Lennox-Gastaut syndrome (LGS) is a severe epileptic encephalopathy with a prevalence of 1-2% of all patients with epilepsy. It is characterized by multiple pharmaco-resistant seizure types, including tonic, atypical absences and tonic or atonic drop attacks, and the presence of electroencephalographic abnormalities, such as slow-spike waves and paroxysmal fast rhythms. Intellectual disability, behavioural and psychiatric disorders are common comorbidities; these disturbances have a multi-factorial pathogenesis. The selection of the most appropriate drug must be tailored to each patient and guided by the prevalent seizure type. In this paper available pharmacological options are discussed and for each pharmacological agent, current evidence of efficacy and tolerability is provided. Valproic acid represents one of the first-line options in the treatment of LGS. Anyway, other antiepileptic drugs (AEDs) may be considered and added: lamotrigine, rufinamide, topiramate, clobazam can be efficacious. The use of felbamate must be carefully evaluated because of its adverse events. Perampanel, zonisamide, levetiracetam and fenfluramine have shown to be useful in the treatment of selected patients; nevertheless, the lack of RCTs does not allow to recommend their use in a systematic way. Recently, cannabidiol has provided high evidence of efficacy against LGS seizures; however, these data must be confirmed by long-term extensive studies and by trials comparing different AEDs, one to each other.

The rare syndrome of perioral myoclonia with absences (POMA) is described as a specific type of idiopathic generalized epilepsy in which absence seizures are accompanied by prominent perioral myoclonus as a consistent symptom. We present a 52-year-old man who was referred to our department due to treatment-resistant epilepsy. Typical seizures were described as rhythmic twitching of the lips which started at six years old, and his first convulsive seizure occurred at around 20 years old. Based on video-EEG recordings, we present two distinct EEG patterns accompanied by slight differences in clinical manifestations, which appear to be atypical of POMA. Firstly, consciousness was preserved during seizures, with no manifestation of absences. Secondly, regarding the EEG features, in some of the seizures, the perioral motor symptoms were tonic rather than myoclonic. The defining features of POMA are discussed in relation to this case.

Dravet syndrome (DS) is a medically refractory epilepsy that onsets in the first year of life with prolonged seizures, often triggered by fever. Over time, patients develop other seizure types (myoclonic, atypical absences, drops), intellectual disability, crouch gait and other co-morbidities (sleep problems, autonomic dysfunction). Complete seizure control is generally not achievable with current therapies, and the goals of treatment are to balance reduction of seizure burden with adverse effects of therapies. Treatment of co-morbidities must also be addressed, as they have a significant impact on the quality of life of patients with DS. Seizures are typically worsened with sodium-channel agents. Accepted first-line agents include clobazam and valproic acid, although these rarely provide adequate seizure control. Benefit has also been noted with topiramate, levetiracetam, the ketogenic diet and vagal nerve stimulation. Several agents presently in development, specifically fenfluramine and cannabidiol, have shown efficacy in clinical trials. Status epilepticus is a recurring problem for patients with DS, particularly in their early childhood years. All patients should be prescribed a home rescue therapy (usually a benzodiazepine) but should also have a written seizure action plan that outlines when rescue should be given and further steps to take in the local hospital if the seizure persists despite home rescue therapy.

In this article, we have traced back the history of typical absence seizures, from their initial clinical description to the more recent nosological position. The first description of absence seizures was made by Poupart in 1705 and Tissot in 1770. In 1824, Calmeil introduced the term "absences", and in 1838, Esquirol for the first time used the term petit mal. Reynolds instead used the term "epilepsia mitior" (milder epilepsy) and provided a comprehensive description of absence seizures (1861). In 1854, Delasiauve ranked absences as the seizure type with lower severity and introduced the concept of idiopathic epilepsy. Otto Binswanger (1899) discussed the role of cortex in the pathophysiology of "abortive seizures", whereas William Gowers (1901) emphasized the importance of a detailed clinical history to identify nonmotor seizures or very mild motor phenomena which otherwise may go unnoticed or considered not epileptic. At the beginning of the 20th Century, the term pyknolepsy was introduced, but initially was not universally considered as a type of epilepsy; it was definitely recognized as an epileptic entity only in 1945, based on electroencephalogram (EEG) recordings. Hans Berger, the inventor of the EEG, made also the first EEG recording of an atypical absence (his results were published only in 1933), whereas the characteristic EEG pattern was reported by neurophysiologists of the Harvard Medical School in 1935. The discovery of EEG made it also possible to differentiate absence seizures from so called "psychomotor" seizures occurring in temporal lobe epilepsy. Penfield and Jasper (1938) considered absences as expression of "centrencephalic epilepsy". Typical absences seizures are now classified by the International League Against Epilepsy among generalized nonmotor (absence) seizures.

Accurate diagnosis of a distinct epilepsy syndrome is based on well-defined electroclinical features that differentiate separate nosological entities. In clinical practice, however, syndromes may overlap and cases may present with unusual manifestations posing a diagnostic challenge. This heterogeneity has been documented in several cases presenting with eyelid myoclonia with or without absences (EMA) diagnosed either as Jeavons syndrome (JS) variants or as genetic generalised epilepsies defined by the presence of this unique clinical entity. The hallmark of JS is the triad: (1) eyelid myoclonia with or without absences, (2) eye closure-induced paroxysms, and (3) photosensitivity. The presence of massive myoclonus, intellectual disability, or slowing of the EEG background are not typical features of the syndrome and may cause delay in making the correct diagnosis. Adding to the variability of clinical features, we describe two female paediatric patients with probable genetic epilepsy who presented with EMA but demonstrated clear atypical features, such as prominent myoclonic seizures, atonic components on video-EEG, and cognitive impairment. We also note the presence of interictal and ictal posterior discharges during eyelid myoclonia in one, supporting similar previous observations leading to consideration of EMA as an occipital cortex-initiated seizure activity. [Published with video sequences on www.epilepticdisorders.com].