Annexe A Appendix 1. Legends of supplementary figures
Figure 2.01. Focal non-localizing 3-Hz spike-wave discharge during light sleep (Stage 2) in a child with CAE. Note the incomplete expression of the 3-Hz GSWD and the normal background.
Figure 2.02. Non-localizing focal spike-wave discharge over the left frontal area in a child with CAE. This child also had similar focal discharges over the right frontal area. Note the normal background that distinguishes this focal spike-wave from a stable epileptogenic focus that relates to a structural change (symptomatic), as in figure 2.03, and also the lack of spatial or temporal associations with the ensuing GSWD (see diagnostic constraints for secondary bilateral synchrony below) (from Koutroumanidis et al. ).
Figure 2.03. The patient hesitates after reciting the number “5”, but is able to continue counting with the correct numerical sequence. Note that the responsible GSWD is briefer than two seconds.
Figure 2.04. Focal regular 3-Hz spike-wave discharge over the right frontal area in a child with a history of “blank spells” and left focal motor seizures. Note the similarities with the discharge in figure 2.01, but also the regional background disturbance which consists of irregular slow rhythms and sharp waves (arrow) maximal over the right central area. Brain MRI showed a large subependymal heterotopia on the right associated with cortical thickening.
Figure 2.05. SBS: Almost continuous pseudo-rhythmic theta and delta activity with intermixed sharp waves over the right anterior temporal inferior frontal area, leading to a high voltage, apparently generalized polyspikes-and-wave discharge (temporal constraint). Note the different morphology of the “triggering” focal ED compared to that of the SBS-GSWD.
Figure 2.06. SBS in a child with atypical absences and generalized convulsions: continuous sharp theta-fast delta activity over the right frontal area (arrows), leading to a high-voltage, apparently generalized 2.5-Hz spike-and-wave discharge (temporal constraint). As in figure 2.04, the morphology of the “triggering” focal ED is different to that of the SBS-GSWD.
Figure 2.07. A 22-year-old woman referred for “absences” that last for 1-2 mins, followed by some confusion and generalized convulsions. (A) Left temporal spikes during wakefulness; (B) left temporal sharp and slow waves during Stage 2 sleep, giving way to apparently generalized polyspike-wave discharges that cause epileptic arousal. The MRI scan showed left temporal cortical dysplasia involving the mesial neocortex and the temporal pole.
Figure 2.08. Long, 23-second GSWD of bilateral and synchronous onset, associated with motionless staring during a positron emission tomography (PET) scan. There are no “triggering” focal ED leading to the GSWD (the criteria of spatial and temporal constraints), but SBS can be assumed from the faster activities over the left temporal-parietal areas compared to the right in the first four seconds of the GSWD. The PET scan revealed left frontal hypometabolism (from Barrington et al., ).
Figure 3.01. Focal spike-wave discharge over the right frontal area without associated regional background disturbance (left trace) and right frontal onset of a 3-Hz GSWD of a typical absence (right trace) in a girl with CAE (video-EEG; 1998). Such topographic correlation does not meet the diagnostic EEG criteria of SBS; the locations of both the focal spike-wave and the onset of GSWD switched sides during the recording (see spatial constraint for SBS), while their morphology is similar to that of the “bi-synchronous paroxysm”, the GSWD of the typical absence and the lead-in is short (see temporal constraint for SBS). The clinical picture was typical for CAE without features to suspect SBS. TA remitted at the age of 11 years and she has remained completely seizure-free and off antiepileptic treatment to date.
Figure 3.02. Complex TA during hyperventilation with breath counting in a girl with CAE (video-EEG): she stops over breathing and counting in the second of the GSWD (grey vertical arrow) and then engages in perioral automatisms until the end. The absence appears to end by hand clapping (white arrow). Note the bilateral OIRDA that becomes “spiky” before the onset of the GSWD (black arrow).
Figure 3.03. Focal spike-wave discharges during Stage 2 of sleep: (A) bi-frontal with the right side leading and skipping the mid-frontal position (Fz); (B) bi-occipital; (C) bilateral synchronous discharge, followed by a run of spike-wave complexes over the left frontal area and (D) bi-occipital (as in [B]), this time “triggering” a generalized polyspike-wave discharge.
Figure 3.04. Complex TA in a child with CAE (de novo bilateral hand automatisms on video-EEG). Note the asymmetric (in terms of voltage) onset of the GSWD with a prominent polyspike component within the first 500 ms over the right frontal areas. Note also the bilateral activation of the temporalis muscle, indicated by muscle artefact over the temporal areas.
Figure 3.05. Same girl as in figure 3.04 following hyperventilation. She stopped ongoing motor activities (moving her hands) at onset and stares. She then swallows (vertical arrow) and presents hand automatisms during the last third of the absence. Note the bilateral frontal onset (more pronounced over the left frontal on this occasion) and the late occurrence of the manual automatisms.
Figure 3.06. Hyperventilation with breath counting in a boy with CAE (video-EEG): he swallows shortly after onset (vertical grey arrow) and 4 seconds later whistles for about 5 seconds; a rare de novo automatism (horizontal grey arrow). Note the temporary discontinuation of the GSWD, caused by noises made by the EEG technologist (white arrow). The GSWD resumed for a while until its spontaneous termination. Also, note a focal spike-wave discharge over the left frontal area 2 seconds before the absence started (black arrow).
Figure 3.07. Spontaneous TA with lateralized de novo automatisms 6 seconds from onset (grey arrow). The black arrow indicates the exact time of the video screen shot. Note the fast frequency and asymmetry of the GSWD during the initial 2 seconds (opening phase) before it becomes regular at 3-4 Hz.
Figure 3.08. Video-EEG of a 50-year-old woman with JAE and persisting absences (but not GTCS). Note the polyspike component in both discharges, which are subclinical.
Figure 3.09. Full EEG montage polysomnography of the same patient as in figure 3.08. Note the single spike/polyspike-wave discharges during Stage 3 (timing shown by the red arrow in the hypnogram), which do not appear to cause any EEG or autonomic arousal. The top two channels record eye movements; montage: longitudinal bipolar (double banana); 20 sec per page.
Figure 3.10. Full montage polysomnography of a 45-year-old woman with JAE and persisting absences and GTCS despite treatment with VPA and LTG. GSWD and bursts of polyspike-wave occurred during all periods of REM sleep (red arrows in top right panels in both [A] and [B] showing different REM phases). Montage: double banana; (A) 60 seconds per page; (B) 30 sec per page. The top two channels record eye movements; other channels have been omitted.
Figure 3.11. Typical absence during hyperventilation with breath counting in a 46-year-old man with JAE; he started having absences at the age of 11 years and GTCS in his early teens. He seems to maintain a minimum level of awareness during the absence as he restarted hyperventilation after being prompted by the EEG technologist (with some delay), and at the end of the seizure he appears to recall the last number he had pronounced when the absence occurred.
Figure 3.12. Light sleep of the patient in figure 3.11. Note on the left part of the trace the brevity of the regular GSWD that have slowed down in frequency compared to the absences while awake (figure 3.11), the emergence of polyspikes, and the “degradation” into solitary brief bursts of GSWD in the right half of the trace.
Figure 3.13. Long absence in an untreated 18-year-old woman with JAE. The patient remained completely unresponsive throughout the seizure that lasted 25 seconds (grey arrow). She had five long absences during this video recording, with the longest lasting 45 seconds (black arrow).
Figure 3.14. Video-EEG of the patient in figures 3.13, showing a variety of de novo motor automatisms.
Figure 3.15. Transition from an absence seizure to generalized tonic-clonic seizure (modified from Panayiotopoulos ).
Figure 3.16. This brief diffuse burst of polyspikes-fast rhythm activity that precedes an otherwise regular 3-Hz GSWD is amongst the atypical JAE EEG features (see text).
Figure 3.17. Massive MS associated with generalized polyspike-wave discharge in a 22-year-old patient 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. The patient hiccups loudly and his eyes open appearing blank for a split second.
Figure 3.18. Onset of a generalized clonic-tonic-clonic seizure in the patient presented in figure 3.17 (same recording). A cluster of three massive MS precedes the onset of the tonic phase of the convulsion.
Figure 3.19. Phantom absence in a 32-year-old woman with JME: a 3.5-second GSWD is associated with hesitation in sequential breath counting; the patient still continues with the correct number but slightly later (at the time marked with the red arrow compared to that marked with the grey arrow). In all probability, she would have recalled a number or a word given by the EEG technologist during the GSWD (as she did on other occasions in that recording).
Figure 3.20. Video-EEG of a 28-year-old woman with resistant JME. (A) Fast GSWD pattern at 4-5 Hz. The arrow marks the time when a number was given by the EEG technologist, which the patient was perfectly able to recall. (B) Polyspike-and-wave discharge on eye closure a few seconds later (A). Note the slight right frontal predominance. (C) Generalized polyspike-wave during light slow sleep, again with right frontal emphasis.
Figure 3.21. SD video-EEG of a 26-year-old woman with JME; she had visual seizures at the age of 3.5 years, which stopped a few years later. She then suffered a GTCS on awakening at 11 years of age, and continued with early morning MS and brief absences soon thereafter. (A) Brief GSWD in early drowsiness, showing right posterior “onset”. (B) Focal right occipital and left frontal spikes. (C) GSWD during light slow sleep, this time with left frontal “onset”. (D) Right frontal spike-wave discharges during light slow sleep.
Figure 3.22. (A) Classic 3-Hz GSWD during wakefulness in a 34-year-old woman with JME. Note the right frontal emphasis of the GSWD at onset. (B) Focal right frontal spike-wave in the same patient. (C) GSWD during Stage 2 of sleep in the same patient. Note the left frontal emphasis of the discharge on this occasion. (D) Focal, non-localizing spikes in a 37-year-old man with JME.
Figure 3.23. SD video-EEG of a 50-year-old woman with JME. (A) GSWD during wakefulness showing typical JME fragmentations; the GSWD on the right side of (A) is independent, separated from the fragmented GSWD by clear normal background rhythms. (B) Fast brief GSWD during early drowsiness. (C) Brief spike and polyspike-wave discharges during Stage 2 sleep (same patient).
Figure 3.24. Generalized polyspike-wave discharge in a 27-year-old man with JME, which occurs following a spontaneous arousal. Note the fast rhythms and the bursts of EMG activity that immediately precede and follow the epileptic discharge.
Figure 3.25. Full EEG montage video polysomnography of the patient presented in figure 3.22D. Note the occurrence of GSWD during REM (shown by the white arrow in the hypnogram).
Figure 3.26. Full EEG montage video polysomnography of a 19-year-old man with JME. Repetitive GSWD during “sleep” (A) evolving into myoclonic status (B); note the spontaneous high-voltage delta arousal from Stage 3 of sleep (blue arrow), followed by the appearance of fast rhythms (green arrow) that precedes the first GSWD. Therefore, despite the apparent occurrence of the MS out of sleep (as a bed-partner would indicate), MS actually occurred post arousal. Also, note that despite their rhythmicity, GSWD are not at 3 Hz but consist of discrete discharges with clear biological activity between them.
Figure 3.27. Video-EEG after partial sleep deprivation in a 36-year-old woman with GTCS-a. (A) Light sleep; (B, C) hyperventilation (HV) with breath counting. During HV, GSWD were activated and became longer (2 sec in [B] and 2.5 sec in [C]) but were not associated with any hesitation or mistake in breath counting (see also box 2). This patient previously had a normal routine EEG during wakefulness, including HV.
Figure 3.28. Video-EEG after partial sleep deprivation in a 41-year-old man with GTCS-a. (A) Brief GSWD during wakefulness; (B) incompletely generalized GSWD during light sleep. Note the right frontal emphasis; (C) focal non-localizing spike-wave discharge over the right superior frontal (F4) electrode; (D) focal non-localizing spike-wave discharge, this time over the left superior frontal electrode (F3) during light sleep. The term “non-localizing” expresses the topographic versatility of the GSWD to “fragment” into focal spike-wave discharges in GGE/IGE (see also introduction on GGE/IGE and SBS).
Figure 3.29. Generalized polyspikes-and-wave discharge during tonic REM sleep in a 45-year-old man with valproate-resistant GTCS-a. Note the absence of rapid eye movements from the top two channels in the left half of the trace and the appearance of phasic REM in the right half of the trace.
Figure 3.30. Breath counting during HV on awakening in a 35-year-old woman with GTCS-a. Sleep had been achieved after partial sleep deprivation the night before this video-EEG. Sequential counting (arrows) showed no mistakes or hesitations.
Figure 3.31. SD video-EEG of a 31-year-old man with six GTCS since the age of 19 years and two episodes of absence status within a week that both ended in GTCS at the age of 26 when he came under our care. He had no history of absences or myoclonic seizures. In this first SDEEG, he had a number of phantom absences after awakening, which manifested with hesitations and mistakes in serial breath counting. In this example, note the brief duration of the GSWD which occurred within the first few seconds of HV, and resulted in clear hesitation (“10” would be expected around the time point indicated by the green arrow). Follow-up EEGs showed the occasional GSWD but no phantom absences. On valproate acid 300 mg bd, he has remained without any seizures during the six years of follow-up.
Figure 3.32. SDEEG of a 35-year-old man with a single episode of absence status (AS) that ended in GTCS at age 26 and a second GTCS a month later. HV after awakening with breath counting activated a number of brief GSWD that were associated with cessation of breathing but no errors in counting. He had no past history of previous absences, myoclonic seizures or prolonged dyscognitive episodes. On valproate acid, he has remained free of GTCS and episodes of AS for nine years, although follow-up EEGs have shown ongoing GSWD and a few PA, but never overt absences. He also reported no absences during these nine years.
Figure 3.33. Video-EEG of a 64-year-old woman with about 35 GTCS since the age of 30. This patient is in AS with moderate clouding of consciousness and is fully ambulatory. The AS was successfully treated with valproate acid and a follow-up video-EEG showed PA. The patient had been treated with carbamazepine for a number of years; she became seizure-free when carbamazepine was replaced by valproate acid.
Figure 3.34. Activation of brief GSWD by HV in E-PA. The patient (same as in figure 3.32) counts his breaths. The discharge on the left is subclinical while that on the right corresponds to a phantom absence.
Figure 3.35. (A) Long GSWD in early drowsiness in a 30-year-old woman with three GTCS, the first at age 18. She had no history of absences, myoclonic seizures or episodes of confusion or difficulty in concentration to suggest AS. (B) Incomplete GSWD on awakening prior to starting HV (same montage and calibration as in [A]).
Figure 3.36. A long, ∼7-second GSWD during HV, performed after awakening in the patient in figure 3.35. The technologist calls loudly and clearly the number “four”, which the patient recalled and repeated after the end of the GSWD. She showed no clear behavioural change during the GSWD. During this HV session, the patient was not counting her breaths.
Figure 3.37. Phantom absence in the same patient as in figures 3.35 and 3.36. In this second HV session, the patient counts her breaths aloud (arrows). Note the hesitation that is apparently due to the second GSWD, which is shorter than the GSWD in figure 3.36. This was the only behavioural change, and the patient continued counting correctly. One would have expected similar hesitation during the GSWD of figure 3.36 had the patient been counting her breaths on that occasion.
Figure 3.38. HV with breath counting in a 27-year-old woman with three GTCS during a period of seven years. She had no history of absences, myoclonic jerks or long dyscognitive periods suggestive of absence status (AS). Note the hesitation in breath counting before repeating the same number, caused by a GSWD of less than 2 seconds (phantom absence). She had no overt absences, while previous EEGs elsewhere had revealed subclinical 3-Hz GSWD.
Figure 3.39. Home video telemetry of a 50-year-old woman with monthly episodes of AS, probably since her early 20s. She had infrequent absences as a child, and four GTCS in total, the first at age 17 and three within one month at age 47. Note that the pattern is discontinuous and arrhythmic. She was able to perform all her usual activities at home (here she irons), including socializing with relatives in the evening, apparently without any undue behavioural changes. However, on other occasions, she reported mild difficulty in maintaining concentration.
Figure 3.40. Absence status ending in GTCS in a 39-year-old woman with absence status epilepsy manifesting with recurrent monthly confusional episodes lasting 3-24 hours. Left trace: ictal EEG showing continuous generalized spike-wave discharges at 2 Hz while the patient shows a moderate confusional state with slurred speech and temporo-spatial disorientation. Right trace: after 88 min of recording, a generalized tonic-clonic seizure occurs starting with a recruiting 7-Hz spike activity that interrupts the AS. The time between the two traces is 23 minutes.
Figure 3.41. Video-EEG of a 63-year-old man with a history of at least 10 prolonged episodes of reduced awareness since the age of 16 years, some of which ended in a GTCS. Left trace: a subclinical GSWD during HV with breath counting. The patient did not hesitate or make any counting error, therefore this is not a PA. Right trace: incomplete GSWD during light slow sleep.
Figure 3.42. Video-EEG of the same patient as in figure 3.41, two years later. GSWD are activated during HV, again without any mistakes or hesitations during breath counting (in two HV sessions).
Figure 3.43. SDEEG of the patient in figure 3.39 (different recording). Brief GSWD during Stage 1 of sleep are followed by a brief delta hypersynchrony and emergence of alpha activity (epileptic arousal).
Figure 3.44. Video-EEG showing AS in a 59-year-old woman with frequent attendances to the emergency department for episodes of prolonged confusion. Throughout this EEG, performed several hours after the onset of AS, she remained in a sitting position with her eyes open and was unresponsive to commands, though she seemed vaguely aware of the presence of people around her. She had some semi-purposeful movements and at times slight shaking of the hands and feet. Note the arrhythmic pattern of the generalized discharge, the frequency of which ranges from ≤2 Hz to 4 Hz.
Figure 3.45. Video-EEG of a 29-year-old woman with a history of a single GTCS at age 23, terminating a two-hour period of severely clouded consciousness. She had several episodes of difficulty in concentration since then that became almost weekly over the three months preceding this recording. She had no history of absences or myoclonic seizures during her childhood or adolescence. Note the brief GSWD that are activated during HV, however, these did not disrupt correct and timely sequential breath counting.
Figure 3.46. Absence status (AS) in a 30-year-old woman with absences since the age of seven years and GTCS since her teens (three-day long home video telemetry). The test recorded a small number of mild fleeting absences and a 34-minute long episode of AS that was not associated with clinically overt behavioural changes or symptoms that would prompt her to activate the event marker. During the AS, she had a sensible conversation with her mother without either of them signalling that something was not right. Consciousness was reportedly more affected in other episodes of AS with the patient not being able to finish sentences, giving the wrong answers to simple questions, perseverating in her speech, and feeling “wobbly” with her body twitching and eyes “wondering off”. (A) Onset of AS at 7.16 am; (B-C) at 7.41 am; (D) spontaneous termination of AS at 7.49 am ([B] and [C]) are continuous).
Figure 3.47.De novo absence status in a 72-year-old woman after benzodiazepine withdrawal. IV levetiracetam resulted in clinical and EEG normalization. She had no past history of epileptic seizures, including prolonged states of confusion. She had no further symptoms and her follow-up EEG six months later was normal. Note that the continuous GSWD has maximal amplitude over the anterior areas and its frequency is 2.5 Hz (at the lower end of the GGE/IGE range).
Figure 3.48.De novo absence status of late onset in a 83-year-old woman after non-ketotic hyperglycaemia and multiple drug withdrawal. (A) Continuous, frontally accentuated 1.5-2-Hz GPSWD. (B) IV 1-mg clonazepam produces perfect EEG normalization and a clear clinical improvement.
Figure 3.49. This 81-year-old woman with no previous neurological problem had a false diagnosis of dnASLO with a progressive confusion shortly after she was treated for a systemic infection with IV cefepime. EEG shows diffuse 2.5-3-Hz triphasic sharp waves. IV 1-mg clonazepam, as well as various IV antiepileptic drug trials (IV fosphenytoin and IV levetiracetam), had no effect. Complete resolution occurred three days after cefepime discontinuation.
Figure 3.50. Semi-continuous rhythmic triphasic waves at around 2 Hz in a patient with hepatic encephalopathy.
Figure 3.51. Diffuse rhythmic triphasic waves at 1.5-2 Hz in a patient with hypoxic encephalopathy.
Figure 3.52. Video-EEG showing absence status in a 34-year-old man with eyelid myoclonia with absences (from Agathonikou et al. ).
Figure 3.53. Video-EEG of the patient in figure 3.52. The typical absence on the left half of the trace occurs when eyes are open and is associated with regular 2.7-Hz GSWD. Note the eye closure-induced GSWD on the right end of the trace, which is associated with eyelid myoclonia.
Figure 3.54. Video-EEG of a 43-year-old woman with eyelid myoclonia with absences, showing interictal eye closure abnormalities with posterior emphasis in the first discharge on the left, and posterior “lead-in” of the GSWD on the right, which is of maximal voltage over the frontal areas.
Figure 3.55. Video-EEG of the patient in figure 3.52, showing interictal, frontally predominant GSWD in brief distinctive bursts (A) and repetitive/confluent GSWD.
Figure 3.56. Video-EEG of a 12-year-old girl with eyelid myoclonia with absences. Note the left posterior focal spikes in (A) and (B) and the right lateral temporal spikes in (C). Note that the GSWD in (A) is prompted by eye closure.
Figure 3.57. Same patient as in figure 3.56. Two eye closure EEG abnormalities were observed at commonly used sensitivity (A) and at higher sensitivity (B). In (A), the first discharge appears as abortive (incompletely) generalized with posterior emphasis, while the second appears generalized. At higher sensitivity, it becomes clear that both are more restricted; the first is posterior focal and the second incompletely generalized with posterior emphasis.
Figure 3.58.Video-EEG of the patient in figure 3.54. Note the activation of subclinical eye closure abnormalities during HV.
Figure 3.59. (A) 3-Hz incompletely generalized spike/polyspike-wave discharges during Stage 2 of sleep in a 22-year-old man with Jeavons syndrome; (B) occipital spike-wave discharges during Stage 1 of sleep in the patient in figures 3.56 and 3.57.
Figure 3.60. Video-EEG of a 64-year-old man with episodes of eyelid myoclonia and absences since childhood and sporadic GTCS. Left trace: diffuse recruiting rhythm giving way to 3-Hz GSWD; right trace: frontally predominant generalized polyspike-wave discharges during Stage 2 of sleep.
Figure 3.61. Video-EEG of the patient in figure 3.52, showing an episode of eyelid myoclonia. Note the GSWD that occurs just before the eye closure (arrow).
Figure 3.62. Typical ictal irregular GSWD/GPSWD in the patient of figure 3.52.
Figure 3.63. Patient of figure 3.52; showing eye closure abnormalities that do not persist over the whole period, during which eyes remain closed. This is in contrast to fixation-off sensitivity (FOS), in which discharges continue for as long as eyes remain closed (see also chapter on FOS).
Figure 3.64. Left trace: episodes of eyelid myoclonia in a 29-year-old woman, facilitated by bright sunlight that may also include a component of pattern effect (window blinds). Right trace: only a few seconds later, dark sunglasses completely abolished the clinical/EEG phenomenon by reducing the amount of epileptogenic stimulus; note that the orientation of the patient towards the sunlight and the shape of the eye closure artefact remained the same.
Figure 3.65. HV with breath counting performed after awakening during SDEEG in a 21-year-old woman with Jeavons syndrome and infrequent independent early morning myoclonic jerks. The patient stops counting in each episode of eyelid myoclonia (eyelid myoclonia with absences).
Figure 3.66. Patient of figures 3.56 and 3.57. Left side of the trace: prolonged eye closure provokes bilateral runs of fast occipital spikes ending with a spike-wave, but does not trigger eyelid myoclonia. Right side of trace: monocular IPS at 30 Hz, performed after awakening and HV. Note that the photoparoxysmal response is far more substantial and appears to be temporarily inhibited by brief eye opening (white arrow), but resumes promptly on the second eye closure, and is also associated with an axial jerk (black arrow).
Figure 3.67. Dissociated response to eye closure and IPS in a 20-year-old woman with eyelid myoclonia with absences. A brief GSWD of posterior emphasis occurs during the ascending (positive) deflection of the eye closure artefact, coinciding with the onset of the IPS (black arrow); a second regular 3-Hz GSWD occurs probably after adequate temporal summation of IPS, showing posterior lead-in (white arrow).
Figure 3.68. Video-EEG day telemetry of a 20-year-old man with eyelid myoclonia with absences and additional SI. Note the “attempts” to induce absences by multiple voluntary eye blinks.
Figure 3.69. Video-EEG of the patient in figure 3.66. Left side of the trace: eye closures on command generate only brief traces of fast alpha activity. Right side of trace: self-motivated eye closures are longer and generate brief bursts of occipital spikes. Pronounced rolling of the eyeball upwards (Evans-Mulholland effect) occurs in both types.
Figure 3.70. Video-EEG day telemetry of a 28-year-old woman with eyelid myoclonia, absences, and infrequent GTCS. She made a few unsuccessful long eye closures (producing only alpha activity but no spikes) after she was left alone for some time reading a magazine. (A) and (B) show the same eye closure at different times (arrows). Note the muscle activity in the frontal channels that reflects eyelid flickering and the substantial upward rolling of her eyeballs indicated by the high-voltage positive deflection following the negative deflection of the eye closure. The complex eye movement is associated with head turning upwards, appreciated on the video (B). The EEG room is moderately lit.
Figure 4.01. Orbitofrontal photomyoclonus. Note the self-limiting EMG response that is induced when eyes are closed, which is maximal frontally and has the same frequency as the IPS.
Figure 4.02. Photoparoxysmal response to IPS when eyes are open.
Figure 4.03. Generalized photoparoxysmal responses associated with symmetric (left) or asymmetric (right) myoclonic jerks.
Figure 4.04. A typical absence provoked by IPS at 8 Hz. The patient remained unresponsive throughout the seizure.
Figure 4.05. IPS-provoked occipital seizure evolving into GTCS.
Figure 4.06. Generalized PPR at 8-Hz IPS, evolving into a GTCS in a patient with a history of photically-induced generalized seizures. Note the asymmetric tonic posturing at the time point marked by the green arrow.
Figure 4.07. Reading-induced jaw myoclonus, associated with left-sided ictal sharp wave discharge in trace (A) and with bilateral synchronous low-voltage spike-wave discharges with left-sided emphasis in traces (B) and (C). Note that while both ictal discharges in traces (B) and (C) correlate with clinically evident jaw jerks, only the ictal discharge in trace (B) appears to associate with a brief EMG potential (from Koutroumanidis et al. , with permission).
Figure 4.08. Reading-induced interictal activation (A) and focal seizure manifesting with alexia and dysphasia (B and C). (A) Reading induces subclinical delta transients over the left (dominant) temporal areas (red arrows), which abate as soon as the patient ceases to read (blue arrow). (B) Soon after the patient started reading aloud, rhythmic monomorphic delta activity at 0.8-1 Hz appeared over the left temporal area (red arrows). The patient was still able to read until he suddenly hesitated and repeated a word for a couple of times (green arrow) as though he tried to understand it, and pressed the event button (black arrow). The EEG normalized for few seconds and then an irregular low-voltage 3.5-5-Hz activity appeared over the left temporal areas (right end of trace [B]), followed by a sharpened rhythmic theta activity at 5 Hz (beginning of trace [C]). The electrical seizure ceased 94 seconds after the onset of the first behavioural changes, followed by a short period of postictal suppression on the left. The patient remained conscious throughout and able to understand simple questions and execute simple commands (yellow arrow), but was unable to make sense of the text and showed expressive dysphasia responding only by nodding of his head. The seizure is depicted in a discontinuous manner to include only the periods during which distinct behavioural and electrical changes occurred (modified from Koutroumanidis et al. , with permission).
Figure 4.09. Video-EEG activated by reading of a 25-year-old student of English literature with reading-induced paroxysmal dyslexia. He had his first generalized convulsion while reading on a train. Treatment with carbamazepine for three years has prevented further GTCS, but reading for a long time still induces episodes of dyslexia. He now reads taking short breaks. Resting EEG is entirely normal, while reading aloud induces brief episodic stuttering, associated with brief runs of left mid- to posterior temporal spike-wave discharges (double arrows) and subclinical discharges (single arrows).
Figure 4.10. Myoclonic seizures associated with solitary and 3-Hz generalized spike/polyspike-wave discharges in a 20-year-old woman with first GTCS. Note the associated deltoid EMG potentials (arrows). No discharges occurred while her eyes remained open fixating, and formal testing revealed FOS (HFF: 70 Hz; TC: 0.3 sec).
Figure 4.11. Diagnostic process in FOS. Top left trace: bilateral synchronous occipital paroxysms (OP), occurring when eyes are closed are promptly inhibited by eye opening and visual fixation; this pattern should arouse suspicion of FOS. Top right trace: ongoing OP when dark goggles are “on” irrespective of whether eyes are open or shut; such reaction suggests that FOS is highly probable, but cannot rule out pure scotosensitivity (scotos: darkness). Lower trace: FOS is demonstrated using translucent goggles that let light through but abolish fixation; eyes are open with dark goggles “on” (left third), dark goggles “off” and visual fixation (middle third), and +10 translucent goggles “on” (right third). Sub-clinical generalised polyspikes-wave discharges interspersing OP are marked with arrows (HFF: 70 Hz; TC: 0.3 sec) (from Koutroumanidis et al. ).
Figure 4.12. Generalized spike/polyspike-wave and 3-Hz spike-wave discharges shortly after awakening in the patient of figure 4.10 with newly diagnosed JME and FOS (sleep-deprived video-EEG; HFF: 70 Hz, TC: 0.3 sec). Note the associated myoclonic jerks on the EMG polygraphy (arrows)
Figure 4.13. FOS in an 18-year-old woman with IGE/GGE with absences and photosensitivity since age eight. Top trace: “eyes closed”-related posterior high-voltage 3-4-Hz delta rhythm with intermixed spikes and more generalised bursts of spike-wave activity (white arrows). Both types of discharge relate to FOS, appear >2 seconds after eye closure, occur while eyes remain closed, and block on eye opening and volitional visual fixation. Note also the brief discharge of polyspike-wave that occurs upon “eye closure” (grey arrow) and relates to her photoparoxysmal response (not shown here). Lower trace: the patient wears goggles completely covered by black tape for absolute darkness. Both posterior high-voltage delta rhythm (black arrow) and the generalised bursts of sharp activity (white arrows) also occur when eyes are open. Note that in complete darkness, the eye closure (photosensitivity-related) paroxysms are blocked (grey arrow) (HFF: 70 Hz, TC: 0.3 sec) (from Koutroumanidis et al. ).
Figure 5.01. Coronal T1-weighted high-resolution brain MRI with (A) left hippocampal atrophy (circle) and (B) high-signal lesion on coronal FLAIR sequences (arrow). Note the cavum septum vergae incidentally. This patient subsequently underwent successful stereotactic laser ablation to become seizure-free.
Figure 5.02. Diffuse slowing of the posterior dominant rhythm to 6 Hz (red arrow) following a recent series of focal seizures with impaired consciousness. Note the lateralized periodic right mid-temporal spikes (black arrows). This patient had a lesion in the mid-hippocampus and was being evaluated for epilepsy surgery.
Figure 5.03. Right temporal intermittent rhythmic delta activity (TIRDA), augmented by hyperventilation. Depth electrode recordings showed right hippocampal onset for his habitual seizures.
Figure 5.04. Right anterior temporal spike-and-slow-wave discharge (sixth second) with ipsilateral regional temporal delta slowing in a patient with right mTLE due to HS.
Figure 5.05. Independent bitemporal epileptiform discharges with a regional temporal field (arrows). This patient had mTLE due to HS and underwent successful laser ablation of the left amygdalohippocampal complex.
Figure 5.06. Scalp ictal EEG demonstrating a unilateral right temporal rhythmic ictal theta discharge in a patient with right mTLE due to HS.
Figure 5.07. Change in electrode nomenclature (black) in the 10-10 system of electrode placement on scalp EEG.
Figure 5.08. Focal right mid-temporal slowing in a male with post-infarction focal seizures after a right middle cerebral artery stroke.
Figure 5.09. Interictal EEG with a right mid-temporal spike and slow wave in a patient with right temporal neocortical epilepsy due to an arteriovenous malformation.
Figure 5.10. Aphasic status epilepticus in a 28-year-old with left neocortical temporal lobe epilepsy. Note the rhythmic left regional temporal 1.5-2.5-Hz delta activity and intermixed lateralized periodic discharges (arrow) and the interictal anterior temporal spike (seconds 7 and 12). Brain MRI was normal.
Figure 5.11. A left mid-temporal isolated wicket spike in a patient without epilepsy referred for an EEG due to complaints of dizziness.
Figure 5.12. EEG with a single left anterior temporal spike-and-slow-wave during sleep in a 19-year-old with episodes of déjà vu. The patient had normal brain MRI, and neurological examination, and three generations of family members had similar symptoms.
Figure 5.13. Left mid-temporal spike with a regional temporal field in a patient with rare temporal lobe seizures preceded by an aura of hearing crickets.
Figure 5.14. Frequent right fronto-polar spikes in a patient with post-traumatic epilepsy and bilateral orbitofrontal encephalomalacia on brain MRI. Note the very focal field identified using a transverse bipolar montage (arrows).
Figure 5.15. Frontal intermittent rhythmic delta activity in a patient with orbitofrontal epilepsy.
Figure 5.16. Video-EEG obtained in a six-year-old girl demonstrating nearly continuous focal bilateral right>left frontal-frontopolar spikes associated with right frontal cortical dysplasia that involves the superior and middle frontal gyrus. This EEG was obtained during the “interictal” state.
Figure 5.17. Left frontal spike (third second) coupled with sleep elements prior to a generalized discharge composed of mixed spikes and polyspike-and-slow waves in a patient with mesial frontal lobe epilepsy (SBS).
Figure 5.18. A 7-second right frontal lobe seizure in a 28-year-old female with left hemiparetic cerebral palsy, manifesting as brief nocturnal left-sided tonic posturing. Note the superimposed myogenic artefact preventing localization.
Figure 5.19. Right frontal seizure occurring in N3 in the girl of figure 5.16. Semiology is subtle with eye deviation to the left and subtle eyelid clonus. Note the paucity of the nearly continuous right frontal spiking, a few seconds prior to the electrographic onset (arrow).
Figure 5.20. Brief left frontal electrographic seizure in a 30-year-old man with left frontal epilepsy and nocturnal seizures since childhood. MRI was normal. He remained unaware of this event. Note the initial attenuation prior to the low-voltage fast ictal discharge that progressively increases in amplitude (arrow).
Figure 5.21. Left panel: ictal EEG with a right frontal lobe seizure in a patient with post-traumatic epilepsy. Ictal symptoms included headache, gustatory hallucinations associated with “sickness” and “emptiness in his head”. He remained conscious and responsive throughout the attack that lasted one minute. Right panel: postictal slowing over the right anterior quadrant persisted for 20 minutes without any associated symptoms. Interictal spikes occurred over the right central area (arrow).
Figure 5.22. Full montage polysomnography obtained for a man with medically intractable non-lesional FLE with seizures arising exclusively from sleep. Note the localization of rhythmic spiking in the left frontal region during REM sleep.
Figure 5.23. Diagnostic video telemetry of a 17-year-old woman with nocturnal “events” since her early teens. Two previous EEGs had been unremarkable. (A) Rhythmic spiking over the left frontal area; the patient simply wakes and sits up. (B) Interictal abnormalities were limited to occasional small spikes over F3. Brain MRI and PET were normal.
Figure 5.24. Sleep-deprived video-EEG of a 28-year-old woman with right OLE since her early teens; brain MRI was normal. During early drowsiness (A), right occipital spike-wave discharges intersperse on-going regional irregular delta rhythm (green arrow). Brief bursts of low-voltage fast polyspike discharges occurred over the right occipital area during sleep ([B]; red arrow). Note the different polarity of the physiological positive occipital transients of sleep (POSTs) (blue arrow), compared to the occipital negativity of the occipital spikes.
Figure 5.25. Right occipital spikes diffusing to the left posterior areas and attenuating on eye opening in a 19-year-old woman with right OLE. Note the occipital electronegativity of the spikes and the lack of regional background disturbance despite the structural lesion. Brain MRI showed a sizable right dysembryoblastic neuroepithelial tumour (DNET); (A) coronal FLAIR and (B) axial TW2 (from Koutroumanidis et al. ).
Figure 5.26. Sleep EEG of a 22-year-old man with right OLE. (A) High-voltage right occipital sharp waves followed by polyspikes that appear to propagate anteriorly amidst sleep spindles. (B) Bilateral occipital high-voltage “triphasic” sharp waves with a very short time lag between the sides (blue arrow), implying propagation to the left occipital areas rather than “diffusion” as in figure 5.25. Note that occasional occipital sharp waves occur independently on the left. Brain MRI was normal.
Figure 5.27. Preoperative (A) and post-operative (B) sleep EEG of the patient in figure 5.25 (both traces are from sleep Stage 1). Note that, post-operatively, spikes do not appear to diffuse to the left posterior areas as they did pre-operatively (see also figure 5.25) and also that their polarity has changed, now phase reversing over the right temporal area (arrow). There is also some irregular delta activity in-between the spikes, which was absent in all her pre-operative recordings.
Figure 5.28. Right occipital spikes of a 12-year-old boy with formed visual hallucinations during wakefulness (A) and sleep Stages 1-3 (B, C and D). Brain MRI was normal.
Figure 5.29. Bilateral bursts of occipital polyspikes (centre of the trace) in a 28-year-old woman with stereotyped formed visual hallucinations since age 14 years, previously misdiagnosed for psychogenic non-epileptic seizures. She had several normal waking EEGs until this recording. Brain MRI was normal.
Figure 6.01. Action myoclonus in Unverricht-Lundborg disease (ULD). Left: this 23-year-old woman with genetically-proven ULD has normal resting EEG. Voluntary movement induces marked action myoclonus superimposed on the EMG traces without associated EEG changes. Intermittent photic stimulation (ILS) triggers fast generalized spike-waves with a posterior predominance and myoclonic jerks without clear EEG/EMG associations. Right: this 13-year-old girl has also genetically-proven ULD. (A) Fast generalized spike-waves with no clinical correlate. (B) Left then right asynchronous myoclonic jerks are followed by bilateral, low-amplitude myoclonus which coincides with a generalized polyspike and polyspike-wave discharge on the EEG (Courtesy of Michelle Bureau, MD Centre Saint-Paul/Hôpital Henri Gastaut, Marseilles, France).
Figure 6.02. EEG/EMG correlates in Unverricht-Lundborg disease (ULD). Four different patients with genetically-proven ULD. Left, middle-left, and middle-right samples show short bursts of 3-4-Hz generalized spike-waves with a rolandic predominance against a normal background. These patients were initially diagnosed with idiopathic generalized epilepsy. Right sample shows left rolandic spike-wave activity that correlates with myoclonic jerks of the right arm (Courtesy of Michelle Bureau, MD Centre Saint-Paul/Hôpital Henri Gastaut, Marseilles, France).
Figure 6.03. Sleep EEG/EMG recording of a 21-year-old patient with ULD, four years after onset. During REM sleep, long bursts of fast, semi-rhythmic, moderate-amplitude 4-5-Hz spike-waves are recorded over the vertex and rolandic areas, with unrelated myoclonus of the chin (Mylo) (Courtesy of Michelle Bureau, MD Centre Saint-Paul/Hôpital Henri Gastaut, Marseilles, France).
Figure 6.04. Post-myoclonic inhibition. These polygraphic examples show positive myoclonic jerks, time-locked to polyspike-wave discharges and followed by a 150-ms EMG silent period, consistent with post-myoclonic inhibition.
Figure 6.05. Axillar skin biopsy in Lafora disease. Electron microscopy of axillar skin biopsy showing characteristic Lafora inclusion bodies (white arrow) in the cells of sweat gland ducts.
Figure 6.06. EEG/EMG correlates in Lafora disease. This EEG of a 14-year-old girl with cognitive decline and myoclonic jerks related to Lafora disease (EPM2A) was recorded less than a year after the presumed onset of the disease, which was initially diagnosed as juvenile myoclonic epilepsy. The patient was asked to raise and keep her arms outstretched. Fast generalized spike-wave discharges of varying amplitude and frequency occur against a slow, disorganized background. The EMG shows negative myoclonus of seemingly cortical origin. Volleys of high-amplitude spike-wave discharges correlate with brief interruptions of muscular contraction without immediate antecedent positive myoclonus (asterisks).
Figure 6.07. Progression of EEG changes in a patient with Lafora disease. (A) At the time of disease onset (age 17 years), the EEG demonstrated normal to slightly slowed background activity. (B) Two years later (age 19 years), the EEG demonstrated asymmetric generalized spikes and polyspikes, maximum over the anterior regions on a slowed background. (C) At age 20 years, the occurrence of fast (4-6 cycles per second) spike-waves was concomitant with head drops. During the final stages of the disease, EEG recordings showed long bursts of diffuse spike-waves and fast polyspikes associated with major volleys or massive myoclonic jerks (D), dramatically enhanced by photic stimulation at low frequency (E) (from Turnbull et al., 2016).
Figure 6.08. A 13-year, four-month-old girl, presenting with Lafora disease. Left: discharges of spikes in the posterior regions of both hemispheres during wakefulness. Centre: eyes closed with a discharge of diffuse spike waves. Right: a posterior polyspike-wave discharge induced by photic stimulation (from Genton and Bureau, 2006).
Prof Samuel Wiebe, Liaison to the ILAE Executive Committee; Prof Edouard Hirsch, Liaison to the ILAE Classification Committee; and Dr Oliver Gubbay, Editorial Office, Epileptic Disorders. The authors have no conflict of interest to disclose.