The validity of a separate classification of cryptogenic localization related epilepsy amongst childhood epilepsies.
BACKGROUND
One-third of children with epilepsy are classified as having a cryptogenic localization related epilepsy (CLRE). In cohort studies CLRE is often grouped together with either symptomatic localization related epilepsy (SLRE) or idiopathic generalized epilepsy (IGE). Therefore, this categorization is not specific enough and will not lead to prognostic or treatment information. We objectified the classification differences between these categories.


METHODS
A total of 114 children admitted to our epilepsy centre underwent a standardized clinical analysis, which yielded age at onset, duration of the epilepsy, seizure frequency, seizure type, percentage of interictal epileptiform activity on EEG (IEA), type of treatment, and full scale IQ. These variables are regarded the characteristics of the epilepsy, and used in a discriminant function analysis.


RESULTS
IEA was found to be the only variable to distinguish between groups of epilepsy. SLRE could easily be distinguished significantly from IGE and CLRE, while the latter two did not differ significantly. Discriminant function analysis combined the variables into two functions, applicable to classify the children. By applying this statistical analysis method, the groups clinically classified as SLRE and IGE were mostly classified as SLRE (71.4%) and IGE (57.9%). However, CLRE appeared difficult to classify (49.2%), and most children were classified as either SLRE (19%) or IGE (31.7%).


CONCLUSIONS
The current opinion that CLRE is 'probably symptomatic' cannot be confirmed in all cases in this study. It is most likely that the current CLRE population consists of both children with eventually SLRE, as well as yet to be described syndromes to be classified as idiopathic epilepsies. We emphasize the need for separate studies regarding children with 'probably symptomatic' (cryptogenic) localization related epilepsy, as this will maximally help children, caretakers and treating physicians to achieve the best possible outcome.
Reijs
Rianne P
RP
Department of Research and Development, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands. rreijs@gmail.com
van Mil
Saskia G M
SG
van Hall
Mariette H J A
MH
Arends
Johan B A M
JB
Weber
Jacobiene W
JW
Renier
Willy O
WO
Aldenkamp
Albert P
AP
D000293:Adolescent; D017668:Age of Onset; D000927:Anticonvulsants / Q000627:therapeutic use; D002648:Child; D015331:Cohort Studies; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000145:classification* / Q000188:drug therapy / Q000473:pathology; D004827:Epilepsy / Q000145:classification* / Q000188:drug therapy / Q000473:pathology*; D004829:Epilepsy, Generalized / Q000145:classification* / Q000188:drug therapy / Q000473:pathology; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013577:Syndrome
D000927:Anticonvulsants