Implications of DNA Methylation Classification in Diagnosing Ependymoma

BACKGROUND

Ependymoma is a central nervous system (CNS) tumor that arises from the ependymal cells of the brain's ventricles and spinal cord. The histopathology of ependymomas is indistinguishable regardless of the site of origin, and the prognosis varies. Recent studies have revealed that the development site and prognosis reflect the genetic background. In this study, we used genome-wide DNA methylation array analysis to investigate the epigenetic background of ependymomas from different locations treated at our hospital.

METHODS

Four cases of posterior fossa ependymomas and 11 cases of spinal ependymomas were analyzed.

RESULTS

DNA methylation profiling using the DKFZ methylation classifier showed that the methylation diagnoses of the 2 cases differed from the histopathological diagnoses, and 2 cases could not be classified. Tumor that spread from the brain to the spinal cord was molecularly distinguishable from other primary spinal tumors.

CONCLUSIONS

Although adding DNA methylation classification to conventional diagnostic methods may be helpful, the diagnosis in some cases remains undetermined. This may affect decision-making regarding treatment strategies and follow-up. Further investigations are required to improve the diagnostic accuracy of these tumors.

Antagonism of metabotropic glutamate receptor type 5 prevents levodopa-induced dyskinesia development in a male rat model of Parkinson's disease: Electrophysiological evidence

Levodopa-induced dyskinesia (LID) is a common complication in patients with advanced Parkinson's disease (PD) undergoing treatment with levodopa. Glutamate receptor antagonists can suppress LID; however, the underlying mechanisms remain unclear. Here, we aimed to evaluate the effect of 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine (MTEP), a metabotropic glutamate receptor 5 (mGluR5) antagonist, on dyskinesia. We recorded the neuronal activity of the entopeduncular nucleus and examined responses to cortical electric stimulation in the control group (n = 6) and three groups of rats (male PD model). Saline was intraperitoneally administered to dopamine lesioned (DL) rats (n = 6), levodopa/benserazide (L/B) was administered to LID rats (n = 8), and L/B combined with MTEP was administered to MTEP rats (n = 6) twice daily for 14 days. We administered L/B to LID and MTEP rats 48 h after the final administration of MTEP to examine the chronic effect of MTEP. The control and DL groups did not have LID. The MTEP group had less LID than the LID group (p < .01) on day 1 and day 18. The control group had a typical triphasic pattern consisting of early excitation (early-Ex), inhibition, and late excitation (late-Ex). However, the inhibition phase disappeared, was partially observed, and was fully suppressed in the DL, LID, and MTEP groups, respectively. The cortico-striato-entopeduncular pathway is important in the pathophysiology of LID. mGluR5 antagonism suppresses LID progression by preventing physiological changes in the cortico-striato-entopeduncular pathway. Future studies are required to validate these results.

Effectiveness and safety of MR-guided focused ultrasound thalamotomy in patients with essential tremor and low skull density ratio: a study of 101 cases

OBJECTIVE

The objective was to investigate the effectiveness and safety of MR-guided focused ultrasound (MRgFUS) treatment in patients with essential tremor, particularly those with low skull density ratio (SDR) and including those with very low SDR, and to identify the factors influencing treatment effectiveness and to provide insights into therapeutic approaches for patients with lower SDR.

METHODS

Real-world data from 101 patients who underwent MRgFUS between July 2019 and March 2022 at a single institution were analyzed. Tremor severity was assessed using the Fahn-Tolosa-Marin Clinical Rating Scale for Tremor (CRST). The patients were categorized into quartile groups based on their mean SDR, and the characteristics, treatment effectiveness, treatment parameters, and adverse events were evaluated among these subgroups.

RESULTS

Patients were classified into 4 quartiles based on the mean SDR: quartile 1 (Q1) (SDR 0.26-0.37), Q2 (SDR 0.38-0.42), Q3 (SDR 0.43-0.49), and Q4 (SDR 0.50-0.75). MRgFUS significantly improved total CRST and tremor score across all SDR subgroups. Additionally, there were no significant differences in the improvement rates among the 4 subgroups. Analysis of the treatment parameters revealed that lower mean SDR was associated with lower target maximum temperature and smaller coagulation volume after focused ultrasound (FUS). Regarding adverse events, headache and nausea during FUS and facial and head edema on the day after surgery were more frequent in the Q1 subgroup (very low-SDR group). In contrast, numbness was more common in the Q4 subgroup. However, all these adverse events had resolved by the 3-month follow-up except numbness.

CONCLUSIONS

This study suggested that MRgFUS is effective and safe for patients with medication-resistant essential tremor, including those with very low mean SDR. However, the very low-SDR group had insufficient temperature elevation at the target site compared with the high-SDR group, suggesting the need for a different strategy. Notably, with careful adjustments and considerations, positive outcomes can still be achieved in patients with very low SDR. Therefore, very low SDR should not be considered an absolute exclusion criterion because it is expected to increase the number of patients who benefit from MRgFUS.

Video Motion Analysis as a Quantitative Evaluation Tool for Essential Tremor during Magnetic Resonance-Guided Focused Ultrasound Thalamotomy

The Clinical Rating Scale for Tremor (CRST) is commonly used to evaluate essential tremor (ET) during focused ultrasound (FUS) thalamotomy. However, it faces challenges such as the ceiling effect and test-retest variability. This study explored the utility of videographic motion analysis as an evaluation index for ET. Forty-three patients with ET performed postural tremor and line-drawing tasks recorded on video, and the data were analyzed using motion analysis software. The test-retest and inter-rater reliability, correlations with the CRST and tremor scores, and pre/post-FUS treatment comparisons were analyzed. The video motion analysis showed excellent test-retest and inter-rater reliability. In the postural tremor tasks, video parameter amplitude significantly correlated with the CRST and tremor scores. Similarly, for the line-drawing task, video parameter amplitude showed significant correlations with CRST and tremor scores, effectively addressing the ceiling effect. Regarding post-FUS treatment improvements, changes in the CRST and tremor scores were significantly associated with changes in video parameter amplitude. In conclusion, quantitative analysis of the video motion of ET enables precise evaluation of kinematic characteristics and effectively resolves the ceiling effect and test-retest variability. The video motion analysis score accurately reflected the tremor severity and treatment effects, demonstrating its high clinical utility.

Three-dimensional gait analysis of the effect of directional steering on gait in patients with Parkinson's disease

INTRODUCTION

Deep Brain Stimulation (DBS) is an option to treat advanced Parkinson's Disease (PD), but can cause gait disturbance due to stimulation side efffects. This study aims to evaluate the objective effect of directional current steering by DBS on gait performance in PD, utilizing a three-dimensional gait analysis system.

METHODS

Eleven patients diagnosed with PD and were implanted with directional lead were recruited. The direction of the pyramidal tract (identified by the directional mode screening) was set as 0°. Patients performed the six-meter-walk test and the time up-and-go (TUG) test while an analysis system recorded gait parameters utilizing a three-dimensional motion capture camera. The gait parameters were measured for the baseline, the directional steering at eight angles (0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°), and the conventional ring mode with 1, 2, and 3 mA. Pulse width and frequency were fixed. Placebo stimulation (0 mA) was used for a control.

RESULTS

Eleven patients completed the study. No significant difference were observed between gait parameters during the directional, baseline, placebo, or ring modes during the six-meter-walk test (p > 0.05). During the TUG test, stride length was significantly different between 0° and other directions (p < 0.001), but no significant differences were observed for the other gait parameters. Stride width was non-significantly narrower in the direction of 0°.

CONCLUSION

Controlling stimulation using directional steering may improve gait in patients with PD, while avoiding pyramidal side effects.

Improvement in Intraoperative Image Quality in Transcranial Magnetic Resonance-Guided Focused Ultrasound Surgery Using Transmitter Gain Adjustment

INTRODUCTION

Transcranial magnetic resonance-guided focused ultrasound surgery (TcMRgFUS) has the advantage of allowing immediate evaluation of therapeutic effects after each sonication and intraoperative magnetic resonance imaging (MRI) to visualize the lesion. When the image shows that the lesion has missed the planned target and the therapeutic effects are insufficient, the target of the subsequent ablation can be finely adjusted based on the image. The precision of this adjustment is determined by the image quality. However, the current intraoperative image quality with a 3.0T MRI system is insufficient for precisely detecting the lesion. Thus, we developed and validated a method for improving intraoperative image quality.

METHODS

Because intraoperative image quality is affected by transmitter gain (TG), we acquired T2-weighted images (T2WIs) with two types of TG: the automatically adjusted TG (auto TG) and the manually adjusted TG (manual TG). To evaluate the character of images with 2 TGs, the actual flip angle (FA), the image uniformity, and the signal-to-noise ratio (SNR) were measured using a phantom. Then, to assess the quality of intraoperative images, T2WIs with both TGs were acquired during TcMRgFUS for 5 patients. The contrast-to-noise ratio (CNR) of the lesion was retrospectively estimated.

RESULTS

The images of the phantom with the auto TG showed substantial variations between the preset and actual FAs (p < 0.01), whereas on the images with the manual TG, there were no variations between the two FAs (p > 0.05). The total image uniformity was considerably lower with the manual TG than with the auto TG (p < 0.01), indicating that the image's signal values with the manual TG were more uniform. The manual TG produced significantly higher SNRs than the auto TG (p < 0.01). In the clinical study, the lesions were clearly detected in intraoperative images with the manual TG, but they were difficult to identify in images with the auto TG. The CNR of lesions in images with manual TG was considerably higher than in images with auto TG (p < 0.01).

CONCLUSION

Regarding intraoperative T2WIs using a 3.0T MRI system during TcMRgFUS, the manual TG method improved image quality and delineated the ablative lesion more clearly than the current method with auto TG.

Cavitation with low-energy sonication during focused ultrasound thalamotomy for a patient with tremor-dominant Parkinson's disease: a potential risk

We report a patient with tremor-dominant Parkinson's disease who had a mild cavitation bioeffect during magnetic resonance-guided focused ultrasound thalamotomy. During the aligning phase with low-energy sonication, cavitation caused mild dysarthria and paresthesia, prompting treatment cessation. At the same time, tremor and rigidity improved. MRI revealed extensive high-intensity lesions in the thalamus 1 day after the procedure followed by steroid infusion, which resulted in resolution of adverse events. Tremor and rigidity improved 1.5 years after the procedure. Although cavitation can relieve tremors and rigidity, it should be carefully monitored due to potential permanent adverse events by unpredictable and unknown behaviors.

Deep brain stimulation in posterior subthalamic area for Holmes tremor: Case reports with review of the literature

Background

Holmes tremor (HT) is a refractory tremor associated with cortico-basal ganglia loops and cerebellothalamic tract abnormalities. Various drug treatments have been attempted; however, no treatment method has yet been established. Historically, thalamic deep brain stimulation (DBS) has been performed in medically refractory cases. Recently, the posterior subthalamic area (PSA) has been used for HT. Here, we report cases of HT and review the effectiveness and safety of PSA-DBS for HT.

Cases

We conducted a retrospective chart review of two patients with HT who underwent PSA-DBS. Improvement in tremors was observed 1 year after surgery without apparent complications.

Literature review

We identified 12 patients who underwent PSA-DBS for HT, including our cases. In six patients, PSA was targeted alone; for the rest, the ventralis intermediate nucleus (Vim) of the thalamus and PSA were simultaneously targeted. The Fahn-Tolosa-Marin Tremor Rating Scale improvement rates were 56.8% (range, 33.9-82.1%; n = 6) and 77.8% (range, 42.6-100%; n = 5) for the PSA-DBS and PSA+Vim-DBS, respectively.

Conclusion

Reasonable improvements in HT were observed after PSA-DBS. PSA might be an appropriate target for improving the symptoms of HT. Long-term observations, accumulation of cases, and randomized studies are required in future.

Role of the subthalamic nucleus in perceiving and estimating the passage of time

Sense of time (temporal sense) is believed to be processed by various brain regions in a complex manner, among which the basal ganglia, including the striatum and subthalamic nucleus (STN), play central roles. However, the precise mechanism for processing sense of time has not been clarified. To examine the role of the STN in temporal processing of the sense of time by directly manipulating STN function by switching a deep brain stimulation (DBS) device On/Off in 28 patients with Parkinson's disease undergoing STN-DBS therapy. The test session was performed approximately 20 min after switching the DBS device from On to Off or from Off to On. Temporal sense processing was assessed in three different tasks (time reproduction, time production, and bisection). In the three temporal cognitive tasks, switching STN-DBS to Off caused shorter durations to be produced compared with the switching to the On condition in the time production task. In contrast, no effect of STN-DBS was observed in the time bisection or time reproduction tasks. These findings suggest that the STN is involved in the representation process of time duration and that the role of the STN in the sense of time may be limited to the exteriorization of memories formed by experience.

White matter and nigral alterations in multiple system atrophy-parkinsonian type

Multiple system atrophy (MSA) is classified into two main types: parkinsonian and cerebellar ataxia with oligodendrogliopathy. We examined microstructural alterations in the white matter and the substantia nigra pars compacta (SNc) of patients with MSA of parkinsonian type (MSA-P) using multishell diffusion magnetic resonance imaging (dMRI) and myelin sensitive imaging techniques. Age- and sex-matched patients with MSA-P (n = 21, n = 10 first and second cohorts, respectively), Parkinson’s disease patients (n = 19, 17), and healthy controls (n = 20, 24) were enrolled. Magnetization transfer saturation imaging (MT-sat) and dMRI were obtained using 3-T MRI. Measurements obtained from diffusion tensor imaging (DTI), free-water elimination DTI, neurite orientation dispersion and density imaging (NODDI), and MT-sat were compared between groups. Tract-based spatial statistics analysis revealed differences in diffuse white matter alterations in the free-water fractional volume, myelin volume fraction, and intracellular volume fraction between the patients with MSA-P and healthy controls, whereas free-water and MT-sat differences were limited to the middle cerebellar peduncle in comparison with those with Parkinson’s disease. Region-of-interest analysis of white matter and SNc revealed significant differences in the middle and inferior cerebellar peduncle, pontine crossing tract, corticospinal tract, and SNc between the MSA-P and healthy controls and/or Parkinson’s disease patients. Our results shed light on alterations to brain microstructure in MSA.

Predictors of thermal increase in magnetic resonance-guided focused ultrasound treatment for essential tremor: histogram analysis of skull density ratio values for 1024 elements

OBJECTIVE

Sufficient thermal increase capable of generating thermocoagulation is indispensable for an effective clinical outcome in patients undergoing magnetic resonance-guided focused ultrasound (MRgFUS). The skull density ratio (SDR) is one of the most dominant predictors of thermal increase prior to treatment. However, users currently rely only on the average SDR value (SDRmean) as a screening criterion, although some patients with low SDRmean values can achieve sufficient thermal increase. The present study aimed to examine the numerical distribution of SDR values across 1024 elements to identify more precise predictors of thermal increase during MRgFUS.

METHODS

The authors retrospectively analyzed the correlations between the skull parameters and the maximum temperature achieved during unilateral ventral intermediate nucleus thalamotomy with MRgFUS in a cohort of 55 patients. In addition, the numerical distribution of SDR values was quantified across 1024 elements by using the skewness, kurtosis, entropy, and uniformity of the SDR histogram. Next, the authors evaluated the correlation between the aforementioned indices and a peak temperature > 55°C by using univariate and multivariate logistic regression analyses. Receiver operating characteristic curve analysis was performed to compare the predictive ability of the indices. The diagnostic performance of significant factors was also assessed.

RESULTS

The SDR skewness (SDRskewness) was identified as a significant predictor of thermal increase in the univariate and multivariate logistic regression analyses (p < 0.001, p = 0.013). Moreover, the receiver operating characteristic curve analysis indicated that the SDRskewness exhibited a better predictive ability than the SDRmean, with area under the curve values of 0.847 and 0.784, respectively.

CONCLUSIONS

The SDRskewness is a more accurate predictor of thermal increase than the conventional SDRmean. The authors suggest setting the SDRskewness cutoff value to 0.68. SDRskewness may allow for the inclusion of treatable patients with essential tremor who would have been screened out based on the SDRmean exclusion criterion.

Case Report: Chronic Adaptive Deep Brain Stimulation Personalizing Therapy Based on Parkinsonian State

We describe the case of a 51-year-old man with Parkinson's disease (PD) presenting with motor fluctuations, who received bilateral subthalamic deep brain stimulation (DBS) with an adaptive DBS (aDBS) device, Percept™ PC (Medtronic, Inc. , Minneapolis, MN). This device can deliver electrical stimulations based on fluctuations of neural oscillations of the local field potential (LFP) at the target structure. We observed that the LFP fluctuations were less evident inside the hospital than outside, while the stimulation successfully adapted to beta oscillation fluctuations during the aDBS phase without any stimulation-induced side effects. Thus, this new device facilitates condition-dependent stimulation; this new stimulation method is feasible and provides new insights into the pathophysiological mechanisms of PD.

[Micro-electrode Recordings in Stereotactic Functional Neurosurgery]

Accurate targeting to the sensorimotor territory of the globus pallidus internus (GPi), the subthalamic nucleus (STN), and the thalamic ventral intermediate nucleus (Vim) is crucial for the stereotactic neurosurgery of lesioning or implantation of a deep brain stimulation electrode. Intra-operative micro-electrode recording can aid in the localization of these structures. Neurons in the GPi are characterized by high-frequency tonic discharge. The STN has a high density of neurons that show irregular discharge. The majority of neurons in the sensorimotor territory of the GPi and STN exhibit neuronal responses to passive manipulation or active movement of the limbs and orofacial parts, and they are somatotopically arranged. Neurons responding to movements of the legs, arms, and face were found along the dorsal-ventral axis in the posterolateral GPi and along the medial-lateral axis in the posterolateral STN. Similarly, in the lateral part of the thalamic Vim nucleus, most neurons exhibit kinesthetic responses that show well-organized somatotopic arrangement, with the leg on the dorsolateral side, arm on the medioventral side, and face on the more medial side. Some Vim neurons have rhythmic bursting discharges synchronous with limb tremor. These electrophysiological findings allow us to achieve better surgical results.

Correction of the skull density ratio for transcranial MRI-guided focused ultrasound thalamotomy: clinical significance of predicting therapeutic temperature

OBJECTIVE

In transcranial magnetic resonance imaging-guided focused ultrasound (TcMRgFUS), a high skull density ratio (SDR) is advantageous to achieve a sufficiently high temperature at the target. However, it is not easy to estimate the temperature rise because the SDR shows different values depending on the reconstruction filter used. The resolution characteristic of a computed tomography (CT) image depends on a modulation transfer function (MTF) defined by the reconstruction filter. Differences in MTF induce unstable SDRs. The purpose of this study was both to standardize SDR by developing a method to correct the MTF and to enable effective patient screening prior to TcMRgFUS treatment and more accurate predictions of focal temperature.

METHODS

CT images of a skull phantom and five subjects were obtained using eight different reconstruction filters. A frequency filter (FF) was calculated using the MTF of each reconstruction filter, and the validity of SDR standardization was evaluated by comparing the variation in SDR before and after FF correction. Subsequently, FF processing was similarly performed using the CT images of 18 patients who had undergone TcMRgFUS, and statistical analyses were performed comparing the relationship between the SDRs before and after correction and the maximum temperature in the target during TcMRgFUS treatment.

RESULTS

The FF was calculated for each reconstruction filter based on one manufacturer's BONE filter. In the CT images of the skull phantom, the SDR before FF correction with five of the other seven reconstruction filters was significantly smaller than that with the BONE filter (p < 0.01). After FF correction, however, a significant difference was recognized under only one condition. In the CT images of the five subjects, variation of the SDR due to imaging conditions was significantly improved after the FF correction. In 18 cases treated with TcMRgFUS, there was no correlation between SDR before FF correction and maximum temperature (rs = 0.31, p > 0.05); however, a strong positive correlation was observed after FF correction (rs = 0.71, p < 0.01).

CONCLUSIONS

After FF correction, the difference in SDR due to the reconstruction filter used is smaller, and the correlation with temperature is stronger. Therefore, the SDR can be standardized by applying the FF, and the maximum temperature during treatment may be predicted more accurately.

[Management of Spinal Disorders in Parkinson's Disease]

Parkinson's disease(PD)is a degenerative disorder of the central nervous system. Its cardinal features are resting tremor, rigidity, bradykinesia, and postural instability. Several years after disease onset, many patients with PD exhibit postural deformities, including camptocormia, Pisa syndrome, and dropped head syndrome, which can lead to spinal deformities. In addition, spinal degenerative disorders are frequently associated with PD and can further impact the patients' quality of life. Current evidence suggests a multifactorial etiology for postural deformities and spinal degenerative disorders in PD, which includes abnormal stress on the spine(biomechanical factors), postural instability and impairment of postural compensation(physiological factors), and imbalance of dopaminergic signals(pharmacological factors). The relative contribution of these factors varies between patients and across symptoms. Consequently, neurologists have difficulty treating these axial problems. Moreover, many studies have reported poor outcomes and high complication rates of spinal surgery in patients with PD, which embarrasses spinal surgeons. An improved understanding of the mechanisms underlying spinal problems in PD might ultimately lead to more effective management of these disabling complications.

Single arm prospective multicenter case series on the use of burst stimulation to improve pain and motor symptoms in Parkinson's disease

Background

In this study we analyze new clinical data in the use of spinal cord stimulation (SCS) for the treatment of pain and motor symptoms in patients with Parkinson's Disease (PD), as both a singular bioelectric therapy and as a salvage therapy after deep brain stimulation (DBS).

Methods

Fifteen patients were recruited and had percutaneous electrodes implanted at the level of the thoracic or cervical spine. Participants were set to one of three stimulation modes: continuous tonic stimulation, continuous Burst stimulation (40 Hz, 500 Hz, 1000 μs), or cycle mode (on time of 10-15 s, off time of 15-30 s) with Burst (40 Hz, 500 Hz, 1000 μs). Patients completed the Visual Analogue Scale (VAS), Unified Parkinson's Disease Rating Scale, Self-Rating Depression Scale, Hamilton Depression Rating Scale, Profile of Mood State, 10-meter walking test, and the Timed Up and Go (TUG).

Results

All patients experienced significant improvement in VAS scores with a mean reduction of 59% across all patients. Patients who chose the cycling burst stimulation parameter had an average 67% reduction in VAS scores, as compared to the continuous burst parameter group, which had an average 48% reduction in VAS scores. Seventy-three percent of patients experienced improvement in the 10-meter walk, with an average improvement of 12%. Sixty-four percent of patients experienced clinically relevant improvements in the TUG, with an average improvement of 21%.

Conclusions

This study points to the potential utility of SCS to address both pain and certain aspects of motor symptoms in PD patients who have and have not received DBS therapy.

[Spinal Intradural Extramedullary Ependymoma:A Case Report]

Ependymoma is the most common primary intramedullary tumor of the spinal cord, accounting for a quarter of these tumors. We experienced a case of 'ependymoma of the spinal cord with a cystic lesion that presented as an intradural extramedullary tumor extending from the thoracic to lumbar vertebrae. In review of past literature on reports of spinal intradural extramedullary ependymoma, lesions spanning three or more vertebrae with cystic lesions were frequent, and about half were World Health Organization grade II or higher. Dissemination or recurrence of these tumors may occur after surgery. There is no consensus on postoperative adjuvant therapy for intradural extramedullary spinal ependymoma, but careful consideration should be given to the intraoperative findings and the characteristics of the tumor.

Efficacy of Atlantoaxial Transarticular Screw Fixation Using Navigation-Guided Drill: Technical Note

BACKGROUND

Atlantoaxial transarticular screw fixation (TASF) is a procedure that involves inserting screws vertically into the articular processes of C1 and C2. However, this procedure is associated with a risk of injury to surrounding structures including the vertebral artery, carotid artery, pharynx, and spinal cord by misinserting K-wires or screws. This study was performed to evaluate the risk of TASF using 3-dimensional navigation-guided drilling and screw insertion tract creation.

METHODS

Three patients underwent the surgical procedure using a navigation system guided by intraoperative computed tomography. The insertion tract of the screw was created using the navigation system to avoid penetration of the C1 anterior arch or damage to the vertebral artery. A blunt-tipped guide wire was used, which was safe to advance to the cortex of the anterior arch of C1.

RESULTS

There were no complications or instrument failures in any of the surgeries. In each case, the total radiation dose delivered was 5.31-7.02 mGy, and total radiation exposure time was 55.6-106.8 seconds. Bone fusion was achieved in all cases.

CONCLUSIONS

TASF using a navigation system for drilling is useful for accurate placement of K-wire and preventing damage of the vital structures, lowering the risk of the procedure.

Resting-State Pallidal-Cortical Oscillatory Couplings in Patients With Predominant Phasic and Tonic Dystonia

Pallidal deep brain stimulation (DBS) improves the symptoms of dystonia. The improvement processes of dystonic movements (phasic symptoms) and tonic symptoms differ. Phasic symptoms improve rapidly after starting DBS treatment, but tonic symptoms improve gradually. This difference implies distinct neuronal mechanisms for phasic and tonic symptoms in the underlying cortico-basal ganglia neuronal network. Phasic symptoms are related to the pallido-thalamo-cortical pathway. The pathway related to tonic symptoms has been assumed to be different from that for phasic symptoms. In the present study, local field potentials of the globus pallidus internus (GPi) and globus pallidus externus (GPe) and electroencephalograms from the motor cortex (MCx) were recorded in 19 dystonia patients to analyze the differences between the two types of symptoms. The 19 patients were divided into two groups, 10 with predominant phasic symptoms (phasic patients) and 9 with predominant tonic symptoms (tonic patients). To investigate the distinct features of oscillations and functional couplings across the GPi, GPe, and MCx by clinical phenotype, power and coherence were calculated over the delta (2-4 Hz), theta (5-7 Hz), alpha (8-13 Hz), and beta (14-35 Hz) frequencies. In phasic patients, the alpha spectral peaks emerged in the GPi oscillatory activities, and alpha GPi coherence with the GPe and MCx was higher than in tonic patients. On the other hand, delta GPi oscillatory activities were prominent, and delta GPi-GPe coherence was significantly higher in tonic than in phasic patients. However, there was no significant delta coherence between the GPi/GPe and MCx in tonic patients. These results suggest that different pathophysiological cortico-pallidal oscillations are related to tonic and phasic symptoms.

Information processing from the motor cortices to the subthalamic nucleus and globus pallidus and their somatotopic organizations revealed electrophysiologically in monkeys

To understand how the information derived from different motor cortical areas representing different body parts is organized in the basal ganglia, we examined the neuronal responses in the subthalamic nucleus (STN), and the external (GPe) and internal (GPi) segments of the globus pallidus (input, relay and output nuclei, respectively) to stimulation of the orofacial, forelimb and hindlimb regions of the primary motor cortex (MI) and supplementary motor area (SMA) in macaque monkeys under the awake state. Most STN and GPe/GPi neurons responded exclusively to stimulation of either the MI or SMA, and one‐fourth to one‐third of neurons responded to both. STN neurons responding to the hindlimb, forelimb and orofacial regions of the MI were located along the medial–lateral axis in the posterolateral STN, while neurons responding to the orofacial region of the SMA were located more medially than the others in the anteromedial STN. GPe/GPi neurons responding to the hindlimb, forelimb and orofacial regions of the MI were found along the dorsal–ventral axis in the posterolateral GPe/GPi, and neurons responding to the corresponding regions of the SMA were similarly but less clearly distributed in more anteromedial regions. Moreover, neurons responding to the distal and proximal forelimb MI regions were found along the lateral–medial axis in the STN and the ventral–dorsal axis in the GPe/GPi. Most STN and GPe/GPi neurons showed kinaesthetic responses with similar somatotopic maps. These observations suggest that the somatotopically organized inputs from the MI and SMA are well preserved in the STN and GPe/GPi with partial convergence.

Atypical findings of perineural cysts on postmyelographic computed tomography: a case report of intermittent intercostal neuralgia caused by thoracic perineural cysts

Background

Perineural cysts are sometimes found incidentally with magnetic resonance imaging, and clinical symptoms requiring treatment are rare. Perineural cysts typically exhibit delayed filling with contrast medium on myelography, which is one of the criteria used by Tarlov to distinguish perineural cysts from meningeal diverticula. We present a case of multiple thoracolumbar perineural cysts, one of which was considered the cause of intermittent intercostal neuralgia with atypical findings on postmyelographic computed tomography seen as selective filling of contrast medium.

Case presentation

A 61-year-old woman presented with intermittent pain on her left chest wall with distribution of the pain corresponding to the T10 dermatome. Magnetic resonance imaging showed multiple thoracolumbar perineural cysts with the largest located at the left T10 nerve root. On postmyelographic computed tomography immediately after contrast medium injection, the largest cyst and another at left T9 showed selective filling of contrast medium, suggesting that inflow of cerebrospinal fluid to the cyst exceeded outflow. Three hours after the injection, the intensity of the cysts was similar to the intensity of the thecal sac, and by the next day, contrast enhancement was undetectable. The patient was treated with an intercostal nerve block at T10, and the pain subsided. However, after 9 months of observation, the neuralgia recurred, and the nerve block was repeated with good effect. There was no recurrence 22 months after the last nerve block.

Conclusions

We concluded that intermittent elevation of cerebrospinal fluid pressure in the cyst caused the neuralgia because of an imbalance between cerebrospinal fluid inflow and outflow, and repeated intercostal nerve blocks resolved the neuralgia. Our case demonstrates the mechanism of cyst expansion.

A rare case of diploic venous anomaly: asymptomatic venous sac expanding in the diploe

BACKGROUND

Vascular anomalies accompanied with the diploic veins are rare. Among them, sinus pericranii, which is characterized by abnormal connections between intra- and extracranial venous systems, is relatively common. Besides sinus pericranii, a few cases of subepicranial varix with connections to diploic veins have been reported, but these varices had no connections to intracranial venous sinuses. Herein, we present a rare case of an expanding venous sac in the diploe which communicated with the intracranial sinus but not with the extracranial venous systems.

CASE PRESENTATION

An adult woman presented to us with a minor transient headache. Although no abnormal appearances were found on her scalp, imaging studies showed a club-shaped venous sac in the left parietal diploe that communicated with the superior sagittal sinus and diploic veins on the medial and lateral sides, respectively. It was revealed that the lesion had expanded as compared with a previous computed tomography image. Surgery was performed to intercept venous supply from the diploic veins, and the lesion was filled with thrombi. In a follow-up of 15 months, there was no recurrence of abnormal venous flow. Histological examination showed the endothelial lining in the membranous wall of the sac, which is typically observed in sinus pericranii. However, no communication with the pericranial veins of the scalp was identified on the imaging studies and intraoperative observation. Accordingly, it was diagnosed as another entity "intradiploic varix".

CONCLUSIONS

The abnormal connection between the intracranial and the diploic venous systems via the large venous sac was surgically treated. It was pathologically similar to sinus pericranii, but anatomically considered to be another form of venous anomaly. In cases of expanding lesions, surgical treatment is recommended.

Frequency-Specific Synchronization in the Bilateral Subthalamic Nuclei Depending on Voluntary Muscle Contraction and Relaxation in Patients with Parkinson's Disease

The volitional control of muscle contraction and relaxation is a fundamental component of human motor activity, but how the processing of the subcortical networks, including the subthalamic nucleus (STN), is involved in voluntary muscle contraction (VMC) and voluntary muscle relaxation (VMR) remains unclear. In this study, local field potentials (LFPs) of bilateral STNs were recorded in patients with Parkinson’s disease (PD) while performing externally paced VMC and VMR tasks of the unilateral wrist extensor muscle. The VMC- or VMR-related oscillatory activities and their functional couplings were investigated over the theta (4–7 Hz), alpha (8–13 Hz), beta (14–35 Hz), and gamma (40–100 Hz) frequency bands. Alpha and beta desynchronizations were observed in bilateral STNs at the onset of both VMC and VMR tasks. On the other hand, theta and gamma synchronizations were prominent in bilateral STNs specifically at the onset of the VMC task. In particular, just after VMC, theta functional coupling between the bilateral STNs increased, and the theta phase became coupled to the gamma amplitude within the contralateral STN in a phase-amplitude cross-frequency coupled manner. On the other hand, the prominent beta-gamma cross-frequency couplings observed in the bilateral STNs at rest were reduced by the VMC and VMR tasks. These results suggest that STNs are bilaterally involved in the different performances of muscle contraction and relaxation through the theta-gamma and beta-gamma networks between bilateral STNs in patients with PD.

Long-term safety and tolerability of ProSavin, a lentiviral vector-based gene therapy for Parkinson's disease: a dose escalation, open-label, phase 1/2 trial

BACKGROUND

Parkinson's disease is typically treated with oral dopamine replacement therapies; however, long-term treatment leads to motor complications and, occasionally, impulse control disorders caused by intermittent stimulation of dopamine receptors and off-target effects, respectively. We aimed to assess the safety, tolerability, and efficacy of bilateral, intrastriatal delivery of ProSavin, a lentiviral vector-based gene therapy aimed at restoring local and continuous dopamine production in patients with advanced Parkinson's disease.

METHODS

We undertook a phase 1/2 open-label trial with 12-month follow-up at two study sites (France and UK) to assess the safety and efficacy of ProSavin after bilateral injection into the putamen of patients with Parkinson's disease. All patients were then enrolled in a separate open-label follow-up study of long-term safety. Three doses were assessed in separate cohorts: low dose (1·9×10(7) transducing units [TU]); mid dose (4·0×10(7) TU); and high dose (1×10(8) TU). Inclusion criteria were age 48-65 years, disease duration 5 years or longer, motor fluctuations, and 50% or higher motor response to oral dopaminergic therapy. The primary endpoints of the phase 1/2 study were the number and severity of adverse events associated with ProSavin and motor responses as assessed with Unified Parkinson's Disease Rating Scale (UPDRS) part III (off medication) scores, at 6 months after vector administration. Both trials are registered at ClinicalTrials.gov, NCT00627588 and NCT01856439.

FINDINGS

15 patients received ProSavin and were followed up (three at low dose, six mid dose, six high dose). During the first 12 months of follow-up, 54 drug-related adverse events were reported (51 mild, three moderate). Most common were increased on-medication dyskinesias (20 events, 11 patients) and on-off phenomena (12 events, nine patients). No serious adverse events related to the study drug or surgical procedure were reported. A significant improvement in mean UPDRS part III motor scores off medication was recorded in all patients at 6 months (mean score 38 [SD 9] vs 26 [8], n=15, p=0·0001) and 12 months (38 vs 27 [8]; n=15, p=0·0001) compared with baseline.

INTERPRETATION

ProSavin was safe and well tolerated in patients with advanced Parkinson's disease. Improvement in motor behaviour was observed in all patients.

FUNDING

Oxford BioMedica.

Electrophysiological evidences of organization of cortical motor information in the Basal Ganglia

During the last two decades, the many developments in the treatment of movement disorders such as Parkinson disease and dystonia have enhanced our understanding on organization of the basal ganglia, and this knowledge has led to other advances in the field. According to many electrophysiological and anatomical findings, it is considered that motor information from different cortical areas is processed through several cortico-basal ganglia loops principally in a parallel fashion and somatotopy from each cortical area is also well preserved in each loop. Moreover, recent studies suggest that not only the parallel processing but also some convergence of information occur through the basal ganglia. Information from cortical areas whose functions are close to each other tends to converge in the basal ganglia. The cortico-basal ganglia loops should be comprehended more as a network rather than as separated subdivisions. However, the functions of this convergence still remain unknown. It is important even for clinical doctors to be well informed about this kind of current knowledge because some symptoms of movement disorders may be explained by disorganization of the information network in the basal ganglia.

Aggressive and invasive growth of tectal glioma after surgical intervention and chemoradiotherapy

A tectal glioma presenting with late-onset aqueduct stenosis and obstructive hydrocephalus is usually categorized as a benign glioma. Apparent clinical or radiological progression justifies biopsy of the tumour. In this case, an unusual tumour shows aggressive and invasive growth after surgical intervention and chemoradiotherapy.

Analyses of the factors influencing bone graft infection after delayed cranioplasty

BACKGROUND

Several factors influencing bone graft infection after delayed cranioplasty are analyzed in order to reduce the occurrence of infection.

METHODS

For about 10 years, from March 1995 to February 2005, delayed cranioplasty was performed for 206 cases. The cases comprised 124 males and 82 females. Age distribution of the patients ranged from 6 months to 79 years old. The mean postoperative follow-up period was 1834 days. Autogenous bone, which was preserved in 100% ethanol at -20 degrees C and autoclaved before operation, was used in 54 patients. Polymethylmethacrylate (PMMA) was used in 55 patients. Custom-made PMMA was used in 3 patients. Custom-made titanium mesh was used in 77 patients. Custom-made ceramics (Alumina-ceramics 10 cases and hydroxyapatite 7 cases) was used in 17 patients.

FINDINGS

Autoclaved and autogenous bone graft and PMMA have a significantly high rate of graft infection. Titanium mesh has the significantly lowest rate of graft infection. Alumina-ceramic has a merit that it has sufficient strength, however the number of cases using custom-made ceramics including alumina-ceramic was relatively small, and thus we cannot find significant differences in infection rate compared with that of other materials. There was no statistically significant difference in the bone graft infection rate among four categories of preceding diseases; cerebrovascular diseases, head trauma, infectious diseases, and brain tumour.

CONCLUSION

Autoclaved and autogenous bone grafts and PMMA have a significantly higher rate of graft infection. Titanium mesh has the significantly lowest rate of graft infection.

Epidermoid tumor arising in the anterior interhemispheric fissure

There have only been 18 cases reported in the literature of an epidermoid tumor arising in the interhemispheric fissure. We report a 45-year-old woman with an epidermoid tumor arising in the interhemispheric fissure. She presented with a focal convulsive seizure. Radiological imaging identified a tumor in the interhemispheric fissure, which was subtotally removed due to adherence to both anterior cerebral arteries and the cerebral cortex. Epidermoid tumor was confirmed by histopathology. Epidermoid tumors rarely arise in the interhemispheric fissure, but are often adherent to surrounding structures and thus, as in the presented case, complete resection may be unwise.

Resolution of spinal epidural haematoma without surgery in a haemophilic infant

Non-traumatic spinal epidural haematoma is a rare complication of haemophilia. We report a seven-month-old boy who presented with symptomatic spinal epidural haematoma. He was found to have a hemophilia B trait, and after factor IX replacement, his neurological signs were stabilized and follow-up MRI demonstrated rapid resolution of the haematoma. This illustrative case suggests that surgical intervention can be deferred as the first step in treating spinal epidural haematoma in a haemophilic infant.

[Peri-operative treatment with botulinum A toxin prior to posterior cervical decompression in a case with cervical spondylosis caused by spasmodic torticollis secondary to cerebral palsy]

Patients with spasmodic torticollis secondary to athetoid cerebral palsy may develop symptomatic degenerative cervical disc disease or spondylosis. In these cases, peri-operative stabilization of the cervical spine is considered to be difficult and recurrence occurs frequently. We reported a case with cervical spondylosis induced by athetoid cerebral palsy. A 44-year-old female with athetoid cerebral palsy had suffered from secondary spasmodic torticollis. 7 years previously, she had been admitted to our hospital for the first time with complaints of gait disturbance, dysesthesia and hypesthesia in all extremities. CT-myelography and MRI showed disc degeneration and spondylosis at the level of C4/5 and C5/6, compressing the spinal cord. She underwent C5 vertebrectomy and C4-6 anterior fusion. However, due to cervical dystonia, it was difficult for her to wear a Philadelphia collar, so she had to under go complete bed rest for postoperative neck stabilization. Her symptoms improved after the operation. 5 years after the first operation, she complained of gait disturbance and sensory disturbance, again. MRI showed compression of the spinal cord at C2-C4, rostral to the level of the previous surgical area. So we planned the second operation. Prior to the operation, we used botulinum A toxin to reduce the athetoid movement of the neck. And we performed C3-6 expansive laminoplasty and partial laminectomy of C2 and C7 laminae. After the second operation, she was able to wear the Philadelphia collar without trouble and her neurological condition improved again. Botulinum A toxin was very effective to control the spasmodic torticollis peri-operatively in this case with cervical dystonia.