Childhood Absence Epilepsy Associated With Concomitant Centrotemporal Spikes.

Objectives The coexistence of generalized epileptiform discharges of 3Hz spike-and-wave complexes, which are the hallmark of childhood absence epilepsy (CAE), and centrotemporal spikes, which are characteristic of benign epilepsy with centrotemporal spikes (BECTs) in the same or subsequent EEGs appears to be very rare. Only a few published reports have shown a possible concomitance of CAE and BECTs electrographic changes. The study aimed to analyze electrographic and clinical features of patients with CAE who had concomitant or subsequent EEG features of BECTs. Method During a five-year analysis period (2014-2018), 277 children with BECTs and 93 children with CAE were diagnosed and treated at the pediatric neurology unit of Sultan Qaboos University Hospital (SQUH) in Muscat, Oman. Nine patients were identified to have overlapping EEG findings of both epileptic syndromes. We then analyzed the nine children's clinical features, outcomes, and EEG findings in detail. Results The clinical onset of all our patients aged 5-14 years (six boys, three girls) was characterized by the absence of seizures, either typical (seven children) or atypical (two children). Six out of nine patients presented with concomitant electrographic features of both syndromes, whereas three patients experienced the EEG pattern of two syndromes at different times. All nine children were treated with valproate as the first-line medication, with reasonable seizure control. However, three patients required a second add-on medication. Despite good seizure control, six of our patients had poor school performance and five children had comorbid conditions such as ADHD and learning disability. Conclusion The coexistence of CAE and BECTS is described in the literature albeit rare. This overlap is mostly in electrographic features with or without the clinical features seen in both syndromes.

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.

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.

EEG Pattern in Neonatal Maple Syrup Urine Disease: Description and Clinical Significance.

Maple Syrup Urine Disease (MSUD) is a rare autosomal recessive disorder characterized by deficiency of branched-chain keto acid dehydrogenase complex, which is required to metabolize the three branched chain amino acids (BCAAs), leucine, isoleucine and valine. This metabolic dysfunction results in progressive encephalopathy manifesting with lethargy, vomiting, posturing and abnormal movements during the neonatal period in the classic form of the disease. If untreated, progressive brain damage causes coma, seizures and death usually within a few weeks. EEG is an essential investigation in a neonate with progressive encephalopathy and seizures. EEG abnormalities in neonatal encephalopathies due to inborn error of metabolism (IEM) are widely variable depending on the severity. Central comb-like rhythm is an EEG marker of neonatal MSUD in appropriate clinical context. This pattern should not be mistaken for epileptic abnormalities, sleep spindles or other similar nonspecific activities. We describe a patient with classic MSUD who presented with an EEG pattern of comb-like rhythm. Background abnormalities and epileptic discharges are common along comb-like rhythm in MSUD patients. EEG technologists and interpreters should be able to identify this pattern to support the early diagnosis and treatment of MSUD.

Vasovagal Syncope in Epilepsy Monitoring Unit: A Case Report and Review.

Falls are a common adverse event (AE) in general hospital admissions and in the epilepsy monitoring unit (EMU) and can cause serious physical injury for patients; however, fall prevention policies widely vary between epilepsy centers. Patient safety, including minimizing AEs, such as falls, continue to be a major goal of quality improvement in the EMU. The bathroom area in an EMU is highly prone for falls due to the need for patient privacy. Syncope is a physiologic non-epileptic event with high prevalence in general population and is a potential cause for fall. It is also reported in people diagnosed with epilepsy. We report a case of vasovagal syncope (VVS) associated with injury in a young female during long-term video EEG recording in our EMU facility. We also briefly address concerns for identifying patients at risk for syncope and its prevention. A multidisciplinary team including EEG technologists can play a vital role in educating patients and caretakers about the risk factors of syncopal fall and its preventive measures.

Clinico-electrographic characteristics and classification of genetic generalized epilepsy in Oman.

PURPOSE: There is a lack of information on the annual incidence of genetic generalized epilepsy (GGE) in the Arab countries, especially Oman. Ascertaining the true burden of illness has crucial implications for health policies and priorities. We aim to study the clinico-electrographic characteristics, classification, and annual incidence of GGE in Oman. METHOD: Using the cross-sectional data of EEGs obtained from all patients with GGE who presented to Sultan Qaboos University hospital (major referral center for epilepsy in Oman) from January 2007 to June 2014. Analyses were performed using univariate statistics. RESULTS: Approximately 10,423 patients had EEG studies during the study period of which 376 patients (3.6 %) had EEG abnormalities suggestive of GGE. Forty two percent of the 376 GGE patients were male with ages ranging from 3 to 58 years. We were able to classify 273 patients to one of the GGE syndromes. Forty-three percent of 130 patients had a positive family history of epilepsy in their first or second-degree relatives. The generalized tonic-clonic seizure was the most common seizure type observed in 242 patients (64 %; 95 %CI: 59.2 %-68.9 %). Juvenile myoclonic epilepsy was the most common epilepsy syndrome (41 % of the total GGE patients) encountered in our region. A significant female predominance (9.7 % vs 2.5 %; p = 0.016) was observed in juvenile absence epilepsy. Certain interictal focal EEG abnormalities did not exclude a diagnosis of GGE. An average annual GGE incidence of 2.9 % (95 % CI: 2.6 %-3.2 %) was observed during the study period. CONCLUSION: This hospital-based study is the first of its kind in the Arabian Gulf region, classifying the different subcategories of GGE. Our results indicate that GGE is a common epilepsy subtype in Oman. A prospective population-based epidemiological study is required to estimate the precise frequency of GGE in Oman.

Nonketotic Hyperglycinemia: Two Case Reports and Review.

Nonketotic hyperglycinemia (NKH) or glycine encephalopathy is an autosomal recessive disorder of glycine metabolism resulting in an excessive accumulation of glycine in all body tissues, including the central nervous system. It is caused by a biochemical defect in the glycine cleavage system and considered as a rare disorder with an estimated prevalence of 1:60,000. The neonatal form presents in the first few days of life with progressive encephalopathy, hypotonia, myoclonic jerks, hiccups, seizures, rapid progression to coma and often death due to central apnea. Surviving infants often have severe developmental delay and refractory seizures. Atypical forms of NKH present with heterogeneous and nonspecific disease course. Classical glycine encephalopathy usually carries a very poor prognosis. We describe two neonates who presented with neonatal encephalopathy, apnea, and progressive lethargy. Increased CSF glycine level along with an elevated CSF to plasma glycine ratio was suggestive of classic NKH. Burst suppression EEG and agenesis of the corpus callosum were supportive findings. Evolution of the EEG patterns and course of the disease are discussed in detail. Transient phases of clinical stabilization and normalized plasma biochemical results may not necessarily reflect the actual encephalopathic process. Serial EEGs are helpful to assess the efficacy of treatment and to modify the therapeutic approach.

Prevalence of Sleep-Disordered Breathing During Routine Electroencephalogram (EEG): A Hospital-Based Descriptive Study.

Sleep-disordered breathing (SDB) in adults is a common condition that is associated with a range of medical problems including hypertension, cardiovascular complications, and increase of seizure frequency in susceptible individuals. Polysomnography (PSG) is considered the gold standard measure in the diagnosis of SDB. This is an observational study on the frequency of SDB in adult patients referred for routine EEG. We found that routine EEG was capable of detecting moderate to severe symptoms of SDB in 14% of adult patients (95% confidence interval = 8.1-19.9%). The state of sleep during a routine EEG recording could help in assessing a SDB pattern and could provide an opportunity for further diagnostic sleep consultation if the patient has not previously reported problems with sleep or if SDB was not considered by the referring physician. This study underscores the need for a practice approach to ensure that patients suffering from SDB are properly referred to a sleep specialist. In the context of this report, some training and experience in PSG can be an added advantage for EEG technologists in the detection of SDB.

The Usefulness of Nap Sleep Recording During Routine Electroencephalography: An Audit Study.

OBJECTIVES: A measure to increase the electroencephalogram (EEG) outcome includes a short period of nap sleep during a routine standard EEG with the aim of increasing its sensitivity to interictal abnormalities or provoking seizures. As part of an ongoing auditing of our EEG data, we aimed to investigate the contribution of nap sleep during routine outpatient department based EEGs requested for a variety of reasons. METHODS: EEG data at the Department of Clinical Physiology at Sultan Qaboos University Hospital, Oman, from July 2006 to December 2007 and from January 2009 to December 2010 (total 42 months) were reviewed. The EEGs were for patients older than 13-years referred for possible epilepsy, blackouts, headache, head trauma, and other non-specified attacks. The recording period was between 20 to 40 minutes. Abnormalities were identified during waking and nap sleep periods. RESULTS: A total of 2 547 EEGs were reviewed and 744 were abnormal (29.2%). Of those abnormal EEGs, nap sleep was obtained in 258 (34.7%) EEGs, and 39 (15.1%) showed abnormalities during nap sleep. Nineteen out of the 39 (48.7%) EEGs were abnormal during awake and nap sleep; and 20 (51.3%) were abnormal during nap sleep, which represented only 2.7% of the total abnormal EEGs (n = 744). CONCLUSIONS: The contribution of the short nap sleep to the pickup rate of interictal abnormalities in EEG was minimal. We recommend the EEG service to include one cycle of spontaneous sleep EEG directed at patients with a history suggestive of epilepsy if their awake EEGs are normal.

Predictive Value of Short-Term EEG Recording in Critically ill Adult Patients.

We assessed the EEG patterns and their prognostic significance in critically ill adult patients with encephalopathy, by digital EEGs lasting lip to 1 hour Of the 110 patients (age: 43.8 ± 19.4 years, male: female:1.6:1) studied, 32% had hypoxic ischemic encephalopathy (HIE), 17% severe infections, and 14.5% stroke. Observed EEG patterns were diffuse slowing (41%), low-voltage cerebral activity (LVCA, 18%), nonconvulsive status epilepticus (NCSE, 13.6%), and periodic abnormalities (9.1%). LVCA, age, Glasgow Coma Score (GCS) < 8, HIE, and modified Hockaday's EEG grades of IV and V were associated with poor outcome (p < 0.005) at hospital discharge; generalized slowing was associated with a relatively good outcome (p = 0.003). On multivariate analysis, factors independently predictive of mortality were LVCA, older age, and poor GCS. In conclusion, LVCA and generalized background slowing were common EEG patterns among critically ill intensive care unit (ICU) patients with encephalopathy of varied etiologies. While LVCA was associated with a poor outcome, generalized background slowing predicted better prognosis. Conventional short-duration, bedside EEG studies could aid in the recognition of electrographic patterns of prognostic importance in facilities where continuous EEG monitoring is lacking.

The Correlation between Electroencephalography Amplitude and Interictal Abnormalities: Audit study.

OBJECTIVES: The aim of this study was to establish the relationship between background amplitude and interictal abnormalities in routine electroencephalography (EEG). METHODS: This retrospective audit was conducted between July 2006 and December 2009 at the Department of Clinical Physiology at Sultan Qaboos University Hospital (SQUH) in Muscat, Oman. A total of 1,718 electroencephalograms (EEGs) were reviewed. All EEGs were from patients who had been referred due to epilepsy, syncope or headaches. EEGs were divided into four groups based on their amplitude: group one ≤20 µV; group two 21-35 µV; group three 36-50 µV, and group four >50 µV. Interictal abnormalities were defined as epileptiform discharges with or without associated slow waves. Abnormalities were identified during periods of resting, hyperventilation and photic stimulation in each group. RESULTS: The mean age ± standard deviation of the patients was 27 ± 12.5 years. Of the 1,718 EEGs, 542 (31.5%) were abnormal. Interictal abnormalities increased with amplitude in all four categories and demonstrated a significant association (P <0.05). A total of 56 EEGs (3.3%) had amplitudes that were ≤20 µV and none of these showed interictal epileptiform abnormalities. CONCLUSION: EEG amplitude is an important factor in determining the presence of interictal epileptiform abnormalities in routine EEGs. This should be taken into account when investigating patients for epilepsy. A strong argument is made for considering long-term EEG monitoring in order to identify unexplained seizures which may be secondary to epilepsy. It is recommended that all tertiary institutions provide EEG telemetry services.

Evolution of epileptic encephalopathy in an infant with non-accidental head injury.

A 5-month-old child, previously healthy, was hospitalized with frequent episodes of tonic seizures. The seizures were controlled with antiepileptic medication. However, the parents did not continue medications after discharge from the hospital. The child was admitted several times with breakthrough seizures. Over time the seizures became refractory to treatment. Neurometabolic work up and imaging studies for uncontrolled seizures revealed non-accidental head injury (shaken baby syndrome) as the underlying cause. His first EEG was normal and changed from normal to an epileptic encephalopathy pattern during his several admissions for uncontrolled seizures. From a normal child at the first admission, the child was severely regressed at the last admission. The present paper highlights the evolution of EEG changes in a child with non-accidental head injuries. This report also highlights considering non-accidental head injury as the underlying cause in younger children presenting with unexplained epileptic encephalopathy.

Mystery case: EEG FOLDer.

A 20-year-old woman underwent sleep-deprived EEG (figure) for evaluation of possible seizure disorder. Interpret the EEG finding.

Evolution of Ohtahara syndrome to continuous spikes and waves during slow sleep in an infant.

Encephalopathy with electrical status epilepticus in sleep (ESES) is defined as an age-related and self-limited electroclinical syndrome whose etiology is unknown and characterized by continuous spikes and waves during slow sleep (CSWS). Typical CSWS starts at an age of 4 to 5 years and ends by an average of 11 years. We report on an unexpected finding of CSWS in an 18-month-old male whose previous EEG at age 45 days was grossly abnormal with the presence of a burst suppression pattern during wakefulness and sleep. The patient had clinical seizures beginning day 1 of life leading to the suspicion of Ohtahara syndrome (the earliest form of epileptic encephalopathy). Patients with ESES usually have normal EEGs and functional development prior to the onset of CSWS pattern. To our knowledge, this presentation of a neonate with a history of neonatal seizures and developmental delay with an evolution to CSWS has not been described. A sleep record is strongly advised in children with epilepsy (despite the recording of awake EEG abnormalities), especially in patients with behavior or cognitive regression, to rule out the presence of CSWS.

Snoring-induced nerve lesions in the upper airway.

The prevalence of habitual snoring is extremely high in the general population, and is reported to be roughly 40% in men and 20% in women. The low-frequency vibrations of snoring may cause physical trauma and, more specifically, peripheral nerve injuries, just as jobs which require workers to use vibrating tools over the course of many years result in local nerve lesions in the hands. Histopathological analysis of upper airway (UA) muscles have shown strong evidence of a varying severity of neurological lesions in groups of snoring patients. Neurophysiological assessment shows evidence of active and chronic denervation and re-innervation in the palatopharyngeal muscles of obstructive sleep apnoea (OSA) patients. Neurogenic lesions of UA muscles induced by vibration trauma impair the reflex dilation abilities of the UA, leading to an increase in the possibility of UA collapse. The neurological factors which are partly responsible for the progressive nature of OSAS warrant the necessity of early assessment in habitual snorers.

Atypical presentation of subclinical rhythmic electrographic discharge of adults (SREDA) in a patient with idiopathic generalized epilepsy.

Subclinical rhythmic electrographic discharge of adults (SREDA) is considered a benign EEG pattern of uncertain significance, although it may closely resemble an electrographic seizure pattern. SREDA was first described by Westmoreland and Klass in 1981 as a distinctive rhythmic and rare EEG pattern primarily seen in older subjects. The typical pattern consists of sharp contoured, non-evolving 5 to 7 Hz theta rhythm with a widespread bilaterally synchronous distribution, but maximal over the parietal and posterior temporal regions. It usually lasts for a few seconds to several minutes without clinical association. Later in 1997, several unusual variants of SREDA were reported consisting of variations infrequency, morphology, topographic distribution, duration, and stage of alertness. We report SREDA in a patient with idiopathic generalized epilepsy which shows some atypical features (such as asynchronous onset, bifid waveforms, asymmetry, and fragmentation) and mimics a secondarily generalized partial seizure. It is important to successfully identify SREDA to avoid misdiagnosis and incorrect treatment. The technologist's contribution is essential and valuable. EEG technologists and interpreters should be aware of typical and atypical features of SREDA and its wide spectrum.

System reference electrode artifacts mimicking alpha coma and electrographic seizures in EEG.

We are presenting a patient with frequent seizures who required an intensive care admission for intubation and ventilation. The patient was monitored with 24-hour EEG and video for clinical and subclinical seizures. Her EEG showed artifactual changes which initially were interpreted as electrographic seizures. Correction of the artifact revealed the actual background activities. The EEG technologist must be aware of such artifacts and correct them promptly to avoid unnecessary intervention with potential negative outcome for the patient.