Illustrations
Figure 1
Video-EEG showing a GTCS in a patient with JME, manifesting with a myoclonic-tonic-clonic sequence. Note the sequential generalised myoclonus that occurs for three seconds just before the onset of the tonic phase and is associated with generalised spike-wave discharges. The timing of the double camera video shot is marked by a blue arrow on the trace. Eyes are open and gaze straight and up. Notice the open mouth and the flexed position of the body and limbs.
Figure 1
Figure 2
(Continued from Figure 1 ). Only 4-5 seconds later (blue arrow), and still within the tonic phase, the posture changes. The semiflexed arms slowly lower to soon become extended, rotated inwards with flexed wrists, while the body is going into extension and the lower limbs are already extended, inward rotating with both feet in plantar flexion. Eyes and mouth remain open .
Figure 2
Figure 3
Grossly asymmetrical posture early into the tonic phase of a GTCS (yellow arrow). The patient suffers from IGE with GTCS alone and the seizure occurs during photic stimulation. Note the generalised photoparoxysmal response that continues as GSWD for 5-6 seconds during which the patient is unresponsive. This gives way to generalised myoclonus associated with polyspike-wave discharges for another three seconds before the onset of the tonic phase. This sequence is essentially a “generalised absence-myoclonic-tonic-clonic seizure”.
Figure 3
Figure 4
This video-EEG shows the onset of a tonic-clonic seizure (the timing of the screenshot is marked on the trace by a green arrow). With the exception of a rapid head version to the right (the patient was watching TV straight ahead), the clinical onset appears generalised: her eyes are open and stare ahead, her mouth is open and her arms are in symmetrical tonic flexion. The EEG onset is almost bilateral synchronous. The patient has only generalised convulsive seizures, but a diagnosis of IGE is rejected because continuous EEG over 70 hours did not show any generalised spike-wave discharge; instead, it demonstrated bilateral independent interictal spikes over the temporal and frontal areas.
Figure 4
Figure 5
Lateralised de novo automatism during a typical absence in an eight-year-old boy with childhood absence epilepsy (CAE). The child raises his right arm and rubs his face (the timing of the screenshot is marked on the trace with a blue arrow). Calibration: vertical line=100 μV; horizontal line=1 sec.
Figure 5
Figure 6
Video-EEG showing hyperventilation with breath counting. Note the hesitation in pronouncing the correct number that is apparently caused by the brief (hardly 1.5-sec long) generalised spike-and-wave discharge (from Koutroumanidis et al . [2017]).
Figure 6
Figure 7
Myoclonic seizure in a 22-year-old man with drug-naïve JME. Note the abduction of both arms and legs and their flexion at the elbows, hips and knees, as well as the slight extension of the neck (from Koutroumanidis et al . [2017]).
Figure 7
Figure 8
Myoclonic atonic seizure in a patient with JME. Note the muscle artefact that is associated with the spike component of the spike-wave complex and reflects the jerk, and the brief loss of tone that follows, associated with the slow-wave component. The patient keeps his arms straight in front, maintaining a baseline muscle tone.
Figure 8
Tableaux
Auteurs
1 Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey
2 Service de Neurologie Pédiatrique, Hôpital Robert Debré, Paris, France
3 Université de Paris, INSERM U1141, F-75019, Paris, France
4 Clinic for Children and Adolescents, Epilepsy Center Kork, Tuberous Sclerosis Center, Kehl-Kork, Germany
5 Medical Faculty of the University of Freiburg, University of Freiburg, Germany
6 Danish Epilepsy Center, Filadelfia, University of Copenhagen, Dianalund, Denmark
7 Guy's and St Thomas’ NHS Foundation Trust, London, UK
* Correspondence: Ayse Deniz Elmali
Istanbul University,
Istanbul Faculty of Medicine,
Department of Neurology,
Istanbul, Turkey
Idiopathic or genetic generalized epilepsies (IGE) constitute an electroclinically well-defined group that accounts for almost one third of all people with epilepsy. They consist of four well-established syndromes and some other rarer phenotypes. The main four IGEs are juvenile myoclonic epilepsy, childhood absence epilepsy, juvenile absence epilepsy and IGE with generalized tonic-clonic seizures alone. There are three main seizure types in IGE, namely generalized tonic-clonic seizures, typical absences and myoclonic seizures, occurring either alone or in any combination. Diagnosing IGEs requires a multidimensional approach. The diagnostic process begins with a thorough medical history with a specific focus on seizure types, age at onset, timing and triggers. Comorbidities and family history should be questioned comprehensively. The EEG can provide valuable information for the diagnosis, including specific IGE syndromes, and therefore contribute to their optimal pharmacological treatment and management.
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