologies that affect the otolith-ocular pathway can lead to a torsional deviation of the eyes as part of the ocular tilt reaction (OTR) that also causes vertical deviation of the eyes (skew deviation) and head tilt. Lesions caudal to the pontomedullary junction (such as the labyrinth, eighth cranial nerve, or vestibular nucleus) result in an OTR with ipsiversive torsional deviation, whereas lesions rostral to the junction result in an OTR with contraversive torsional deviation. Furthermore, torsional deviation of the eyes in the OTR is conjugate (incyclotorsion in the higher eye and excyclotorsion in the lower eye), whereas torsional deviation from ocular palsy in peripheral lesions is disconjugate (e.g., exyclotorsion only in the higher eye with superior oblique palsy). Therefore, the pattern of torsional eye deviation can be helpful in localizing the lesion. Several techniques including fundus photography, double Maddox rod testing, optical coherence tomography, and video-oculography are used to measure torsional eye position.

Structural Integrity and Functional Neural Activity Associated with Oral Language Function after Stroke.

(1) Background: The impairment of language function after a stroke is common. It is unclear how the brain reorganizes for language function after cerebral infarction. The aim of this observational study is to investigate the association of structural integrity and functional neural activity with language function in aphasic patients with middle cerebral artery infarction. (2) Methods: Magnetic resonance images and scores from the Western Aphasia Battery on 20 patients were retrieved from medical records. A Voxel-wise linear regression analysis was performed using fractional anisotropy maps or the fractional amplitude of low-frequency fluctuation maps as dependent variables and scores of oral language function as independent variables while controlling for age and time elapsed after stroke. (3) Results: Spontaneous speech was positively associated with fractional anisotropy in the left dorsal stream and the right posterior corpus callosum and with the fractional amplitude of the low-frequency fluctuation of cranial nuclei in the pontomedullary junction. Comprehension was positively associated with the left ventral stream. Naming was positively associated with the left ventral stream and the bilateral occipitofrontal fasciculus, as well as with the fractional amplitude of low-frequency fluctuation of the supramarginal gyrus in the left hemisphere. (4) Conclusions: The dorsal and ventral streams are important for articulation and meaning after the reorganization of neural circuits following stroke. Subdomains of oral language function with a visual component are dependent on the visual association areas located in the right hemisphere.

Radiological anatomy of the vertebrobasilar artery in a select South African population

IntroductionThe vertebrobasilar artery is the combination of the bilateral vertebral artery and the basilar artery. The basilar artery extends from the confluence of the bilateral vertebral arteries at the pontomedullary junction, terminating at the ponto-mesencephalic junction. Depending on the geometry of the intracranial vertebral arteries and the incidence of arterial tortuosity, the basilar artery may exhibit variable course patterns. This morphologic deformation has negative implications on the hemodynamic of blood flow in the posterior circulatory territory by inducing the development of infarcts and thus increasing the risk of vascular pathologies. Lateral displacement of the basilar artery has been associated with migraines and frequent headaches. The present study aimed to investigate the radiological anatomy of the basilar artery within a select South African cohort of patients in terms of the course patterns and morphometry. Materials and methodThe study is an observational retrospective chart review of 100 radiographic images (Average age: 59; Males: 60%; Females: 40%) of multidetector computed tomography angiography, of the vertebrobasilar artery to establish the course pattern of the basilar artery. ResultsAsymmetry of the intracranial vertebral artery as well as lateral displacement of the basilar artery have been reported with varying course patterns. The average length and diameter of the basilar artery were reported as 25.41 ± 6.44 mm 2.72 ± 0.85 mm, respectively. ConclusionThe geometric characteristics of the vertebrobasilar system in the population studied can predispose to some cerebrovascular diseases in the posterior circulatory territory and influence the build-up of atherosclerotic plaque. Knowledge of this variant anatomy is imperative to the clinician in the diagnosis of many vascular-related pathologies.