The utility of Multicentre Epilepsy Lesion Detection (MELD) algorithm in identifying epileptic activity and predicting seizure freedom in MRI lesion-negative paediatric patients.

AIM: Paediatric patients with drug-resistant focal epilepsy (DRFE) who have no clear focal lesion identified on conventional structural magnetic resonance imaging (MRI) are a particularly challenging cohort to treat and form an increasing part of epilepsy surgery programs. A recently developed deep-learning-based MRI lesion detection algorithm, the Multicentre Lesion Detection (MELD) algorithm, has been shown to aid detection of focal cortical dysplasia (FCD). We applied this algorithm retrospectively to a cohort of MRI-negative children with refractory focal epilepsy who underwent stereoelectroencephalography (SEEG) to determine its accuracy in identifying unseen epileptic lesions, seizure onset zones and clinical outcomes. METHODS: We retrospectively applied the MELD algorithm to a consecutive series of MRI-negative patients who underwent SEEG at our tertiary Paediatric Epilepsy Surgery centre. We assessed the extent to which the identified MELD cluster or lesion area corresponded with the clinical seizure hypothesis, the epileptic network, and the positron emission tomography (PET) focal hypometabolic area. In those who underwent resective surgery, we analysed whether the region of MELD abnormality corresponded with the surgical target and to what extent this was associated with seizure freedom. RESULTS: We identified 37 SEEG studies in 28 MRI-negative children in whom we could run the MELD algorithm. Of these, 14 (50 %) children had clusters identified on MELD. Nine (32 %) children had clusters concordant with seizure hypothesis, 6 (21 %) had clusters concordant with PET imaging, and 5 (18 %) children had at least one cluster concordant with SEEG electrode placement. Overall, 4 MELD clusters in 4 separate children correctly predicted either seizure onset zone or irritative zone based on SEEG stimulation data. Sixteen children (57 %) went on to have resective or lesional surgery. Of these, only one patient (4 %) had a MELD cluster which co-localised with the resection cavity and this child had an Engel 1 A outcome. CONCLUSIONS: In our paediatric cohort of MRI-negative patients with drug-resistant focal epilepsy, the MELD algorithm identified abnormal clusters or lesions in half of cases, and identified one radiologically occult focal cortical dysplasia. Machine-learning-based lesion detection is a promising area of research with the potential to improve seizure outcomes in this challenging cohort of radiologically occult FCD cases. However, its application should be approached with caution, especially with regards to its specificity in detecting FCD lesions, and there is still work to be done before it adds to diagnostic utility.

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.

Amplitude-reduction alert criteria and intervention during complex paediatric cervical spine surgery.

Objective: To determine the utility of widely used intraoperative neuromonitoring (IONM) alert criteria and intervention for predicting postoperative outcome following paediatric spinal surgery. Methods: Retrospective analysis of somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) in consecutive cervical spine fixations. An intervention protocol followed amplitude-reductions in SSEPs (≥50 %) and/or MEPs (≥80 %). Alert breaches were reversed when SSEP/MEP amplitude was restored to > 50 %/20 % of baseline. Sensorimotor function was assessed preoperatively and 3-months postoperatively via the Modified McCormick Scale score (MMS). We explored associations between postoperative outcome, demographic/surgical and IONM variables. Results: Forty-five procedures in 38 children (mean age:9 ±â€¯4 years;55 % female) were monitored, 42 %of which breached alert criteria. Instrumentation (6/19,32 %) and hypotension (5/19,26 %) were common causes for alert and the majority (13/19,68 %) were reversed following intervention. There was an association between pre- and post-MMS and the type of breach (p = 0.002). All children with worse postoperative MMS (3/38,8%) had irreversible breaches. Conclusions: IONM in this small sample accurately detected neurological injury. The majority of breaches reversed following an intervention protocol. Irreversible breaches frequently led to worse postoperative sensorimotor function. Significance: An intervention protocol which reversed IONM alerts never resulted in postoperative worsening of sensorimotor function.

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.

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.

Clinical correlates of fatigue in chronic inflammatory demyelinating polyneuropathy.

INTRODUCTION: Fatigue is a recognized manifestation of immune-mediated neuropathies, but its causes and implications are unclear. In this study, we explored the correlates of fatigue among a number of clinical parameters in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) to better understand potential contributing factors and resulting consequences. METHODS: Twenty-six clinically stable patients with CIDP underwent assessments of motor and sensory function, disability, quality of life, and depression and anxiety. Experienced fatigue was assessed by using the Rasch-built Fatigue Severity Scale and the Checklist of Individual Strength. RESULTS: The two fatigue scales provided evidence of significant intercorrelation. Only depression scores and grip strength predicted experienced fatigue levels in multivariate regression analyses. Fatigue scores inversely correlated with strength, sensory, disability, and quality of life scores. DISCUSSION: Experienced fatigue is likely multifactorial in CIDP, with both physical and neuropsychiatric components. Fatigue is associated with lower functional and quality-of-life outcomes in CIDP.

Prevalence and clinical correlates of non-convulsive status epilepticus in elderly patients with acute confusional state: A systematic literature review.

Non-convulsive status epilepticus (NCSE) is a potentially treatable condition that poses considerable diagnostic challenges. NCSE is thought to be more common in the elderly than in the general population, however additional diagnostic challenges complicate its recognition in older patients, because of the wide differential diagnosis with common underlying causes of acute confusional state in this age group. We set out to review the existing evidence on the clinical correlates of NCSE in the elderly population. A systematic literature review was conducted according to the methodological standards outlined in the PRISMA statement to assess the clinical correlates of NCSE in patients aged 60 or older. Our literature search identified 11 relevant studies, which confirmed that the incidence of NCSE increases with age, in particular with regard to focal forms with impairment of consciousness. Female gender, history of epilepsy (or a recently witnessed seizure with motor features), and abnormal ocular movements appeared to correlate with the diagnosis of NCSE in the elderly, prompting prioritization of electroencephalography tests for diagnostic confirmation. Epidemiological data in the elderly vary widely because of the heterogeneity of definitions and diagnostic criteria applied across different studies. Based on our findings, it is recommended to keep a low threshold for requesting electroencephalography tests to confirm the diagnosis of NCSE in elderly patients with acute confusional state, even in the presence of a presumed symptomatic cause.

The role of electroencephalography in the early diagnosis of non-convulsive status epilepticus in elderly patients with acute confusional state: Two possible strategies?

Non-convulsive status epilepticus (NCSE) can pose considerable diagnostic challenges, especially in the elderly, because of the wide differential diagnosis with common underlying causes of acute confusional state in this age group. We reviewed the proposed electroencephalography (EEG) strategies to improve the diagnostic yield of non-convulsive status epilepticus in the elderly population. Specifically, a debated topic of clinical relevance is the exact role of the EEG in the early diagnosis of NCSE in the elderly. Two EEG strategies have been proposed to improve the diagnostic yield of NCSE: emergent abbreviated EEG (EAEEG) recordings with reduced montages, and continuous EEG (CEEG) monitoring. Both approaches appear to be potentially advantageous, but at the same time subject to intrinsic limitations. Our literature review found initial evidence that the diagnostic yield for NCSE of prolonged EEG recordings is superior to routine EEGs. Further research is needed to confirm these preliminary findings and to explore strategies to improve the feasibility of a more widespread use of prolonged recordings within acute clinical settings.

Motor unit number index (MUNIX) in chronic inflammatory demyelinating polyneuropathy: A potential role in monitoring response to intravenous immunoglobulins.

OBJECTIVE: To compare motor unit number index (MUNIX) values in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and healthy controls, to assess correlations between MUNIX and clinical assessments used in CIDP and to assess short-term changes in MUNIX in CIDP following intravenous immunoglobulins (IVIg). METHODS: MUNIX sum scores were calculated from three muscles in patients and healthy controls. CIDP patients also underwent a series of clinical assessments and completed the Overall Neuropathy Limitations Scale (ONLS) and the Rasch-built Overall-Disability Scale (R-ODS). Repeat assessments were performed in CIDP patients receiving IVIg and CIDP patients not on active treatment. RESULTS: MUNIX sum scores were significantly lower in CIDP patients than healthy controls (mean values 214.0 vs 516.9, respectively; p < 0.001). MUNIX sum scores correlated with clinical assessment of motor and sensory function and ONLS and R-ODS scores in CIDP patients. Significant short-term improvements were seen in MUNIX values on repeat testing following IVIg (188.3-226.4, p = 0.001), but not in CIDP patients not receiving IVIg. CONCLUSIONS: MUNIX values show stronger correlation with commonly-used clinical assessments and disability scores than other routinely used electrophysiological parameters. Rapid improvements in MUNIX sum scores are seen following IVIg. SIGNIFICANCE: MUNIX sum score may provide an objective marker of response to IVIg.

Impact of video-ambulatory electroencephalography on the medical management of epilepsy.

Video-ambulatory electroencephalography (video-AEEG) is increasingly being used in secondary care centres for the diagnostic work-up of new cases with suspected epilepsy and for the review of known cases with active seizures despite medical treatment. We reviewed how the outcome of video-AEEG influenced the medical management of patients who underwent this investigation at a neurophysiology department within a secondary care centre. Out of a total of 171 consecutive video-AEEG studies performed over a period of two years, 111 could be included in our retrospective analysis, based on availability and completeness of relevant clinical information pre- and post-investigation. In our sample, 55.9% of patients had typical clinical events captured on video-AEEG and diagnostic yield was higher in patients with a previously established diagnosis of epilepsy (n=62; diagnostic yield 62.9%). A total of 27 patients (24.3%) had changes in medical treatment following video-AEEG, most frequently antiepileptic drug introduction/increase when epileptic seizures were captured. This proportion was similar between patients with or without a previously established diagnosis of epilepsy. Our findings in a real-life setting confirm the usefulness of video-AEEG in influencing the clinical attitude towards complex patients with suspected or longstanding history of epilepsy.

Posterior interosseous neuropathy: the diagnostic benefits of a multimodal approach to investigation.

Posterior interosseous neuropathy should be considered in patients presenting with finger and wrist drop and no sensory deficit. Clinical and electrophysiological assessments are key to a diagnosis. MRI may disclose etiological information not available to clinical or neurophysiological assessment, and should be thought as a complementary diagnostic tool.

Video-ambulatory EEG in a secondary care center: A retrospective evaluation of utility in the diagnosis of epileptic and nonepileptic seizures.

The development and optimization of protocols using simultaneous video recording alongside long-term electroencephalography (EEG), such as ambulatory EEG (AEEG), expanded the range of available techniques for the investigation of paroxysmal clinical events. In particular, video-AEEG has received increasing attention over the last few years because of its potential to further improve diagnostic utility in the differential diagnosis between epileptic and nonepileptic seizures. We retrospectively evaluated 88 video-AEEG studies in order to assess the diagnostic utility of video-AEEG in 87 patients consecutively referred to a neurophysiology department. Typical clinical events occurred during 55 studies (62.5%). In 26 of these, at least one event was also clearly seen on video recording, contributing to a confident diagnosis. Clinical events were classified according to three diagnostic categories: epileptic seizures (6 studies, 6.8%), physiologic nonepileptic events (13 studies, 14.8%), or psychogenic nonepileptic seizures (36 studies, 40.9%). Of the studies with an event not recorded on video, a confident diagnosis could be reached in 55.2% of cases. The main reason for unsuccessful video recording was failure to activate the camcorder by the patient or carer. We found an overall diagnostic utility of 67.0%, which confirms the findings of previous reports evaluating the diagnostic yield of AEEG. Implementation of video-AEEG protocols in a secondary care center appears to have high diagnostic utility, particularly for patients with psychogenic nonepileptic seizures. Our findings prompt further research into the potential applications of video-AEEG, in consideration of important implications for successful patient management and healthcare resource allocation.

The role of outpatient ambulatory electroencephalography in the diagnosis and management of adults with epilepsy or nonepileptic attack disorder: A systematic literature review.

Electroencephalography (EEG) is an established diagnostic tool with important implications for the clinical management of patients with epilepsy or nonepileptic attack disorder. Different types of long-term EEG recording strategies have been developed over the last decades, including the widespread use of ambulatory electroencephalography (AEEG), which holds great potential in terms of both clinical usefulness and cost-effectiveness. In this paper, we present the results of a systematic review of the scientific literature on the use of AEEG in the diagnosis of epilepsy and nonepileptic attacks in adult patients. Taken together, our findings confirmed that AEEG is a useful diagnostic tool in patients with equivocal findings on routine EEG studies and influences management decisions in the majority of studies. There is evidence that AEEG is also more likely to capture events than sleep-deprived EEG; however, there are currently insufficient data available to compare the diagnostic utility of modern AEEG technology with inpatient video-telemetry. Further research on the combined use of AEEG and home-video recording is, therefore, warranted.