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seizures. The recognition of epileptic syndromes and diseases, most of which are well defined
and easy to diagnose, offers a clearly more precise and useful picture:

‘An epileptic syndrome is a cluster of seizures, other symptoms, physical signs
and laboratory findings, which are associated in a non-fortuitous manner’2.

Identification of an epileptic syndrome requires clinical findings (type of seizure(s), age at
onset, precipitating factors, severity and chronicity, circadian distribution, aetiology,
anatomical location and prognosis) and data from ancillary studies (EEG, brain anatomical
and metabolic imaging, haematology and biochemistry).

‘A disease (as opposed to a syndrome) has common aetiology and prognosis
despite variations in expression between individuals’2.

In the current Classification of the International League Against Epilepsy (ILAE)2 there are
two major dichotomies/divisions:

 Whether the predominant seizure type is localised (localisation-related epilepsies and
syndromes) or generalised (generalised epilepsies and syndromes), and

 Whether the aetiology is idiopathic (with a genetic predisposition, normal physical
signs and development), symptomatic (structural), or cryptogenic (supposed of
symptomatic, i.e. structural, cause but not demonstrable on MRI).

The combination of these divisions shapes the first two major groups of epileptic syndromes
and diseases. A third group covers syndromes with seizures of uncertain focal or generalised
nature, often the case in nocturnal seizures. The fourth and final group refers to syndromes
where the seizures are related to a specific situation like fever, drugs or metabolic imbalance2.

There is a long list of syndromes in each of the major divisions. Table 1 shows the syndromic
classification of the generalised epileptic syndromes. Most syndromes start at an early age
and there are profound differences in prognosis between syndromes with similar
seizure/symptom diagnosis2.

This classification2 is not infallible: syndromes may overlap or evolve from one to another,
syndrome definitions maybe inadequate, terminology may difficult or inappropriate and
classification is sometimes complex. Such problems should pose a challenge to arrive at the
proper medical diagnosis, and should not be used as an excuse against making one. Many of
the proposed diseases/syndromes are common, well defined and easy to diagnose, such as
juvenile myoclonic epilepsy12. In some diseases/syndromes, like benign familial neonatal
convulsions, genetics and pathophysiology have been dramatically clarified13,14. Others, like
the syndromes of idiopathic generalised epilepsy (IGE) with typical absence seizures15,16,
need further research and understanding for a better categorisation. Molecular genetics is
already making decisive discoveries in the identification of epilepsies; new single-gene
syndromes of partial epilepsy, like autosomal dominant nocturnal frontal lobe epilepsy, are
now well documented17,18.

If a syndromic/disease diagnosis is not possible, a symptom/seizure categorisation should be
used and seizure type(s) should be clearly defined. A tentative disease/syndrome diagnosis
should be used in conjunction with the seizure categorisation, and serve as basis for
monitoring the natural history.