Diagnostic Accuracy of Ambulatory EEG vs Routine EEG in Patients With First Single Unprovoked Seizure.

Background and Objective: To evaluate the diagnostic accuracy of the ambulatory EEG (aEEG) at detecting interictal epileptiform discharges (IEDs)/seizures compared with routine EEG (rEEG) and repetitive/second rEEG in patients with a first single unprovoked seizure (FSUS). We also evaluated the association between IED/seizures on aEEG and seizure recurrence within 1 year of follow-up. Methods: We prospectively evaluated 100 consecutive patients with FSUS at the provincial Single Seizure Clinic. They underwent 3 sequential EEG modalities: first rEEG, second rEEG, and aEEG. Clinical epilepsy diagnosis was ascertained based on the 2014 International League Against Epilepsy definition by a neurologist/epileptologist at the clinic. An EEG-certified epileptologist/neurologist interpreted all 3 EEGs. All patients were followed up for 52 weeks until they had either second unprovoked seizure or maintained single seizure status. Accuracy measures (sensitivity, specificity, negative and positive predictive values, and likelihood ratios), receiver operating characteristic (ROC) analysis, and area under the curve (AUC) were used to evaluate the diagnostic accuracy of each EEG modality. Life tables and the Cox proportional hazard model were used to estimate the probability and association of seizure recurrence. Results: Ambulatory EEG captured IED/seizures with a sensitivity of 72%, compared with 11% for the first rEEG and 22% for the second rEEG. The diagnostic performance of the aEEG was statistically better (AUC: 0.85) compared with the first rEEG (AUC: 0.56) and second rEEG (AUC: 0.60). There were no statistically significant differences between the 3 EEG modalities regarding specificity and positive predictive value. Finally, IED/seizure on the aEEG was associated with more than 3 times the hazard of seizure recurrence. Discussion: The overall diagnostic accuracy of aEEG at capturing IED/seizures in people presenting with FSUS was higher than the first and second rEEGs. We also found that IED/seizures on the aEEG were associated with an increased risk of seizure recurrence. Classification of Evidence: This study provides Class I evidence supporting that, in adults with First Single Unprovoked Seizure (FSUS), 24-h ambulatory EEG has increased sensitivity when compared with routine and repeated EEG.

Use of Antibacterial Envelopes for Prevention of Infection in Neuromodulation Implantable Pulse Generators.

BACKGROUND: Neuromodulation unit placement carries a historic infection rate as high as 12%. Treatment of such requires surgical removal and a long course of systemic antibiotics. Antibiotic-impregnated envelopes have been effective in preventing infection in implantable cardiac devices. At our center, 1 surgeon uses these envelopes with all implanted neuromodulation units. OBJECTIVE: To assess the efficacy of antibacterial envelopes in prevention of infection in neuromodulation device placement. METHODS: We conducted a retrospective cohort study of consecutive implantable pulse generator (IPG) unit implantation with an antibacterial envelope at a single center between October 2014 and December 2019. We collected demographic data, including postoperative infections, reoperations, and complications, associated with the IPGs. This cohort was then compared with a historical cohort of consecutive patients undergoing surgery before envelope usage (October 2007-April 2014). RESULTS: In the pre-envelope cohort of 151 IPGs placed in 116 patients, there were 18 culture-confirmed infections (11.9%). In the antibacterial envelope cohort of 233 IPGs placed in 185 patients, there were 5 culture-confirmed infections (2.1%). The absolute risk reduction of the antibacterial envelope was 9.85% (95% CI 4.3%-15.4%, P < .01). The number needed to treat was 10.1 (95% CI 6.5-23.1, P < .01) envelopes to prevent 1 IPG infection. CONCLUSION: We saw a reduced rate of infections in the antibacterial envelope cohort. Although this is likely multifactorial, our results suggest a benefit of antibacterial envelopes on infection after neuromodulation surgery.

Definitions and Risk Factors for Drug-Resistant Epilepsy in an Adult Cohort.

Background: Less than one-third of people with epilepsy will develop drug-resistant epilepsy (DRE). Establishing the prognosis of each unique epilepsy case is an important part of evaluation and treatment.Most studies on DRE prognosis have been based on a pooled, heterogeneous group, including children, adults, and older adults, in the absence of clear recognition and control of important confounders, such as age group. Furthermore, previous studies were done before the 2010 definition of DRE by the International League Against Epilepsy (ILAE), so data based on the current definitions have not been entirely elucidated. This study aimed to explore the difference between 3 definitions of DRE and clinical predictors of DRE in adults and older adults. Methods: Patients with a new diagnosis of epilepsy ascertained at a Single Seizure Clinic (SSC) in Saskatchewan, Canada were included if they had at least 1 year of follow-up. The first study outcome was the diagnosis of DRE epilepsy at follow-up using the 2010 ILAE definition. This was compared with 2 alternative definitions of DRE by Kwan and Brodie and Camfield and Camfield. Finally, risk factors were analyzed using the ILAE definition. Results: In total, 95 patients with a new diagnosis of epilepsy and a median follow-up of 24 months were included. The median age of patients at the diagnosis of epilepsy was 33 years, and 51% were men. In the cohort, 32% of patients were diagnosed with DRE by the Kwan and Brodie definition, 10% by Camfield and Camfield definition, and 15% by the ILAE definition by the end of follow-up. The only statistically significant risk factor for DRE development was the failure to respond to the first anti-seizure medication (ASM). Conclusion: There were important differences in the percentage of patients diagnosed with DRE when using 3 concurrent definitions. However, the use of the ILAE definition appeared to be the most consistent through an extended follow-up. Finally, failure to respond to the first ASM was the sole significant risk factor for DRE in the cohort after considering the age group.

Diagnostic Accuracy of the Ambulatory EEG vs. Routine EEG for First Single Unprovoked Seizures and Seizure Recurrence: The DX-Seizure Study.

Background: The DX-Seizure study aims to evaluate the diagnostic accuracy (sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio) of the ambulatory EEG in comparison with the first routine EEG, and a second routine EEG right before the ambulatory EEG, on adult patients with first single unprovoked seizure (FSUS) and define the utility of ambulatory EEG in forecasting seizure recurrence in these patients after 1-year follow-up. Methods: The DX-Seizure study is a prospective cohort of 113 adult patients (≥18-year-old) presenting with FSUS to the Single Seizure Clinic for evaluation. These patients will be assessed by a neurologist/epileptologist with the first routine EEG (referral EEG) and undergo a second routine EEG and ambulatory EEG. The three EEG (first routine EEG as gold standard) will be compared and evaluated their diagnostic accuracy (sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratios) with respect of epileptiform activity and other abnormalities. One-year follow-up of each patient will be used to assess recurrence of seizures after a FSUS and the utility of the ambulatory EEG to forecast these recurrences. Discussion: To the best of our knowledge, this will be the first study to prospectively examine the use of ambulatory EEG for a FSUS in adults and its use for prediction of recurrence of seizures. The overarching goal is to improve diagnostic accuracy with the use of ambulatory EEG in patients with their FSUS. We anticipate that this will decrease incorrect or uncertain diagnoses with resulting psychological and financial cost to the patient. We also anticipate that an improved method to predicting the recurrence of seizures will reduce the chances of repeated seizures and their consequences.

Forced normalization after turning off vagus nerve stimulation in Lennox-Gastaut syndrome.

Forced normalization is the development of psychiatric symptoms in a patient experiencing remission of seizures. We present a case of Lennox Gastaut syndrome in which forced normalization developed after vagus nerve stimulation was stopped. The patient had drug resistant epilepsy and failed anti-seizure drugs, vagus nerve stimulation, and a partial callosotomy. The patient had multiple types of seizures including drop attacks, absences, and tonic-clonic seizures. He tried vagus nerve stimulation for two years without success. Forced normalization developed after the vagus nerve stimulator was turned off. This is the first case to our knowledge to describe forced normalization after turning off the vagus nerve stimulator.

Efficacy of Vagal Nerve Stimulation for Drug-Resistant Epilepsy: Is it the Stimulation or Medication?

BACKGROUND: Vagus nerve stimulation (VNS) therapy has been widely recognized as an alternative for the treatment of drug-resistant epilepsy, although modification of antiepileptic drugs (AEDs) during VNS treatment could explain the improvement in patients. METHODS: We retrospectively assessed the efficacy of VNS in 30 adult patients with epilepsy treated with >6 months of follow-up. The criteria for implantation were the following: (1) not a candidate for resective epilepsy surgery, (2) drug-resistant epilepsy, (3) impairment of quality of life, (4) no other option of treatment, and (5) patients with idiopathic generalized epilepsy who fail to be controlled with appropriate AEDs. We assessed sociodemographics, seizure etiology, seizure classification, and AEDs used during treatment with VNS. We assessed adverse effects and efficacy. Responder rate was defined as >50% seizure improvement from baseline. RESULTS: Thirty patients (females, 18; males, 12; age, 35.1±13.3 years) were included. After 6, 12, 24, and 36 months of follow-up, the response rates were: 13/30 (43%), 13/27 (48%), 9/22 (41%), and 8/16 (50%), respectively; none was seizure free. Fifty-seven percent, 33%, 59%, and 81% of patients had changes of medication type or dose at 6, 12, 24, and 36 months respectively. In the majority of patients, the change of medication consisted of an increase in the dose of AEDs. CONCLUSIONS: Our study shows that VNS is an effective therapy, although significant changes in medications were done along with the therapy; therefore, the real effect of VNS could be controversial.

Evaluating the single seizure clinic model: Findings from a Canadian Center.

INTRODUCTION: The effect of the single seizure clinic (SSC) model on patient diagnose, work-up, wait-times, and clinical care is poorly characterized and its efficacy unclear. The present study assesses patient characteristics and evaluates the impact of a single seizure clinic (SSC) model on wait-times and access to care. MATERIAL AND METHODS: A prospective study of all patients (n=200) referred to our SSC for first seizure evaluation. Demographic, clinical, and paraclinicial variables were systematically collected and analyzed against a historical cohort. Binary logistic regression analysis was performed to predict impact of dichotomized variables on diagnosis of epilepsy. Diagnostic concordance between SSC nurses and epileptologists was also assessed. RESULTS: Predominant referral sources were emergency department physicians and general practitioners. Mean wait-time for first assessment was significantly reduced by 70.5% employing the SSC model versus historical usual care. A diagnosis was established at first-contact in 80.5% of cases while 16.0% of patients required a second visit. Eighty-two patients (41.0%) were diagnosed with epilepsy. An abnormal EEG was found in 93.9% of patients diagnosed with epilepsy. Sixty-three patients were started on anti-epileptic drugs (63.5% lamotrigine, 7.0% levetiracetam, 5.0% phenytoin, and 5.0% topiramate). In 18% of cases driving restrictions were initiated by the SSC. The most common non-seizure diagnosis was syncope (24.0%). DISCUSSION: The SSC reduced wait-times for assessment and investigations, clarified diagnoses, affected management decisions with respect to further workup, pharmacotherapy, and driving. There was moderate correlation between SSC nurses and physicians (kappa=0.54; p<0.001) as physicians were significantly more likely to diagnose epilepsy. Key factors identified as predictors of epilepsy were: presence of abnormalities on electroencephalography and imaging studies, patients stratified as high or medium-risk for seizure recurrence, semiological characteristics such as amnesia and limb stiffening, and presence of tongue trauma, or incontinence. CONCLUSIONS: The SSC model reduces wait-times, streamlines assessments, and impacts clinical care decisions.