Spinal cord stimulation may improve gait and cognition in hereditary spastic paraplegia with mental retardation: a case report

BACKGROUND

Hereditary spastic paraplegia (HSP) include various sporadic and hereditary neurodegenerative disorders, characterized by progressive spasticity and weakness of lower limbs, possibly associated to additional features.

CASE PRESENTATION

We report a male HPS patient in his 40 s, showing mental retardation associated with language impairment, dysarthria, and increased urinary frequency. Three months after treatment with electric chronic high-frequency cervical spinal cord stimulation (HF-SCS), he showed an amelioration of motor symptoms (lower limbs spasticity and gait), dysarthria, cognitive functioning (language and constructive praxic abilities), and urinary symptoms (decreased urinary frequency). Single-photon emission computed tomography (SPECT) showed a postoperative increase of cerebral perfusion in right frontal cortex and temporal cortex bilaterally.

CONCLUSION

In our patient, HF-SCS might have induced an activation of ascending neural pathways, resulting in changes in activity in various cortical areas (including sensory-motor cortical areas), which may give rise to a modulation of activity in spared descending motor pathways and in neural networks involved in cognitive functions, including language. Although further studies in patients with HPS are needed to clarify whether HF-SCS can be a suitable treatment option in HSP, our observation suggests that HF-SCS, a minimally invasive neurosurgical procedure, might induce beneficial effects of on various symptoms of such orphan disease.

Balloon-Assisted Corpus Callosotomy. Reducing the Impact of Transcallosal Approaches

BACKGROUND

The interhemispheric transcallosal approach is widely used to remove intraventricular lesions. Corpus callosotomy gives immediate access to the ventricular chambers but is invasive in nature. Loss of callosal fibers, although normally tolerate, may cause disturbances ranging from a classical disconnection syndrome up to minor neuropsychological changes.

OBJECTIVE

To open an operative window in the corpus callosum through separation rather than disconnection of the white matter fibers.

METHODS

In 7 patients undergoing the interhemispheric transcallosal approach for intraventricular lesions, lying around or below the foramen of Monro, a stoma was created within the corpus callosum by using a 4F Fogarty catheter. The series included 3 colloid of the third ventricle, 2 thalamic cavernomas, 1 subependymoma, and 1 ependymoma of the foramen of Monro. We illustrate the technique and the clinico-radiological outcome, focusing on the size of callosotomy as seen on postoperative MRI.

RESULTS

The balloon-assisted corpus callosotomy provided a circular, smooth-walled access to the ventricular chambers, which allowed uncomplicated removal of the lesions. On postoperative MRI, the size of the callosotomy shrinked compared with surgery (2.8-6.4 mm at follow-up vs 6-9 mm as measured intraoperatively). No signs of disconnection syndrome or new permanent deficits were observed in this series.

CONCLUSION

The balloon-assisted technique produces a small callosotomy, without clinical consequences, showing a self-closing trend on postoperative MRI. This technique is a rewarding tool to reduce the impact of callosotomy while keeping the advantages of microsurgical interhemispheric approaches.

Subpial technique in supratentorial glioma resection: state of the art and analysis of costs and effectiveness in a single institute experience

BACKGROUND

Many neurosurgeons advocate subpial technique as the best technique to remove supratentorial gliomas. However, few authors clearly defined advantages and features of this technique. The aim of our study is to describe microsurgical subpial technique related to glioma surgery, with regard to its safety and cost effectiveness.

METHODS

We analyzed retrospectively all consecutive patients surgically treated for supratentorial glioma from January 2017 to April 2018 at Neurosurgery Department of Neuromed Institute. All patients underwent to surgical glioma resection performing microsurgical subpial technique. Extent of resection and neurological complications were evaluated as primary outcomes; Karnofsky Performance Status and postoperative edema extent were secondary outcomes. Statistical analysis was obtained.

RESULTS

The study included 70 patients. Gross Total Removal was obtained in 91.3% of patients with low grade glioma (LGG) and in 81% of patients with high grade glioma. Neurological complications amounted to 34% at early assessment in LGG patients, which were permanent at 3 months in 17% of patients. In high grade glioma patients, neurological complications amounted to 51% at early assessment, which were permanent at 3 months in 25% of them.

CONCLUSIONS

We obtained good postoperative results with regard to the extent of tumor resection using this technique. Subpial resection is an effective surgical technique to get a safer and more complete tumor resection. It should be combined with other modern neurosurgical tools such as neuronavigation, ultrasound and cortical mapping to obtain the best tumor resection and functional neurological preservation.

Long-term quality of life and functional outcomes in adults surgically treated for intramedullary spinal cord tumor

Introduction

Intramedullary spinal cord tumors (IMSCTs) are rare but clinically significant entities that may cause severe neurological decline with progressive pain and motor or sensory deterioration. Beyond the beneficial effects of surgical treatment and the long-term progression-free survival, neurological deficits may still persist after surgery, and information about the long-term patients' health-related quality of life (QoL) is still lacking. In this study, we investigate the patients' health perception 15 years after the surgery in an overall patients' wellbeing framework.

Methods

Patients surgically treated for IMSCT over a period from 1996 to 2011 were selected. After a mean of 15 years from the surgery, patient's self-administered questionnaire on disability, pain, sleep quality, and QoL was collected and neurological postoperative evaluation at the chronic stage was reexamined.

Results

Neurological deficits are reported in half of the patients in the postoperative chronic phase. After 15 years of surgery, half of the patients still report mild or severe disability grades associated with significantly higher pain and poor sleep and QoL. In accordance, the neurological condition measured at the chronic stage is significantly related not only to disease-specific symptoms (i.e., pain) but even to sleep quality complaints and poor QoL, measured at 15 years follow-up.

Conclusions

Health-related QoL is an important secondary outcome in patients. Although the progression-free survival, worse postoperative neurological conditions could predict long-term sequelae reflecting patients' poor health perception. It suggests the importance of preserving patients' functional status and globally evaluating patients' wellbeing to handle disease-specific symptoms but even more general aspects of QoL.

Structural Brain Network Reorganization Following Anterior Callosotomy for Colloid Cysts: Connectometry and Graph Analysis Results

Introduction:

The plasticity of the neural circuits after injuries has been extensively investigated over the last decades. Transcallosal microsurgery for lesions affecting the third ventricle offers an interesting opportunity to investigate the whole-brain white matter reorganization occurring after a selective resection of the genu of the corpus callosum (CC).

Method

Diffusion MRI (dMRI) data and neuropsychological testing were collected pre- and postoperatively in six patients with colloid cysts, surgically treated with a transcallosal-transgenual approach. Longitudinal connectometry analysis on dMRI data and graph analysis on structural connectivity matrix were implemented to analyze how white matter pathways and structural network topology reorganize after surgery.

Results

Although a significant worsening in cognitive functions (e.g., executive and memory functioning) at early postoperative, a recovery to the preoperative status was observed at 6 months. Connectometry analysis, beyond the decrease of quantitative anisotropy (QA) near the resection cavity, showed an increase of QA in the body and forceps major CC subregions, as well as in the left intra-hemispheric corticocortical associative fibers. Accordingly, a reorganization of structural network topology was observed between centrality increasing in the left hemisphere nodes together with a rise in connectivity strength among mid and posterior CC subregions and cortical nodes.

Conclusion

A structural reorganization of intra- and inter-hemispheric connective fibers and structural network topology were observed following the resection of the genu of the CC. Beyond the postoperative transient cognitive impairment, it could be argued anterior CC resection does not preclude neural plasticity and may subserve the long-term postoperative cognitive recovery.

Continuous subcortical monitoring of motor pathways during glioma surgery with ultrasonic surgical aspirator: technical description in a single institute experience

BACKGROUND

Actual challenge in surgical treatment of intra-axial gliomas involving eloquent areas is maximal safe resection. Mapping and monitoring of cortical and subcortical motor functionsare important tools to avoid postoperative deficits. In the present study, we present our experiencewith a continuous dynamic motor mapping technique pairing a traditional monopolar stimulatorwith a Cavitron Ultrasonic Surgical Aspirator (CUSA) to perform a continuous stimulation ofthe white matter avoiding removal interruption.

METHODS

We describe a single center retrospective analysis of 1-year consecutive patients with intraxial tumors located adjacent to corticospinal tract and treated with surgical resection adopting "continuous dynamic mapping technique". With the support of a reconstruction software (3D Slicer), we classified the Extent Of Resection (EOR) as Gross Total Resection (GTR) (>98%), Sub-Total Resection (STR) (from 90% to 97%), and Partial Resection (<90%). Medical Research Council (MRC) grading was adopted to evaluate neurological outcomes (from 0 to 5), assessed on 1st post-operative day, at 1 week, 1 month and 3 months.

RESULTS

From July 2017 to July 2018, 29 patients underwent to surgical removal of intraxial tumor adjacent to motor areas, using continuous dynamic subcortical mapping. Median age was 54 years old (range 12-75 years). At pre-operative MRI tractography reconstruction, mean distance between tumor and corticospinal tract was 4,4 mm (range At 1 week post-operative assessment, motor deficits were still present in 12 patients (41%). At 1 month, 10 patients (35%) had persisting deficits, which required admission to rehabilitation department. At 3 months, 4 patients (14%) had persistent motor impairment and overall 28 patients (98%) were able to walk by themselves.

CONCLUSIONS

Our early experience showed that a combination of dynamic subcortical mapping with transcranial and cortical strip MEP (Motor Evoked Potentials) monitoring is useful in tumors close to motor eloquent areas to extend surgical resection avoiding permanent consequences. However, we need for further experience to consolidate and improve this technique.

Selective effects of a brain tumor on the metric representation of the hand: a pre- versus post-surgery comparison

Body representation disorders are complex, varied, striking, and very disabling in most cases. Deficits of body representation have been described after lesions to multimodal and sensorimotor cortical areas. A few studies have reported the effects of tumors on the representation of the body, but little is known about the changes after tumor resection. Moreover, the impact of brain lesions on the hand size representation has been investigated in few clinical cases. Hands are of special importance, as no other body part has the ability for movement and interaction with the environment that the hands have, and we use them for a multitude of daily activities. Studies with clinical population can add further knowledge into the way hands are represented. Here, we report a single case study of a patient (AM) who was an expert bodybuilder and underwent a surgery to remove a glioblastoma in the left posterior prefrontal and precentral cortex at the level of the hand's motor region. Pre- (20 days) and post- (4 months) surgery assessment did not show any motor or cognitive impairments. A hand localization task was used, before and after surgery (12 months), to measure possible changes of the metric representation of his right hand. Results showed a post-surgery modulation of the typically distorted hand representation, with an overall accuracy improvement, especially on width dimension. These findings support the direct involvement of sensorimotor areas in the implicit representation of the body size and its relevance on defining specific size representation dimensions.

Pre-surgical fMRI Localization of the Hand Motor Cortex in Brain Tumors: Comparison Between Finger Tapping Task and a New Visual-Triggered Finger Movement Task

Introduction: Pre-surgical mapping is clinically essential in the surgical management of brain tumors to preserve functions. A common technique to localize eloquent areas is functional magnetic resonance imaging (fMRI). In tumors involving the peri-rolandic regions, the finger tapping task (FTT) is typically administered to delineate the functional activation of hand-knob area. However, its selectivity may be limited. Thus, here, a novel cue-induced fMRI task was tested, the visual-triggered finger movement task (VFMT), aimed at eliciting a more accurate functional cortical mapping of the hand region as compared with FTT.

Method: Twenty patients with glioma in the peri-rolandic regions underwent pre-operative mapping performing both FTT and VFMT. The fMRI data were analyzed for surgical procedures. When the craniotomy allowed to expose the motor cortex, the correspondence with intraoperative direct electrical stimulation (DES) was evaluated through sensitivity and specificity (mean sites = 11) calculated as percentage of true-positive and true-negative rates, respectively.

Results: Both at group level and at single-subject level, differences among the tasks emerged in the functional representation of the hand-knob. Compared with FTT, VFMT showed a well-localized activation within the hand motor area and a less widespread activation in associative regions. Intraoperative DES confirmed the greater specificity (97%) and sensitivity (100%) of the VFMT in determining motor eloquent areas.

Conclusion: The study provides a novel, external-triggered fMRI task for pre-surgical motor mapping. Compared with the traditional FTT, the new VFMT may have potential implications in clinical fMRI and surgical management due to its focal identification of the hand-knob region and good correspondence to intraoperative DES.

The Impact of COVID-19 Lockdown on People With Epilepsy and Vagal Nerve Stimulation

Objectives: Restrictive measures adopted during the COVID-19 pandemic, in order to limit contagion, have had a severe impact on mental health. The burden of lockdown has been particularly heavy on patients with chronic neurologic diseases such as People with Epilepsy (PwE). Our survey aims to describe the struggles and needs of Drug-Resistant (DR) PwE with implanted Vagal Nerve Stimulator (VNS) during the first wave of the COVID-19 lockdown in order to find strategies that help patients cope with present or future periods of restriction. Methods: We collected answers from 30 respondents who underwent an online survey including socio-demographic and clinical information and COVID-19-related information. Depression, anxiety symptoms, and sleep quality were investigated in patients through BDI II, GAD-7, and the PSQI scale. Results: In all, 46% of our sample reported an increase in the number of seizures; the entire sample complained of epilepsy-related issues (medication availability, VSN adjustments, anxiety, sleep disturbance); one out of three participants reported major epilepsy issues felt urgent; 30% had to postpone scheduled examination. Significantly higher scores for depression and anxiety scales were found in patients who perceived seizure frequency worsening and reported major epilepsy-related issues. Conclusion: Preliminary findings showed that the first lockdown influenced the clinical and psychological status of PwE and was related to seizures worsening. The lack of medical assistance and control on VNS therapy left patients to cope with the situation without a chance to contact a specialist. We discuss how a wider implementation of telemedicine programs could facilitate remote assistance of PwE with a VNS implant.

A fully integrated wireless system for intracranial direct cortical stimulation, real-time electrocorticography data transmission, and smart cage for wireless battery recharge

Wireless transmission of cortical signals is an essential step to improve the safety of epilepsy procedures requiring seizure focus localization and to provide chronic recording of brain activity for Brain Computer Interface (BCI) applications. Our group developed a fully implantable and externally rechargeable device, able to provide wireless electrocorticographic (ECoG) recording and cortical stimulation (CS). The first prototype of a wireless multi-channel very low power ECoG system was custom-designed to be implanted on non-human primates. The device, named ECOGIW-16E, is housed in a compact hermetically sealed Polyether ether ketone (PEEK) enclosure, allowing seamless battery recharge. ECOGIW-16E is recharged in a wireless fashion using a special cage designed to facilitate the recharge process in monkeys and developed in accordance with guidelines for accommodation of animals by Council of Europe (ETS123). The inductively recharging cage is made up of nylon and provides a thoroughly novel experimental setting on freely moving animals. The combination of wireless cable-free ECoG and external seamless battery recharge solves the problems and shortcomings caused by the presence of cables leaving the skull, providing a safer and easier way to monitor patients and to perform ECoG recording on primates. Data transmission exploits the newly available Medical Implant Communication Service band (MICS): 402–405 MHz. ECOGIW-16E was implanted over the left sensorimotor cortex of a macaca fascicularis to assess the feasibility of wireless ECoG monitoring and brain mapping through CS. With this device, we were able to record the everyday life ECoG signal from a monkey and to deliver focal brain stimulation with movement elicitation.

rTMS of medial parieto-occipital cortex interferes with attentional reorienting during attention and reaching tasks

Unexpected changes in the location of a target for an upcoming action require both attentional reorienting and motor planning update. In both macaque and human brain, the medial posterior parietal cortex is involved in both phenomena but its causal role is still unclear. Here we used on-line rTMS over the putative human V6A (pV6A), a reach-related region in the dorsal part of the anterior bank of the parieto-occipital sulcus, during an attention and a reaching task requiring covert shifts of attention and planning of reaching movements toward cued targets in space. We found that rTMS increased RTs to invalidly cued but not to validly cued targets during both the attention and reaching task. Furthermore, we found that rTMS induced a deviation of reaching endpoints toward visual fixation and that this deviation was larger for invalidly cued targets. The results suggest that reorienting signals are used by human pV6A area to rapidly update the current motor plan or the ongoing action when a behaviorally relevant object unexpectedly occurs in an unattended location. The current findings suggest a direct involvement of the action-related dorso-medial visual stream in attentional reorienting and a more specific role of pV6A area in the dynamic, on-line control of reaching actions.

Behavioral investigation on the frames of reference involved in visuomotor transformations during peripheral arm reaching

BACKGROUND

Several psychophysical experiments found evidence for the involvement of gaze-centered and/or body-centered coordinates in arm-movement planning and execution. Here we aimed at investigating the frames of reference involved in the visuomotor transformations for reaching towards visual targets in space by taking target eccentricity and performing hand into account.

METHODOLOGY/PRINCIPAL FINDINGS

We examined several performance measures while subjects reached, in complete darkness, memorized targets situated at different locations relative to the gaze and/or to the body, thus distinguishing between an eye-centered and a body-centered frame of reference involved in the computation of the movement vector. The errors seem to be mainly affected by the visual hemifield of the target, independently from its location relative to the body, with an overestimation error in the horizontal reaching dimension (retinal exaggeration effect). The use of several target locations within the perifoveal visual field allowed us to reveal a novel finding, that is, a positive linear correlation between horizontal overestimation errors and target retinal eccentricity. In addition, we found an independent influence of the performing hand on the visuomotor transformation process, with each hand misreaching towards the ipsilateral side.

CONCLUSIONS

While supporting the existence of an internal mechanism of target-effector integration in multiple frames of reference, the present data, especially the linear overshoot at small target eccentricities, clearly indicate the primary role of gaze-centered coding of target location in the visuomotor transformation for reaching.

Covert shift of attention modulates the ongoing neural activity in a reaching area of the macaque dorsomedial visual stream

Background

Attention is used to enhance neural processing of selected parts of a visual scene. It increases neural responses to stimuli near target locations and is usually coupled to eye movements. Covert attention shifts, however, decouple the attentional focus from gaze, allowing to direct the attention to a peripheral location without moving the eyes. We tested whether covert attention shifts modulate ongoing neuronal activity in cortical area V6A, an area that provides a bridge between visual signals and arm-motor control.

Methodology/Principal Findings

We performed single cell recordings from 3 Macaca Fascicularis trained to fixate straight-head, while shifting attention outward to a peripheral cue and inward again to the fixation point. We found that neurons in V6A are influenced by spatial attention. The attentional modulation occurs without gaze shifts and cannot be explained by visual stimulations. Visual, motor, and attentional responses can occur in combination in single neurons.

Conclusions/Significance

This modulation in an area primarily involved in visuo-motor transformation for reaching may form a neural basis for coupling attention to the preparation of reaching movements. Our results show that cortical processes of attention are related not only to eye-movements, as many studies have shown, but also to arm movements, a finding that has been suggested by some previous behavioral findings. Therefore, the widely-held view that spatial attention is tightly intertwined with—and perhaps directly derived from—motor preparatory processes should be extended to a broader spectrum of motor processes than just eye movements.