Sleep-deprived EEG Research Articles

Assessing the Yield of Reduced Duration-EEG Recordings in Children: A Cross-Sectional Study.

Introduction An EEG is an important tool in the diagnosis of neurological diseases. Performing an EEG on children can be challenging due to their tendency to not cooperate for the recommended duration. We aim to optimize the duration of EEG recording in children by finding the optimal duration of recording. Materials and methods A single-center prospective observational study was done after appropriate ethical clearance. Children aged 0-14 were recruited and examined, and the recommended EEG was done. Data were collected and analyzed. Results Of the 112 EEGs analyzed, 29 EEGs were normal, i.e., no diagnostic anomaly was noticed. In the remaining 83 EEGs, if the duration of the EEG was reduced to 20 minutes, it resulted in missing the diagnostic anomaly in 20 cases (24.1%; 95% CI: 11.2%-26.2%). Reducing the duration of the EEG recording to 10 minutes resulted in missing 63 of the diagnostic anomalies (75.9%; 95% CI: 46.6%-65.6%). Of the 86 drug-inducedEEGs, 22 were normal (25.6%; 95% CI: 16.8%-36.1%). Of the 24 routine EEGs, seven were normal (29.2%; 95% CI: 12.6%-51.1%). Of the two sleep-deprived EEGs, neither was normal (0.0%; 95% CI: 0.0%-84.1%). Conclusion In our study, we observed that optimization of the duration ofEEG recording can be done to 20 minutes in all populations. We also observed that if we find a diagnostic abnormality early during EEG recording, then continuation of the EEG may not be necessary to make a valid report. Having said so, having a negative EEG may not necessarily rule out a diagnosis. We did not find the superiority of any of the EEG protocols over others, as their yield was comparable.

EEG findings and clinical severity and quality of life in non-epileptic patients with autism spectrum disorders

ABSTRACT Electroencephalogram (EEG) abnormalities could be seen in up to 60% of non-epileptic children with autism spectrum disorder (ASD). They have been used as biomarkers of ASD severity. The objective of our study is to identify EEG abnormalities in children with different degrees of ASD severity based on the Autism Treatment Evaluation Checklist (ATEC). We also want to assess the quality of life for children with ASD. All of the children underwent at least one hour of sleep-deprived EEG. Forty-five children were enrolled, of whom 42 were male. EEG abnormalities were found in 10 (22.2%) children, predominantly in the bilateral frontal areas. There were no differences in EEG findings among the mild, moderate, and severe ASD groups. The severity of ASD was associated with female sex (p-value = 0.013), ASD with attention deficit hyperactivity disorder (ADHD) (p-value = 0.032), ASD children taking medications (p-value = 0.048), and a lower Pediatric Quality of Life Inventory (PedsQL) (p-value <0.001). Social and emotional domains were the most problematic for health-related quality of life in ASD children, according to parent reports of PedsQL. Further studies with a larger sample size will help to clarify the potential associations between EEG abnormalities and the severity of ASD, as well as the impact on quality of life.

Yield of Sleep Deprivation EEG in Suspected Epilepsy. A Retrospective Study.

Background. Sleep is an activation procedure and is considered the most potent and best-documented modulator of seizures and interictal epileptiform discharges (IEDs) on electroencephalogram (EEG). The precise role of sleep deprivation in the diagnostic process of epilepsy has not been fully clarified after more than 50 years of use. Sleep deprivation is a procedure that is accompanied by discomfort for patients and their families. Therefore, an accurate indication according to each patient-specific characteristic is needed. This study aims to assess the effectiveness of sleep deprivation EEG in the diagnostic process of patients with suspected epilepsy in our center. Methods. We included patients with a first unprovoked seizure and patients with paroxysmal events suspecting seizures who underwent a sleep deprivation EEG (sdEEG) or routine EEG (rEEG). All patients were subsequently classified with confirmed epilepsy or not. Results. We included 460 patients. The group with sdEEG consisted of 115 patients, while the group with rEEG comprised 345 patients. In the sdEEG group, 19 patients (17%) were confirmed with epilepsy, of which 17 presented interictal epileptiform discharges (IEDs). For the rEEG group, 66 patients (19%) were confirmed with epilepsy, of which 63 presented IEDs. The difference was not statistically significant. Conclusion. Our study failed to find a difference in the yield of sleep deprivation versus routine EEG in patients with epilepsy, but there are many significant confounders/sample biases that limit the generalizability of the findings, particularly to the majority of adult practices.

The Role of Serial Follow-up and Sleep Deprivation Methods in Improving Electroencephalography Diagnostic Yield in a Cohort of Omanis Aged 13 Years and Above: A Clinical Audit Study

ABSTRACT The aim of this audit study was to establish the utility of follow-up and sleep-deprived electroencephalography testing to improve the detection of interictal abnormalities in a tertiary referral center in Oman. As part of our ongoing auditing process, a total of 3010 EEGs were included in this study. All EEGs were routinely performed for Omanis aged 13 years and above, who were referred for possible diagnosis of seizure disorders. Each EEG was performed over an average period of 20–30 minutes. Of the 3010 EEGs, there were 553 follow-up and sleep-deprived EEGs, including initial baseline EEG studies which were analyzed for this study. The total progressive yield of serial follow-up EEGs to detect overall EEG changes was 53.5%, distributed as 8.8%, 11.4%, 0%, and 33.3% for the second, third, fourth, and fifth serial EEG studies, respectively. For the sleep deprivation EEG group, the yield was 6.5% for detecting overall EEG changes compared to the initial EEG studies. A limitation in this study was the small sample size in the subsequent follow-up and sleep deprivation EEGs. In conclusion, we found a minimal contribution of serial follow-up and sleep deprivation methods in improving the EEG abnormality detection in our study. National guidelines and an increase in awareness among physicians are required to increase the benefit of these well-established, yet not optimally utilized EEG methods.

Evaluation of absences and myoclonic seizures in adults with genetic (idiopathic) generalized epilepsy: a comparison between self-evaluation and objective evaluation based on home video-EEG telemetry.

People with focal epilepsies are known to under-document their seizures, but there is no data on self-documentation in adults with genetic (idiopathic) generalized epilepsy (GGE/IGE). We assessed the accuracy of self-evaluation of typical absences (TA) or myoclonic seizures (MS) in adults with IGE based on home video-EEG telemetry (HVET). Patients' own estimates were compared to the objective count of definite TA and MS, performed visually. We considered definite TA as generalized spike-wave discharges (GSWD) that met any of the following criteria: 1) coinciding with clear behavioural arrest on video, 2) followed after a few seconds by positive indication that an absence occurred, or 3) in the absence of video, consistently coinciding with clear motor arrest, as evidenced by interruption of continuous muscle activity. For each patient, we also classified probable TA as GSWDs that were longer than those corresponding to the shortest definite TA on HVET or based on the most recent sleep-deprived EEG (SDEEG). From the first 300 consecutive adults who had HVET, 24 had IGE with TA and / or MS; 23 were women. Only one patient had newly diagnosed IGE. Erroneous self-assessment of TA and MS was noted in 16/24 patients (66.7%). Seizures were overestimated in nine (37.5%) and underestimated in seven (29.2%). Only one patient (4.2%) documented all her TA and MS without false-positive estimates. Overestimation (but not underestimation) of TA on HVET could be predicted when patients reported daily or multiple weekly TA and a recent SDEEG was either normal or contained only subclinical GSWD (p=0.0095). Under- and over-self-documentation of TA and MS occurred in two thirds of adults with GGE/IGE, with substantial impact on their outpatient management and treatment. Diagnostic HVET is a useful tool for the detection of erroneous self-evaluation in these patients.

The effect of photic stimulation alone and in combination with sleep deprivation after a seizure-like event – reappraisal by using linear and nonlinear EEG methods

ABSTRACT Objectives The present study aimed to compare the effectiveness of different provocation tests used for the study of the ‘susceptibility to seizure’ by quantitative electroencephalography (EEG) analysis. Methods Eight subjects with a history of a seizure-like disturbed consciousness participated in this preliminary study. A routine EEG was carried out with photic stimulation (eyes closed and after eyes open) at the beginning of the investigation. Some days later, a sleep-deprived EEG was recorded with the same protocol. Selected epochs (in eyes closed condition) after the stimulations were analysed with Point(wise) Correlation Dimension (PD2i) and Synchronization Likelihood (SL) methods. The results were compared to those obtained by similar analysis of the resting state (control) epochs with Wilcoxon Signed Rank Test (p ≤ 0.05). Results In our study, significantly lower grand mean PD2i and higher delta SL values were found in sleep-deprived state after stimulation with eyes closed compared to the control. Our results indicated a lower-dimensional, hypersynchronous state of the brain as a consequence of these combined provocations. Discussion This may correspond to a possible ’preictal’ state of the brain. Accordingly, it is suggested that photic stimulation together with sleep deprivation seems to be more effective in provocation – especially when the stimulation was made with eyes closed.

820 An Unusual Case of Post-Traumatic Brain Injury Kleine-Levin Syndrome with Anti-GAD-65 Autoantibodies

Abstract Introduction Kleine-Levin Syndrome (KLS) is a rare clinical syndrome, and is precipitated by traumatic brain injury (TBI) in 9% of cases. An autoimmune component to KLS has previously been suggested. Autoantibody profiles in KLS are diverse and its overlap with autoimmune encephalitis is still not well described or understood. Here, a case of KLS in a patient with autoimmune diabetes with very high levels of serum autoimmune GAD-65 antibodies is presented. Report of case(s) A 36-year-old male Veteran with a history of alpha-thalassemia minor, prior history of insomnia with nightly sleep of 6 hours, prior history of mild OSA with AHI of 5.8 on PSG in 2018, sustained a mild TBI on 11/13/2019 after a 50-pound box fell on his head. CT head and cervical spine were normal. One week later, he developed recurrent episodes of hypersomnia, sleeping up to 80 hours continuously, waking briefly only to urinate or eat, with hyperphagia, irritability, and derealization present during episodes. One month after the TBI, he was diagnosed with Latent Autoimmune Diabetes in Adults (LADA) after blood glucose was found to be elevated at 566. Serum GAD-65 antibody level was very elevated at 10,594 U/mL (ref range: 0–5 U/mL), hemoglobin a1c was 7.7%, and insulin was started. Six months later, he was evaluated in the VA Sleep Clinic for continued hypersomnia, despite controlled diabetes. Neurological examination, MRI brain, and sleep-deprived EEG were normal. Cerebrospinal fluid testing was normal, with the exception of a CSF autoimmune encephalitis panel with a positive GAD-65 titer of 0.24 nmol/L (range &amp;lt;0.02 nmol/L) – non-diagnostic for autoimmune encephalitis. HLA-DQ1B status is pending. Conclusion Autoimmunity is an emerging topic of clinical significance in KLS. GAD-65 serum antibodies have both endocrine and neurologic significance, with high levels seen in autoimmune diabetes, encephalitis, stiff-person syndrome, and cerebellar ataxia. An autoantibody panel can be considered in patients with KLS, as the presence of autoimmune encephalitis may support the use of immunotherapy. Support (if any) Portland VA Research Foundation to Dr. Lim. The contents do not represent the views of the United States Government.

Eye closure sensitivity and genetic generalized epilepsies: A prospective study of 123 cases

PurposeTo investigate the possible relationship between eye closure sensitivity (ECS) and genetic generalized epilepsy (GGE) in terms of epilepsy syndromes, photosensitivity (PS), and prognosis. MethodOne hundred and twenty-three patients diagnosed with GGE were classified according to epilepsy syndromes. Among them, ECS and PS were detected in repeated video-EEGs. In patients with ECS, the impact of sleep deprived EEG on awakening on ECS was evaluated. To explore the ECS as a possible accurate predictor designating the prognosis in GGEs, we defined the ECS rate in poor prognosis group (n = 21) and in patients without antiseizure drug (ASD) treatment and seizure-free for at least for 2–5 years (n = 20). ResultsECS was found in almost all types of GGE but at different rates. ECS was detected in all groups with highest rate in eyelid myoclonia with or without absences (EMA). Sleep deprived EEG on awakening was performed in 44 of 59 patients with ECS and enhanced ECS prominently. In all groups except EMA, PS rate was lower compared with ECS. Both ECS and PS were observed in 15 patients with poor prognosis (71 %) and one patient with good prognosis (5%). ConclusionsECS can occur in all types of the GGEs. We claim that ECS can be asserted as a syndrome-specific feature for EMA among GGEs. Sleep deprived EEG on awakening can enhance ECS prominently in all types of GGE. ECS and PS might overlap but their impact on prognosis is different. In the poor prognosis group, the number of patients having ECS together with PS was high compared to the group without ASD and excellent prognosis. Therefore, we suggest that this combination predicts worse outcome in GGEs.

The Impact of 24-Hour Ambulatory EEG in the Clinical Approach to Patients with Suspected Epilepsy

Background: The Electroencephalogram (EEG) is the gold standard technique to assess the epileptogenic cortical activity. However, due to the neurophysiology of the bioelectrical signal and the short duration of the routine EEG (rEEG) and sleepdeprived EEG (sEEG) registers, the sensitivity is low. The 24-hour Ambulatory EEG (aEEG), being a prolonged recording, could significantly improve the diagnostic capability, in an attractive cost-effective way. In this study, we analyzed the aEEG of patients with suspected epilepsy, addressing its specificity and sensitivity for the clinical diagnosis of epilepsy. Additionally, we endeavour to ascertain any other possible predictive factors of diagnosis. Methods and Findings: Retrospective observational study enrolling consecutive patients with suspected epilepsy who underwent aEEG between May 2011 and May 2018 at the Neurophysiology Laboratory from Local Health Unit of Matosinhos – Pedro Hispano Hospital. A sample of 83 individuals was obtained, with a mean age of 44.5 years (79 adults and 4 paediatric). aEEG showed a good diagnostic capacity for the clinical diagnosis of epilepsy with a specificity of 97% and sensitivity of 68%. The rate of false-negatives and false-positives was 7% and 5%, respectively. It’s expected that patients with an indication of syncope or loss of consciousness will not have epilepsy diagnosis. Conclusion: The aEEG can be a useful tool to assess patients with suspected epilepsy and unremarkable routine and sleep-deprived EEGs, or in cases of suspected non-epileptic seizures, particularly to exclude the epilepsy diagnosis given its high specificity. This approach can lessen the time required to identify the diagnosis.

Interictal epileptiform discharges vary across age groups

ObjectiveTo investigate whether the occurrence and morphology of interictal epileptiform discharges (IEDs) in scalp-EEG change by age. Methods10,547 patients who had a standard or sleep deprived EEG recording reported using the SCORE standard were included. 875 patients had at least one EEG with focal IEDs. Focal IED morphology was analyzed by age using quantitative measures in EEGLAB and by visual classification based on the SCORE standard. We present distributions of IED measures by age group, with medians, interquartiles, 5th and 95th percentiles. ResultsFocal IEDs occurred most frequently in children and elderly. IED morphology and localization depended on age (p < 0.001). IEDs had higher amplitudes, sharper peaks, larger slopes, shorter durations, larger slow-wave areas and wider distributions in children. These morphological characteristics diminished and the IEDs became more lateralized with increasing age. Spike asymmetry was stable across all age groups. ConclusionsIEDs have age-dependent characteristics. A spike detector, human or computer, should not operate with the same set of thresholds for patients at various age. With increasing age, focal IEDs are less sharp, have lower amplitudes, have less prominent slow-waves and they become more lateralized. Our findings can help EEG readers in detecting and correctly describing IEDs in patients of various age. SignificanceEEG readers should always consider patient age when interpreting interictal epileptiform discharges.

P03-T A review of patients with possible Occipital-lobe-seizures (OLS) seen at University-Hospital-of-Wales (UHW) in 2018

Introduction Patients having experienced OLS describe their seizures as featuring bright colours, and severe blurring of their vision, occasionally ictal vomiting, deviation of the eyes, and hypersalivation with or without impairment of consciousness. OLS are thought to account for between 5% and 10% of epilepsies with photo-sensitive epilepsies occurring in 1–5% of epilepsies. Method EEG’s including prolonged, sleep deprived and video monitoring EEG’s including (where appropriate) hyperventilation and photic-stimulation were reviewed in 929 patients referred at the UHW during 2017–2018. Results Four patients were found to have evidence of occipital lobe seizures. One was a juvenile patient with suspected idiopathic occipital lobe epilepsy. One patient was found to have posterior temporal/occipital lobe abnormality on Magnetic Resonance Imaging as a result of childhood injury. MELAs and concordant occipital stroke were thought to be the cause of the third patient. The final patient has been treated intensively because of injury due to collapse. Vomiting was not a feature of any seizure semiology. Hypersalivation and spitting were observed late into the seizure of one patient (spread temporally with secondary generalization). All described visual disturbance ranging from simple colored 2-dimensional shapes in the vision to more complex kaleidoscopic manifestations. Electrographic correlate was similar comprising repetitive sharp wave discharges. Conclusion Although thought to account for 5–10% of epilepsies, we at UHW (the largest teaching hospital in Wales) found OLS accounted for a very small percentage of confirmed epilepsies.

Epileptology of the first tonic-clonic seizure in adults and prediction of seizure recurrence.

The risk of seizure recurrence after a first unprovoked seizure is influenced by certain risk factors. To understand their effect in people with early diagnosed new epilepsy, we assessed the risk of recurrence of focal to bilateral tonic-clonic or generalized tonic-clonic seizures and the associated factors in a clinically well-characterized cohort of adults with a first unprovoked tonic-clonic seizure. We prospectively studied 150 consecutive adults with a first unprovoked tonic-clonic seizure and full clinical, EEG, and brain imaging assessment within the first four weeks. New epilepsy was diagnosed and classified according to the International League Against Epilepsy criteria. Time to second focal to bilateral tonic-clonic or generalized tonic-clonic seizure was analysed using the Kaplan-Meier method. Early diagnosis of new epilepsy, including type or syndrome and aetiology, was possible in 109 patients (72.7%). The diagnostic yield of sleep-deprived EEG was high in both genetic and non-genetic localized focal epilepsies. A second focal to bilateral tonic-clonic or generalized tonic-clonic seizure occurred in 100 patients (66.7%) during a three-year mean observation period. The risk was higher in non-genetic focal epilepsies and lower in genetic epilepsies. Concurrent absences or myoclonic seizures and a first occurrence after awakening were predictors of a second generalized tonic-clonic seizure in patients with genetic generalized epilepsy, while diagnosis of temporal or frontal lobe epilepsy, focal EEG discharges, and focal changes on brain imaging were related to an increased risk of focal to bilateral tonic-clonic seizure recurrence, showing additive effects. Identifiable modulators or triggers for the first tonic-clonic seizure, early treatment, and older age showed inverse association. The risk of a second generalized or focal to bilateral tonic-clonic seizure and the factors involved vary across epilepsy aetiologies and syndromes. Early diagnosis and classification of new epilepsy is possible in most patients and may enable important adjustments to their management and treatment.

Clinical Features at the Time of Diagnosis of Benign Epilepsy With Centrotemporal Spikes Do Not Predict Subsequent Seizures

BackgroundBenign epilepsy with centrotemporal spikes (BECTs) usually follows a self-limited course, with a single or few seizures. Assessing the likelihood of a second seizure after the first event may help establishing the need for antiepileptic drug therapy at the time of diagnosis. We aimed at identifying clinical and/or electrographic features that could predict the occurrence of a second seizure. MethodsWe reviewed the clinical and electroencephalographic (EEG) data of children diagnosed with BECTs between 2006 and 2012. Demographic, clinical, routine, and sleep-deprived EEG findings were analyzed. FindingsSeventy-three patients were reviewed who had been followed for four to 10 years. Age at first seizure ranged between three and 16 years (median nine years). In 28 children the first seizure occurred after 10 years age. Ten children were aged three to six years. EEG data were available for 64 individuals. No specific clinical features or seizure semiology were predictive of a second seizure. Neither the type nor the location of interictal EEG discharges was indicative of a second seizure. Among children whose EEG records depicted sleep-related enhancement of interictal discharges, 58.8% sustained a second seizure. This finding did not reach statistical significance. Forty children sustained a second seizure, mostly within 12 months in 30 (P < 0.0001). Among these 30 children, the second event occurred after a median period of 156 days, compared with 654 days for cases with a second seizure after 12 months. ConclusionsNeither clinical features, seizure characteristics, nor routine EEG findings were effective in predicting the likelihood of a second seizure in children with BECTs.

Modulation of epileptiform EEG discharges in patients with JME

PurposeTo study modulation of epileptiform EEG discharges in patients with JME. Method50 subjects with JME underwent a sleep deprived EEG recording along with conventional provocative methods and testing with cognitive tasks (CTs). Both categories of tests were evaluated for their effect on occurrence of IEDs. Number of IEDs per unit time was calculated at baseline as well as with each task. Statistical and arbitrary methods were used to assess modulation. By arbitrary method if frequency of IEDs was more than twice that of baseline, it was considered as provocation and if less than half, it was considered as inhibition. To account for spontaneous fluctuation of IEDs, 95% CI was calculated for baseline IEDs in each patient and provocation/inhibition was considered if frequency of IEDs exceeded/remained below limits of CI respectively. ResultsThere was no significant difference in rates of provocation of IEDs by conventional or CTs. However there was exclusive provocation of IEDs by CTs in 4 patients, 3 of whom were already on AEDs. There was a significant inhibitory effect of CTs as mean baseline discharge frequency was 0.4 ± 1.16 IEDS/min and during CTs was 0.1 ± 0.38 IEDs/min. However when spontaneous fluctuation was accounted for, inhibition was seen in only 22.23% patients by statistical method as compared to 90.91% by arbitrary method. ConclusionsInclusion of CTs may assist in provocation of IEDs, thereby increasing yield of routine EEG. Spontaneous fluctuation of IEDs accounts for much observed inhibition by CTs in JME patients.

Visual EEG reviewing times with SCORE EEG

ObjectiveVisual EEG analysis is the gold standard for clinical EEG interpretation and analysis, but there is no published data on how long it takes to review and report an EEG in clinical routine. Estimates of reporting times may inform workforce planning and automation initiatives for EEG. The SCORE standard has recently been adopted to standardize clinical EEG reporting, but concern has been expressed about the time spent reporting. MethodsElapsed times were extracted from 5889 standard and sleep-deprived EEGs reported between 2015 and 2017 reported using the SCORE EEG software. ResultsThe median review time for standard EEG was 12.5 min, and for sleep deprived EEG 20.9 min. A normal standard EEG had a median review time of 8.3 min. Abnormal EEGs took longer than normal EEGs to review, and had more variable review times. 99% of EEGs were reported within 24 h of end of recording. Review times declined by 25% during the study period. ConclusionStandard and sleep-deprived EEG review and reporting times with SCORE EEG are reasonable, increasing with increasing EEG complexity and decreasing with experience. EEG reports can be provided within 24 h. SignificanceClinical standard and sleep-deprived EEG reporting with SCORE EEG has acceptable reporting times.

Evaluation of the "non-epileptic" patient in a tertiary center epilepsy clinic

PurposeThe epilepsy clinic at the Montreal Neurological Institute receives a high volume of referrals. Despite most patients assessed in the clinic eventually being diagnosed with epilepsy, other disorders causing alteration of consciousness or paroxystic symptoms that could be misdiagnosed as seizures are seen frequently. The incidence and clinical characteristics of such patients have not yet been determined. We aimed to determine the proportion and clinical characteristics of patients referred to our epilepsy clinic who had a final diagnosis other than epilepsy. MethodsWe performed a retrospective chart analysis of consecutive patient referrals to the epilepsy clinic from January 2013 to January 2015, inclusively. ResultsFour hundred four patient referrals were evaluated, 106 (or 26%) had a final diagnosis other than epilepsy. Referrals came primarily from general practitioners and nonneurology specialists. Although most patients had a normal routine electroencephalography (EEG) prior to the clinic visit, sleep-deprived EEG and cardiac investigations were rarely performed. Patients received a final diagnosis other than epilepsy after 1 to 2 visits in 92% of cases and with minimal paraclinical investigations. Prolonged video-EEG recording was required in 27% of patients. The most common diagnoses were syncope (33%), psychiatric symptoms (20%), followed by migraine (10%), and psychogenic nonepileptic seizures (9%). ConclusionsA significant proportion of patients seen in our tertiary care epilepsy clinic is in fact, not patients with epilepsy. Enhanced knowledge of these differential diagnosis and important anamnesis components to rule out seizures will help improve guidelines for referral to Epilepsy clinic and cost-effectively optimize the use of paraclinical investigations.

Detecting interictal discharges in first seizure patients: ambulatory EEG or EEG after sleep deprivation?

PurposeUncertainty about recurrence after a first unprovoked seizure is a significant psychological burden for patients, and motivates the need for diagnostic tools with high sensitivity and specificity to assess recurrence risk. As the sensitivity of a routine EEG after a first unprovoked seizure is limited, patients often require further diagnostics. Here, we study if ambulatory EEG (aEEG) has similar diagnostic accuracy as sleep deprived EEG (sdEEG). MethodsIn this retrospective cohort, we included patients with an unprovoked first seizure and a normal routine EEG who subsequently underwent an sdEEG or aEEG. All EEGs were reviewed for the presence of interictal epileptiform discharges (IEDs). We calculated specificity and sensitivity of sdEEG and aEEG, using the clinical diagnosis of epilepsy as golden standard. All patients had a follow-up of one year. ResultsWe included 104 patients. Sensitivities for sdEEG and aEEG were 45% (specificity 91%) and 63% (specificity 95%), respectively. Independent risk factor for recurrent seizure were IEDs on the additional EEG, with a relative risk of 1.5 of having a recurrent seizure within a year. ConclusionDiagnostic accuracies of sdEEG and aEEG are similar and depending on patients’ and clinicians’ preference both can be considered in patients with a first seizure and a normal routine EEG to determine recurrence risk.

How valuable is inpatient electroencephalogram for medical decision-making?

The electroencephalogram (EEG) can support the diagnosis of epilepsy, diagnose nonconvulsive status epilepticus and aid in the classification of epileptic seizures. Its contribution to the diagnosis of other medical conditions or to decision-making in other clinical situations was not established. Practically, EEG laboratories frequently encounter EEG referrals that are not based on current recommendations. To assess the value of inpatient EEG in medical decision-making. We retrospectively reviewed the inpatient computerized medical information management system and the EEG laboratory computerized database for all adult inpatient standard, sleep-deprived and bedside EEGs performed during a one-year period. Change in diagnosis and/or treatment and the clinical justification for ordering an EEG recording were determined. The study group included 584 patients, 313 (54%) men, aged 55·5 ± 20·8 years (range 18-95 years). The EEG was clinically justified in 372 (63·7%) and led to change in diagnosis and/or treatment in 47 (8%) patients. These patients were significantly more likely to be admitted to the neurology department (P = 0·033), have an admission and discharge diagnosis of seizure or epilepsy (P = 0·0001), have a clinically justified EEG (P = 0·0001) and have an EEG recording with electrographic seizures (P = 0·0001), interictal epileptiform discharges (P = 0·0001) and background abnormalities (P = 0·003). Inpatient EEG can mostly contribute to diagnosis and treatment in patients with a seizure or epilepsy. An informed use of the EEG can increase its yield and reduce the number of unnecessary referrals, thus shortening waiting time and enabling earlier diagnosis and treatment in yet undiagnosed patients.

5. Sleep deprivation in the activation of interictal spikes and epileptic seizures

Objective To describe and review the use of sleep deprived EEG in the activation of interictal spikes and epileptic seizures. Background Sleep deprivation (SD) has been used to enhance EEG sensitivity in the diagnosis of epilepsy. However, standardized guidelines for the use of SD-EEGs are lacking. Here, we provide an update in the literature of sleep SD-EEG and epilepsy as well as presenting data from a retrospective study. Design/methods A literature search using PubMed was carried out to identify papers focusing on sleep deprivation EEG and interictal discharges. A total of 39 abstracts were obtained, 13 were screened and included in this review. We also present data from a retrospective study of 156 patients that were assessed with a short and long-monitoring EEG as well as SD-EEG at Son Espases Hospital (Spain) and evaluated their sensitivity in the diagnosis of interictal discharges in patients with suspected epilepsy. Results Further studies are needed to evaluate the role of SD-EEG in patients with suspected epilepsy. In our retrospective study 21% of patients with a previous normal awake EEG showed interictal discharges in the SD-EEG. Conclusions Some studies have shown that SD-EEG increases sensitivity and specificity diagnosing interictal activity. However, the duration of sleep deprivation and length of the test varies according to the different studies. The role of SD-EEG should be further evaluated. The use of subtemporal electrodes may contribute to the diagnosis of temporal lobe epileptiform focus.

Is it time for individualized testing in the electroencephalogram (EEG) laboratory?

The interictal electroencephalogram (EEG) has an important role in the classification and treatment of epilepsy. In busy EEG laboratories, valuable resources are used in order to comply with current recommendations regarding the length of EEG recordings. Our aim was to examine the time to first interictal epileptiform discharge (IED) in standard and sleep-deprived EEGs. Standard and sleep-deprived EEG recordings with IEDs were retrospectively reviewed during a 2-year period. Bedside EEGs and long-term video-EEGs were excluded. IED latency according to EEG type, age group and inpatient/outpatient status was analyzed with the Kaplan-Meier estimator. The study group included 684 patients, 372 (54%) males, aged 0.2-89 years. Standard (n = 316) and sleep-deprived (n = 368) EEGs were performed in 245 inpatients and 439 outpatients. The EEG was requested in 96% of the inpatients following a seizure. Most IEDs were recorded whilst the patients were awake (43%) or drowsy (34%). Ninety percent of the IEDs were recorded within 18.5 min, earlier in standard (14.6 vs. 21.3 min) (P = 0.024) EEGs and in inpatients (14 vs. 21.3 min) (P = 0.002). IED latency was unaffected by age. Electroencephalogram type and admission status may be used for individual determination of the duration of EEG recording. Reducing the duration of standard and sleep-deprived EEGs may be considered especially in inpatients.