Gilles de la Tourette syndrome as a rare co-morbidity of Klinefelter syndrome

BACKGROUND

Klinefelter syndrome (47, XXY) is the most common sex chromosome aneuploidy. In addition to male hypergonadotropic hypogonadism, a wide range of neurodevelopmental disorders, anxiety and affective symptoms have been reported in a substantial proportion of cases.

CASE DESCRIPTION

We document the rare case of a 43-year-old man diagnosed with Klinefelter syndrome and co-morbid Gilles de la Tourette syndrome. He presented with multiple motor and vocal tics since adolescence, as well as anxiety and affective symptoms as his main tic-exacerbating factors. Tic severity was rated as marked (Yale Global Tic Severity Scale score of 78/100), and recommendations for the treatment of both tics and psychiatric co-morbidities were formulated.

DISCUSSION

Neurodevelopmental tics in the context of Klinefelter syndrome have been previously documented in three cases only. Gilles de la Tourette syndrome is 3-4 times more common in males than females and its etiological factors include multiple genetic components (genetic heterogeneity). Our case report widens the spectrum of neurodevelopmental disorders observed in the context of Klinefelter syndrome and contributes to genetic research on the role of the X chromosome in the pathophysiology of tic disorders.

Functional tics: Expanding the phenotypes of functional movement disorders?

BACKGROUND AND PURPOSE

Until the outbreak reported during the COVID-19 pandemic, functional tics were considered to be a relatively rare clinical phenotype, as opposed to other functional movement disorders such as functional tremor and dystonia. To better characterize this phenotype, we compared the demographic and clinical characteristics of patients who developed functional tics during the pandemic and those of patients with other functional movement disorders.

METHODS

Data from 110 patients were collected at the same neuropsychiatry centre: 66 consecutive patients who developed functional tics without other functional motor symptoms or neurodevelopmental tics and 44 patients with a mix of functional dystonia, tremor, gait, and myoclonus.

RESULTS

Both groups were characterized by female sex preponderance (70%-80%) and (sub)acute onset of functional symptoms (~80%). However, patients with functional tics had a significantly earlier age at onset of functional symptoms (21 vs. 39 years). Exposure to relevant social media content was reported by almost half of the patients with functional tics, but by none of the patients with other functional movement disorders. Comorbidity profiles were similar, with relatively high rates of anxiety/affective symptoms and other functional neurological symptoms (nonepileptic attacks).

CONCLUSIONS

Patients who developed functional tics during the pandemic represent a phenotypic variant of the wider group of patients with functional movement disorders, associated with younger age at onset and influenced by pandemic-related factors, including increased exposure to specific social media content. Diagnostic protocols and treatment interventions should be tailored to address the specific features of this newly defined phenotype.

The contribution of sleep and co-occurring neurodevelopmental conditions to quality of life in children with epilepsy

BACKGROUND

Health-related quality of life (HRQOL) in children with epilepsy (CWE) is multifactorial and can be affected not only by epilepsy-specific variables but also co-occurring conditions such as sleep disturbances, autism, and attention deficit hyperactivity disorder (ADHD). While highly prevalent in CWE, these conditions are underdiagnosed despite having a significant impact on HRQOL. Sleep problems have a complex relationship with epilepsy and neurodevelopmental characteristics. However, little is known about how these issues interact and contribute to HRQOL.

OBJECTIVES

The current study aims to explore the relationship between sleep and neurodevelopmental characteristics on HRQOL in CWE.

METHODS

36 CWE aged 4-16 years old were recruited from two hospitals and asked to wear an actiwatch for a period of 14 days and caregivers completed a series of questionnaires assessing co-occurrences and epilepsy-specific variables.

RESULTS

A high proportion of CWE (78.13%) presented significant sleep problems. Informant-reported sleep problems were significantly predictive of HRQOL above seizure severity and the number of antiseizure medications. Interestingly, informant-reported sleep problems were no longer significantly predictive of HRQOL when neurodevelopmental characteristics were considered, indicating a possible mediating effect. Similarly, actigraphy-defined sleep (variability in sleep onset latency) displayed a similar effect but only for ADHD characteristics, whereas autistic characteristics and variability in sleep onset latency continued to exert an individual effect on HRQOL.

CONCLUSION

These data from our study shed light on the complicated relationship between sleep, neurodevelopmental characteristics and epilepsy. Findings suggest that the impact of sleep on HRQOL in CWE is possibly mediated by neurodevelopmental characteristics. Furthermore, the impact this triangular relationship exerts on HRQOL is dependent on the type of tool used to measure sleep. These findings highlight the importance of a multidisciplinary approach to epilepsy management.

Neurodevelopmental versus functional tics: A controlled study

BACKGROUND

An unprecedented increase in newly developed functional tics, mainly in young females, has been reported during the COVID-19 pandemic. We set out to complement existing case series with the largest controlled study to date on the clinical phenomenology of functional tics versus neurodevelopmental tics.

METHODS

Data from 166 patients were collected at a specialist clinic for tic disorders during a three-year period overlapping with the COVID-19 pandemic (2020-2023). We compared the clinical features of patients who developed functional tics during the COVID-19 pandemic (N = 83) to patients with Tourette syndrome matched for age and gender (N = 83).

RESULTS

Female adolescents and young adults accounted for 86% of the clinical sample of patients with functional tics, who were less likely to report a family history of tic disorders than their matched controls with Tourette syndrome. Co-morbidity profiles were significantly different: anxiety and other functional neurological disorders were more strongly associated with functional tics, whereas attention-deficit and hyperactivity disorder and tic-related obsessive-compulsive behaviors co-occurred more frequently with neurodevelopmental tics. Overall, absence of tic-related obsessive-compulsive behaviors (t = 8.096; p < 0.001) and absence of a family history of tics (t = 5.111; p < 0.001) were the strongest predictors of the diagnosis of functional tics. Compared to neurodevelopmental tics, functional tics were more likely to present acutely/subacutely at a later age (21 versus 7 years), without a clear rostro-caudal progression. Coprophenomena, self-injurious behaviors, and complex clinical manifestations such as blocking tics, throwing tics, and tic attacks, were all over-represented in the functional group.

CONCLUSIONS

Our findings provide robust confirmation of both patient-related variables and tic characteristics contributing to the differential diagnosis between functional tics developed during the pandemic and neurodevelopmental tics reported by patients with Tourette syndrome.

New-onset functional tics during the COVID-19 pandemic: clinical characteristics of 105 cases from a single centre

BACKGROUND AND PURPOSE

The COVID-19 pandemic has been associated amongst others with a sharp increase in adolescents and young adults presenting acutely with functional tics. Initial reports have suggested clinically relevant differences between functional tics and neurodevelopmental tics seen in primary tic disorders such as Tourette syndrome. We aimed to provide confirmatory findings from the largest single-centre cohort to date.

METHODS

In the present study, we present data from 105 consecutive patients who developed functional tics during a three-year period overlapping with the COVID-19 pandemic (April 2020 to March 2023). All patients underwent a comprehensive neuropsychiatric assessment at a single specialist centre for tic disorders.

RESULTS

Female adolescents and young adults accounted for 69% of our sample. Functional tics had an acute/subacute onset in most cases (75% with a peak of severity within one month). We found a disproportionately high frequency of complex movements (81%) and vocalizations (75%). A subset of patients (23%) had a pre-existing primary tic disorder (Tourette syndrome with functional overlay). The most common psychiatric co-morbidities were anxiety (70%) and affective disorders (40%). Moreover, 41% of patients had at least one functional neurological disorder in addition to functional tics. Exposure to tic-related social media content was reported by half of the patients.

CONCLUSIONS

Our findings confirm substantial clinical differences between functional tics developed during the pandemic and neurodevelopmental tics. Both patient- and tic-related red flags support the differential diagnostic process and inform ongoing monitoring in the post-pandemic era.

Feasibility of non-invasive neuro-monitoring during extracorporeal membrane oxygenation in children

INTRODUCTION

Detection of neurological complications during extracorporeal membrane oxygenation (ECMO) may be enhanced with non-invasive neuro-monitoring. We investigated the feasibility of non-invasive neuro-monitoring in a paediatric intensive care (PIC) setting.

METHODS

In a single centre, prospective cohort study we assessed feasibility of recruitment, and neuro-monitoring via somatosensory evoked potentials (SSEP), electroencephalography (EEG) and near infrared spectroscopy (NIRS) during venoarterial (VA) ECMO in paediatric patients (0-15 years). Measures were obtained within 24h of cannulation, during an intermediate period, and finally at decannulation or echo stress testing. SSEP/EEG/NIRS measures were correlated with neuro-radiology findings, and clinical outcome assessed via the Pediatric cerebral performance category (PCPC) scale 30 days post ECMO cannulation.

RESULTS

We recruited 14/20 (70%) eligible patients (median age: 9 months; IQR:4-54, 57% male) over an 18-month period, resulting in a total of 42 possible SSEP/EEG/NIRS measurements. Of these, 32/42 (76%) were completed. Missed recordings were due to lack of access/consent within 24 h of cannulation (5/42, 12%) or PIC death/discharge (5/42, 12%). In each patient, the majority of SSEP (8/14, 57%), EEG (8/14, 57%) and NIRS (11/14, 79%) test results were within normal limits. All patients with abnormal neuroradiology (4/10, 40%), and 6/7 (86%) with poor outcome (PCPC ≥4) developed indirect SSEP, EEG or NIRS measures of neurological complications prior to decannulation. No study-related adverse events or neuro-monitoring data interpreting issues were experienced.

CONCLUSION

Non-invasive neuro-monitoring (SSEP/EEG/NIRS) during ECMO is feasible and may provide early indication of neurological complications in this high-risk population.

The Western origins of mindfulness therapy in ancient Rome

Stoic philosophy has multiple parallels with cognitive behavioural therapy interventions. In their ancient texts, the Roman Stoics present a set of theoretical principles and behavioural strategies that are directly relevant to the clinical care of patients with a wide range of neuropsychiatric conditions. Mindfulness is a key component of the 'third wave' of modern psychotherapy that closely resembles the ancient Stoic practice of attention or 'concentration on the present moment'. Stoic mindfulness draws attention to one of the main principles driving both Stoicism and modern psychotherapy: the assumption that cognitive activity (reasoning) mediates emotions and behaviours. This principle can be traced back to Epictetus' Enchiridion, where he recognises that 'men are disturbed not by things, but by the views which they take of things'. It has been shown that cognitive behavioural therapies and mindfulness-based interventions directed at patients with neuropsychiatric disorders were originally developed as Stoic-inspired treatment interventions. Both Albert Ellis and Aaron Beck (the founders of rational emotive behaviour therapy and cognitive behavioural therapy, respectively) explicitly acknowledged the role of Stoicism as the philosophical precursor of their treatment approaches. The effective implementation of evidence-based guidelines would benefit from an increased awareness of the influence of the Stoic tradition of philosophical therapy on the treatment approaches currently in use in neuropsychiatry.

A Hypothalamic Mechanism Regulates the Duration of a Migraine Attack: Insights from Microstructural and Temporal Complexity of Cortical Functional Networks Analysis

The role of the hypothalamus and the limbic system at the onset of a migraine attack has recently received significant interest. We analyzed diffusion tensor imaging (DTI) parameters of the entire hypothalamus and its subregions in 15 patients during a spontaneous migraine attack and in 20 control subjects. We also estimated the non-linear measure resting-state functional MRI BOLD signal's complexity using Higuchi fractal dimension (FD) and correlated DTI/fMRI findings with patients' clinical characteristics. In comparison with healthy controls, patients had significantly altered diffusivity metrics within the hypothalamus, mainly in posterior ROIs, and higher FD values in the salience network (SN). We observed a positive correlation of the hypothalamic axial diffusivity with migraine severity and FD of SN. DTI metrics of bilateral anterior hypothalamus positively correlated with the mean attack duration. Our results show plastic structural changes in the hypothalamus related to the attacks severity and the functional connectivity of the SN involved in the multidimensional neurocognitive processing of pain. Plastic changes to the hypothalamus may play a role in modulating the duration of the attack.

Functional hemispherotomy for epilepsy in the very young

OBJECTIVE

Epilepsy is one of the most common neurological disorders in children. Among very young children, one-third are resistant to medical treatment, and lack of effective treatment may result in adverse outcomes. Although functional hemispherotomy is an established treatment for epilepsy, its outcome in the very young child has not been widely reported. In this study the authors investigated seizure and developmental results after hemispherotomy in children younger than 3 years.

METHODS

The authors reviewed a prospective database of all children younger than 3 years with medically intractable epilepsy who underwent functional hemispherotomy at the authors' institution during the period between 2012 and 2020. Demographic data, epilepsy history, underlying etiology, operative and transfusion details, and seizure and developmental outcomes were analyzed.

RESULTS

Twelve patients were included in this study. The mean age (± SD) at seizure onset was 3 ± 2.6 months and at surgery was 1.3 ± 0.77 years, with a mean follow-up of 4 years. Diagnoses included hemimegalencephaly (n = 5), hemidysplasia (n = 2), hypoxic/hemorrhagic (n = 2), traumatic (n = 1), Sturge-Weber syndrome (n = 1), and mild hemispheric structural abnormality with EEG/PET correlates (n = 1). Eleven patients achieved an Engel class I outcome, and 1 patient achieved Engel class IV at last follow-up. No deaths, infections, cerebrovascular events, or unexpected long-term neurological deficits were recorded. All children progressed neurodevelopmentally following surgery, but their developmental levels remained behind their chronological age, with an overall mean composite Vineland Adaptive Behavior Scale score of 58 (normal: 86-114, low: < 70). One patient required insertion of a subdural peritoneal shunt, 1 patient required dural repair for a CSF fluid leak, and 1 patient required aspiration of a pseudomeningocele. In 2 patients, both of whom weighed less than 5.7 kg, the first operation was incomplete due to blood loss.

CONCLUSIONS

Hemispherotomy in children younger than 3 years offers excellent seizure control and an acceptable risk-to-benefit ratio in well-selected patients. Families of children weighing less than 6 kg should be counseled regarding the possibility of staged surgery. Postoperatively, children continue to make appropriate, despite delayed, developmental progress.

Systematic approach to outcome assessment from coded electronic healthcare records in the DaRe2THINK NHS-embedded randomized trial. EUROPEAN HEART JOURNAL. DIGITAL HEALTH 2022;3:426-436. [PMID: 36712153 PMCID: PMC9708037 DOI: 10.1093/ehjdh/ztac046]

Aims

Improving the efficiency of clinical trials is key to their continued importance in directing evidence-based patient care. Digital innovations, in particular the use of electronic healthcare records (EHRs), allow for large-scale screening and follow up of participants. However, it is critical these developments are accompanied by robust and transparent methods that can support high-quality and high clinical value research.

Methods and results

The DaRe2THINK trial includes a series of novel processes, including nationwide pseudonymized pre screening of the primary-care EHR across England, digital enrolment, remote e-consent, and 'no-visit' follow up by linking all primary- and secondary-care health data with patient-reported outcomes. DaRe2THINK is a pragmatic, healthcare-embedded randomized trial testing whether earlier use of direct oral anticoagulants in patients with prior or current atrial fibrillation can prevent thromboembolic events and cognitive decline (www.birmingham.ac.uk/dare2think). This study outlines the systematic approach and methodology employed to define patient information and outcome events. This includes transparency on all medical code lists and phenotypes used in the trial across a variety of national data sources, including Clinical Practice Research Datalink Aurum (primary care), Hospital Episode Statistics (secondary care), and the Office for National Statistics (mortality).

Conclusion

Co-designed by a patient and public involvement team, DaRe2THINK presents an opportunity to transform the approach to randomized trials in the setting of routine healthcare, providing high-quality evidence generation in populations representative of the community at risk.

Perioperative electroencephalography in cardiac surgery with hypothermic circulatory arrest: a narrative review

OBJECTIVES

Cardiac surgery with hypothermic circulatory arrest (HCA) is associated with neurological morbidity of variable severity and electroencephalography (EEG) is a sensitive proxy measure of brain injury. We conducted a narrative review of the literature to evaluate the role of perioperative EEG monitoring in cardiac surgery involving HCA.

METHODS

Medline, Embase, Central and LILACS databases were searched to identify studies utilizing perioperative EEG during surgery with HCA in all age groups, published since 1985 in any language. We aimed to compare EEG use with no use but due to the lack of comparative studies, we performed a narrative review of its utility. Two or more reviewers independently screened studies for eligibility and extracted data.

RESULTS

Fourty single-centre studies with a total of 3287 patients undergoing surgery were identified. Most were observational cohort studies (34, 85%) with only 1 directly comparing EEG use with no use. EEG continuity (18, 45%), seizures (15, 38%) and electrocerebral inactivity prior to circulatory arrest (15, 38%) were used to detect, monitor, prevent and prognose neurological injury. Neurological dysfunction was reported in almost all studies and occurred in 0–21% of patients. However, the heterogeneity of reported clinical and EEG outcome measures prevented meta-analysis.

CONCLUSIONS

EEG is used to detect cortical ischaemia and seizures and predict neurological abnormalities and may guide intraoperative cerebral protection. However, there is a lack of comparative data demonstrating the benefit of perioperative EEG monitoring. Use of a standardized methodology for performing EEG and reporting outcome metrics would facilitate the conduct of high-quality clinical trials.

Structural-covariance networks identify topology-based cortical-thickness changes in children with persistent executive function impairments after traumatic brain injury

Paediatric traumatic brain injury (pTBI) results in inconsistent changes to regional morphometry of the brain across studies. Structural-covariance networks represent the degree to which the morphology (typically cortical-thickness) of cortical-regions co-varies with other regions, driven by both biological and developmental factors. Understanding how heterogeneous regional changes may influence wider cortical network organization may more appropriately capture prognostic information in terms of long term outcome following a pTBI. The current study aimed to investigate the relationships between cortical organisation as measured by structural-covariance, and long-term cognitive impairment following pTBI. T1-weighted magnetic resonance imaging (MRI) from n = 83 pTBI patients and 33 typically developing controls underwent 3D-tissue segmentation using Freesurfer to estimate cortical-thickness across 68 cortical ROIs. Structural-covariance between regions was estimated using Pearson's correlations between cortical-thickness measures across 68 regions-of-interest (ROIs), generating a group-level 68 × 68 adjacency matrix for patients and controls. We grouped a subset of patients who underwent executive function testing at 2-years post-injury using a neuropsychological impairment (NPI) rule, defining impaired- and non-impaired subgroups. Despite finding no significant reductions in regional cortical-thickness between the control and pTBI groups, we found specific reductions in graph-level strength of the structural covariance graph only between controls and the pTBI group with executive function (EF) impairment. Node-level differences in strength for this group were primarily found in frontal regions. We also investigated whether the top n nodes in terms of effect-size of cortical-thickness reductions were nodes that had significantly greater strength in the typically developing brain than n randomly selected regions. We found that acute cortical-thickness reductions post-pTBI are loaded onto regions typically high in structural covariance. This association was found in those patients with persistent EF impairment at 2-years post-injury, but not in those for whom these abilities were spared. This study posits that the topography of post-injury cortical-thickness reductions in regions that are central to the typical structural-covariance topology of the brain, can explain which patients have poor EF at follow-up.

The AMPA receptor antagonist perampanel suppresses epileptic activity in human focal cortical dysplasia

Focal cortical dysplasia (FCD) is one of the most common malformations causing refractory epilepsy. Dysregulation of glutamatergic systems plays a critical role in the hyperexcitability of dysplastic neurons in FCD lesions. The pharmacoresistant nature of epilepsy associated with FCD may be due to a lack of well‐tolerated and precise antiepileptic drugs that can target glutamate receptors. Here, for the first time in human FCD brain slices, we show that the established, noncompetitive α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) receptor antagonist, perampanel has potent antiepileptic action. Moreover, we demonstrate that this effect is due to a reduction in burst firing behavior in human FCD microcircuits. These data support a potential role for the treatment of refractory epilepsy associated with FCD in human patients.

Efficacy of color lenses in abolishing photosensitivity: Beyond the one-type-fits-all approach?

OBJECTIVE

Red-light filtering lenses represent an additional option to medication in photosensitive epilepsy. Blue lenses (Clarlet Z1 F133) can dramatically reduce seizure frequency, with a substantial restriction in luminance that can limit their applicability in daily life. We investigated the efficacy of 4 blue lenses with higher transmittance and reduced chromatic distortion in abolishing the photoparoxysmal EEG response (PPR) compared to the gold-standard Z1 lenses.

METHODS

We reviewed EEG data during photic-and pattern stimulation in 19 consecutive patients (6-39 years) with photosensitivity (PS). Stimulation was performed at baseline and while wearing Z1 and the four new lenses. Lenses were tested in the same session by asking the patient to wear them in a sequentially randomized fashion while stimulating again with the most provocative photic/pattern stimuli. The primary outcome was the change in the initial PPR observed for each lens, categorized as no change, reduction, and abolition.

RESULTS

Photosensitivity was detected in 17 subjects (89.5%); pattern sensitivity (PtS) was identified in 14 patients (73.7%). The highest percentages of PPR abolition/reduction were observed with Z1, for both PS and PtS. Regarding the new lenses, B1 + G1 offered the best rates, followed by B1 + G2. B1 + G3 and B1 showed lower efficacy rates, particularly for PtS. In the comparative analysis, no significant differences in PPR suppression were detected between the five lenses for PS. For PtS, the capacity of Z1 for PPR abolition was significantly higher compared with B1 + G3 and B1.

CONCLUSIONS

This preliminary study suggests efficacy of the new group of blue lenses with potentially greater tolerability, particularly in regions with fewer sunlight hours during winter. In line with the current trend for personalized approach to treatment, this study suggests that in some patients there might be scope in extending the testing to offer the lens with the higher transmittance effective in abolishing the PPR.

Hypothalamic structural integrity and temporal complexity of cortical information processing at rest in migraine without aura patients between attacks

The hypothalamus has been attributed an important role during the premonitory phase of a migraine attack. Less is known about the role played by the hypothalamus in the interictal period and its relationship with the putative neurocognitive networks previously identified in the pathophysiology of migraine. Our aim was to test whether the hypothalamic microstructure would be altered during the interictal period and whether this co-existed with aberrant connectivity at cortical level. We collected multimodal MRI data from 20 untreated patients with migraine without aura between attacks (MO) and 20 healthy controls (HC) and studied fractional anisotropy, mean (MD), radial (RD), and axial diffusivity of the hypothalamus ROI as a whole from diffusion tensor imaging (DTI). Moreover, we performed an exploratory analysis of the same DTI metrics separately for the anterior and posterior hypothalamic ROIs bilaterally. From resting-state functional MRI, we estimated the Higuchi's fractal dimension (FD), an index of temporal complexity sensible to describe non-periodic patterns characterizing BOLD signature. Finally, we correlated neuroimaging findings with migraine clinical features. In comparison to HC, MO had significantly higher MD, AD, and RD values within the hypothalamus. These findings were confirmed also in the exploratory analysis on the sub-regions of the hypothalamus bilaterally, with the addition of lower FA values on the posterior ROIs. Patients showed higher FD values within the salience network (SN) and the cerebellum, and lower FD values within the primary visual (PV) network compared to HC. We found a positive correlation between cerebellar and SN FD values and severity of migraine. Our findings of hypothalamic abnormalities between migraine attacks may form part of the neuroanatomical substrate that predisposes the onset of the prodromal phase and, therefore, the initiation of an attack. The peculiar fractal dimensionality we found in PV, SN, and cerebellum may be interpreted as an expression of abnormal efficiency demand of brain networks devoted to the integration of sensory, emotional, and cognitive information related to the severity of migraine.

Pediatric stereo-electroencephalography: effects of robot assistance and other variables on seizure outcome and complications

OBJECTIVE

The safety of stereo-electroencephalography (SEEG) has been investigated; however, most studies have not differentiated pediatric and adult populations, which have different anatomy and physiology. The purpose of this study was to assess SEEG safety in the pediatric setting, focusing on surgical complications and the identification of patient and surgical risk factors, if any. The authors also aimed to determine whether robot assistance in SEEG was associated with a change in practice, surgical parameters, and clinical outcomes.

METHODS

The authors retrospectively studied all SEEG cases performed in their department from December 2014 to March 2020. They analyzed both demographic and surgical variables and noted the types of surgery-related complications and their management. They also studied the clinical outcomes of a subset of the patients in relation to robot-assisted and non-robot-assisted SEEG.

RESULTS

Sixty-three children had undergone 64 SEEG procedures. Girls were on average 3 years younger than the boys (mean age 11.1 vs 14.1 years, p < 0.01). The overall complication rate was 6.3%, and the complication rate for patients with left-sided electrodes was higher than that for patients with right-sided electrodes (11.1% vs 3.3%), although the difference between the two groups was not statistically significant. The duration of recording was positively correlated to the number of implanted electrodes (r = 0.296, p < 0.05). Robot assistance was associated with a higher number of implanted electrodes (mean 12.6 vs 7.6 electrodes, p < 0.0001). Robot-assisted implantations were more accurate, with a mean error of 1.51 mm at the target compared to 2.98 mm in nonrobot implantations (p < 0.001). Clinical outcomes were assessed in the first 32 patients treated (16 in the nonrobot group and 16 in the robot group), 23 of whom proceeded to further resective surgery. The children who had undergone robot-assisted SEEG had better eventual seizure control following subsequent epilepsy surgery. Of the children who had undergone resective epilepsy surgery, 42% (5/12) in the nonrobot group and 82% (9/11) in the robot group obtained an Engel class IA outcome at 1 year (χ2 = 3.885, p = 0.049). Based on Kaplan-Meier survival analysis, the robot group had a higher seizure-free rate than the nonrobot group at 30 months postoperation (7/11 vs 2/12, p = 0.063). Two complications, whose causes were attributed to the implantation and head-bandaging steps, required surgical intervention. All complications were either transient or reversible.

CONCLUSIONS

This is the largest single-center, exclusively pediatric SEEG series that includes robot assistance so far. SEEG complications are uncommon and usually transient or treatable. Robot assistance enabled implantation of more electrodes and improved epilepsy surgery outcomes, as compared to those in the non-robot-assisted cases.

MEG detection of high frequency oscillations and intracranial-EEG validation in pediatric epilepsy surgery

OBJECTIVE

To assess the feasibility of automatically detecting high frequency oscillations (HFOs) in magnetoencephalography (MEG) recordings in a group of ten paediatric epilepsy surgery patients who had undergone intracranial electroencephalography (iEEG).

METHODS

A beamforming source-analysis method was used to construct virtual sensors and an automatic algorithm was applied to detect HFOs (80-250 Hz). We evaluated the concordance of MEG findings with the sources of iEEG HFOs, the clinically defined seizure onset zone (SOZ), the location of resected brain structures, and with post-operative outcome.

RESULTS

In 8/9 patients there was good concordance between the sources of MEG HFOs and iEEG HFOs and the SOZ. Significantly more HFOs were detected in iEEG relative to MEG t(71) = 2.85, p < .05. There was good concordance between sources of MEG HFOs and the resected area in patients with good and poor outcome, however HFOs were also detected outside of the resected area in patients with poor outcome.

CONCLUSION

Our findings demonstrate the feasibility of automatically detecting HFOs non-invasively in MEG recordings in paediatric patients, and confirm compatibility of results with invasive recordings.

SIGNIFICANCE

This approach provides support for the non-invasive detection of HFOs to aid surgical planning and potentially reduce the need for invasive monitoring, which is pertinent to paediatric patients.

Reliability in the assessment of paediatric somatosensory evoked potentials post cardiac arrest

OBJECTIVE

To measure inter- and intra-rater agreement in the interpretation of cortical somatosensory evoked potential (SSEP) components following paediatric cardiac arrest (CA) in multi-professional neurophysiology teams.

METHODS

Thirteen professionals blinded to patient outcome interpreted 96 SSEPs in paediatric patients 24-/48-/72-hours following CA. Of these, 34 were duplicates used to assess intra-rater agreement. Consistent interpretations (absent/present/indeterminate) between scientists (who record/identify SSEP components) and neurophysiologists (who provide prognostic SSEP interpretation) were expressed as percentages. Rates of agreement were calculated using Fleiss' kappa coefficient (K).

RESULTS

Unanimous agreement between professionals was present in 40% (95%CI: 28-54%) of the interpreted SSEPs, with a K value of 0.62 (95%CI: 0.55-0.70) based on average agreement. Agreement was similar between neurophysiologists (K = 0.67; 95%CI: 0.57-0.77) and scientists (K = 0.62; 95%CI: 0.54-0.70) but lower in patients < 2 years old (K = 0.23; 95%CI: 0.14-0.33) and in those with poor outcome (K = 0.21; 95%CI: 0.07-0.35). No SSEP was unanimously interpreted as absent and 92% (95%CI: 89-95%) of duplicate SSEPs were interpreted consistently.

CONCLUSION

Despite substantial agreement when interpreting prognostic SSEPs, this was significantly lower in children with poor outcome and of younger age.

SIGNIFICANCE

Clinicians using SSEPs in the intensive care unit should be aware of the inter-rater variability when interpreting SSEPs as absent.

Sleep disruption in children and adolescents with epilepsy: A systematic review and meta-analysis

This systematic review and meta-analysis aims to assess and quantify putative differences in sleep architecture, sleep efficiency, sleep timing and broadly-defined sleep difficulties between children with and without epilepsy. Databases were searched systematically, and studies identified in PubMed, EMBASE, PsychINFO and Medline. The meta-analysis included 19 studies comparing a total of 901 children with epilepsy to 1470 healthy children. Relative to healthy children, children with epilepsy experienced reduced sleep time, sleeping on average 34 mins less across self-report, actigraphy, 24-h video-EEG and polysomnography measures. They had more sleep difficulties specifically in the domains of night waking, parasomnias and sleep disordered breathing. The analysis also revealed a significantly increased percentage of N2 sleep and decreased sleep efficiency in children with epilepsy compared to healthy children. These results illustrate that children with epilepsy are vulnerable to more sleep difficulties compared to healthy children. This suggests that screening for sleep difficulties should be an integral part in a diagnosis of epilepsy to ensure that clinically relevant sleep difficulties are identified and treated. Such an approach may ultimately aid in the development of treatment strategies which can contribute to improvements in both developmental and diagnostic outcomes for children with epilepsy.

Peripheral nerve electrophysiology studies in relation to fatigue in patients with chronic inflammatory demyelinating polyneuropathy

OBJECTIVE

To explore the relationship between fatigue, standard electrophysiological parameters and number and size of functioning motor units in patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODS

Experienced fatigue was assessed using the linearly-weighted, modified Rasch-built fatigue severity scale (R-FSS) and the multidimensional Checklist of Individual Strength (CIS). Averaged electrophysiology values were calculated from multiple nerves. Motor Unit Number Index (MUNIX) technique was utilised to assess motor unit function. Assessments were repeated in 15 patients receiving regular intravenous immunoglobulin therapy, with changes in parameters calculated.

RESULTS

R-FSS and CIS scores did not correlate MUNIX or MUSIX sum scores from 3 different muscles. Inverse correlation was observed only between distal CMAP area and R-FSS but not CIS scores. However, changes in distal CMAP area and R-FSS scores on repeat assessment were not correlated.

CONCLUSIONS

Experienced fatigue does not appear to correlate with loss of functioning motor units in patients with CIDP. Changes in experienced fatigue on repeat assessment did not correlate with changes in any of the electrophysiological parameters, suggesting fatigue experienced in CIDP is not strongly correlated with peripheral nerve dysfunction.

SIGNIFICANCE

Nerve conduction studies and MUNIX values do not appear to be useful surrogate markers for fatigue in CIDP.

The cognitive neuropsychiatry of Tourette syndrome

Introduction: Converging evidence from both clinical and experimental studies has shown that Tourette syndrome (TS) is not a unitary condition, but a cluster of multiple phenotypes, which encompass both tics and specific behavioural and cognitive symptoms (mainly attention-deficit and hyperactivity disorder and obsessive-compulsive disorder). Methods: We conducted a narrative review of the recent literature on the cognitive neuropsychiatry of TS. Results: Although clinical research has shown that TS is not associated with cognitive deficits per se, the findings of recent studies have suggested the presence of subtle alterations in specific cognitive functions. A promising line of research on imitative behaviour could provide a common background for the alterations in executive control and social cognition observed in TS. Two different (but not mutually exclusive) neurocognitive theories have recently suggested that TS could originate from altered perception-action binding and social decision-making dysfunction, respectively. Conclusions: Since the presence of behavioural comorbidities influences individualised treatment approaches, it is likely that a more precise characterisation of TS phenotypes, including cognitive aspects, will result in improved levels of care for patients with tic disorders.

Light-emitting-diode and Grass PS 33 xenon lamp photic stimulators are equivalent in the assessment of photosensitivity: Clinical and research implications

The assessment of the effect of photic stimulation is an integral component of an EEG exam and is especially important in patients referred for ascertained or suspected photosensitivity with or without a diagnosis of epilepsy. A positive test result relies on eliciting a specific abnormality defined as the "photoparoxysmal response". Reliability of this assessment is strongly influenced by technical and procedural variables, a critical one represented by the physical properties of the stimulators used. Established clinical norms are based on data acquired with the "gold-standard" Grass PS stimulators. These are no longer commercially available and have been replaced by stimulators using light emitting diode (LED) technology. To our knowledge no comparative study on their efficacy has been conducted. To address this gap, we recruited 39 patients aged 5-54 years, referred to two specialized centers with confirmed of suspected diagnosis of photosensitive epilepsy or generalized epilepsy with photosensitivity in a prospective randomized single-blind cross-over study to compare two commercially available LED-bases stimulation systems (FSA 10® and Lifeline® stimulators) against the Grass PS 33 xenon lamp device. Our findings indicate that the LED systems tested are equivalent to the Grass stimulator both in identifying the PPR in affected individuals.

Abolishing spontaneous epileptiform activity in human brain tissue through AMPA receptor inhibition

Objective

The amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptor (AMPAR) is increasingly recognized as a therapeutic target in drug‐refractory pediatric epilepsy. Perampanel (PER) is a non‐competitive AMPAR antagonist, and pre‐clinical studies have shown the AMPAR‐mediated anticonvulsant effects of decanoic acid (DEC), a major medium‐chain fatty acid provided in the medium‐chain triglyceride ketogenic diet.

Methods

Using brain tissue resected from children with intractable epilepsy, we recorded the effects of PER and DEC in vitro.

Results

We found resected pediatric epilepsy tissue exhibits spontaneous epileptic activity in vitro, and showed that DEC and PER inhibit this epileptiform activity in local field potential recordings as well as excitatory synaptic transmission.

Interpretation

This study confirms AMPAR antagonists inhibit epileptiform discharges in brain tissue resected in a wide range of pediatric epilepsies.

Motor stereotypies in adult patients with Tourette syndrome

Aim: Correctly diagnosing repetitive behaviors in patients with Tourette syndrome (TS) can be challenging. The differential diagnosis between tics and stereotypies is of particular importance, because of treatment implications. Methods: We assessed the prevalence and clinical characteristics of stereotypies in a large sample of adult patients with TS attending a specialist clinic. Results: Mild stereotypies were reported by 21/148 patients (14.2%). Patients with stereotypies were significantly more likely to have a comorbid diagnosis of Asperger syndrome, attention-deficit and hyperactivity disorder, and obsessive-compulsive disorder, compared with patients without stereotypies. Multiple linear regression analysis revealed that the presence of Asperger syndrome significantly predicted stereotypy severity. Conclusion: Stereotypies are not rare in adults with TS and other neurodevelopmental conditions, especially Asperger syndrome.

Mapping language networks and their association with verbal abilities in paediatric epilepsy using MEG and graph analysis

Recent theoretical models of language have emphasised the importance of integration within distributed networks during language processing. This is particularly relevant to young patients with epilepsy, as the topology of the functional network and its dynamics may be altered by the disease, resulting in reorganisation of functional language networks. Thus, understanding connectivity within the language network in patients with epilepsy could provide valuable insights into healthy and pathological brain function, particularly when combined with clinical correlates. The objective of this study was to investigate interactions within the language network in a paediatric population of epilepsy patients using measures of MEG phase synchronisation and graph-theoretical analysis, and to examine their association with language abilities. Task dependent increases in connectivity were observed in fronto-temporal networks during verb generation across a group of 22 paediatric patients (9 males and 13 females; mean age 14 years). Differences in network connectivity were observed between patients with typical and atypical language representation and between patients with good and poor language abilities. In addition, node centrality in left frontal and temporal regions was significantly associated with language abilities, where patients with good language abilities had significantly higher node centrality within inferior frontal and superior temporal regions of the left hemisphere, compared to patients with poor language abilities. Our study is one of the first to apply task-based measures of MEG network synchronisation in paediatric epilepsy, and we propose that these measures of functional connectivity and node centrality could be used as tools to identify critical regions of the language network prior to epilepsy surgery.

Headache in patients with Tourette syndrome: A systematic literature review

Aim:

To systematically review the available literature on the prevalence and clinical characteristics of headache in patients with Tourette syndrome (TS), a neurodevelopmental condition characterized by the chronic presence of motor and vocal tics.

Design:

We conducted a systematic literature review of original studies using three clinical databases (Medline, EMBASE and PsycInfo), according to the standards outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Outcome measures included both tic severity and tic frequency.

Results:

Our systematic literature review identified six studies on the prevalence and characteristics of headache in patients with TS (data on paediatric patients were available from five studies and data on adult patients from four studies). The proportion of patients with TS who had a diagnosis of headache ranged from 29% to 62%. Migraine was the most commonly investigated headache disorder in this patient population. The findings of the reviewed studies showed that the prevalence of migraine in patients with TS ranges between 13% and 43% and is significantly higher compared to the two control groups ( p < 0.05).

Discussion:

The prevalence of headache in patients with TS could be higher than in the general population, with the most reliable data being available for migraine. Overall, the literature on the prevalence and characteristics of headache in TS is sparse and highly heterogeneous. Further research on the prevalence and clinical correlates of migraine, tension-type headache and other types of headache in patients with TS across the lifespan is needed to inform clinical practice aimed at improving health-related quality of life in patients with tics.

Developmental divergence of structural brain networks as an indicator of future cognitive impairments in childhood brain injury: Executive functions

Brain insults during childhood can perturb the already non-linear trajectory of typical brain maturation. The diffuse effects of injury can be modelled using structural covariance networks (SCN), which change as a function of neurodevelopment. However, SCNs are estimated at the group-level, limiting applicability to predicting individual-subject outcomes. This study aimed to measure the divergence of the brain networks in paediatric traumatic brain injury (pTBI) patients and controls, and investigate relationships with executive functioning (EF) at 24 months post-injury. T1-weighted MRI acquired acutely in 78 child survivors of pTBI and 33 controls underwent 3D-tissue segmentation to estimate cortical thickness (CT) across 68 atlas-based regions-of-interest (ROIs). Using an 'add-one-patient' approach, we estimate a developmental divergence index (DDI). Our approach adopts a novel analytic framework in which age-appropriate reference networks to calculate the DDI were generated from control participants from the ABIDE dataset using a sliding-window approach. Divergence from the age-appropriate SCN was related to reduced EF performance and an increase in behaviours related to executive dysfunctions. The DDI measure showed predictive value with regard to executive functions, highlighting that early imaging can assist in prognosis for cognition.

Levels of diagnostic certainty for nonepileptic attack disorder in the neuropsychiatry setting

Nonepileptic attack disorder (NEAD) is a medical condition commonly seen in neuropsychiatry services, often as a differential diagnosis of other neuropsychiatric conditions. Recommendations by the International League Against Epilepsy (ILAE) Nonepileptic Seizures Task Force propose a four-level hierarchical approach to the diagnosis of NEAD, based on history, witnessed event, and electroencephalographic (EEG) investigation. We set out to provide the first description of the diagnostic levels of patients with NEAD at a specialist neuropsychiatry clinic. Comprehensive clinical data from 148 consecutive patients with NEAD attending the specialist Neuropsychiatry Clinic run by a single Consultant in Behavioral Neurology were retrospectively reviewed. Patients with NEAD were primarily referred to neuropsychiatry by Consultant Neurologists (n = 94; 63.5%). The majority of patients were female (n = 108; 73.0%), with a disease duration of 7.9 years (standard deviation: 10.4). Anxiety was the most common comorbidity (n = 43; 26.7%). Categorization of patients according to the ILAE Nonepileptic Seizures Task Force criteria was mainly based on clinical features and EEG findings, as only 7 (4.7%) patients had attacks witnessed by a specialist. The largest diagnostic categories were 'possible' (n = 54; 36.5%) and 'clinically established' (n = 40; 27.0%), followed by 'documented' (n = 12; 8.1%) and 'probable' (n = 5; 3.4%). In 125 patients (84.4%), EEGs were performed. Selective serotonin reuptake inhibitors were the most frequently prescribed psychotropic medications (n = 48; 32.4%); 89 patients (60.1%) received behavioral therapy. There were no differences in pharmacological or behavioral management strategies across the patients categorized under different diagnostic levels. Patients with NEAD seen within neuropsychiatry settings are mainly assigned 'possible' and 'clinically established' levels of diagnostic certainty. Difficulty in capturing typical clinical events witnessed by an experienced clinician while on video-EEG can limit the clinical application of the 'documented' diagnostic level. If appropriate, active interventions can be implemented irrespective of diagnostic levels to minimize delays in the neuropsychiatric care pathways.

Establishing a Developmentally Appropriate fMRI Paradigm Relevant to Presurgical Mapping of Memory in Children

Functional magnetic resonance imaging (fMRI) is an established eloquent cortex mapping technique that is now an integral part of the pre-operative work-up in candidates for epilepsy surgery. Emerging evidence in adults with epilepsy suggests that material-specific fMRI paradigms can predict postoperative memory outcomes, however these paradigms are not suitable for children. In pediatric age, the use of memory fMRI paradigms designed for adults is complicated by the effect of developmental stages in cognitive maturation, the impairment experienced by some people with temporal lobe epilepsy (TLE) and the normal representation of memory function during development, which may differ from adults. We present a memory fMRI paradigm designed to activate mesial temporal lobe structures that is brief, independent of reading ability, and therefore a novel candidate for use in children. Data from 33 adults and 19 children (all healthy controls) show that the paradigm captures the expected leftward asymmetry of mesial temporal activation in adults. A more symmetrical pattern was observed in children, consistent with the progressive emergence of hemispheric specialisation across childhood. These data have important implications for the interpretation of presurgical memory fMRI in the pediatric setting. They also highlight the need to carefully consider the impact of cognitive development on fMRI tools used in clinical practice.

A Wireless Neuroprosthesis for Patients with Drug-refractory Epilepsy: A Proof-of-Concept Study

Objective Acute or protracted cortical recording may be necessary for patients with drug-refractory epilepsy to identify the ictogenic regions before undergoing resection. Currently, these invasive recording techniques present certain limitations, one of which is the need for cables connecting the recording electrodes placed in the intracranial space with external devices displaying the recorded electrocorticographic signals. This equates to a direct connection between the sterile intracranial space with the non-sterile environment. Due to the increasing likelihood of infections with time, subdural grids are typically removed a few days after implantation, a limiting factor in localizing the epileptogenic zone if seizures are not frequent enough to be captured within this time-frame. Furthermore, patients are bound to stay in the hospital, connected by the wires to the recording device, thus increasing substantially the treatment costs. To address some of the current shortcomings of invasive monitoring, we developed a neuroprosthesis made of a subdural silicone grid connected to a wireless transmitter allowing prolonged electrocorticografic recording and direct cortical stimulation. This device consists of a silicone grid with 128-platinum/iridium contacts, connected to an implantable case providing wireless recording and stimulation. The case also houses a wirelessly rechargeable battery for chronic long-term implants. We report the results of the first human proof-of-concept trial for wireless transmission of electrocorticographic recordings using a device suited for long-term implantation in three patients with drug-refractory epilepsy.  Methods Three patients with medically refractory epilepsy underwent the temporary intraoperative placement of the subdural grid connected to the wireless device for recording and transmission of electrocorticographic signals for a duration of five minutes before the conventional recording electrodes were placed or the ictal foci were resected. Results Wireless transmission of brain signals was successfully achieved. The wireless electrocorticographic signal was judged of excellent quality by a blinded neurophysiologist. Conclusions This preliminary experience reports the first successful placement of a wireless electrocorticographic recording device in humans. Long-term placement for prolonged wireless electrocorticographic recording in epilepsy patients will be the next step.

Social stigma and self-perception in adolescents with tourette syndrome

Tourette syndrome (TS) is a complex neurodevelopmental disorder characterized by multiple motor and vocal tics, which commonly presents with multiple behavioral problems, including co-morbid attention-deficit and hyperactivity disorder and obsessive-compulsive disorder. Both tics and co-morbid conditions have been shown to potentially affect patients’ health-related quality of life. While TS typically presents in childhood, its manifestations peak in severity during adolescence, a critical period in which affected individuals are exposed to potential stigma from peers. Physical and behavioral manifestations can also contribute to stigma, which subsequently leads to poorer health outcomes, discrimination, and a reduced willingness to seek help. The available evidence suggests that young patients with TS can experience reduced social acceptance from peers and difficulties establishing relationships. There is also evidence that some health care professionals share the unhelpful belief that young patients with TS should be disciplined in order to correct their disruptive behavior, based on the erroneous assumption that tics can be consciously controlled. Studies focussed on self-perception in patients with TS have yielded inconsistent results, with some studies showing problems in the domains of self-concept and self-esteem. Feelings of isolation, loneliness, and experiences of bullying have been reported more consistently. Interventions are required to reduce misconceptions about the condition and thus reduce stigma through targeted education and behavioral interventions. A multi-faceted approach that focuses on educating children, adults, and educators about TS would be beneficial to help alleviate stigma. This can be combined with self-advocacy and tailored psychological therapies for young patients with TS. The present paper reviews the current literature on stigma and self-perception in adolescents with TS in order to inform clinical decisions about management strategies and possible interventions to improve health-related quality of life.

A systematic review of cross-sectional differences and longitudinal changes to the morphometry of the brain following paediatric traumatic brain injury

Paediatric traumatic brain injury (pTBI) is a leading cause of disability for children and young adults. Children are a uniquely vulnerable group with the disease process that occurs following a pTBI interacting with the trajectory of normal brain development. Quantitative MRI post-injury has suggested a long-term, neurodegenerative effect of TBI on the morphometry of the brain, in both adult and childhood TBI. Changes to the brain beyond that of anticipated, age-dependant differences may allow us to estimate the state of the brain post-injury and produce clinically relevant predictions for long-term outcome. The current review synthesises the existing literature to assess whether, following pTBI, the morphology of the brain exhibits either i) longitudinal change and/or ii) differences compared to healthy controls and outcomes. The current literature suggests that morphometric differences from controls are apparent cross-sectionally at both acute and late-chronic timepoints post-injury, thus suggesting a non-transient effect of injury. Developmental trajectories of morphometry are altered in TBI groups compared to patients, and it is unlikely that typical maturation overcomes damage post-injury, or even 'catches up' with that of typically-developing peers. However, there is limited evidence for diverted developmental trajectories being associated with cognitive impairment post-injury. The current review also highlights the apparent challenges to the existing literature and potential methods by which these can be addressed.

EPINETLAB: A Software for Seizure-Onset Zone Identification From Intracranial EEG Signal in Epilepsy

The pre-operative workup of patients with drug-resistant epilepsy requires in some candidates the identification from intracranial EEG (iEEG) of the seizure-onset zone (SOZ), defined as the area responsible of the generation of the seizure and therefore candidate for resection. High-frequency oscillations (HFOs) contained in the iEEG signal have been proposed as biomarker of the SOZ. Their visual identification is a very onerous process and an automated detection tool could be an extremely valuable aid for clinicians, reducing operator-dependent bias, and computational time. In this manuscript, we present the EPINETLAB software, developed as a collection of routines integrated in the EEGLAB framework that aim to provide clinicians with a structured analysis pipeline for HFOs detection and SOZ identification. The tool implements an analysis strategy developed by our group and underwent a preliminary clinical validation that identifies the HFOs area by extracting the statistical properties of HFOs signal and that provides useful information for a topographic characterization of the relationship between clinically defined SOZ and HFO area. Additional functionalities such as inspection of spectral properties of ictal iEEG data and import and analysis of source-space magnetoencephalographic (MEG) data were also included. EPINETLAB was developed with user-friendliness in mind to support clinicians in the identification and quantitative assessment of HFOs in iEEG and source space MEG data and aid the evaluation of the SOZ for pre-surgical assessment.

An evaluation of kurtosis beamforming in magnetoencephalography to localize the epileptogenic zone in drug resistant epilepsy patients

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Objective localizations of interictal spikes using a kurtosis beamformer.

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Kurtosis Beamforming can provide confidence to scattered dipoles.

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Kurtosis beamforming can assist in localizing the epileptogenic zone.

Objective

Kurtosis beamforming is a useful technique for analysing magnetoencephalograpy (MEG) data containing epileptic spikes. However, the implementation varies and few studies measure concordance with subsequently resected areas. We evaluated kurtosis beamforming as a means of localizing spikes in drug-resistant epilepsy patients.

Methods

We retrospectively applied kurtosis beamforming to MEG recordings of 22 epilepsy patients that had previously been analysed using equivalent current dipole (ECD) fitting. Virtual electrodes were placed in the kurtosis volumetric peaks and visually inspected to select a candidate source. The candidate sources were compared to the ECD localizations and resection areas.

Results

The kurtosis beamformer produced interpretable localizations in 18/22 patients, of which the candidate source coincided with the resection lobe in 9/13 seizure-free patients and in 3/5 patients with persistent seizures. The sublobar accuracy of the kurtosis beamformer with respect to the resection zone was higher than ECD (56% and 50%, respectively), however, ECD resulted in a higher lobar accuracy (75%, 67%).

Conclusions

Kurtosis beamforming may provide additional value when spikes are not clearly discernible on the sensors and support ECD localizations when dipoles are scattered.

Significance

Kurtosis beamforming should be integrated with existing clinical protocols to assist in localizing the epileptogenic zone.

Kurtosis-Based Detection of Intracranial High-Frequency Oscillations for the Identification of the Seizure Onset Zone

Pathological High-Frequency Oscillations (HFOs) have been recently proposed as potential biomarker of the seizure onset zone (SOZ) and have shown superior accuracy to interictal epileptiform discharges in delineating its anatomical boundaries. Characterization of HFOs is still in its infancy and this is reflected in the heterogeneity of analysis and reporting methods across studies and in clinical practice. The clinical approach to HFOs identification and quantification usually still relies on visual inspection of EEG data. In this study, we developed a pipeline for the detection and analysis of HFOs. This includes preliminary selection of the most informative channels exploiting statistical properties of the pre-ictal and ictal intracranial EEG (iEEG) time series based on spectral kurtosis, followed by wavelet-based characterization of the time-frequency properties of the signal. We performed a preliminary validation analyzing EEG data in the ripple frequency band (80-250 Hz) from six patients with drug-resistant epilepsy who underwent pre-surgical evaluation with stereo-EEG (SEEG) followed by surgical resection of pathologic brain areas, who had at least two-year positive post-surgical outcome. In this series, kurtosis-driven selection and wavelet-based detection of HFOs had average sensitivity of 81.94% and average specificity of 96.03% in identifying the HFO area which overlapped with the SOZ as defined by clinical presurgical workup. Furthermore, the kurtosis-based channel selection resulted in an average reduction in computational time of 66.60%.

Support vector machines to detect physiological patterns for EEG and EMG-based human-computer interaction: a review

Support vector machines (SVMs) are widely used classifiers for detecting physiological patterns in human-computer interaction (HCI). Their success is due to their versatility, robustness and large availability of free dedicated toolboxes. Frequently in the literature, insufficient details about the SVM implementation and/or parameters selection are reported, making it impossible to reproduce study analysis and results. In order to perform an optimized classification and report a proper description of the results, it is necessary to have a comprehensive critical overview of the applications of SVM. The aim of this paper is to provide a review of the usage of SVM in the determination of brain and muscle patterns for HCI, by focusing on electroencephalography (EEG) and electromyography (EMG) techniques. In particular, an overview of the basic principles of SVM theory is outlined, together with a description of several relevant literature implementations. Furthermore, details concerning reviewed papers are listed in tables and statistics of SVM use in the literature are presented. Suitability of SVM for HCI is discussed and critical comparisons with other classifiers are reported.

Phenobarbital for Neonatal Seizures: Response Rate and Predictors of Refractoriness

Background Phenobarbital is the first-line choice for neonatal seizures treatment, despite a response rate of approximately 45%. Failure to respond to acute anticonvulsants is associated with poor neurodevelopmental outcome, but knowledge on predictors of refractoriness is limited. Objective To quantify response rate to phenobarbital and to establish variables predictive of its lack of efficacy. Methods We retrospectively evaluated newborns with electrographically confirmed neonatal seizures admitted between January 1999 and December 2012 to the neonatal intensive care unit of Parma University Hospital (Italy), excluding neonates with status epilepticus. Response was categorized as complete (cessation of clinical and electrographic seizures after phenobarbital administration), partial (reduction but not cessation of electrographic seizures with the first bolus, response to the second bolus), or absent (no response after the second bolus). Multivariate analysis was used to identify independent predictors of refractoriness. Results Out of 91 newborns receiving phenobarbital, 57 (62.6%) responded completely, 15 (16.5%) partially, and 19 (20.9%) did not respond. Seizure type (p = 0.02), background electroencephalogram (EEG; p ≤ 0.005), and neurologic examination (p  ≤  0.005) correlated with response to phenobarbital. However, EEG (p  ≤  0.02) and seizure type (p  ≤  0.001) were the only independent predictors. Conclusion Our results suggest a prominent role of neurophysiological variables (background EEG and electrographic-only seizure type) in predicting the absence of response to phenobarbital in high-risk newborns.

Acute Exposure to Terrestrial Trunked Radio (TETRA) has effects on the electroencephalogram and electrocardiogram, consistent with vagal nerve stimulation

BACKGROUND

Terrestrial Trunked Radio (TETRA) is a telecommunications system widely used by police and emergency services around the world. The Stewart Report on mobile telephony and health raised questions about possible health effects associated with TETRA signals. This study investigates possible effects of TETRA signals on the electroencephalogram and electrocardiogram in human volunteers.

METHODS

Blinded randomized provocation study with a standardized TETRA signal or sham exposure. In the first of two experiments, police officers had a TETRA set placed first against the left temple and then the upper-left quadrant of the chest and the electroencephalogram was recorded during rest and active cognitive processing. In the second experiment, volunteers were subject to chest exposure of TETRA whilst their electroencephalogram and heart rate variability derived from the electrocardiogram were recorded.

RESULTS

In the first experiment, we found that exposure to TETRA had consistent neurophysiological effects on the electroencephalogram, but only during chest exposure, in a pattern suggestive of vagal nerve stimulation. In the second experiment, we observed changes in heart rate variability during exposure to TETRA but the electroencephalogram effects were not replicated.

CONCLUSIONS

Observed effects of exposure to TETRA signals on the electroencephalogram (first experiment) and electrocardiogram are consistent with vagal nerve stimulation in the chest by TETRA. However given the small effect on heart rate variability and the lack of consistency on the electroencephalogram, it seems unlikely that this will have a significant impact on health. Long-term monitoring of the health of the police force in relation to TETRA use is on-going.

Impaired brainstem and thalamic high-frequency oscillatory EEG activity in migraine between attacks

Introduction

We investigated whether interictal thalamic dysfunction in migraine without aura (MO) patients is a primary determinant or the expression of its functional disconnection from proximal or distal areas along the somatosensory pathway.

Methods

Twenty MO patients and twenty healthy volunteers (HVs) underwent an electroencephalographic (EEG) recording during electrical stimulation of the median nerve at the wrist. We used the functional source separation algorithm to extract four functionally constrained nodes (brainstem, thalamus, primary sensory radial, and primary sensory motor tangential parietal sources) along the somatosensory pathway. Two digital filters (1–400 Hz and 450–750 Hz) were applied in order to extract low- (LFO) and high- frequency (HFO) oscillatory activity from the broadband signal.

Results

Compared to HVs, patients presented significantly lower brainstem (BS) and thalamic (Th) HFO activation bilaterally. No difference between the two cortical HFO as well as in LFO peak activations between the two groups was seen. The age of onset of the headache was positively correlated with HFO power in the right brainstem and thalamus.

Conclusions

This study provides evidence for complex dysfunction of brainstem and thalamocortical networks under the control of genetic factors that might act by modulating the severity of migraine phenotype.