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About benign idiopathic partial epilepsies in infancy Volume 4, numéro 3, September 2002

We read with interest the paper by Bureau et al. [1] reporting on an EEG marker in infancy-onset focal epilepsies. Their data confirm our previous observation published in Brain & Development in the year 2000 [2]. But, in our report, we described not only a peculiar and characteristic EEG pattern (very similar to Bureau's cases), but we hypothesized on the existence of a previously unreported idiopathic benign partial epilepsy in infancy. We proposed to define it as "benign partial epilepsy in infancy and early childhood with vertex spikes and waves during sleep" (BVSE). In our description, characteristic spikes and waves appeared isolated or grouped in short series, localized in the vertex regions spreading to the central areas. Their particular morphology (a low voltage fast spike followed by a higher bell-shaped slow wave) is clearly distinct from both physiological sleep vertex spikes and benign BECT spikes. In a more recent paper [3], we reported on a case whose critical EEG was recorded using video-EEG. We showed both the critical picture and the vertex abnormalities that appeared one month later. In the same paper, we also reported on some personal cases with a more precocious onset (8 and 10 months) and some colleagues (Dr Meregalli from Milan and Dr Peruzzi from Novara) from Italy showed us two typical cases whose seizure onset was at 5 and 6 months respectively. In the past year, we also observed this electroclinical picture in a 15-month-old boy of north-African origin and in a 19-month-old boy of Indian origin (unpublished data, 2001). Moreover, follow-up of the our first published cases is now longer (our paper was sent to Brain & Development in August 1998 and follow-up data are relative to that month), and some of our cases are now pubescent with no seizure recurrence, so confirming their benign evolution. Some differences are evident between our and Bureau's cases, mostly for the seizure frequency, which is much higher in the French series. This could explain the difference in therapeutic approach, as our cases were not treated or, in few cases, for a short period only. Another difference is the lack, in our previous cases, of generalized SW discharges. In two more recently observed cases we found this EEG trait during the evolution. In their conclusion, Bureau et al. hypothesized that vertex spike paroxysms could be overlooked in previous reports that stressed the absence of EEG abnormalities in infants with benign focal epilepsies, both during awake and sleep EEG. These cases, described firstly by Vigevano and Watanabe [4, 5], have been recently placed in a proposed revision of ILAE epilepsy classification [6] and termed benign familial infantile seizures and benign infantile seizures (non-familial). This certainly could be possible, because this particular EEG pattern can be easily overlooked because of its particular appearance. In 1997, we published a series of 12 non-Japanese patients presenting with complex partial seizures in infancy and benign outcome, matching Watanabe's cases perfectly [7]. Of course, because we were aware of the existence of vertex spikes and waves abnormalities, we carefully evaluated both awake and sleep EEG records in the search for this specific and "subtle" EEG marker. None of our benign infantile seizures (non-familial) showed the presence of vertex spike abnormalities. Moreover, as stressed in our previous papers, ictal semiology of Watanabe's cases is different from our new proposed syndrome of BVSE. In conclusion, we think that two different benign idiopathic partial epileptic syndromes do exist in infancy. One is the form described by Vigevano and Watanabe, as benign infantile seizures, with the variant of familial and non-familial cases. The other form is BVSE, as described by us in 2000.

Références

1. Bureau M, Cokar O, Maton B, Genton P, Dravet C. Sleep-related, low voltage Rolandic and vertex spikes: an EEG marker of benignity in infancy-onset focal epilepsies. Epileptic Disord 2002; 4: 15-22.

2. Capovilla G, Beccaria F. Benign partial epilepsy in infancy and early childhood with vertex spikes and waves during sleep: a new epileptic form. Brain Dev 2000; 22: 93-9.

3. Capovilla G, Vigevano F. Benign idiopathic partial epilepsies in infancy. J Child Neurol 2001; 16: 874-81.

4. Vigevano F, Fusco L, Di Capua M, Ricci S, Sebastianelli R, Lucchini P. Benign infantile familial convulsions. Eur J Pediatr 1992; 151: 608-12.

5. Watanabe K, Yamamoto N, Negoro T, Takahashi I, Aso K, Maehara M. Benign infantile epilepsy with complex partial seizures. J Clin Neurophysiol 1990; 7: 409-16.

6. Engel J. A proposed diagnostic scheme for people with epileptic seizures and with epilepsy: report of the ILAE Task Force on Classification and Terminology. Epilepsia 2001; 42: 796-803.

7. Capovilla G, Giordano L, Tiberti S, Valseriati D, Menegati E. Benign partial epilepsy in infancy with complex partial seizures (Watanabe's syndrome): 12 non-Japanese new cases. Brain Dev 1998; 20: 105-11.