Benign Myoclonic Epilepsy In Infancy Research Articles

A Loss-of-Function HCN4 Mutation Associated With Familial Benign Myoclonic Epilepsy in Infancy Causes Increased Neuronal Excitability.

HCN channels are highly expressed and functionally relevant in neurons and increasing evidence demonstrates their involvement in the etiology of human epilepsies. Among HCN isoforms, HCN4 is important in cardiac tissue, where it underlies pacemaker activity. Despite being expressed also in deep structures of the brain, mutations of this channel functionally shown to be associated with epilepsy have not been reported yet. Using Next Generation Sequencing for the screening of patients with idiopathic epilepsy, we identified the p.Arg550Cys (c.1648C>T) heterozygous mutation on HCN4 in two brothers affected by benign myoclonic epilepsy of infancy. Functional characterization in heterologous expression system and in neurons showed that the mutation determines a loss of function of HCN4 contribution to activity and an increase of neuronal discharge, potentially predisposing to epilepsy. Expressed in cardiomyocytes, mutant channels activate at slightly more negative voltages than wild-type (WT), in accordance with borderline bradycardia. While HCN4 variants have been frequently associated with cardiac arrhythmias, these data represent the first experimental evidence that functional alteration of HCN4 can also be involved in human epilepsy through a loss-of-function effect and associated increased neuronal excitability. Since HCN4 appears to be highly expressed in deep brain structures only early during development, our data provide a potential explanation for a link between dysfunctional HCN4 and infantile epilepsy. These findings suggest that it may be useful to include HCN4 screening to extend the knowledge of the genetic causes of infantile epilepsies, potentially paving the way for the identification of innovative therapeutic strategies.

Common pediatric epilepsy syndromes.

Benign rolandic epilepsy (BRE), childhood idiopathic occipital epilepsy (CIOE), childhood absence epilepsy (CAE), and juvenile myoclonic epilepsy (JME) are some of the common epilepsy syndromes in the pediatric age group. Among the four, BRE is the most commonly encountered. BRE remits by age 16 years with many children requiring no treatment. Seizures in CAE also remit at the rate of approximately 80%; whereas, JME is considered a lifelong condition even with the use of antiepileptic drugs (AEDs). Neonates and infants may also present with seizures that are self-limited with no associated psychomotor disturbances. Benign familial neonatal convulsions caused by a channelopathy, and inherited in an autosomal dominant manner, have a favorable outcome with spontaneous resolution. Benign idiopathic neonatal seizures, also referred to as "fifth-day fits," are an example of another epilepsy syndrome in infants that carries a good prognosis. BRE, CIOE, benign familial neonatal convulsions, benign idiopathic neonatal seizures, and benign myoclonic epilepsy in infancy are characterized as "benign" idiopathic age-related epilepsies as they have favorable implications, no structural brain abnormality, are sensitive to AEDs, have a high remission rate, and have no associated psychomotor disturbances. However, sometimes selected patients may have associated comorbidities such as cognitive and language delay for which the term "benign" may not be appropriate.

Nocturnal variant of benign myoclonic epilepsy of infancy: a case series

Myoclonus is a brief, rapid, involuntary muscle jerk originating in the central nervous system that can be physiological or a symptom of disease. We report a group of five children with excessive myoclonic jerks, only during sleep, and abnormal EEG during the events. Although only one third of the events had EEG epileptiform correlate, the presence of myoclonus without epileptiform EEG correlate has been described in patients with benign myoclonic epilepsy of infancy. We hypothesize that these findings may represent a variant of benign myoclonic epilepsy of infancy.

Epilepsia mioclónica benigna del lactante: evolución natural y pronóstico neurocognitivo y conductual

Benign myoclonic epilepsy in infancy (BMEI) is a well-defined electro-clinical syndrome, classically associated with a good prognosis. However, in the last years several studies have been published with variable results of neuropsychological outcome in BMEI. AIM. To analyze the natural history and the cognitive and behavioral outcome in BMEI patients. We report a long-term follow-up of 10 patients with BMEI. During the follow-up, all the patients underwent neurocognitive and behavioral evaluations. Sixty percent of patients became seizure free on valproic acid. The intelligence quotient of the whole cohort was between 74 and 93, with three patients in the range of borderline intelligence and six in the range of medium-to-low intelligence. Nine of the 10 patients met criteria for attention deficit hyperactivity disorder, and two patients associated another learning disorder. All patients showed poor motor and visuospatial coordination signs and three patients had a behavior disorder. The term 'benign' in BMEI has to be used with caution in refer to its behavioral and cognitive outcome. Early onset of seizures and a worse epilepsy control may be risk factors of a poor neuropsychological outcome.

Reflex myoclonic epilepsy in infancy: a critical review

Benign myoclonic epilepsy in infancy, classified among the generalised idiopathic epilepsies, is characterised by the occurrence of myoclonic seizures in the first three years of life in otherwise normal infants. Some authors have described cases of myoclonic seizures as a reflex response to sudden unexpected tactile or acoustic stimuli and this clinical entity has been proposed as a separate nosographic syndrome, referred to as "reflex myoclonic epilepsy in infancy" (RMEI). We reviewed all published articles and case reports on RMEI in order to clarify clinical and electroencephalographic findings, with particular attention to outcome and treatment. RMEI appears to be a benign variant of idiopathic myoclonic epilepsy in infancy with specific features that occur in neurologically and developmentally normal children. This rare clinical entity is often under-described and under-diagnosed, and for this reason should be brought to the attention of paediatricians in order to avoid extensive investigations and reassure parents of the lack of long-term complications.

Benign myoclonic epilepsy in infancy with preceding afebrile generalized tonic–clonic seizures in Japan

Benign myoclonic epilepsy in infancy (BMEI) is the youngest form of idiopathic generalized epilepsy, characterized by myoclonic seizures (MS) in the first three years of life in otherwise normal infants, and the lack of other seizure types except for rare simple febrile seizures. Although afebrile generalized tonic–clonic seizures (GTCS) have been described to develop later in the clinical course of BMEI, mostly during adolescence, an association with GTCS in the early stage of BMEI has never been recognized. We herein report seven children who satisfied the criteria of BMEI except for the recurrence of GTCS before the onset of MS. The age of onset and ictal video-polygraphic features of MS, as well as the long-term seizure and developmental outcome in these children were similar to those of children with typical BMEI. Furthermore, these GTCS mostly disappeared within several months and were replaced by MS. Our study indicates that these children may constitute a BMEI subgroup, expanding the spectrum of BMEI.

“Benign” myoclonic epilepsy of infancy as the initial presentation of glucose transporter‐1 deficiency

We report the case of a young boy carrying a de novo missense mutation (c.1199G>T; p.R400L) in the SLC2A1 gene who presented initially with benign myoclonic epilepsy of infancy. Eventually, he had a poor outcome with refractory generalised tonic-clonic, myoclonic and absence seizures, ataxia, significant mental impairment and slowing of head growth. He responded poorly to ketogenic diet. This case extends the phenotype of GLUT1-related syndromes and also sheds light on the genetic basis of myoclonic epilepsies of infancy suggesting that variable outcome may depend on genetic factors. [Published with video sequences].

Benign myoclonic epilepsy in infancy followed by childhood absence epilepsy

Benign myoclonic epilepsy in infancy (BMEI) is a rare syndrome included among idiopathic generalized epilepsies (IGE) and syndromes with age-related onset. Recently, it has been shown that a few patients with BMEI later had other epilepsy types mainly IGE but never childhood absence epilepsy (CAE). We report a patient who at 11 months of age showed isolated myoclonic jerks occurring several times a day. The ictal video-EEG and polygraphic recording revealed generalized discharge of spike-wave (SW) lasting 1–2 s associated with isolated bilateral synchronous jerk involving mainly the upper limbs controlled by valproic acid (VPA). At 6 years and 8 months the child developed a new electroclinical feature recognized as CAE. The ictal EEG disclosed a burst of rhythmic 3 Hz generalized SW. Our case is the first patient with BMEI reported in the literature who later developed a CAE. This finding suggests a common neurobiological and genetic link between different age-related epileptic phenotypes.

P23.5 Benign myoclonic epilepsy of infancy as the initial clinical presentation of a SLC2A1 mutation

P23.5 Benign myoclonic epilepsy of infancy as the initial clinical presentation of a SLC2A1 mutation

Absence seizures in the first 3 years of life: An electroclinical study of 46 cases

Early onset absence seizures have been considered a rare heterogeneous group with a poor prognosis. Only few patients may be categorized into well-known syndromes. We have evaluated electroclinical features, evolution, and the nosologic boundaries of early onset absence seizures. Forty-six neurologically normal patients with absence seizures associated with bilateral, synchronic, or asynchronic, and symmetric or asymmetric spike-and-wave paroxysms with onset in the first 3 years of life were included. Patients with abnormal neurologic examination and brain imaging were excluded from the study. In our study, 39 patients met the clinical and electroencephalography (EEG) criteria of well-defined epileptic syndromes. Childhood absence epilepsy was found in 11 patients, benign myoclonic epilepsy in infancy in 18 patients, eyelid myoclonic epilepsy in 4, and epilepsy with myoclonic absences in 6. We did not find clinical and EEG criteria of well-recognized epileptic syndromes in seven children. Nine of 11 patients with simple absence seizures became seizure free. All these patients had normal neurologic and neuropsychological evaluations. Of the 35 patients who had absence seizures associated with myoclonic seizures, 20 became seizure free. Fifteen of 35 children continue having seizures. At the last visit, 20 of these 35 patients had normal neurologic and neuropsychological evaluations, 11 presented with mild mental retardation, and 4 with severe mental retardation. Epilepsies with absence seizures of early onset are relatively uncommon. Most of the patients had well-defined epileptic syndromes with a variable evolution. The evolution depended on the epileptic syndromes.

Clinical and Neuropsychological Considerations in a Case of Unrecognized Myoclonic Epileptic Jerks Dramatically Controlled by Levetiracetam

The International League Against Epilepsy (ILAE) classification recognizes 2 forms of myoclonic epilepsy with a good prognosis: benign myoclonic epilepsy of infancy (BMEI) and juvenile myoclonic epilepsy (JME); recent studies confirm the efficacy of levetiracetam (LEV) in treating idiopathic generalized epilepsies (IGE) in patients with myoclonic seizures. We report a girl referred to our Child Neuropsychiatry Unit at age 9 years because of massive myoclonic jerks, previously diagnosed as tics. Neuropsychological examination evidenced mild cognitive impairment. The clinical and electroencephalogram (EEG) data led to diagnosis of BMEI with late presentation. A dramatic suppression of interictal and ictal epileptiform activity was achieved after only one intake of LEV. Another neuropsychological examination after 6 months of treatment showed performance improvement probably related to EEG modifications. LEV may be suitable for the first-line treatment of myoclonic idiopathic seizures.

Benign Myoclonic Epilepsy of Infancy Evolving to Jeavons Syndrome

Benign myoclonic epilepsy of infancy is a rare idiopathic generalized epileptic syndrome occurring below the age of 3 years. Although benign outcome is presumed, some recent studies suggest less favorable outcome. A 14-year-old boy had a history of repeated episodes of myoclonic jerks of the shoulders and upper limbs in infancy (age 5 months). An ictal electroencephalogram indicated generalized spike-wave discharges associated with the myoclonic seizures, and the diagnosis of benign myoclonic epilepsy of infancy was made. Valproate treatment resulted in control of the myoclonic seizures, and the drug was withdrawn when the patient was 5 years of age. At the age of 10, he presented with episodes of eyelid jerks associated with brief lapses in concentration triggered by sunlight. Electroencephalography revealed photosensitivity and a pattern of eye-closure sensitivity. These features were compatible with the diagnosis of eyelid myoclonia with absences, or Jeavons syndrome. Lamotrigine eliminated the seizures. The evolution of benign myoclonic epilepsy of infancy to eyelid myoclonia with absences has been reported in one other case. A possible continuum of myoclonic epileptic syndromes, mediated by a common genetic abnormality, suggests the need for longer monitoring of patients with benign myoclonic epilepsy of infancy.

Epilepsy in hemiplegic cerebral palsy due to perinatal arterial ischaemic stroke

Study of the cerebral palsies requires their separation into pathological entities at the least and ideally into clinico-pathological causal pathways (which has now become possible with modern imaging).1 The study of epilepsy in hemiplegic cerebral palsy by Wanigasinghe et al.2 appropriately selects from a population-based sample the group with early arterial stroke. It is generally accepted that many of these events occur in the immediate prenatal period for uncertain reasons but a proposed mechanism is placentally shed thrombi passing through the right to left shunt.3 The characteristic imaging finding is of a large full thickness cortical deficit often amounting to porencephaly which provides the substrate for epileptic seizures. In the absence of a clear risk factor (e.g. amnionitis) it is not known as to whether the severity of involvement may vary with the quality of antenatal care from one obstetric centre to another. It is interesting that middle cerebral arterial infarcts at a later age have less cortical involvement and cause less epilepsy. From many studies of early onset brain syndromes it is clear that cerebral cortical damage is commonly associated with three groups of impairments: epileptic, cognitive, and psychiatric. Their coexistence is so common that the presence of, for example, cognitive impairment tends to predict the presence of epilepsy. Similarly the presence of epilepsy generally predicts a lower IQ in congenital hemiplegia generally.4 Thus despite the positive features of this study it would have been helpful to have cognitive data and test its value as a predictor of seizure occurrence and remission in this specific group. In this study the finding of severity of motor deficit as a risk factor for epilepsy relates presumably to the extent of the infarct. Neonatal seizures are more a measure of the precise timing of the infarct than its extent and might well not correlate as was found in the study. The seizure semiology is of interest. It would be intriguing to correlate the high rate of spasms (56%) with cognitive outcome and whether electroencephalogram abnormality was unilateral. Not surprisingly, partial seizures are common but some of the specific features are important. Nausea and vomiting are generally regarded as uncommon features of seizures and are associated with involvement of the temporal neocortex. They were present in 50% of seizures in this series but in under 3% of a consecutive series of 178 patients with intractable temporal lobe epilepsy.5 Visual hallucinations indicate an occipital source of seizures. The observation that seven patients had aphasia is also of interest since it might imply that some aspects of language localization remain in the damaged hemisphere, but we need more detail of the timing of the speech arrest within the seizure to be sure of the significance of these observations. Only two patients had reflex focal seizures which are thought to be a common feature of seizures with congenital hemiplegia but needs careful enquiry to identify them. The close resemblance of one patient’s epilepsy syndrome to benign myoclonic epilepsy of infancy may, with other patients, allow insight into this rather problematic condition. It is helpful to know that just over half the study group had epilepsy with a rate of about 25% in all with congenital hemiplegia, but that many went into seizure remission leaving only 15% with active epilepsy after 10 years. The ability to predict such remission would be helpful in the context of surgical decision-making. Only two patients have had epilepsy surgery and one more is being considered for this, which in the context of an active paediatric epilepsy surgery programme (and both surgeries being performed under the age of 15mo) suggests that the requirement for surgery is quite low. This study therefore is part of a process whereby the broad category of congenital hemiplegia is split into its pathological components, thus allowing much more precise delineation of the phenotype, management, and prognosis.6 It also shows that careful clinical study of seizures can provide interesting evidence about semiology and localization.

PO18-WE-34 Eyelid myoclonia after benign myoclonic epilepsy in infancy: is there a continuum between myoclonic epileptic syndromes?

PO18-WE-34 Eyelid myoclonia after benign myoclonic epilepsy in infancy: is there a continuum between myoclonic epileptic syndromes?

Is benign myoclonic epilepsy of infancy truly idiopathic and generalized?

Benign myoclonic epilepsy of infancy is recognized as a generalized and idiopathic epilepsy by the International League Against Epilepsy. Unprovoked and reflex seizures have been reported in these patients. We describe a child diagnosed with benign myoclonic epilepsy of infancy, whose strictly unilateral and localized reflex myoclonias broaden the clinical spectrum of this idiopathic and generalized epileptic syndrome, and raise interrogations about its underlying pathophysiological mechanisms. [Published with video sequences].

Differentiation of myoclonic seizures in epileptic syndromes: A video‐polygraphic study of 26 patients

We conducted a video-polygraphic study of myoclonic seizures (MS) in different epileptic syndromes to clarify semiologic and electroencephalography (EEG) differences among them. The subjects were 26 children with MS, including benign myoclonic epilepsy in infants (BME) in 10, severe myoclonic epilepsy in infants (SME) in 6, idiopathic epilepsy with myoclonic-astatic seizures (IEMAS) in 4, and juvenile myoclonic epilepsy (JME) in 6. We reviewed the video-polygraphs of MS, including the predominant area of muscle involvement (neck, trunk, and proximal or distal upper extremities), postural changes including astatic falling, and mode of appearance. We also analyzed the frequency of a corresponding generalized spike-and-wave complex (GSW) and the duration of myoclonic electromyography (EMG) activity. A total of 550 MS were documented in the 26 cases. MS manifested with proximal predominance/forward flexion/single occurrence in BME, proximal predominance/forward astatic flexion/single occurrence in IEMAS, proximal predominance/extension/succession in SME, and distal predominance/extension/succession in JME. The median frequency of GSW was 1.5, 1.3, 3.2, and 3.1 Hz, respectively, and the median duration of the myoclonic EMG activity was 387, 587, 81, and 65 ms, respectively. MS in the four different epileptic syndromes show significant semiologic and EEG differences, as well as similarities. Although our study has the limitations of the small number of patients and retrospective methodology, these results should be considered in the classification and differential diagnosis of myoclonic epileptic syndromes.

Benign myoclonus of early infancy or Fejerman syndrome

Benign myoclonus of early infancy (BMEI) was first described in 1976 by Natalio Fejerman and presented as a preliminary communication of 10 patients in a southern Latin American meeting. The paper was published in 1977 in the Proceedings of the above-mentioned child neurology meeting (Fejerman, 1977a), in a local journal (Fejerman, 1977b), and the cases were described in the first edition of the book Convulsiones en la Infancia (Fejerman & Medina, 1977). A report including six more cases collected by Cesare T. Lombroso also appeared in 1977 (Lombroso & Fejerman, 1977). Several years later, I took part in a collaborative study reporting four new cases registered with polygraphic ictal recordings, and we interpreted the motor paroxysmal phenomena as spasms. We proposed to name the syndrome benign nonepileptic infantile spasms (BMEI; Dravet et al., 1986). We observed that the motor manifestations included myoclonic jerks, spasms, brief tonic contractions, and shuddering. Fejerman also described one case with atonic head-drops in his first series (Fejerman, 1977a, 1977b). Pachatz et al. (1999) reported five cases, all monitored with video-EEG (electroencephalography) and polygraphic recordings in three, and defined the motor events as “a shudder type, paroxysmal motor manifestation involving mainly the trunk and sometimes the head, associated with tonic limb contractions of variable intensity….” Obviously, in these cases the ictal EEG was also normal. Shuddering was also considered a main feature of BMEI by Kanazawa (2000). The present contribution of Caraballo et al. (2009) documents very well how wide the spectrum of the clinical and neurophysiologic motor manifestations characterizing BMEI can be, and how variable these manifestations can be even in the same subject depending on vigilance and posture and the stage of development of the child. In our experience, for example, the coexistence in the same subject of quite different types of motor manifestations is even more frequent than that reported in this paper. Furthermore it is not exceptional to observe the recurrence of motor manifestations in clusters with a pseudo-periodic–type pattern similar to the clusters in epileptic spasms. It has been repeatedly emphasized, on the other hand, that this syndrome is the main differential diagnosis of West syndrome (WS; Maydell et al., 2001; Fejerman, 2008). Idiopathic and cryptogenic West syndrome affects babies of the same age range and is the most frequent epileptic encephalopathy, with onset during the first year of life. In infants with epileptic spasms in clusters without hypsarrhythmia the differential diagnosis is, of course, more difficult (Caraballo et al., 2003). Considering the variable motor manifestations of BMEI, the use of a term evoking only one of them (benign myoclonus or benign nonepileptic spasms) seems at this point restrictive and misleading. In addition, the use of terms such as benign myoclonus of early infancy or benign nonepileptic spasms creates a risk of ambiguity in considering the differential diagnosis with benign myoclonic epilepsy of infancy and infantile spasms. It, therefore, seems desirable to use a new term to define this condition that must be considered a nonepileptic paroxysmal motor manifestation characterized by variable motor manifestations. Accordingly, and considering that Dr. Natalio Fejerman has demonstrated a continuous interest in following up these cases for more than 40 years (Fejerman, 1984; Fejerman & Caraballo, 2002; Caraballo et al. (2009) and that Dr. Fejerman’s name has already been attached to this condition in several publications by authors from Argentina, France, and Italy (Gobbi et al., 1982; Beltramino, 1987; Pachatz et al., 2002), I propose that this syndrome is formally given the eponymic title of Fejerman syndrome. I confirm that I have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines. Disclosure: I have no conflicts of interest to disclose.

Epilepsia mioclónica benigna del lactante: un caso curioso

Benign myoclonic epilepsy in infants is a rare condition that belongs to the group of epilepsies and generalised epileptic syndromes. Doubts have recently arisen as to whether it is really benign, with some reports of cases of compromised psychomotor development when therapy is started late. The differential diagnosis can be associated with epileptic and non-epileptic diseases, and it is important to preclude it from the former due to their severity. Lombroso and Fejerman's benign myocloni are the non-epileptic diseases that create most problems as far as the differential diagnosis is concerned. Congenital defects of the cranial vault are quite rare and are sometimes associated with other malformations. Exceptionally they appear in isolation, and familial cases have been reported. Here we describe the case of a female infant, who had been subject to a follow-up in the Children's Neurology department from the age of 7 months and who had been diagnosed as suffering from unspecific bone erosion of the cranial vault and benign myoclonic epilepsy in infants. Psychomotor development has taken place within the range of parameters that can be considered to be normal and the patient is currently 25 months old. From the clinical point of view, in this case we can rule out the most severe epileptic situations. This is a clinical case that is atypical, not only because of the coexistence of two rare diagnoses, but also due to the clinical features and electroencephalographic manifestations. Both situations are very uncommon and there is no apparent relationship between them.

Benign Myoclonic Epilepsy in Infancy (BMEI): A Longitudinal Electroclinical Study of 22 Cases

Benign myoclonic epilepsy in infancy (BMEI) is a nosologically well-defined entity, characterized by myoclonic seizures (MS) in normal children younger than 3 years and by a good long term prognosis. In some cases the seizures are reflex. We studied 22 cases to better define the electroclinical semeiology and evolution of the disorder. Serial electroclinical and neuropsychological assessments, both during wakefulness and during sleep, were performed in 22 otherwise healthy children with spontaneous (17) or reflex (5) MS, recorded by video-EEG-polygraphy since clinical onset. Seizure onset was between 3 months and 4 years 10 months (50% during first year, 86% before the third year); in reflex cases onset, was earlier than the 14th month. MS recurred during wakefulness and slow sleep in all cases and during REM sleep in reflex cases. MS and related EEG discharges were synchronous or asynchronous. Often ictal EEG discharges were limited to the rolandic and vertex regions (falsely focal paroxysms). Several seizures were subtle and could have escaped recognition. Unusually frequent sleep startles were recorded mostly in reflex cases. MS were well controlled by treatment. At follow-up, between ages 3 and 19 years, four patients had occasional seizures; two had cognitive impairment and three had learning difficulties. No other seizures or cognitive deficits were observed in reflex cases. Seizures associated with BMEI are rarely truly generalized and are often so subtle and related to falsely focal paroxysms that their frequency can be underestimated. The reflex form is a well-defined variant with an early onset, peculiar electroclinical features, and a good prognosis.

Photosensitive Benign Myoclonic Epilepsy in Infancy

To describe the electroclinical features of subjects who presented with a photosensitive benign myoclonic epilepsy in infancy (PBMEI). The patients were selected from a group of epileptic subjects with seizure onset in infancy or early childhood. Inclusion criteria were the presence of photic-induced myoclonic seizures and a favorable outcome. Cases with less than 24 month follow up were excluded from the analysis. Eight patients were identified (4 males, 4 females). Personal history was uneventful. All of them had familial antecedents of epilepsy. Psychomotor development was normal in 6 cases, both before and after seizure onset. One patient showed a mild mental retardation and a further patient showed some behavioral disturbances. Neuroradiological investigations, when performed (5 cases), gave normal results. The clinical manifestations were typical and could vary from upward movements of the eyes to myoclonic jerks of the head and shoulders, isolated or briefly repetitive, never causing a fall. Age of onset was between 11 months and 3 years and 2 months. Characteristically, the seizures were always triggered by photic stimulation. Non photo-induced spontaneous myoclonic attacks were reported in 2 cases during the follow-up. Other types of seizures were present at follow-up in 2 cases. The outcome was favorable, even if, usually, seizure control required high AED plasma levels. Since the clinical symptoms were not recognized early, some patients were treated only many years after the onset of symptoms. Among BMEI patients, our cases constitute a subgroup in which myoclonic jerks were always triggered by photostimulation, in particular at onset of their epilepsy.