Treatment and Long-term Prognosis of Myoclonic-Astatic Epilepsy of Early Childhood



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Oguni et al.

Treatment and Long-term Prognosis of Myoclonic-Astatic Epilepsy of Early Childhood


Hirokazu Oguni, MD, Teruyuki Tanaka, MD, Kitami Hayashi,MD, Makoto Funatsuka, MD, Masako Sakauchi, MD, Seigo Shirakawa, MD, Makiko Osawa, MD
Department of Pediatrics, Tokyo Women's Medical University, 8-1 Kawada-cho,

Shinjuku-ku, Tokyo 162, Japan


Key words: Myoclonic-astatic epilepsy, long-term prognosis, treatment response, myoclonic-astatic seizures, Doose syndrome


Running title: Treatment and prognosis of MAE
Address correspondence to: Hirokazu Oguni, Department of Pediatrics, Tokyo

Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162, Japan.

Tel. 81-3-3353-8111, Fax. 81-3-5269-7338,

e-mail: hoguni@ped.twmu.ac.jp


SUMMARY

PURPOSE: We retrospectively studied patients with myoclonic-astatic epilepsy of early childhood (MAE) to investigate the most effective treatment and long-term seizure and intellectual prognosis. SUBJECTS: Eighty-one patients with MAE were recruited from among 3600 patients with childhood epilepsy according to the ILAE criteria of MAE. METHODS: We retrospectively investigated the clinical characteristics and ultimate prognosis of the patients with MAE from the medical records. The effects of various antiepileptic drugs, ketogenic diet and ACTH treatments on myoclonic-astatic seizures (MS/AS), apparently a hallmark of this unique epileptic syndrome, were also studied. RESULTS: MS/AS in 89% of the patients disappeared within 1 to 3 years despite initial resistance, but generalized tonic-clonic or clonic seizures [G(T)CS] tended to continue. The most effective treatment for the MS/AS was ketogenic diet, followed by ACTH and ESM. At the last follow-up, 55 patients or 68% of all the patients entered remission of epilepsy, 11 patients or 14 % experienced a recurrence of GTCS after a long-remission period but easily regained control, and the remaining 15 patients or 18% had continued to have seizures and intellectual outcomes were poor. In one half of these patients with poor outcomes, repeated minor epileptic status and nocturnal generalized tonic seizures persisted. A family history of epilepsy and a combination of minor epileptic status are risk factors for poor outcomes. CONCLUSION: MAE is considered to form a clinical spectrum ranging in a main seizure type from myoclonic to atonic type, and in seizure and intellectual outcomes from benign to malignant. The overall prognosis, despite initial resistance to treatment, appears to be much better than originally thought when ILAE definitions excluding SME are followed.

INTRODUCTION

Myoclonic-astatic epilepsy of early childhood (MAE) was first described by Doose and has been included as cryptogenic epilepsy with myoclonic-astatic seizures in the International Classification of Epileptic Syndrome [8,34] . It has long been argued about the classification of cryptogenic or idiopathic myoclonic epilepsies during childhood [1,2,4-6,10-12,18,20,23,35], and the current ILAE has finally recognized four distinct epileptic syndromes including MAE, benign and severe myoclonic epilepsy in infants defined by Dravet [11,12], and cryptogenic (myoclonic variant of) Lennox-Gastaut syndrome (LGS) [34], although the last one is not truly a myoclonic epilepsy. Although there have been a number of publications regarding the clinical and EEG characteristics in the latter three syndromes from many different authors [3,13,22,29,31,33,36], MAE has received attention mainly in relation to nosological issues and few detailed studies have been done except for those by Doose and his coworkers [6-9,15,17,21,26,32]. One of the main values of syndrome classification is that it enables physicians to predict outcomes as well as select treatments specific for the syndrome. Especially since half of MAE patients run an unfavorable clinical course [8], it is crucial for clinical practice to identify better treatment strategies as well as the expected outcomes of this epileptic syndrome. The present study applied the international syndromic classification system for patients with childhood epilepsies consulting our clinic, identifying those fulfilling the definition of MAE, then retrospectively studied the response to treatment of myoclonic-astatic seizures and long-term mental development and seizure outcome.

SUBJECTS

We recruited patients who fulfilled the criteria for MAE defined by the ILAE [34] from among 3600 patients registered in the database as having epilepsy. All of these patients had consulted our hospital between April 1968 and 1992. The ILAE criteria for MAE are as follows:

1. Normal development before onset of epilepsy and absence of organic cerebral abnormalities, 2. Onset of myoclonic, myoclonic-astatic seizures or astatic seizures (MS/AS) between 7 months and 6 years of age, 3. Presence of generalized spike- or polyspike-wave EEG discharges at 2-3 Hz, without focal spike discharges, 4. Follow-up for more than three years, 5. Exclusion of severe and benign myoclonic epilepsy in infants (SME, BME) as well as cryptogenic Lennox-Gastaut syndrome (LGS) based on ILAE definitions.

The exclusion of SME is mainly based on the clinical evolution lacking the following characteristics; the onset of epileptic seizures less than 1 year old, repeated febrile or afebrile prolonged unilateral and generalized seizures, appearance of complex partial seizures after 1 year old [31]. That of BME is mainly based on the presence of other seizure types than massive myoclonus, except for febrile convulsion [11]. Cryptogenic LGS is differentiated from MAE with the combination of generalized tonic seizures as a main seizure type during the early clinical course [3,13,29].

METHODS
We retrospectively investigated clinical characteristics and evolution of MAE including seizure and intellectual prognosis, as well as responses to various medical treatments from the medical records. The seizure type was ascertained based on either the description given by surrounding adults including medical stuff or on video-ictal EEG or polygraphic recordings. Routine EEG performed approximately every 6 months and ictal EEGs were also studied.

The effects of various antiepileptic drugs, ketogenic diet and ACTH treatments on the MS/AS, apparently a hallmark of this unique epileptic syndrome, were analyzed. Effectiveness of the treatments were assessed by the following criteria; Excellent: disappearance of MS/AS, Good: > 50% reduction of MS/AS, Poor: < 50% reduction of MS/AS, Aggravated: > 50% increase of MS/AS.

The intellectual outcome was evaluated on the basis of intelligence quotient test (IQ test= Modified Binet IQ or WISC-R) and educational achievement for those patients with no available psychometric data. Patients were considered normal if IQ was over 80, borderline to mild if IQ was between 60 and 79, moderately retarded if IQ was between 30 and 59, and severely retarded if IQ was under 30.  

By comparing the various clinical characteristics, we attempted to identify risk factors for poor seizure outcome, capable of predicting the prognosis at the onset of MAE. Chi-square test or Fisher’s exact probability test was used when n was less than 5 and ANOVA testing was used for comparisons. P<0.05 was considered significant.

RESULTS

Eighty-one patients fulfilling the criteria for MAE were included in this study. The follow-up period ranged from 36 to 320 months with a mean of 130±73 months. There were more boys than girls by a ratio of 61 : 20. Family histories of epilepsy (n=11), febrile convulsions (FC, n=15) and other seizures (n=2) were seen in 28 patients accounting for 35% within 3rd degree relatives. Onset of epilepsy ranged from 6 months to 52 months of age with an average of 32±9 months. Age at onset of MS/AS ranged from 7 to 63 months with a mean of 36±11 months (Fig. 1). First seizure type other than MS/AS was always generalized tonic-clonic or clonic seizures [G(T)CS], seen in 63 patients or 78% of the patients. The interval between the first G(T)CS and the MS/AS ranged from 0 to 35 months with a median period of 1 month.

CLINICAL SEIZURE MANIFESTATIONS

MS/AS was precisely investigated by video-EEG (n=5), polygraph (n=2) or video-polygraph (n=22) in 29 patients. They consisted of myoclonic seizures in 17 cases, brief atonic seizures with or without preceding minor myoclonus in 11 cases and myoclonic-atonic seizures in 3 cases (3 cases had two seizure types). Although the type of MS/AS in the remaining 48 patients was assessed from the history taking, seizure type analysis and long-term follow-up appeared to be reliable since 70% of patients were admitted to our hospital for detailed investigation of the epilepsy at the onset of epilepsy. Thirty-nine patients had astatic seizures, described as head-nodding attacks or drop attacks with immediate recovery and 18 patient had myoclonic seizures. Over all, drop attacks involving falling to the ground due to the seizure were recognized in 52 cases (64%) by either ictal monitoring or history. With respect to the seizure characteristics, myoclonic or atonic seizures occurred during wakefulness in 70 cases or 86%, during sleep only in three each and in both the waking and sleeping state in the remaining 8. The attacks occurred daily in 57% of patients having less than 10 attacks per day, 31% having 10 to 50 attacks per day, and 12% having more than 50 attacks per day.

The most frequent accompanying seizures except for MS/AS were G(T)CS seen in 75 patients (Fig. 2A). Although it was difficult to estimate the exact number of patients, the brief GCS resembling the repetition of massive myoclonic attacks was clearly recognized. It was characterized by rhythmic opening of the mouth, arms and legs, suddenly collapsing backward on the floor and starting when the patient was sitting (Fig. 2B). In 52 of 75 patients, G(T)CS occurred during both wakefulness and sleep. Generalized tonic vibrating seizures with a few clonic components were confirmed in the late clinical course in those with unfavorable outcome (Fig. 3). Atypical absence seizures corresponding to runs of generalized irregular spike-and-slow waves at 2-3 Hz were seen in 44 patients (Fig. 4A). Eighteen of these patients also had recurrences of prolonged clouding of consciousness with random segmental myoclonus whose ictal EEG showed disorganized marked slow background activity with random spike and wave discharges, identical with the status of minor seizures or minor epileptic status (Fig. 4B,C). This peculiar seizure tended to start after awakening from the sleep and lasted for hours.

EEG FINDINGS
The MS/AS recorded in 33 patients including 4 with ictal EEG only corresponded to diffuse spike-and-waves or polyspikes-and-waves in all cases. Background activity during the active seizure period was evaluated in 72 children, in whom 66 children showed slowing of background activity consisting mainly of 4-7Hz theta rhythm. The remaining 6 were considered to have normal background activity during the active seizure period. Photosensitivity was recorded in only 8 patients during the late childhood.

SEIZURE OUTCOMES

Age at last MS/AS ranged from 12 to 151 months with a mean of 51±22 months and a median age of 46m in 77 patients (Fig. 1). The cumulative percent remission of MS/AS after the onset of the attacks reached 40% within 6 months, 63% within one year and 89% within 3 years (Fig. 5). Minor epileptic status was also resistant but disappeared with MS/AS except in 5 patients with persistent nocturnal generalized tonic or tonic-clonic seizures. Thirty-five patients continued to have G(T)CS after remission of MS/AS. The remaining 4 patients had persistent MS/AS at the last follow-up. A seizure-free state longer than two years was attained in 55 patients or 68% of all patients by the age of 50±16 months or a median age of 48 months. Remission of seizures appeared to be spontaneous in 21 patients, because the attacks disappeared suddenly or progressively without any change in medications. In 11 patients, or 14% overall, recurrence of GTCS was seen after a long remission period ranging from 3 years and 8 months to 17 years and 11 months with a mean of 9 years and 2 months±4 years and 4 months. However, GTCS were controlled easily by reinstitution or increasing the dose of AED. Finally, the remaining 15 patients or 18% continued to have frequent attacks. Seven patients had weekly nocturnal generalized tonic or tonic-clonic seizures, and minor epileptic status resistant to the currently available AEDs. Five patients continued to have weekly GTCS only. Two patients continued to have daily myoclonic seizures at the final examination. The remaining one continued to have complex partial seizures of frontal origin, which have developed since age 18 years, long after remission of myoclonic seizures.

INTELLECTUAL OUTCOMES
As to the intellectual outcomes, 48 patients or 59% of all the patients showed a normal IQ level at the final follow-up, 16 patients or 20 % were borderline or had mild retardation, and 17 patients or 21% had less than moderate retardation, respectively. The 17 patients with less than moderate retardation continued to have seizures at the final follow-up.
RESPONSES TO THE VARIOUS ANTIEPILEPTIC DRUGS
The antiepileptic drugs (AEDs) including valproic acid (VPA), ethosuximide (ESM), clonazepam (CZP), nitrazepam (NTZ), ACTH and ketogenic diet were most frequently attempted to control MS/AS. VPA, CZP, NTZ and ESM were either introduced individually or added to the preexisting drug regimen in 57, 43, 36 and 34 patients, respectively (Table 1). Among these therapies, ketogenic diet treatment with either classical or MCT types, followed by ACTH, ESM, CZP, VPA and NTZ in this order was most effective, exhibiting excellent effect in 58% of the patients. Among the AEDs, ESM was most effective inducing a good or better response in 64% of the patients, achieving results almost comparable with those of ACTH. Although the response to treatments for other seizure types was difficult to evaluate, ketogenic diet treatment also appeared to be effective for convulsive and nonconvulsive seizures.
IDENTIFYING FACTORS THAT PREDICT AN UNFAVORABLE PROGNOSIS

The following clinical findings were compared among 55 patients with a favorable prognosis, 11 patients with an intermediate prognosis (recurrences of GTCS after a long-remission period and requiring medications) and 15 patients with unfavorable outcomes; the age at onset of epilepsy, the age at onset of MS/AS, incidences of nocturnal seizures, atypical absence seizures, absence status or minor epileptic status, combination of drop attacks and incidences of family histories of epilepsy and febrile convulsions (Table 2). There was a significant difference in positive family history of epilepsy and incidences of absence status or minor epileptic status (P<0.05).

REPRESENTATIVE CASES

Case 1 was a 15-year- 3-month-old boy with a favorable outcome (Fig. 6). He first developed GTCS at the age of 2 years and 3 months. Subsequently he had recurrent GTCS and atonic drop attacks every day. He sometimes showed a prolonged mild cloudiness with random myoclonus diagnosed as minor epileptic status (Fig. 4B). As VPA with combination of ESM was not effective, ACTH treatment was initiated at the age of 3 years. The attacks were controlled immediately except for nocturnal GTCS, which gradually disappeared within a few months (Fig. 2A). He has been seizure-free for more than 12 years and his IQ was 103 at the last follow-up.

Case 2 was a 21-year- 7-month-old man with intermediate outcome (Fig. 7). He developed a febrile convulsion followed by recurrence of afebrile GTCS at age 3 years. Within a few months, astatic seizures including head dropping or collapsing of the body occurred every day, and were resistant to AEDs. ACTH and ketogenic diet were only partially effective. However, all attacks gradually disappeared without any impressive effect of AEDs. GTCS recurred after a long-remission period when he did not take VPA for one day at age 14 years and 1 month and again at 17 years and 10 months.

Case 3 was a 17-year-10-month-old boy with unfavorable outcome (Fig. 8)

He started to have GTCS at the age of 4 years and 2 months. Atonic drop attacks and atypical absence seizures developed subsequently. Although all the available AEDs were not effective, ketogenic diet treatment controlled atonic drop attacks and reduced the number of the remaining attacks. However, subsequently, nocturnal generalized tonic seizures and minor epileptic status persisted and remained uncontrolled until the last follow-up, leaving the patient moderately retarded (Fig. 3, 4C ).


DISCUSSION

There have been several distinct studies and reviews regarding the cryptogenic or idiopathic myoclonic epilepsies during childhood since the first description by Harper who reported 14 children with true myoclonic epilepsy [18]. Harper previously described an astatic symptomatology that often followed violent myoclonic attacks, and was often resistant to antiepileptic drugs (AEDs). Then, Doose reported the detailed analysis of 50 children with so called centrencepahlic myoclonic-astatic petit mal [6], later designated as myoclonic-astatic epilepsy [8,9]. In the following years, Aicardi et al. studied children with predominantly myoclonic seizures and classified those without permanent neurological signs into myoclonic-petit mal, petit-mal variant with myoclonic jerks, generalized epilepsy with myoclonic jerks and cryptogenic myoclonic epilepsy of childhood according to a detailed study of the clinical and EEG features [1]. Subsequently, various authors have proposed various terminologies describing those with similar features; intermediate cryptogenic myoclonic epilepsy of childhood because of clinical and EEG characteristics between idiopathic and symptomatic etiology [35], myoclonic variant of Lennox-Gastaut syndrome (LGS) because of the combination of atypical absence seizures or status, and slow-spike-and-wave complexes activated by sleep sharing the features of LGS [1, 10,35]. Dravet et al. finally established benign myoclonic epilepsy in infants (BME) [11] and severe myoclonic epilepsy in infants (SME) [12] as a distinct epileptic syndrome, both of which are accepted by ILAE along with MAE proposed by Doose [34].

However, as Aicardi pointed out, the nosological confusion has remained unsolved because of the subdivision of these epilepsies by different methodologies based on the clinical and EEG features or on the etiology [4]. In his latest publication, Aicardi himself attempts to formulate a concept in which these heterogeneous myoclonic epilepsies of childhood and cryptogenic LGS form a spectrum with LGS at the malignant end and BME at the benign end, with myoclonic variant of LGS and MAE or other cryptogenic myoclonic epilepsies existing at intermediate points along the continuum [4]. In our previous studies, we reached a similar conclusion that 60 children with cryptogenic or idiopathic myoclonic epilepsies and ultimately favorable outcomes appeared to form a clinical continuum with respect to seizure and intellectual outcomes that depended largely on the persistence of nocturnal G(T)CS rather than on MS/AS [24,25]. However, we favored considering these patients as representing one clinical entity with a rather wide clinical spectrum rather than an assemblage of heterogeneous epilepsies after excluding SME.

Most authors have claimed that MAE is a merely a group of heterogeneous epileptic syndromes and should be limited to those involving myoclonic-astatic seizures or astatic seizures [4,10,15,17,21,35]. However, Doose himself has resisted the separation of MAE by clinico- electrical features into many overlapping subdivisions [8,9]. As the etiology of MAE, Doose and Baier extensively studied the convulsive trait in families of MAE patients and demonstrated the pathogenic importance of multifactorial inheritance of this type of epilepsy [7]. They concluded that the neurobiological approach for MAE would provide a clue to the ultimate understanding of the pathogenesis of MAE rather than sticking to the rigidly defined syndromatic classification. Recent advances in molecular biology have come to shed a light on his concept and are providing more concrete evidence [38].

With respect to the characteristic symptomatology of the myoclonic/astatic seizure (MS/AS) itself, the recent advent of video-EEG monitoring system has clarified differences in these brief events very precisely. As we have already shown that drop attacks in MAE consisted either of brief atonic seizure with or without preceding minor myoclonic events or flexor spasms both associated with generalized spike-and-wave [26,27,30,32]. Thus, the astatic symptomatology itself created by the heterogeneous seizure types does not appear to be an appropriate indicator for subdividing the epileptic syndromes [32]. In addition, we should pay more attention to the evidence that tonic drop attacks, a hallmark of LGS, appear to be more common than atonic attacks [16,19]. Thus, the exclusion of cryptogenic LGS may not be easier unless we carefully evaluate drop attacks by taking a detailed seizure history or by ictal video-polygraphic study.

Guerrini et al. as well as Dulac et al. have proposed that MAE should be limited to those with massive myoclonic or drop attacks with or without absence or GTCS excluding BME, SME and cryptogenic LGS [15,17]. Most recently, Kaminska et al. have justified their subdivision into favorable and unfavorable MAE by multiple corresponding analysis [21]. In this study, we recruited patients according to the ILAE defined criteria of MAE excluding those with BME, SME and cryptogenic LGS. Thus, our series may include heterogeneous epileptic syndromes, which are of concern to some investigators, but at least excluded other ILAE defined subgroups similar to their concept.

In comparison with nosological issues described above, only a few detailed studies have been performed concerning the long-term prognosis and treatment of MAE [17,21,32]. Doose has recommended the combination of valproic acid and ethosuximide for MS/AS and primidone for GTCS [8]. In addition, he used ACTH to treat minor epileptic status. He has also suggested the use of bromide for the severe form of MAE, which shows clinical characteristics identical to those of SME [28]. Most other authors more or less described MS/AS as relatively resistant to therapy but did not include further details of the treatment other than those Doose recommended [2,4,10,17,18,21,35,40]. Despite being a retrospective study, the present result showed that MS/AS were initially resistant to conventional AEDs commonly recommended for myoclonic seizures and atonic seizures. However, Doose as well as other investigators suggested that ethosuximide appeared to be the most favorable AED for the MS/AS, although it was difficult to assess whether combination with VPA was better [4,8,40]. The combination of ESM with VPA has been reported to be effective for refractory absence seizures [37] and considered to have a synergic effect on absence seizures or burst of spike-and-wave complexes. In our previous studies as well as the present ictal EEG series of MS/AS, these attacks all corresponded to generalized spike-and-wave complexes, as is similar in part to the ictal EEG of absence seizures despite differences in frequency and duration [26,27,30,32]. Much better responses to ACTH and ketogenic diet than that to ESM should be for the same reason, because both treatments have been shown to be most effective for atypical absence seizures and myoclonic seizures but not so effective for generalized tonic seizures which is rare in MAE [39,41]. Recently, lamotrigine has been successfully tried for some of MAE patients [14], although we have no experience to treat MAE with this drug.

As for seizure outcomes, it is evident that the prognosis of MAE in our series is clearly better than that demonstrated by Doose [8,9] probably because of the exclusion of SME. In the clinical course, we tentatively separated patients into three groups, favorable, intermediate and unfavorable outcomes, according to the seizure prognosis. However, we should keep in mind that even in those with a favorable clinical course, the attacks were initially resistant to the AEDs, sometimes requiring additional ACTH or ketogenic treatment as shown in the case example. The patients with an unfavorable outcome appeared to be identical to those reported by Kaminska et al. [21], characterized by the combination of MA/AS, atypical absence seizures, minor epileptic status and recurrent GTCS at the early clinical course, although later accompanied by nocturnal GTCS or GTS. The course of patients with an intermediate outcome resembled that of those with BME to some extent, experiencing recurrences of GTCS after long-remission periods [11].

With respect to the prognosis of the MS/AS, a hallmark of MAE, they ultimately disappeared within 1 to 3 years after the onset. Minor epileptic status was also resistant but two thirds of them disappeared with MS/AS. Then, generalized convulsive seizures tended to continue, especially during sleep after disappearance of the MS/AS. However, nocturnal attacks gradually disappeared and only 18% of those finally became truly intractable. Half of those with an unfavorable outcome were characterized by a combination of weekly brief nocturnal GTS and daily or weekly minor epileptic status, persisting for years, being left with moderate to severe mental retardation. The clinical characteristic appeared to different from those of cryptogenic LGS because this seizure combination was consistent in MAE with an unfavorable outcome.

Doose himself identified the following risk factors for an unfavorable prognosis; onset with febrile and afebrile GTCS during the first and second year of life, status of minor seizures, and tonic seizures, the persistence of 4-7Hz rhythms until adolescence and adulthood and failure to develop a stable occipital alpha rhythm [9]. In our series, we confirmed that the family history of epilepsy and the combination of minor epileptic status were significantly higher in incidences in the unfavorable group. The other authors also indicated the following risk factors; the presence of epileptic seizures prior to myoclonic seizures, abnormal mental development antecedent to myoclonia, the lack of familial antecedent, the presence of tonic and absence seizures, persistence of epilepsy over 3 years, vibrating tonic seizures and the occurrence of myoclonic status [2,21]. However, further prospective study is necessary to confirm which risk factors can legitimately predict the outcome.

During the clinical follow-up of MAE, we noticed the apparent spontaneous remission of the attacks without changing medications in 21 cases as Doose also indicated [8,9]. In some cases, there was a sudden disappearance of attacks while in other cases, disappearance was gradual. In that sense, the response to treatment appeared to also be influenced by the timing of treatment, as the response was poor at the peak of epileptic condition then later improved as shown by the increased remission rate with time in patients with the favorable and intermediate outcomes.

The concept of MAE still contains some nosological problems and it may be difficult to reach to a conclusion as long as we depend largely on clinico-electrical manifestations to classify the epilepsies. Precise resolution of nosological issues may await the further development of molecular biological analysis. However, from a practical perspective, we are able to determine the appropriate treatment strategy and to predict prognosis more accurately. At present, MAE should be recognized as an epileptic syndrome with a relatively wide clinical spectrum ranging in main seizure type from myoclonic to atonic attacks, and in the seizure and intellectual outcomes from favorable to unfavorable. However, the final prognosis in most patients with MAE, despite the initial resistance, appears to be better when we follow ILAE definitions excluding SME from the original MAE series.

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FIGURE LEGENDS

Fig. 1. Age at onset and last MS/AS

Age at onset of MS/AS, represented by black bar, scattered from 7 months to 5 years with a peak age at 2 to 4 years. Age at the last MS/AS represented by mesh bar scattered from 1 year to 12 years with a peak age at 2 to 6 years.


Fig. 2. Ictal simultaneous video-polygraph of generalized (tonic)-clonic seizures

(A) Generalized tonic-clonic seizures: The patient was a 3-year-old boy with favorable MAE (shown in the Fig. 6). During sleep, he suddenly developed GTCS, characterized by sudden extension of both arms and clonic jerks of the trunk several times followed by tonic-clonic activity lasting for 4 minutes. Ictal video showed diffuse clonic activity of the whole body with extension of both arms (A, starting video), which gradually became smaller (B), and terminated (C).

(B) Generalized clonic seizures: The patient was a 4-year-7 month-old girl with unfavorable MAE. The polygraph showed sudden appearance of diffuse irregular spike-and-waves followed by EMG artifact and irregular rhythmic spike-and-slow discharges at 1-2 Hz lasting for 15 seconds. Ictal video showed that she suddenly extended both arms in front of her body, then fell backward (A) when she was sitting. This was immediately followed by clonic jerking of the trunk and both legs (B,C) as well as rhythmic opening of the mouth and finally by entire body movement at D.

Fig. 3. Ictal simultaneous video-EEG of nocturnal generalized tonic vibrating seizure

The patient was an 11-year-10 month-old boy shown in Fig. 8. The EEG showed the sudden appearance of runs of generalized spike and waves followed by recruiting fast discharges, which were immediately obscured by EMG artifacts. In the ictal video, he showed gradual tonic flexion of both arms at A, then tonic extension of both arms at B, which vibrated incrementally and terminated with a few big jerks at C.

Fig. 4. Ictal EEG of atypical absence seizures and minor epileptic status

(A) Ictal EEG of atypical absence seizure: The patient was a 5-year-3-month-old girl with unfavorable MAE the same as the patient shown in Fig. 2B. EEG showed runs of generalized spike and waves at 2.5 Hz, corresponding to arrest of motion and unresponsiveness.

(B) Ictal EEGs of minor epileptic status: The patient was a 3-year-old boy with favorable MAE (shown in the Fig. 6). EEG showed almost continuous high amplitude irregular slow wave discharges at times mixed with spike discharges, when the patient was sitting and listen to the story his mother was telling. He showed mild cloudiness of consciousness with occasional random myoclonus of the extremities.

(C) Ictal EEGs of minor epileptic status: The patient was a 15-year-1 month-old boy with unfavorable MAE (shown in the Fig. 8). He showed mild cloudiness of consciousness and reduced responsiveness corresponding to diffuse slowing background activity mixed with spike-and-wave discharge, lasting for hours after awakening.

Fig. 5. Actual remission curve of myoclonic-astatic seizures for the 81 patients with MAE

Seventy-seven patients finally achieved remission of myoclonic-astatic seizures (seizure-free state for longer than 2 years). The most predominant seizures characterizing MAE despite initial resistance gradually disappeared or were controlled within 1 to 3 years from the onset.

Fig. 6. Clinical evolution of a 15-year-3 month-old boy with favorable MAE

Abbreviation: dense oblique line = active epileptic EEG abnormality, oblique line = inactive epileptic abnormality, FC=Febrile convulsion, G(T)CS= Generalized Tonic-Clonic Seizures or Generalized Clonic Seizures


Fig. 7. Clinical evolution of a 21-year-7 month-old boy with intermediate outcome

Abbreviations were the same as those in Fig. 3



Fig. 8. Clinical evolution of a 17 year-10 month-old boy with unfavorable MAE

Abbreviation: Noc GCS= Nocturnal Generalized Clonic seizures


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