1Department of Pediatric Neurology, Epilepsy Monitoring Unit (EMU), Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Iran
2Skull Base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Iran
3Pediatric Neurology Research Center, Mofid Children Hospital, Shahid Beheshti University of Medical Sciences, Iran
4Master of Midwifery, Skull Base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Iran
Submission: February 08, 2021;Published: March 10, 2021
*Corresponding author: Alireza Rezayi, Department of Pediatric Neurology, Epilepsy Monitoring Unit (EMU), Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Iran Loghman hakim hospital, kamali St, South Karghar, Tehran, Iran
How to cite this article: Mahmoud M, Alireza R, Mahmoudreza A, Gholmamreza Z, Reza Shervin B, et al. Diagnostic Value of Long-Term Video-EEG
0096 Monitoring in Children with Refractory Absence Epilepsy. Open Access J Neurol Neurosurg 2021; 14(5): 555900 DOI: 10.19080/OAJNN.2021.14.555900.
Objective: Absence seizures are commonly seen in a few pediatric genetic generalized epilepsy syndromes including childhood and juvenile absence epilepsies (CAE, JAE), absence with eyelid myoclonias (EMA–EM or Jeavons syndrome), atypical absence seizures as a component of Lenox-Gastaut Syndrome (LGS). Here, we report the clinical and electroencephalographic features of patients with refractory absence epilepsy.
Methods: Twenty-five children referred with refractory absence epilepsy were retrospectively enrolled from more than 1100. We have used tow digital VEEG instruments with the international 10-20 system and standard montages. Patients and their Clinical history and VEEG recordings were studied to find data including age, sex, seizure types, electrographic features, and family history of epilepsy.
Results: According to exclusion criteria we had 16 patients that 4 of them had CAE and 2 of them had atypical absence epilepsy (AAE) and 10 had EMA–EM. Focal interictal SWD (spike-wave discharges) was seen in both atypical absence patients (100%), 2 from 4(50%) patients of CAE, and 7 of 10(70%) patients EMA–EM. Focal ictal onset was seen in 1 of 4 (25%) of CAE patients and one of 10(10%) of EMA-EM patients. All EMA–EM and atypical absence patients were diagnosed after long-term EEG-monitoring (LTM)and they had other diagnoses before LTM.
Significance: EMA–EM should be considered in refractory childhood absence epilepsy and video-EEG recording is a useful method if EMA-EM is suspected. Focal interictal and ictal onset might be recorded in generalized epilepsy especially in CAE which the importance of this issue should be considered in future investigations.
Absence seizures, are characterized by frequent sudden discontinuation of activities, brief staring episodes, with loss of awareness and abrupt recovery are commonly seen in a few pediatric generalized epilepsy syndromes including childhood and juvenile absence epilepsies (CAE, JAE), and juvenile myoclonic epilepsy (JME), absence with eyelid myoclonias (EMA–EM or Jeavons syndrome), epilepsy with myoclonic-atonic seizures (Doose Syndrome) and Lenox-Gastaut Syndrome (LGS). The EEG feature in CAE and JAE patients usually demonstrates generalized Spike-Wave Discharges (SWD) averaging 3HZ frequency with the normal background. This type of absence seizure respond to specific antiepileptic drugs including ethosuximide and valproic acid, however some patients with absence seizures may having drug-resistant epilepsy by International League Against Epilepsy (ILAE) definition . failure rate is about 53% and 58% for ethosuximide and valproic acid, after 16 weeks of therapy . Atypical Absence Seizures (AAS) have slower SWD on EEG (1.5-2.5 HZ), Interictal Epileptic Discharges (IEDs) usually have multifocal epileptiform features. This type of seizure begins before 5 years of age and sometimes associated with diminished postural tone,
tonic, or myoclonic activity. AAS often diagnosed as a component
of LGS . Eyelid myoclonia with or without absences (EMA-EM)
is recognized as a seizure type by the International League Against
Epilepsy (ILAE). Idiopathic EMA-EM (or JS) has been described
as a long-lasting condition beginning in childhood and having a
higher incidence in girls [4,5]. The EEG presentation of JS has been
described as focal occipital or frontal predominant SWD in both
interictal and ictal stages [6,7].
To diagnose this syndrome presence of the following triad is
a. Eyelid myoclonia,
c. Eye-closure sensitivity, or fixation off sensitivity (EEG
paroxysm or absence seizure within 0.5 to 4 second after eye
closure). All subjects of EMA-EM are normal at disease onset and
it is a life-long condition and can be difficult to treat and should be
considered in the patients with drug-resistant absence epilepsy
. Brief 20–30 min standard EEG recording with or without
video is not useful for differentiating patients with refractory
absence epilepsy. Misdiagnosis of epilepsy subtypes can lead to
inappropriate treatment, or no treatment, with considerable
associated costs in health and economic terms [8,9]. Clinicians
should consider long term EEG- monitoring to provide answers in
such cases as well as ILAE recommendation .
The objective of this study is to review the clinical and EEG
features of patients with drug-resistant absence epilepsy to
observe epilepsy syndromes featuring absence seizures.
a. Twenty-five children referred with refractory absence
epilepsy were retrospectively enrolled from more than 1100
VEEG recordings monitored in our hospital between August 2014
and August 2019. Inclusion criteria
b. Absence epilepsy, Childhood Absence Epilepsy (CAE), or
Juvenile Absence Epilepsy (JAE) were identified by history.
c. Normal findings on neurological examination,
d. Normal epilepsy protocol magnetic resonance imaging
e. Normal metabolic screening tests
f. Normal developmental status before seizure beginning
6) Normal CSF analysis including CSF glucose for GLUT1-
a. Subjects with focal epilepsy syndromes for instance
frontal lobe epilepsy or temporal lobe epilepsy that referred to as
b. Subjects with LGS that they had atypical absence epilepsy.
According to exclusion criteria we had had only 16 patients that
4 of them had CAE and 2 of them had Atypical Absence Epilepsy
(AAE) and 10 had EMA–EM.
VEEG monitoring was performed by two Nihon Kohden
digital video-EEG-1100 K instruments for approximately 24-72
hours, in both awake and asleep states. Electrodes were placed
on the scalp according to the international 10-20 system, with
standard montages including bipolar and referential montages
with some extra leads and surface electromyography to record the
activities of the deltoid muscle. At wakefulness, hyperventilation,
open-close eyes test, and IPS were performed in all patients. all
VEEG reviewed by authors for the following aspects: background
activity, sleep architecture, normal variants, artifacts, PPR (photo
paroxysmal response), PCR (Photo Convulsive Response), HV
(hyperventilation) response, IED (Interictal Epileptic Discharge)
during asleep and wakefulness and ictal electrographic features.
Clinical history and VEEG recordings were studied to find
data including age, sex, age at seizure onset, seizure types,
electrographic features, and family history of epilepsy as well as
treatments. Psychomotor development was evaluated clinically in
all patients. This study was approved by the Ethical Committee
of children’s medical center, and written informed agreements
were attained from parents of the children. All investigations were
performed with related guidelines. All data were analyzed by the
Out of 1100 patients that referred from epilepsy clinic of
children medical center for long term video EEG monitoring
(LTM) 25 patients had refractory staring spells but 16 patients
met inclusion criteria. Then we analyzed the LTM of 16 patients.
The mean age was 7yr (2m to 16y7m). The mean age of seizure
onset was 2.5(2m to7). 8 patients were female and 8 were male.
4 patients had CAE, 2 had atypical absence and 10 of them had
EMA–EM. There were male predominate among the EMA–EM
patients and female predominates in the CAE and atypical absence
group. Both atypical absences had the previous history of GTCs,
but only two of 10 EMA–EM had pure staring and most of them
had mixed type of seizures. Background activity was normal in
the group of CAE and atypical absence patients but in 3 patients
of EMA–EM was slow regarding the patient’s age. 10 patients
(62.5%) had focal interictal SWD. Focal interictal SWD was seen
in both atypical absence patients (100%), 2 from 4(50%) patients
of CAE, and 7 of 10(70%) patients EMA–EM. The most common
focal interictal was seen in the frontal region (80%) commonly in
the EMA–EM and multifocality was seen in one of atypical absence
patient. Ictal focal SWD onset was seen in 3(18.75%) which has
happened in one patient (25%) of CAE and 2 (20%) patients of
EMA–EM. PPR and PCR were seen in all patients of CAE and EMA–
EM but it was not seen in atypical absence patients. AII EMA–EM
and atypical absence patients were diagnosed after LTM and they had other diagnoses before LTM. CAE patients did not get any
medication during the LTM but some patients in EMA–EM and
atypical absence used their medication with minimum dosage
due to the previous history of GTCs. The family history of epilepsy
and febrile seizure was seen commonly in the EMA–EM patients.
Fixation off sensitivity or eye closure sensitivity (ECS) is positive
in all cases of EMA–EM patients.
This study examines the diagnostic value of long-term EEGmonitoring
in patients who do not respond to common treatment
of absence epilepsy. The most common diagnosis between children
with refractory absence epilepsy is EMA–EM (Jeavons syndrome).
This is an important point because they had other diagnoses
before LTM. The following reasons may be responsible for this
issue. First, conventional standard EEG recording in our country
is recorded by undertrained EEG technician who does not detect
fixation off sensitivity(Figure 1&2), characterized by the absence
seizure or EEG paroxysmal activity within 0.5 to 4 second after eye
closure and we usually miss it in the conventional EEG recording
but it could be recorded and determined by LTM. Secondly,
standard EEG does not have synchronized video recording and as
a consequence, minor staring or absence seizures after eye closure
could be overlooked. We recommend, therefore, that standard
EEG in tertiary centers should have the video recording and EEG
technicians should be selected from well-trained technicians.
Thirdly under-diagnosis of Jeavons syndrome is common in our
country because this condition is very rare and child neurologists
do not have enough information about it. This finding is compatible
with the survey on Jeavons syndrome in china that conducted by
. The majority of Jeavons syndrome is male that is compatible
with Chinese patients but not supported by other studies. It could
be due to patients’ selection because our center is a referral center
or could be due to different genetic characteristics between the
western and eastern populations. Two types of IEDs are reported
in Jeavons syndrome; those which are more frontal predominant
and those which are occipital predominant. Our study shows a
case with both of them and some cases with parieto-occipital or
temporo-parietal predominant SWD during tracing but frontal
predominant IEDs are most commonly seen just like previous
studies . Ictal spiky posterior alpha was reported in previous
studies which were concordant with EEG findings of one of our
cases . JS is believed to have a genetic etiology, and, in our
study, 90 percent of JS has a positive history of epilepsy or febrile
seizure but in CAE patient only one patient had a family history of
febrile seizure. It can be understood the genetic basis of CAE and
JS is totally different. This point is mentioned in previous studies
 (Figure 3&4).
In the majority of JS background activity is normal for the
patient’s age but in three (30%) is slower than normal for age.
All of these patients had intellectual disabilities. This finding is
similar to other studies  (Figure 4A, 4B). Focal interictal spikes
in JAE patients is common (50%) and frontocentral predominant
SWD also is common in the CAE patients (Focal and generalized
SWD) . one of the most interesting points in our study is a case
of CAE with ictal focal onset from right posterior which according
to our knowledge has not reported so. In this patient’s epilepsy
protocol, MRI was normal and there was not any focal abnormality in the right posterior regions (Figure 5,6). This issue should be
observed carefully in future investigations about CAE. Clinically,
AAE is often a component of Lennox–Gastaut syndrome associated
with mental retardation and behavioral problems, for instance,
inattention hyperactivity, aggressiveness, and autistic features
. in the present study we detected two patients with clinical
and electrographic findings close to AAE without any intellectual
disabilities and also, they had normal development and behavior.
These patients had normal Brain MRI but focal IEDs were seen
which was bifrontal in one and multifocal in another one. Both
of them had a positive family history of epilepsy. It could be due
to distinct genetic susceptibility in AAE patients. This issue needs
further investigations to report the AAE as a distinct epilepsy
syndrome. In conclusion, JS or EMA–EM should be considered in
refractory childhood absence epilepsy and video-EEG recording
is a useful method if EMA-EM is suspected. Focal ictal onset could
be recorded in generalized epilepsies which should be considered
in future investigations. Pure Atypical Absence Epilepsy (AAE)
without LGS could be added as a distinct epilepsy syndrome in