Several studies have demonstrated that seizure manifestations evolve according to developmental age. Although myelination is largely complete by two years of age, clinical seizure manifestations continue to evolve beyond this age (probably reflecting the caudorostral pattern of brain development), with an adult pattern of semiology unlikely before age 6 years. A high index of suspicion is therefore required when evaluating the clinical description of events for focality. The assessment will have obvious management implications, particularly for the diagnosis of an epilepsy syndrome. Most studies evaluating seizure semiology have been performed in surgical cohorts, where documentation of seizure type is made with video EEG telemetry and confirmed by seizure freedom after removal of the suspect area.
One study examined the localizing and lateralizing value of behavior change in focal seizures in childhood and found it was much more likely at seizure onset for children under age 6 years, occurring in 46% (25/56) compared to only 8/53 in the older group.1 Behavioral change was far more likely to be of an affective type (agitation, fearful expression, looking for shelter) than an arrest type. Both could represent an aura that could not be verbalized by children in this age group.
In another study of autonomic symptoms (respiratory, gastrointestinal, cutaneous, papillary, urinary) in children age 10 months to 12 years with temporal and extratemporal focal epilepsy, 60/100 patients produced at least one autonomic symptom during their seizures: 43 (70%) of 61 with temporal lobe epilepsy and 17 (44%) of 39 with extratemporal epilepsy. Apnea/bradycardia were more frequent in children <3 years2 with temporal lobe onset. Only twelve reported an epigastric aura, the youngest presenting at age 5.3 years reported as abdominal pain or discomfort. It was most frequently associated with temporal lobe onset, and was not lateralizing.
Age dependence has also been demonstrated in ictal automatisms, lateralizing signs and secondary generalization in studies of children with temporal lobe onset seizures.3 However emotional expressions and autonomic signs did not show age dependent manifestation. Emotional expressions (fear, crying, smile, pain, happiness, and laughing) appear more frequently in extratemporal (49%) than temporal (26%) lobe seizures.4 Positive emotional expressions were more frequently associated with right sided seizure onset.
Frontal lobe semiology under the age of 7 years is characterized by high seizure frequency (up to 40 per day), approximately half of whom show a tendency to cluster. In a study of 111 seizures in 14 patients, 47% attacks arose from sleep and were of short duration; no correlation was seen between age and duration.5 Auras were infrequent. Motor manifestations were most common. All had motor seizures; in fact, only 6 of 11 analyzed attacks displayed no motor signs at all. Besides tonic seizures, clonic components and epileptic spasms were the leading manifestations. Epileptic spasms typically began from age 2 to 16 months, and persisted well beyond infancy. Psychomotor seizures were rare. Behavior change however was ...