|Budget Amount *help
¥1,600,000 (Direct Cost : ¥1,600,000)
Fiscal Year 1992 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1991 : ¥1,300,000 (Direct Cost : ¥1,300,000)
To clarify the difference or relation between genetic factors for febrile convulsions (FC) and epilepsy (EP), two studies were carried out ; (1)a prospective neurophysiological follow-up of cohort of 113 offspring of 64 epileptic patients supposed to have high risk for convulsive disorders, particularly for EP,and(2)a clinicoelectrical study on 113 sibling of 88 patients with FC.
1)Among 103 children born to 64 epileptic parents, clinical seizures developed in 20 children (19.4%) and epileptic discharges in 27 (26.2%). Of clinical seizures, FC appeared in 13 cases (12.6%), recurrent afebrile seizures in 5 (4.9%), an isolated afebrile seizure (probably benign infantile convulsion) and a post-traumatic early seizure in one each (1.0%). According to Ohtahara' classfication, FC cases were subclassfied into 4 cases (3.9%) of simple FC,one case (1.0%) of complex FC,and 8 cases (7.8%) of epileptic FC.Thus, incidence of recurrent afebrile seizures (4.9%) was about 5 times higher than the preval
ence rate of childhood epilepsy in general population, i.e.0.82% in Okayama Prefecture. Adding epileptic FC,it rose up to over 10 times. But, no increase was observed in the incidence of simple FC (3.9%) or non-epileptic FC (4.9%) compared to the reported prevalence rates of FC in the general population (5-10%).
2)With 66 offspring of epileptic parents over 3 years of age, clinical seizures were noted in as many as 12 cases (42.9%) among 28 cases with additional genetic factor (AGF) within the second degree of relatives. This sate was significantly higher than 13.1% (5 cases) in 38 cases without such additional family history of convulsive disorders. Although FC occurred in 28.6% (8 cases) of the AGF group and 10.5% (4 cases) of the non-AGF group, epileptic FC consisted 87.5% (7/8 cases) of FC in the AGF group compared to 25.0% (1/4 cases) in the non-AGF group. These finding suggested that the inherited factor through epileptic parents is the epileptic predisposition.
3)39 (34.5%) of 113 sibling of 88 FC children had FC,including 13 cases (11.5%) with epileptic FC whose EEG showed epileptic discharges. It was also noteworthy that no epileptic FC was noted in sibling of simple FC.
4)Pseudo petit mal discharge and hypnagogic paroxysmal spike-wave activity, which have been considered characteristic to FC,were rarely detected in simple FC,but frequently in epileptic FC.Accordingly, these EEG pattern, particularly the latter, were suggested to relate the epileptic predisposition in infancy and early childhood.
In conclusion, this investigation supported the difference between convulsive and epileptic predisposition. Epileptic FC may closely relate to the epileptic predisposition which is pathological, but simple FC will be a specific group based on the convulsive predisposition which will be universally predisposed to human being, regulating the convulsive threshold.