EEG Requests Research Articles

From Request To Result: The Clinical Significance of EEG in a Tertiary Hospital in Turkey

Objective: This study aimed to assess the clinical and demographic profiles of patients undergoing electroencephalography (EEG) over one year, evaluate EEG's impact on patient management, and ascertain the appropriateness of EEG requests. Methods: A retrospective analysis was conducted in the neurophysiology department at XXX University Faculty of Medicine over 12 months from October 2022 to October 2023. The study included the EEG request to the neurophysiology department; pediatrics and the cases that had artifacts or technical issues were excluded. Age, gender, imaging characteristics, EEG findings, and the reasons for EEG requests were recorded. The contribution of EEG to patient management was analyzed. Results: The study included 1217 patients with a mean age of 34.4±16.5 years, ranging from 18 to 90 years. Of these, 656 were female and 561 male. A history of epilepsy was reported in 821 patients. Neurology outpatient clinics, inpatient wards, and intensive care units requested the majority of EEGs. Epilepsy, presyncope/syncope, and psychogenic non-epileptic seizures (PNES) were the top reasons for EEG requests. Among the newly diagnosed epilepsy patients, 13 showed abnormal EEG results. The study identified MRI abnormalities in 202 patients, with a 27% concordance between EEG and MRI findings. EEG significantly influenced patient management in 577 cases (46.5%), demonstrating its crucial role in clinical decision-making. Conclusion: EEG's diagnostic value, particularly in epilepsy and complex neurological conditions, remains unique. Advocating suiting EEG requests and increasing physician knowledge of seizures can optimize patient care and resource use.

Paroxysmal Nonepileptic Events in Children With Epilepsy and Cerebral Palsy.

To determine the frequency of paroxysmal nonepileptic events in children with cerebral palsy due to brain injury who have epilepsy and to describe the factors associated with paroxysmal nonepileptic events. Methods: Retrospective, population-based study of children from the Victorian CP Register born 1999-2006. Neuroimaging, medical records, electroencephalograms (EEG), and EEG requests were analyzed. Results: Of the included 256 children, 87 had epilepsy. EEGs (with video correlation) were available for 82 of 87. Eighteen (18/82, 22%) had epileptic events captured on EEG. Twenty-one (21/82, 26%) had paroxysmal nonepileptic events captured on EEG. The majority (13/18, 77%) of children with epileptic events also had paroxysmal nonepileptic events captured. Ten parents and carers continued to report events as epileptic despite there being no ictal EEG correlate for specific events on multiple EEGs. There were no clear associations to identify which children would have ongoing paroxysmal nonepileptic events reported. Conclusions: Paroxysmal nonepileptic events were captured on EEG in one-fourth of children from this cerebral palsy cohort with epilepsy and available EEG. Half the parents and carers reported previously identified paroxysmal nonepileptic events as epileptic on subsequent EEGs, highlighting the need for clearer counseling so that parents better understand seizure semiology in children with EEG-proven paroxysmal nonepileptic events.

Frequency of Nonconvulsive Seizures among Pediatric Systemic Cancer Patients with Acute Encephalopathy: Emergent Bedside EEG in Resource Constrained Communities

Purpose: To determine the incidence of nonconvulsive seizures (NCSz) among children with systemic cancer, who underwent unexplained acute severe encephalopathy (GCS≤8) during admission in ICUs and Neuro-ICUs.
 Study Design: Multicenter prospective observational study describing sub-clinical seizures and electroencephalographic (EEG) features of children (1-16 years) with acute unexplained encephalopathy who underwent emergent bedside EEG≥30min monitoring.
 Material and Methods: We conducted a prospective longitudinal observational study design and EEG assessment of 40 systemic cancer patients age ≤16years, consecutively diagnosed and admitted in intensive care units (ICUs) and neurointensive care units (Neuro-ICUs) of different cancer hospitals with unexplained acute impaired consciousness (GCS≤08) within ≤6hr of such deterioration. Bed-side EEG recordings of ≥30min were done according to the clinical scenario and the requirements of the treating neurologist/intensivist. Patients with brain tumor, brain metastasis, seizures or those with known cause of coma were excluded. Data surrounding clinical, electrographic, and treatment factors were collected Via a prospective systematic review of medical records and EEGs for correlation with diagnosis, change in the diagnosis and management.
 Results: Over a period of 2 years, 40 children, 22.5% 1-5yeras, 37.5% 6-10years, 40% 11-16years; boys 65% and girls 35%, who had systemic cancer with a median age of 9.8 years with unexplained acute deterioration of conscious level (GCS≤08). This cohort underwent bed-side EEG of ≥30 min, which was abnormal in 100% of the records. The main reasons for EEG requests were: 1) unexplained impaired consciousness 22(55%) and 2) reason one plus subtle convulsion 18(45%). The most common EEG abnormalities were invariant mixed theta-delta slowing (27.5%), followed by Low-amplitude delta pattern plus epileptiform discharges (20%) and there was electrographic evidence of EEG seizures in 17(42.5%) of the cohort. These electrographic seizures were present in 55.5% of 18 patients with subtle convulsions, whereas were documented only in 20% of the 22 patients without such movements. Electrographic seizures among patients with subtle convulsions responded to antiseizure drugs in 75% cases as compared 50% such response among patients without such convulsions.
 Conclusion: Emergent bed-side EEG record of ≥30 min is useful in systemic cancer patients admitted in NCUs and Neuro-ICUs with acutely impaired consciousness with or without abnormal body movements. Neurology consultation and EEG studies in these comatose patients provide useful diagnostic information.

Electroencephalography at the time of Covid-19 pandemic in Italy.

ObjectiveDuring the Covid-19 pandemic, government restrictions limited health care to urgent needs. Neurophysiology centers had to suddenly reschedule their activities, with a lack of specific recommendations about electroencephalography (EEG) execution. During the pandemic phase 1, we launched an online survey to understand the flaws and strengths of the EEG management in Italy at the time of Covid-19 pandemic.MethodsA 45-item online survey (published from April 16 to 30, 2020), endorsed by the Italian Society of Clinical Neurophysiology (SINC), the Italian League Against epilepsy (LICE), and the Italian Association of Neurophysiology technologists (AITN), collected EEG management data (EEG’s number and type, indications, personnel and patients safety, devices’ sanification) during the Covid-19 pandemic.ResultsWe received responses from 206 centers. The number of EEGs performed was reduced by 76 ± 20%, and several types of specific EEG (video-EEG, ambulatory-EEG, LTM, polysomnography) were reduced at a minimum. Half of the centers performed inpatient EEGs only for urgencies. Repetitive seizures, encephalitis, and non-convulsive status epilepticus were the most common indications. Covid-19-positive patients received less EEG than negative ones (p < 0.0001). EEG requests came mainly not only from neurologists (n = 176) but also from general practitioners (n = 40), emergentists (n = 79), intensivists (n = 72), and other specialists (n = 53). Those centers which continued performing outpatient EEG examinations were instructed to perform the EEG after a Covid-19-related symptom screening for patients and using personal protective equipment (PPE) through all the procedure. Inpatient EEGs were performed using FFP2/FFP3 masks by neurophysiology technologists in only 50% of cases. Patients executed hyperventilation only for real clinical needs, but often (56%) with a mask.ConclusionsItalian neurophysiology centers strongly adhered to government restrictions of lockdown. Some issues emerged, ranging from the evaluation of a proper indication for EEG, technical procedures of EEG recording, and protection of neurophysiology technicians.

Autoimmune encephalitis as an increasingly recognised cause of non-convulsive status epilepticus: A retrospective, multicentre evaluation of patient characteristics and electroencephalography (EEG) results

PurposeStatus epilepticus (SE) is a severe condition of unrelenting seizures requiring urgent identification and treatment. SE may be unprovoked, occurring in someone with epilepsy, or may be provoked by acute intracranial disease or metabolic derangement. Increasingly encephalitis, particularly autoimmune types, is reported to cause refractory seizures. Whilst convulsive SE is readily identified, non-convulsive SE (NCSE) can be difficult to identify clinically, and electroencephalography (EEG) is required. Therefore, it is critical to identify the key clinical features associated with NCSE on EEG to inform future use of EEG. MethodsWe conducted a multicentre, retrospective analysis of EEG requests from four general and one specialist neurology hospital in the Northwest of England (2015–2018). Cases were identified from EEG requests for patients with suspected NCSE or other indications such as encephalopathy. We compared demographic and clinical characteristics between EEG-confirmed cases of NCSE and a randomly selected sample of negative controls. Results358 EEGs were reviewed, and 8 positive cases of NCSE were identified. Epilepsy was identified as the aetiology in 2 of these cases, and autoimmune encephalitis another 2 cases (one patient with N-methyl-d-aspartate receptor antibodies and another with voltage gated potassium channel antibodies). Previous alcohol excess (p = 0.005) and subtle motor signs (p = 0.047) on examination were observed more frequently in patients with NCSE compared to controls. ConclusionPhysicians should have a low threshold for urgent EEG in patients with suspected or previous encephalitis, especially if autoimmunity is suspected or subtle motor signs are present.

V29. Audit of routine EEGs performed at a German tertiary neurology hospital – Need for change in clinical practice?

Objective To evaluate the likelihood and kind of EEG pathology in the most common neurological conditions in which a routine EEG exam was performed at a neurological tertiary referral center to guide future clinical practice. Method Retrospective analysis of all EEGs ordered at the Department of Neurology and Neurooncology, University Hospital, Goethe-University Frankurt (Germany) in 2009; for the 70% most common main discharge ICD 10 diagnoses, the incidence of a normal or a pathological initial EEG report was assessed. Pathological reports were sub-classified according to reported generalized slow activity (“gen. slow”), focal slow activity (“focal slow”), and epileptiform activity with or without additional focal slow activity (“epil. act.”). Hence, a single EEG could fall into two categories. Continuous vs. intermittent pathology were not distinguished. Results 1491 (8% of all considered cases) of 1725 EEG reports were included in the analysis ( Figure , Table ). The Table indicates the nine main discharge diagnoses covering two thirds of all EEGs ranging from 19 to 323 EEG examinations per diagnosis and lists the proportion of pathologies by diagnosis ( Figure ) and the proportion of patients with a given diagnosis referred to EEG. Almost half of all EEGs were reported normal; in equal parts (20% each) of the remainder, generalized or focal slowing, or epileptiform activity were observed. The highest yield of pathological findings (>80%) was obtained in patients with intracranial mass or cerebral hemorrhage, the lowest (11%, all focal slow) in patients with multiple sclerosis. Patients in whom “epilepsy” or “intracranial mass” were diagnosed formed the largest cohort of patients referred to EEG and together with cerebral hemorrhage exhibited the highest incidence of epileptiform activity, while in only 6% of hemorrhage patients an EEG exam was ordered. Proportionally, given a certain diagnosis, an EEG was most frequently requested in patients eventually diagnosed with syncope, cerebral ischemia, or CNS inflammation. While 4/5 of “syncope EEGs” were normal, in each of the other two conditions, 20% of EEGs exhibited focal and another 20% generalized slow activity. Conclusion Whenever an EEG was deemed necessary, chances of a pathological finding were approximately 50% with conditions characterized by space occupying lesions taking the lead. This suggests that in such conditions EEG will likely confirm a clinical suspicion of relevant brain dysfunction likely prompting treatment modifications. In contrary, our data suggests that EEG requests could be more restricted in patients diagnosed with multiple sclerosis, Parkinson’s disease, syncope, or a psychiatric condition as 70–90% of such EEGs can be expected normal and only 2% of these to reveal epileptiform – and hence treatment relevant – activity. This is especially so, since a normal EEG is of low negative predictive value in general. In the 14% of epilepsy patients referred to EEG, focal EEG pathology was found in 42% encouraging the use of EEG when trying to confirm a focal epilepsy syndrome or even identify an irritative zone. A limitation of our study is that our data describes only those patients in whom an EEG was performed, and we do not know which circumstances triggered this investigation.

THE ELECTROENCEPHALOGRAM: MISUSED AND MISUNDERSTOOD?

Electroencephalograms (EEG9s) are a popular non-invasive test with a minimal side effect profile. However, previous studies have found that more than half of the requests for EEG9s are inappropriate. There is a two-fold importance for ensuring EEG9s are used effectively. Firstly, despite being relatively inexpensive compared with other tests, an inappropriate investigation is a waste of time and resources. Secondly, there are limitations to the capabilities of the EEG. An inappropriate request can lead to a false positive result and incorrect diagnosis with life changing consequences. An audit conducted in St George9s Hospital, London in 2003–2004 found that over a quarter of EEG requests were “inappropriate” and rarely altered management. We audited 35 EEG requests made at the Manchester Royal Infirmary from 01/06/2013–31/07/2013. We used case notes and discharge letters to help assess whether EEG9s were requested appropriately, whether they altered management and whether they were performed within the national target of four weeks. We found 71.4% of EEG requests were inappropriate, similar to the SGH audit. As there has been little improvement in 7 years, further discussion and clearer guidelines on EEG requesting are needed.

The role of the electroencephalogram as a tool for the investigation of syncope

Sir, Syncope, defined as sudden loss of consciousness associated with the inability to maintain postural tone, followed by spontaneous recovery is a common cause for referral to emergency departments. Incidence of a first syncopal episode has been estimated at 6.2 per 1,000 person years or a 10-year cumulative rate of 6 % [1]. Associated risk factors are increasing age and a history of cardiovascular disease. History taking and obtaining a detailed eye-witness account of the event is of paramount importance in correctly assessing people with paroxysmal episodes of loss of consciousness. Electroencephalograms (EEGs) are frequently requested as part of the work up for patients presenting with syncope despite the fact that the potential yield from this is very low [2, 3]. We carried out a retrospective audit over 6 months of all EEG requests for the investigation of syncope. Cases with referral letters containing one or more of the following key terms were included: ‘syncope’, ‘faint’, ‘loss of consciousness’, and ‘micturition associated syncope’. The subsequent EEG results and any comments made upon the simultaneous ECG tracings were recorded. The following data were obtained from the referrals: • Referring team and specialty • Age and sex of the patient • Whether loss of consciousness was documented in the referral • Presence of cardiac symptoms at time of event • Family history of epilepsy • EEG result • Presence of ECG abnormalities, as reported by the attending neurophysiologist

The role of electroencephalogram in childhood neurological disorders

The aim of this study was to obtain a baseline for clinical application of electroencephalography (EEG) in children and to evaluate the EEG findings in children with various acute and chronic central nervous system disorders and nonepileptic events. EEG records of 250 patients were studied in Neurophysiology Departments of Queen Rania Al-Abdullah Hospital for Children in Jordan. For each patient who had undergone EEG the following data were recorded: age, sex, source of referral (inpatient or outpatient department), reason for EEG, diagnostic impressions, clinical presentation, the result of the EEG examinations and clinical correlation between the seizure type and EEG finding. Males (55%) were slightly outnumbered than females. The majority of cases were between 6-12 years. Total of 63.2% of all referrals for EEG were from outpatient clinics while inpatients accounted for 36.8% of referred cases, with Pediatric Neurology Department referrals being the highest (28.8%). Majority of diagnosis at referral were suspected epilepsy (80%) with epileptiform EEG abnormalities in 32%. Over all 64% the EEG records were normal, including all EEG records of children with syncope and headache. We conclude that there are many unnecessary routine EEG recordings in children. Investigation of epilepsy and acute encephalopathies appear to be the most valuable indications for routine pediatric EEG. EEG can be helpful in classification of seizures. Finding a way to reduce EEG requests is recommended.

Apport d’une démarche électroclinique dans le diagnostic de l’épilepsie chez une population de sujets âgés confus

Delusion symptoms often occur in old people; epilepsy is one of the main reasons behind these acute episodes. Current guidelines and recommendations from the Academy of Medicine have proposed a double clinical and electroencephalographic approach. Recently, a working group of French experts has issued an electro-clinical scale. The aim of our study was to compare the usual approach with the new one based on the electro-clinical score. All EEG requests performed since December 2008 in Bretonneau Hospital for elderly people aged over 75 years for delusion syndromes were retained for this study. One hundred and fifteen old patients from a geriatric-hospital (age 83.5+/-6.06 years) were included in this protocol. The classical diagnostic process yielded the diagnosis of epilepsy for 50 subjects. The electro-clinical scale confirmed the diagnosis of epilepsy in 30 patients and ruled it out in 29 patients. This study underscores the importance of evidence-based medicine for the diagnosis of epilepsy in old people and points out the underuse of the new technical tool, EEG-monitoring, for the management of these patients.

Newly diagnosed single unprovoked seizures and epilepsy in Stockholm, Sweden: First report from the Stockholm Incidence Registry of Epilepsy (SIRE)

To describe and report initial findings of a system for prospective identification and follow-up of patients with newly diagnosed single unprovoked seizures and epilepsy in Stockholm, Sweden, the Stockholm Incidence Registry of Epilepsy (SIRE). From September 2001 through August 2004, a surveillance system has been in use to identify incident cases of first unprovoked seizures (neonatal seizures excluded) and epilepsy among residents of Northern Stockholm, an urban area with approximately 998,500 inhabitants. Potential cases are identified through multiple mechanisms: Network of health care professionals, medical record screening in specific hospital units, including outpatient clinics, emergency room services, and review of requests for electroencephalography (EEG) examination. Potential cases are classified 6 months after the index seizure based on review of medical records. After screening approximately 10,500 EEG requests and 3,300 medical records, 1,015 persons met the criteria for newly diagnosed unprovoked seizures (430 single seizures; 585 epilepsy). The crude incidence for first unprovoked seizures and epilepsy was 33.9/100,000 person years, (the same adjusted to the European Standard Million), highest the first year of life (77.1/100,000) and in the elderly. No cause could be identified in 62.4%. We have established a sustainable system for prospective identification of new onset epilepsy cases in Stockholm. Despite a possible under-ascertainment, the registry provides a useful starting point for follow-up studies.

The role of the standard EEG in clinical psychiatry

The EEG is a commonly requested test on patients attending psychiatric services, predominantly to investigate for a possible organic brain syndrome causing behavioural changes. To assess referrals for EEG from psychiatric services in comparison with those from other sources. We determine which clinical factors were associated with an abnormal EEG in patients referred from psychiatric sources. A retrospective review of EEG requests in a 1-year period was performed. Analysis of referral reasons for psychiatric patients was undertaken, and outcome of patients referred from psychiatric services post-EEG was reviewed. One thousand four hundred and seventy EEGs were reviewed, of which 91 (6.2%) were referred from psychiatry. Neurology service referrals had detection rates of abnormal EEGs of 27%, with psychiatric referrals having the lowest abnormality detection rate of 17.6% (p < 0.1). In psychiatric-referred patients the only significant predictors found of an abnormal EEG were a known history of epilepsy (p < 0.001), being on clozapine (p < 0.05), and a possible convulsive seizure (RR = 6.51). Follow-up data of 53 patients did not reveal a significant clinical impact of EEG results on patient management. Many patients are referred for EEG from psychiatric sources despite a relatively low index of suspicion of an organic brain disorders, based on reasons for referral documented, with an unsurprising low clinical yield.

Screening of EEG Referrals by Neurologists Leads to Improved Healthcare Resource Utilization

The objective of this study was to determine if screening by a neurologist of all non-neurologist electroencephalogram (EEG) referrals prior to approval reduces the number of inappropriate requests. This retrospective survey included 600 consecutive EEG requisitions referred to the Anaheim Kaiser Permanente Neurodiagnostic Laboratory to rule out epilepsy. Patients with established epilepsy referred for a repeat EEG for management issues were excluded. Three groups of EEG referrals were analyzed. Each group consisted of 200 EEGs (100 pediatric and 100 adult EEGs). The first group was referred directly by non-neurologists, the second group was referred by non-neurologists with scrutiny by a neurologist, and the third group was referred by a neurologist directly. In the pediatric group, the ratio of abnormal EEG vs normal EEG was 1:3.35 in the first group, 1:0.69 in the second group and 1:0.33 in the third group. In the adult group, the ratio of abnormal EEGs vs normal EEGs was 1:2.23 in the first group, 1:0.82 in the second group and 1:0.45 in the third group. In the combined pediatric and adult groups, the ratio of abnormal EEG vs normal EEG was 1:2.70 in the first group, 1:0.75 in the second group and 1:0.39 in the third group. There was a significant difference between the results of the EEGs ordered by non-neurologists directly versus non-neurologists with scrutiny (p=.334, chi-square test). Scrutiny by a neurologist of EEG referrals from non-neurologists led to a reduction in the number of normal EEG results. This suggests that inappropriate EEG requests for non-epileptic patients that yield normal EEG results are significantly reduced with scrutiny. This can help reduce the indiscriminate overuse of EEGs by non-neurologists thereby leading to better utilization of healthcare resources.

How often does routine pediatric EEG have an important unexpected result?

Electroencephalogram recordings are requested for the assessment of many childhood disorders. To assess the utility of the EEG in children, we studied how often routine EEG results can be correctly predicted from the EEG requisition. Five hundred consecutive initial EEG requests from the IWK Grace Health Centre from two time epochs were examined. All EEGs were 16 channel (10-20 electrode system). Based only on the requisition (patient demographics, referring physician, and reason for EEG), we coded our prediction of the result and then the actual result. When results were discordant from prediction, a judgment was made about the potential importance of the result. Overall, EEG results were correctly predicted in 81%. Prediction for all nonepilepsy reasons was accurate in 91% (n=320) and 96% for paroxysmal nonepileptic events (n=158) but only 59% for epileptic disorders (n=141) (p<0.0001). Neurologists ordered 45% of EEGs, pediatricians 32%, and GP's 17%. Predictions were least accurate for neurologists' requests (p<0.006) however, neurologists were more likely to request EEG for epileptic disorders (p<0.0001). Age of the child and urban versus rural address did not affect the accuracy of prediction. Results of routine pediatric EEG for most nonepilepsy reasons appear highly predictable and therefore, possibly of little value to an experienced clinician. When requested for epilepsy, this "ancient" test remains full of surprises.

An audit of the appropriateness of EEG requests in a District Hospital setting

An audit of the appropriateness of EEG requests in a District Hospital setting

CHANGES IN THE USE OF EEG FOLLOWING CLINICAL AUDIT

SUMMARY An audit of the clinical use of EEG in mentally handicapped patients was performed over a three‐year period. EEG requests seemed inappropriate in more than one‐quarter of cases. Changes in clinical practice during the 10 months following presentation of these audit results were examined. There was a marked reduction in EEG requests, which were subsequently used in a more cost‐effective and clinically appropriate way. There was also a reduction in the time taken to process requests.

The use of electroencephalography in an in-patient mental handicap population

The use of electroencephalography over a three year period in a large mental handicap hospital was studied. There were no significant differences in its use according to sex or intelligence. The majority of requests were made following seizures and in the investigation of behavioural abnormality. In over a quarter of cases the EEG requests appeared to be inappropriate. It is suggested that a more cost-effective use would result if EEGs were requested only in those cases in which the result will lead to a change in the management of the patient.