A big advance in epileptology has been the recognition of syndromes with distinct aetiology, clinical and EEG features, treatment and prognosis. A prime and common example of this is rolandic epilepsy that is well known by the general paediatricians for over 50 years, thus allowing a precise diagnosis that predicts an excellent prognosis. However, rolandic is not the only benign childhood epileptic syndrome. Converging evidence from multiple and independent clinical, EEG and magnetoencephalographic studies has documented Panayiotopoulos syndrome (PS) as a model of childhood autonomic epilepsy, which is also common and benign. Despite high prevalence, lengthy and dramatic features, PS as well as autonomic status epilepticus had eluded recognition because emetic and other ictal autonomic manifestations were dismissed as non-epileptic events of other diseases. Furthermore, PS because of frequent EEG occipital spikes has been erroneously considered as occipital epilepsy and thus confused with the idiopathic childhood occipital epilepsy of Gastaut (ICOE-G), which is another age-related but rarer and of unpredictable prognosis syndrome. Encephalitis is a common misdiagnosis for PS and migraine with visual aura for ICOE-G. Pathophysiologically, the symptomatogenic zone appears to correspond to the epileptogenic zone in rolandic epilepsy (sensory-motor symptomatology of the rolandic cortex) and the ICOE-G (occipital lobe symptomatology), while the autonomic clinical manifestations of PS are likely to be generated by variable and widely spread epileptogenic foci acting upon a temporarily hyperexcitable central autonomic network. Rolandic epilepsy, PS, ICOE-G and other possible clinical phenotypes of benign childhood focal seizures are likely to be linked together by a genetically determined, functional derangement of the systemic brain maturation that is age related (benign childhood seizure susceptibility syndrome). This is usually mild but exceptionally it may diverge to serious epileptic disorders such as epileptic encephalopathy with continuous spike and wave during sleep. Links with other benign and age-related seizures in early life such as febrile seizures, benign focal neonatal and infantile seizures is possible. Overlap with idiopathic generalized epilepsies is limited and of uncertain genetic significance. Taking all these into account, benign childhood focal seizures and related epileptic syndromes would need proper multi-disciplinary re-assessment in an evidence-based manner.

Purpose. To define the spectrum of the epileptic syndromes and epilepsies (other than the idiopathic epilepsies of childhood with occipital paroxysms) that can be associated with fixation-off sensitivity (FOS), delineate the electrographic types of FOS abnormalities and identify the patterns that can be associated with clinical seizures, and examine whether there may be a pure form of fixation-off sensitive epilepsy. Methods. We reviewed the clinical and video EEG data of all our patients with FOS over the last 12 years. Children with idiopathic focal epilepsies and occipital EEG paroxysms were excluded. Results. From January 1995 to December 2006, 19 of about 8,500 patients had had one or more video-EEGs with FOS, yielding an approximate incidence of 0.2%. From the 14 patients with full clinical and EEG data available, 12 had various epilepsies that included IGE phenotypes (7), symptomatic or probably symptomatic focal (3), cryptogenic generalised (1), and adult onset idiopathic photosensitive occipital (1), and two had no seizures. Seven patients (50%) were photosensitive. FOS EEG abnormalities were occipital in six patients, generalised in eight, and generalised with posterior emphasis in two patients. Seven of these patterns were associated with habitual seizures in seven patients, but actual FOS-induced seizures (absences) were documented with video EEG in only one patient; three others had some historical evidence suggesting that, under some circumstances, their FOS EEG abnormalities might generate clinical seizures. Conclusions. Despite the association of FOS with generalised and focal, symptomatic and cryptogenic and mild or pharmaco-resistant epilepsies, closer analysis of our data, and supportive evidence from functional imaging and physiological observations on alpha rhythm generation, disclose a prominent role of the occipital areas, even when FOS EEG abnormalities and seizures are ostensibly generalised. Although FOS appears to be of relatively low epileptogenicity, an electroclinical profile of pure FOS epilepsy may exist [Published with video sequences].

These findings demonstrate that the contribution of the EEG technologists to the diagnosis of people with epilepsies can expand well beyond their established role of recording and describing an EEG. We propose that technologists should be actively involved in prospective electroclinical studies if carefully designed protocols are used.