Differential diagnosis of staring spells in children: a video-EEG study

Staring Spells: An Age-based Approach Toward Differential Diagnosis

Evaluations to rule out epileptic vs nonepileptic staring spells may entail unnecessary evaluations that can be costly and time consuming. Our study aims to identify common etiologies for staring spells across 3 different pediatric age groups and to propose an age-based clinical guidance to help determine which patients warrant further workup. Methods: This was a single-center retrospective chart analysis of 1496 patients aged 0.0-17.9 years presenting with confirmed staring spell diagnosis from January 2011 to January 2021. The patients were divided into 3 groups based on their age: 0.0-2.9, 3.0-12.9, and 13.0-17.9 years. Patient information collected included demographics, clinical presentation, comorbidities, and final diagnosis. Multilevel likelihood ratios and a receiver operating characteristic curve were determined using 8 of the 11 clinical variables. A total of 1142 patients who met the inclusion criteria were included for the final analysis. The most common final diagnosis was attention-deficit hyperactivity disorder (ADHD) (35%), followed by normal behavior (33%). Generalized and focal epilepsy were diagnosed in 8% and 4% of the patients, respectively. In the 0.0-2.9-year age group, normal behavior was the final diagnosis in 72% patients. In the 3.0-12.9-year and 13.0-17.9-year age groups, ADHD was the most frequent final diagnosis in 46% and 60%, respectively. Overall, ADHD and normal behaviors remain the most common final diagnoses. Multilevel likelihood ratios can be used to develop an age-based guidance to differentiate between epileptic and nonepileptic staring spell diagnoses.

Staring Spells: How to Distinguish Epileptic Seizures from Nonepileptic Staring

OBJECTIVE

To determine the nature of staring spells and factors distinguishing epileptic from nonepileptic staring spells, we studied the clinical and demographic features of children with staring spells referred to a regional new-onset seizure clinic.

STUDY DESIGN

Our retrospective chart review encompassed 2818 consecutive patients evaluated in the new-onset seizure clinic between September 22, 2015, and March 19, 2018. We identified 121 patients with newly presenting staring spells.

RESULTS

Sixty-two of 121 (51%) children were diagnosed with nonepileptic staring spells and 59 (49%) with epileptic seizures (24 with absence epilepsy, 35 with focal epilepsy). Patients with nonepileptic staring spells were younger (4.8 vs 7.1 years, P = .001) and more likely to have developmental delay (P = .005) than the seizure group. There was an 8.9-month delay on average from the onset of staring spells to the new-onset seizure clinic visit. The emergency department was a referral source for 80% (28/35) of focal seizures. In children with focal seizures, the staring spells typically lasted >1minute (29/35, 83%), whereas only 19 of 62 (31%) of children with nonepileptic staring spells had events lasting this long (P = .04). All children had a routine electroencephalography (EEG) on the day of new-onset seizure clinic visit. EEG was diagnostic in 100% (24/24) of absence seizures and 51% (18/35) of focal seizures.

CONCLUSIONS

In children presenting with staring spells, the differential diagnosis of epileptic staring spells vs nonepileptic staring spells can be made by history and routine EEG. Staring was as likely to be epileptic as nonepileptic spells. Younger children with developmental delay were more likely to have nonepileptic events. Our simple approach based on event duration, postictal symptoms, and EEG allowed identification of epileptic staring on first visit to new-onset seizure clinic but requires validation in future prospective studies including long-term video EEG monitoring and follow-up.

Using Semiology to Classify Epileptic Seizures vs Psychogenic Nonepileptic Seizures: A Meta-analysis

Background and objectives:

Misdiagnosis of psychogenic nonepileptic seizures (PNES) and epileptic seizures (ES) is common. In the absence of the diagnostic gold standard (video EEG), clinicians rely on semiology and clinical assessment. However, questions regarding the diagnostic accuracy of different signs remain. This meta-analysis aims to evaluate the diagnostic accuracy of semiology in PNES and ES.

Methods:

We systematically searched PubMed, PsycInfo and Medline for original research publications published before 8 February 2021 with no restriction on search dates to identify studies that compared semiology in ES and PNES in epilepsy monitoring units. Non-English publications, review articles, studies reporting on only PNES or ES and studies limited to patients with developmental delay were excluded. Study characteristics and proportions of ‘event groups’ and ‘patient groups’ demonstrating signs were extracted from each article. Bivariate analysis was conducted, and data were pooled in a random effects model for meta-analysis. The I2 statistic was calculated to assess statistical heterogeneity. The QUADAS-2 tool was utilized to assess risk of bias in included studies. The positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were calculated. A PLR > 10 or an NLR < 0.1 has a large impact on the post-test probability of a diagnosis (ES or PNES) whereas a PLR between 5-10 or an NLR between 0.1- 0.2 has a moderate impact on the post-test probability of a diagnosis (ES or PNES).

Results:

The meta-analysis included 14 studies comprising of 800 patients with ES and 452 patients with PNES. For PNES, ictal eye closure (PLR 40.5 95%CI: 16.2-101.3; I2 = 0, from three studies) and asynchronous limb movements (PLR 10.2; 95%CI: 2.8-37.7; I2 = 0, from three studies) reached a PLR threshold > 5. No single sign reached a PLR threshold >5 for ES.

Conclusions:

While all signs require interpretation in the overall clinical context, the presence of ictal eye closure and asynchronous limb movements are reliable discriminative signs for PNES.

A Practical Guide to Treatment of Childhood Absence Epilepsy

Childhood absence epilepsy (CAE) is a common pediatric epilepsy syndrome with distinct seizure semiology, electroencephalography (EEG) features, and treatment. A diagnosis of CAE can be obtained during an office visit with a careful history, physical exam including prolonged hyperventilation, and a routine EEG. The treatment of choice for CAE with absence seizures only is ethosuximide. Valproic acid and lamotrigine are also effective treatments for many patients, but when compared to ethosuximide, valproic acid has more adverse effects and lamotrigine is less effective. Attention to predictors of response to treatment, including clinical, electrographic, and genetic factors, is increasing. Refractory CAE occurs in fewer than half of patients, and treatment strategies are available, though efficacy data are lacking. Careful assessment and treatment of psychosocial comorbidities is essential in caring for patients with CAE.

Utility of long-term video-EEG monitoring for children with staring

OBJECTIVE

Staring spells are a common reason for referral to overnight epilepsy monitoring unit (EMU) evaluation. However, inpatient EMU admissions are expensive and time consuming. This study determined what percentage of those referred for staring had a confirmed epileptic seizure on long-term video-EEG monitoring (LTM) and developed a scoring system to help prioritize which patients should undergo this procedure.

METHODS

We performed a four-year retrospective chart review of all children at a tertiary pediatric hospital who received LTM (long-term monitoring) for the purposes of characterizing staring. The two goals were to: a) assess how often an LTM admission captured a staring spell that was diagnosed as a seizure and b) determine if any baseline factors predicted this particular positive result. We coded several characteristics of the most recent prior routine EEG if available. We also coded parental reports of the duration, frequency, and breakability of the events as well as post-ictal mental status and the presence/absence of automatisms. Finally, we coded previous neurological and psychiatric diagnoses and medications, as well as family history of epilepsy.

RESULTS

Of the 276 admissions, only 29 (11%) captured a staring spell and diagnosed it as seizure. Several baseline variables predicted the likelihood of this positive result. Based on this information, we created a scoring system as follows: -3 points if the previous EEG was normal, -1 point if the child took a medication for a psychiatric condition, +1 point if the child took an anti-epileptic drug for epilepsy, and +1 point if the spells lasted less than 1min. If the total score was zero or less, staring spells diagnosed as seizures rarely occurred (less than 5% of the studies).

SIGNIFICANCE

Our scoring system shows how consideration of prior EEG findings, medication history, and staring spell duration can help prioritize patients for LTM admission to evaluate if staring spells are epileptic seizures.

The yield of video-EEG telemetry evaluation for non-surgical candidate children

BACKGROUND

Video EEG (VEEG) is performed for most pediatric patients in order to evaluate unclear paroxysmal events and improve our understanding of difficult to control epileptic patients.

PURPOSE

To characterize the video EEG studies on children who are not candidates for surgery in order to identify the parameters that affect results in level of improving the rate of acquisition, as well as improving the ability to expect the likelihood of epilepsy and of gathering new information as a result of the VEEG.

METHODS

Retrospective chart analysis of all consecutive patients who underwent VEEG in two VEEG monitoring units.

RESULTS

323 children of a mean age of 7 years (STD 4.73, range 0-17 years) were monitored for a mean duration of 2 days (STD 1.65, range 1-10 days). The main reasons for monitoring were: evaluation of unclear events (n = 234), evaluation of previously diagnosed epilepsy (n = 36) and confirmation of Electrical Status Epilepticus in Sleep (ESES) (n = 34). The main event types for evaluation were: staring episodes (n = 67), myoclonic jerks (n = 35) and abnormal eye movement (n = 22). Suspected events were captured in 70% of the patients. There was a positive correlation between acquisition of suspected events and each of the following: duration of the monitoring, the frequency of investigated events per history, the type of investigated events. A prior interictal epileptic activity on routine EEG was a positive predictor of an event to be epileptic (p = 0.003). Amongst the group of known epileptic patients, VEEG had role in changing diagnosis in 53% of patients. Many of them had focal interictal epileptiform activity in their routine EEG.

CONCLUSIONS

Selecting patients with frequent events and longer monitoring periods increase the yield of VEEG. Looking carefully into clinical characteristics of the patient prior to VEEG can clarify diagnosis therefore render the VEEG test superfluous to subgroups of patients. Prior routine epileptic EEG, coexistence of other seizure types, behaviors accompanying the investigated habitual behavior and abnormalities in other investigations (MRI, cognitive function and EEG) are the parameters that can predict diagnosis of epilepsy. Precise diagnosis in known epileptic patients as a result of VEEG is more likely for those with focal interictal epileptiform discharges in routine EEG.

Paroxysmal nonepileptic events in infancy, childhood, and adolescence

There are a wide variety of paroxysmal nonepileptic events (PNEEs) in children that can mimic seizures. The type of PNEEs that need to be considered in the differential diagnosis depends on the age of symptom onset and the clinical features. In infants and toddlers, conditions that are relatively common in clinical practice such as apnea, jitteriness, shuddering attacks, and breath-holding spells may not present much of a diagnostic conundrum, whereas unusual conditions such as hyperekplexia may cause concern. Similarly, although most types of migraine are easily distinguished from seizures in school-aged children, certain variants such as the "Alice in Wonderland" syndrome or basilar migraine can create diagnostic confusion. Most types of PNEE are exclusive to childhood; therefore, the pediatrician must be familiar with a variety of physiological processes and pathological entities that can raise concern in parents. The pediatrician is in the unique position of being able to reassure families and/or guide further work-up. Many of the PNEEs in young children require no treatment and resolve spontaneously. It is important to distinguish these episodes from true seizures as to avoid unnecessary testing and pharmacological treatment. This review highlights common PNEEs in children, beginning with the neonatal age group and moving upward to adolescence.

Paroxysmal nonepileptic events in pediatric patients confirmed by long-term video-EEG monitoring--Single tertiary center review of 143 patients

The purpose of the study was to evaluate the clinical characteristics of paroxysmal nonepileptic events (PNEs) in pediatric patients. Reports of 1108 patients who underwent long-term video-EEG monitoring at Seoul National University Children's Hospital were reviewed retrospectively. One hundred forty-three (12.9%) patients were diagnosed as having PNEs. The most common type of PNE was staring. Staring, tonic posturing, sleep myoclonus, and sleep-related disorders were more common in patients younger than 6 years old. Psychogenic nonepileptic seizure was the most common PNE in patients older than 6 years. Patients who were younger than 6 years old showed shorter disease duration and more varied types of PNEs when compared to older patients (6 years old or older). Presence of epilepsy was not significantly related to clinical difference in PNEs. In patients with developmental delay, staring and tonic posture were significantly more frequent than patients without developmental delay. Thirty-two patients without concurrent epilepsy were misdiagnosed with epilepsy, and AEDs were discontinued after the correct diagnosis of PNEs. Whenever the diagnosis of paroxysmal abnormal behavior is uncertain, correct diagnosis should be made using long-term video-EEG monitoring, especially in younger pediatric patients and patients with developmental delay.

Nonepileptic paroxysmal events in a pediatric population

Nonepileptic paroxysmal events in children are common, and may be more diverse in etiology than those seen in adults. We determined the types of nonepileptic events that are most prominent in the pediatric population, and stratified those events by age group. Ninety-four of 416 pediatric patients monitored during a 3-year period (23%) were found to have had nonepileptic events. Thirty-eight percent of these children were diagnosed with psychogenic nonepileptic seizures, and 72% of those were adolescents. In children younger than 5 years of age, behavioral events and parasomnias were the most common mimickers of epilepsy. Other events, including stereotyped movements and myoclonus, were also diagnosed. We suggest that children with refractory paroxysmal events should be considered for early inpatient monitoring.

The differential diagnosis of epilepsy: a critical review

The wrong diagnosis of epilepsy is common. At referral epilepsy centers, psychogenic non-epileptic attacks are by far the most common condition found to have been misdiagnosed as epilepsy, with an average delay of 7-10 years. There are many "red flags" that can raise the suspicion of psychogenic non-epileptic attacks. Syncope is the second most common condition misdiagnosed as epilepsy, and it is probably more common in outpatient populations. Other conditions more rarely misdiagnosed as epilepsy include hypoglycemia, panic attacks, paroxysmal movement disorders, paroxysmal sleep disorders, TIAs, migraines, and TGA. Conditions specific to children include nonepileptic staring spells, breath-holding spells, and shudder attacks. At all ages, the over-interpretation of EEGs plays an important part in the misdiagnosis of epilepsy.

Factors influencing clinical features of absence seizures

PURPOSE

The clinical features of absence seizures in idiopathic generalized epilepsy have been held to be syndrome-specific. This hypothesis is central to many aspects of epilepsy research yet has not been critically assessed. We examined whether specific factors such as epilepsy syndrome, age, and state determine the features of absence seizures.

METHODS

Children with newly presenting absence seizures were studied using video electroencephalography (EEG) recording. We analyzed whether a child's epilepsy syndrome, age, state of arousal, and provocation influenced specific clinical features of their absence seizures: duration, eyelid movements, eye opening, and level of awareness during the seizure.

RESULTS

Seizures (509) were evaluated in 70 children with the following syndromes: Childhood absence epilepsy (CAE), 37; CAE plus photoparoxysmal response (PPR), 10; juvenile absence epilepsy (JAE), 8; juvenile myoclonic epilepsy (JME), 6; unclassified, 9. Seizure duration was associated with epilepsy syndrome as children with JME had shorter seizures than in other syndromes, independent of age. Age independently influences level of awareness and eye opening. Arousal or provocation affected all features except level of awareness. Specific factors unique to the child independently influenced all features; the nature of these factors has not been identified.

DISCUSSION

The view that the clinical features of absence seizures have syndrome-specific patterns is not supported by critical analysis. We show that confounding variables profoundly affect clinical features and that syndromes also show marked variation. Variation in clinical features of absence seizures results from a complex interaction of many factors that are likely to be genetically and environmentally determined.

The frequency of non-epileptic spells in children: results of video-EEG monitoring in a tertiary care center

RATIONALE

the diagnosis of non-epileptic spells (NES) in children can be challenging, even for experienced clinicians. Our objective was to describe the characteristics of such events.

METHODS

this was a retrospective study conducted from January 2004 to December 2006. Inclusion criteria were age >1 month and <18 years and the diagnosis of NES established by video-EEG monitoring.

RESULTS

among 746 monitored children (1203 recorded video-EEG sessions), 109 (14.6%) had NES. The mean age of patients with NES was 6.6 years (range 0.1-18). Seventy patients were diagnosed with NES alone; the remaining 39 with both NES and epilepsy. Developmental delay was more frequent among patients with a co-morbid diagnosis of epilepsy (p<0.001). Similar clinical events were reported in both of these groups, save for crying spells/irritability which was more common in children with epilepsy. Frequent manifestations of NES included staring spells in preschool children, crying/irritability, tremor and eye deviation in young children and preschoolers, and limb shaking in adolescents. All of the patients with epilepsy and 19 (27%) of those without epilepsy were receiving antiepileptic drugs.

CONCLUSION

our data highlights the importance of accurate diagnosis of NES toward the appropriate treatment of affected children.

Transgenic mice over-expressing GABA(B)R1a receptors acquire an atypical absence epilepsy-like phenotype

In this study, we tested whether over-expressing the GABA(B) receptor R1a subtype in transgenic mouse forebrain neurons would be sufficient to induce spontaneous absence seizures. As hypothesized, these transgenic mice develop spontaneous, recurrent, bilaterally synchronous, 3-6 Hz slow spike and wave discharges between 2 and 4 months of age. These discharges are blocked by ethosuximide and exacerbated by baclofen confirming their absence nature. The discharges occur coincident with absence-like behaviors such as staring, facial myoclonus, and whisker twitching. However, in contrast to typical absence epilepsy models, these mice move during the ictal event, display spike and wave discharges in both thalamocortical and limbic circuitry, exhibit impaired hippocampal synaptic plasticity, and display significantly impaired learning ability. Collectively, these features are more characteristic of the less common but more debilitating atypical form of absence epilepsy. Thus, these data support a role for the GABA(B)R1a receptor subtype in the etiology of atypical absence epilepsy.

Typical versus atypical absence seizures: network mechanisms of the spread of paroxysms

PURPOSE

Typical absence seizures differ from atypical absence seizures in terms of semiology, EEG morphology, network circuitry, and cognitive outcome, yet have the same pharmacological profile. We have compared typical to atypical absence seizures, in terms of the recruitment of different brain areas. Our initial question was whether brain areas that do not display apparent paroxysmal discharges during typical absence seizures, are affected during the ictal event in terms of synchronized activity, by other, distant areas where seizure activity is evident. Because the spike-and-wave paroxysms in atypical absence seizures invade limbic areas, we then asked whether an alteration in inhibitory processes in hippocampi may be related to the spread seizure activity beyond thalamocortical networks, in atypical seizures.

METHODS

We used two models of absence seizures in rats: one of typical and the other of atypical absence seizures. We estimated phase synchronization, and evaluated inhibitory transmission using a paired-pulse paradigm.

RESULTS

In typical absence seizures, we observed an increase in synchronization between hippocampal recordings when spike-and-wave discharges occurred in the cortex and thalamus. This indicates that seizure activity in the thalamocortical circuitry enhances the propensity of limbic areas to synchronize, but is not sufficient to drive hippocampal circuitry into a full paroxysmal discharge. Lower paired-pulse depression was then found in hippocampus of rats that displayed atypical absence seizures.

CONCLUSIONS

These observations suggest that circuitries in brain areas that do not display apparent seizure activity become synchronized as seizures occur within thalamocortical circuitry, and that a weakened hippocampal inhibition may predispose to develop synchronization into full paroxysms during atypical absence seizures.

5-HT2 modulation of AY-9944 induced atypical absence seizures

We investigated the role of 5-HT(2A) and 5-HT(2C) receptors in atypical absence seizures (AAS) induced by trans-1,4-bis[2-chloro-benzylaminomethyl] cyclohexane, dihydrocholoride (AY-9944). The total duration and number and mean duration of the spontaneous bursts of slow spike-and-wave discharges (SSWD) that characterize the AY model were measured using electrocorticographic (ECoG) recordings in freely moving animals. In a randomized counterbalanced dose response design, rats were treated with either the 5-HT(2A) agonist 1-[2,5-dimethoxy-4-iodophenyl]-2-aminopropane (DOI, 0.5, 1 or 2 mg/kg), the 5-HT(2C) preferring agonist m-chlorophenylpiperazine (mCPP, 1, 2, or 4 mg/kg), the 5-HT(2A) antagonist ketanserin (2.5 or 5 mg/kg), or vehicle. DOI significantly reduced the total duration and number of SSWD. In contrast, mCPP had no effect on total duration or number of SSWD. Ketanserin exacerbated the number of SSWD at 2.5 mg/kg but produced mixed results at 5.0 mg/kg. However, none of the treatments affected the mean SSWD duration. These data support the hypothesis that 5HT(2A) receptors are involved in the pathology of experimental atypical absence seizures.

Serotonin Depletion Attenuates AY-9944-Mediated Atypical Absence Seizures

PURPOSE

To test the hypothesis that serotonin (5-HT) plays a role in the modulation of experimental atypical absence seizures.

METHODS

Male Long-Evans hooded rats were treated from postnatal day (P) 2 to P20 with the cholesterol inhibitor AY-9944 (AY). Epidural electrodes were implanted for electrocorticography (ECoG) followed by serotonin depletion by using para-cholorophenylalanine (PCPA). High-performance liquid chromatography (HPLC) was used to measure the levels of serotonin and its metabolite (5-HIAA) in various brain regions. Serotonin metabolism was computed by using the 5-HIAA/5-HT ratio and used to ascertain differences between groups.

RESULTS

PCPA treatment was associated with a significant decrease in the total slow spike-and-wave discharge (SSWD) duration in AY-treated rats compared with controls (p < 0.01). HPLC data confirmed the PCPA depletion of 5-HT and 5-HIAA in cortex, thalamus, hippocampus, and brainstem compared with naïve rats. AY-treated rats showed higher levels of 5-HIAA and 5-HT in the same brain regions, with a concomitant decrease in rates of serotonin turnover.

CONCLUSIONS

The data indicate that serotonin depletion protects against experimental atypical absence seizures. The increased levels of 5-HIAA and 5-HT and altered rates of serotonin turnover suggest that the serotonergic neurotransmission may be perturbed in the AY rat.

Nonepileptic disorders imitating generalized idiopathic epilepsies

Differential diagnosis between epileptic and nonepileptic paroxysmal disorders is fundamental not only to allow correct management of patients but also to avoid the burden of unnecessary antiepileptic medication. The focus of this chapter is limited to imitators of idiopathic generalized epilepsies (IGE) which are expressed through myoclonic, tonic-clonic, tonic, atonic, and absence seizures. Apparent losses of consciousness and drop attacks also have to be considered. Benign myoclonus of early infancy is the main nonepileptic disorder in the differential diagnosis of infantile spasms, but is not dealt with here because West syndrome is not an IGE. Hyperekplexia, metabolic disorders, hypnagogic myoclonus, and disturbed responsiveness caused by the use of drugs are listed in Table 1. Other conditions that may imitate more focal epileptic seizures are omitted. Benign neonatal sleep myoclonus, apnea and apparent life-threatening events in infants, cyanotic and pallid breath-holding spells, syncope, staring spells, psychogenic seizures, hyperventilation syndrome, and narcolepsy have been selected based on frequency or difficulties in differential diagnosis with the intention to cover the most conspicuous imitators of IGE in different ages.

Clinical and neurophysiologic spectrum associated with atypical absence seizures in children with intractable epilepsy

The aim of this study was to describe the clinical and neurophysiologic correlates of atypical absence seizures in children with intractable epilepsy. In a retrospective review, 19 children with videoelectroencephalographic monitoring (female n=14; male n=5) fulfilled the electroclinical criteria for this seizure type. Atypical absence seizures occurred in a spectrum of clinical conditions associated with educational disability and intractable seizures. In comparison with children with only atypical absence seizures, children with atypical absence in association with multiple seizure types were more likely to have severe educational disability (n=11 of 13; P = .01), a slower ictal frequency (n=10 of 13; P = .01), and slow background rhythms for age (n = 13 of 13; P = .03). This study illustrates the broad clinical spectrum in which atypical absence seizures are encountered. Differentiation between children with only atypical absence seizures and children with multiple seizure types can be useful with respect to potential academic ability.

Learning and memory impairment in rats with chronic atypical absence seizures

Atypical absence seizures (AASs) represent a pediatric malignant seizure type that commonly exists as a component of Lennox-Gastaut syndrome. AAS involves both the hippocampal and thalamocortical circuitry in slow spike-and-wave discharges (SSWD) and is associated with cognitive dysfunction. The electrographic, behavioral, and pharmacological features of clinical AAS have been reproduced in rats chronically in the AY-9944 (AY) model. AY rats show spontaneous SSWD involving the hippocampus, a structure that is highly implicated in learning and memory. The purpose of the present study was to determine whether AY rats exhibit cognitive deficits that mirror those observed in AAS clinically. Hippocampal function was examined in AY animals both in vitro with electrophysiology (i.e., synaptic plasticity) and in vivo with a hippocampus-dependent radial arm maze (RAM) task that is designed to assess spatial cognition. In vitro tests of synaptic plasticity revealed impairments in long-term potentiation (LTP), paired-pulse facilitation (PPF), and presynaptic depression (PD). Consistently, performance of AY animals in RAM revealed fewer perfect entries, a greater number of errors, and required more training days to learn the task than saline-treated controls. The abolishment of spontaneous seizures by ethosuximide failed to recover the perturbed spatial learning and working memory in AY animals. AY rats demonstrate altered hippocampal functioning as manifested by altered synaptic plasticity and cognition. The relationship between AAS and cognitive deficit remains uncertain and the pathophysiology of both in AY treated requires further investigation.

Psychogenic status epilepticus in children

Epilepsy features, psychiatric profile, psychosocial factors, and outcome are described for six children (three males) aged 5-15 years (mean 12.1) with psychogenic status epilepticus (PSE), i.e., prolonged or repetitive psychogenic seizures (PSs), >30 minutes, simulating status epilepticus. They had epilepsy, they were on chronic anticonvulsants (ACVs), and some had other neurological deficits. All received intravenous and/or rectal ACVs prior to suspicion of PSE. PSE was confirmed via video/EEG, demonstrating no epileptogenic activity during alleged seizures. Provocation and placebo therapy techniques were used in two. Psychiatric assessment identified comorbid disorders such as depression, anxiety disorder, obsessive-compulsive disorder, obsessive-compulsive symptoms, and posttraumatic stress disorder. Psychosocial stressors were almost ubiquitous. Psychiatric intervention included psychotherapy, family therapy, and medical treatment in one patient. Outcome was monitored for an average of 3.6 years (3-5 years). PSE did not recur. PSs recurred in three. Psychiatric comorbidity improved in four, who accepted psychiatric intervention and whose epilepsy also improved. In conclusion, the occurrence of PSE in children and adolescents with epilepsy is stressed. Prompt diagnosis was often missed in the acute care setting, and this carries important implications for iatrogenic complications. PSE diagnosis resulted in identification and management of comorbid psychiatric disorders. This was probably important in reducing the predominating anxiety and affective disorders in most patients as well as PSE recurrence. Epilepsy severity and associated deficits were most likely important factors in determining outcome.

Hormonal regulation of atypical absence seizures

A time course study that examined the effects of the female estrous cycle on the chronic slow spike-and-wave discharges (SSWDs), gamma-aminobutyric B receptor (GABA(B)R) binding, and GABA(B)R protein expression was conducted in Long Evans hooded rats treated during development with a cholesterol synthesis inhibitor AY9944 (AY). In addition, a pharmacological study using the hormones progesterone, 17 beta-estradiol, mifepristone (intracellular progesterone receptor antagonist), tamoxifen (intracellular estrogen receptor antagonist), and allopregnanolone (progesterone metabolite) was performed to determine their effects on AY-induced seizures. The data indicate that there is a significant increase in both the duration of SSWD and GABA(B)R binding in the AY model, during the proestrus stage of the estrous cycle, the stage during which the levels of progesterone are at their highest. No changes in GABA(B)R1a or R2 protein levels were observed. In addition, the administration of both progesterone and allopregnanolone exacerbated seizures in the AY model, whereas 17 beta-estradiol attenuated the SSWD duration. Neither mifepristone nor tamoxifen blocked the effects of progesterone and 17 beta-estradiol, respectively, on SSWD duration in the AY model, suggesting that these two sex hormones are working in a manner independent of their intracellular receptors. These data suggest an important role for steroid hormones in the regulation and maintenance of AY-induced atypical absence seizures.

Treatment considerations: role of surgery

Patients with developmental disabilities, including retardation and global developmental delay, are not ideal candidates for epilepsy surgery. Because they have an increased likelihood of diffuse brain dysfunction and multifocal or generalized epileptogenic zones, there is an increased chance that a focal cortical resection will not confer a major improvement in their seizure frequency and severity. There is also increased concern that cortical resection will lead to increase in the patient's disability. However, by applying the basic principles of epilepsy surgery selection (i.e., convergence of multiple lines of localizing evidence) to this population, patients with a reasonable likelihood of good seizure control can be identified. Various means of localizing seizure onset are reviewed, including history and examination, electroencephalography, magnetic resonance imaging, position emission tomography, single-photon-emission tomography, and magnetoencephalography.

Pseudostatus epilepticus in childhood

Pseudostatus epilepticus in childhood has not been well reported in the literature. We describe the clinical presentation and management of a 9-year-old child with well-controlled epilepsy who presented in a prolonged period of pseudoseizures. Intensive care management over a number of weeks with multiple high-dose antiepileptic drugs, anesthesia, and ventilation at a tertiary care pediatric center was performed before the diagnosis of pseudostatus epilepticus was made. Initiation of family counseling and behavior therapy after diagnosis of the nonepileptic nature of the protracted paroxysmal events with video telemetry in our pediatric epilepsy unit was followed by remission. The patient reported herein illustrates the risks of iatrogenic morbidity that may result from a delay in the diagnosis of pseudoseizures and pseudostatus epilepticus in childhood.

Intractable pediatric epilepsy: vagal nerve stimulation and the ketogenic diet

The KD has been proven an effective alternative epilepsy treatment in children refractory to standard anticonvulsants. Children to be placed on the diet must be carefully selected, monitored, and followed. The diet is to be regarded as a strict medical regimen and requires a comprehensive medical team approach in concert with intensive parental involvement. With better understanding of the scientific principles underlying brain ketosis, we should be able to optimize the KD to achieve even better results.

Overtreatment in children with epilepsy

Children with epilepsy are at risk for overtreatment, defined as the use of an excessive number or amount of antiepiletic drugs (AEDs). While the extent of overtreatment of epilepsy in children is not known, there is increasing awareness that overtreatment with AEDs contributes to the morbidity associated with childhood epilepsy. Reasons for overtreatment include using AEDs in a child with seizures who does not require therapy, choosing an inappropriate AED for the seizure type or syndrome; treating non-epileptic behaviors as seizures, use of polytherapy when monotherapy would suffice, and inadequate therapeutic options. Despite the introduction of eight new AEDs in the United States during the last decade, many children continue to be treated with the older generation sedative AEDs. Numerous investigators have now demonstrated that sedative AEDs can be safely removed from the drug regimen of children with epilepsy with resultant improvement in behavior, alertness, and improved seizure control. However, the biggest obstacle to overtreatment is the lack of effective therapies for many of the childhood epileptic syndromes. Until there are more effective therapies developed it is highly likely that children will continue to be over-medicated on ineffective and detrimental AEDs.

The spectrum of nonepileptic events in children

Nonepileptic events (NEE) are common in children, and can be difficult to distinguish from epileptic events. Several strategies can assist in differentiation. The first is an age-based approach to the differential of commonly presenting EEs in neonates, infants, and adolescents. The next strategy is to identify key elements of the patient's history to narrow the possibilities, and third is a rational approach to ancillary testing. There are additional challenges to the diagnosis and evaluation of NEEs in patients with cognitive impairments or mental retardation (MR). Twenty to 25% of neurologically normal patients (34), and up to 60% of children with MR (35) referred for an evaluation of seizures, have NEE. In most instances, the clinical history leads to the diagnosis, and ancillary testing serves as confirmation. But in certain populations, neonates, children with concurrent epilepsy, children in whom pseudoseizures are suspected, and children with MR, early use of video-EEG telemetry is indicated to establish the diagnosis and avoid overtreatment with antiepileptic drugs (AEDs).

Symptom differences in children with absence seizures versus inattention

Objective. Differentiation between the diagnoses of absence seizures and Attention Deficit Hyperactivity Disorder (ADHD), Predominantly Inattentive Type, is frequently confounded by similarities in symptom presentation. The purpose of the present study was to determine symptoms that would distinguish between the disorders.Methods. Prior to diagnosis, parents of children with absence seizures (n=17) or ADHD, Predominantly Inattentive Type (n=26), were administered the Attention Deficit Disorder Evaluation Scale-Home Version (ADDES-HV). A statistical model was developed based on age, gender, race, and items from the Inattentive Scale of the ADDES-HV.Results. Two items, "does not complete homework" and "does not remain on task," correctly classified 40 of 43 children. Children with absence seizures were rated by their parents as having a low rate of occurrence of these behaviors.Conclusion. Lack of sustained attention distinguished between the groups and was much more prevalent in children with ADHD, Predominantly Inattentive Type.

Adolescent issues in epilepsy

Approximately one third of new cases of epilepsy have their onset before age 20 years. Many children will enter adolescence with epilepsy or have an onset of seizures during adolescence. Adolescence is a time of dramatic change in growth, hormonal, psychologic, and social situations. Seizure frequency, teenage pregnancy, driving, and alcohol and drug use often become major issues during the adolescent years. Furthermore, adolescents often have difficulty accepting the chronicity of epilepsy and complying with medications, which can result in physical injury and perceived or real obstacles to employment, thereby contributing to low morale. Both pediatricians and neurologists should be aware of adolescent issues in epilepsy.

Long-term EEG monitoring: a clinical approach to electrophysiology

Long-term electroencephalographic monitoring (LTM) is the capability of recording the EEG over long periods of time and not a specific duration. Prolonged EEG recording is used primarily for epilepsy monitoring, but LTM is also used in the intensive care unit, the operating room, and in the emergency department. The purpose of LTM is to expand the limited time sampling associated with shorter "routine" EEG recording. Audiovisual monitoring may also be used in conjunction with LTM to evaluate simultaneously a specific clinical behavior that may or may not be associated with EEG alteration. This is typically performed in a hospital setting for safety and ancillary testing purposes. LTM is used most frequently in the diagnosis and management of seizures and "spells," but has also gained wider application in the evaluation of sleep disorders, cerebrovascular disease, psychiatric conditions, and movement disorders. Computer-assisted LTM systems that process, analyze, compress, and store data digitally have become widely available in clinical practice both in the hospital as well as outside the hospital when the patient is ambulatory.

Psychiatric Manifestations of Epilepsy in Children and Adolescents

There is a high incidence of psychiatric difficulties in children and adolescents with epilepsy. The severity and range of the problems that exist are broad. In pseudoseizures, which may coexist with true epileptic seizures, the primary problem is psychiatric. Optimal management of children and adolescents with epilepsy involves a team approach, or at least a multidisciplinary effort, with close coordination between neurologist, primary health care provider, mental health professional, psychologist, educational specialist, and other providers (eg, physical therapist), depending on the associated features and particular case. Because many children and adolescents with epilepsy ultimately will be taking psychotropic medication and because of their psychiatric difficulties, a knowledge of interactions between anticonvulsants and psychotropic medication is crucial.

Diagnostic value of short duration outpatient video electroencephalographic monitoring

There is little published on the diagnostic value of short duration outpatient video electroencephalographic (VEEG) monitoring in children. The authors performed a prospective study on 37 patients (mean age = 10.4 years), with daily paroxysmal events who underwent short duration (mean = 3.2 hours) outpatient VEEG monitoring. Events were detected in 23 patients (62.2%), and a change in management as a result of outpatient VEEG monitoring was documented in 25 patients (67.6%). Despite the short duration of the outpatient VEEG in this study, the detection rate was comparable with the previously reported studies with longer duration monitoring. The authors found it convenient for the patient and less costly. The study demonstrated that short duration outpatient VEEG monitoring was able to differentiate between seizures and nonseizures in 11 patients (78.6%) and resulted in changing seizure classification in five patients (62.5%), and in selecting epilepsy surgery candidates in nine patients (60%). Short duration outpatient VEEG is useful as a diagnostic tool in patients with daily paroxysmal events, particularly in identifying nonepileptic events.

Staring spells in children: descriptive features distinguishing epileptic and nonepileptic events

OBJECTIVE

To identify questions sensitive and specific for staring spells of epileptic (absence seizures [AS]) or nonepileptic etiology to increase the yield of history taking.

STUDY DESIGN

A questionnaire was completed by parents of 40 children who presented with staring spells. Results from 17 children with AS and 23 with nonepileptic staring (NES) were compared.

RESULTS

Features with moderate sensitivity (43% to 56%) but high specificity (87% to 88%) for NES included preserved responsiveness to touch, lack of interruption of playing, and initial identification by a teacher or health professional. These features were more frequent in NES than in AS (P = .013, .016, .030). Body rocking occurred only in NES, but sensitivity was low (13%). Features with high specificity (91% to 100%) for AS included limb twitches, upward eye movements, and urinary incontinence; but sensitivities were low (13% to 35%).

CONCLUSION

In children with normal interictal electroencephalography findings and without neurologic disease, staring spells are most likely nonepileptic when parents report preserved responsiveness to touch, body rocking, or initial identification by a teacher or health professional without limb twitches, upward eye movements, interruption of play, or urinary incontinence. In these cases a diagnosis of NES may be confidently applied, with confirmation based on long-term follow-up.

Differential diagnosis of sleep disorders, non-epileptic attacks and epileptic seizures

Making a correct diagnosis in patients presenting with attack disorders is important. The clinical features of autosomal dominant nocturnal frontal lobe epilepsy and concussive seizures are reviewed. Recent work on the diagnosis and investigation of psychogenic non-epileptic attacks, drop attacks, falls, syncope and sleep disorders is discussed.