Validity of parentally reported febrile seizures: the generation R study.

The objective of this study was to examine the validity of the diagnosis of "febrile seizure" as reported by parents. The study was embedded in a population-based prospective cohort study. Information on paroxysmal events was obtained by screening questions at ages 1, 2, and 3 years. One of these questions was the following: "Did your child have a febrile seizure?" If a screen-positive result was found, an additional questionnaire was sent and the medical record was consulted. Based on this information, paroxysmal events were classified by a pediatric neurologist as febrile seizure or other event. The validity of a positive reply to the screening question on febrile seizures was assessed, taking this classification as reference standard. Analyses were based on participants who reported at least one paroxysmal event (n = 610). The sensitivity of the positive reply to the question, "Did your child have a febrile seizure?", for the diagnosis of febrile seizures was 92%, the specificity 72%, the positive predictive value 41%, and the negative predictive value 98%. In conclusion, the sensitivity of the question, "Did your child have a febrile seizure?", is high. The positive predictive value is only 41%. Although this question may be appropriate as a screening instrument for febrile seizures, a second stage of evaluation is necessary to identify true cases.

Febrile seizures and behavioural and cognitive outcomes in preschool children: the Generation R study.

AIM: General developmental outcome is known to be good in school-aged children who experienced febrile seizures. We examined cognitive and behavioural outcomes in preschool children with febrile seizures, including language and executive functioning outcomes. METHOD: This work was performed in the Generation R Study, a population-based cohort study in Rotterdam from early fetal life onwards. Information about the occurrence of febrile seizures was collected by questionnaires at the ages of 1, 2, and 3 years. At the age of 3 years, behaviour and emotion were assessed using the Child Behavior Checklist. Information on expressive language development was obtained by the Language Development Survey at the age of 2 years 6 months. To assess executive functioning, parents completed the Behaviour Rating Inventory of Executive Function - Preschool Version when their children were 4 years old. Final analyses were based on 3157 children. RESULTS: No associations were found between febrile seizures and the risk of behavioural problems or executive functioning. In contrast to single febrile seizures, recurrent febrile seizures were significantly associated with an increased risk of delayed vocabulary development (odds ratio 3.22, [95% confidence interval 1.30-7.94]). INTERPRETATION: Febrile seizures are not associated with problem behaviour or executive functioning in preschool children, but the results suggest that children with recurrent febrile seizures might be at risk for delayed language development.

Frequent fever episodes and the risk of febrile seizures: the Generation R study.

AIM: To examine the association between the number of fever episodes and the risk of febrile seizures. METHODS: This study was embedded in a population-based prospective cohort study from early foetal life onwards. Information about the occurrence of febrile seizures and fever episodes was collected by questionnaires at the ages of 12, 24 and 36 months. Analyses were based on 3033 subjects. The risk of febrile seizures was compared between children with frequent fever episodes (>2 per year), and children with only 1 or 2 fever episodes per year. RESULTS: The frequency of fever episodes was not associated with the risk of febrile seizures in the age range of 6-12 months. In the second and third year of life, having more than 2 fever episodes was associated with an increased risk of febrile seizures (odds ratios 2.02 [95% confidence interval 1.13-3.62] and 2.29 [95% confidence interval 1.00-5.24], respectively). In the age range between 6 and 36 months, we observed a significant trend between the frequency of fever episodes (<2, 3-4 or >4 per year) and the risk of febrile seizures (p-value for trend < 0.001). The association between the number of fever episodes and the occurrence of febrile seizures was stronger for children with recurrent febrile seizures. CONCLUSION: Frequent fever episodes are associated with an increased risk of febrile seizures in the second and third years of life. Further studies are needed to identify the mechanisms underlying this association.

Fetal growth retardation and risk of febrile seizures.

OBJECTIVE: The goal was to examine the associations between fetal growth characteristics in different trimesters of pregnancy and the occurrence of febrile seizures in early childhood. METHODS: This study was embedded in a population-based, prospective, cohort study from early fetal life onward. Fetal growth characteristics (femur length, abdominal circumference, estimated fetal weight, head circumference, biparietal diameter, and transverse cerebellar diameter [TCD]) were measured with ultrasonography in the second and third trimesters of pregnancy. Information on the occurrence of febrile seizures was collected with questionnaires at the ages of 12 and 24 months. Analyses were based on data for 3372 subjects. RESULTS: In the second trimester, children in the lowest tertile of TCDs were at increased risk of developing febrile seizures, compared with children in the highest tertile (odds ratio 2.87 [95% confidence interval: 1.31-6.28]). In the third trimester, children in the lowest tertile of all general growth characteristics (femur length, abdominal circumference, and estimated fetal weight) were at increased risk of developing febrile seizures. This association was strongest for children in the lowest tertile of estimated fetal weight (odds ratio: 2.57 [95% confidence interval: 1.34-4.96]). Children in the lowest tertile of biparietal diameter in the third trimester also were at increased risk of febrile seizures. Similar but not statistically significant tendencies were observed for head circumference and TCD. CONCLUSIONS: Fetal growth retardation is associated with increased risk of febrile seizures in the first 2 years of life. Adverse environmental and genetic factors during pregnancy may be important in the development of febrile seizures.

Paroxysmal disorders in infancy and their risk factors in a population-based cohort: the Generation R Study.

AIM: To examine the incidence of paroxysmal epileptic and non-epileptic disorders and the associated prenatal and perinatal factors that might predict them in the first year of life in a population-based cohort. METHOD: This study was embedded in the Generation R Study, a population-based prospective cohort study from early fetal life onwards. Information about the occurrence of paroxysmal events, defined as suddenly occurring episodes with an altered consciousness, altered behaviour, involuntary movements, altered muscle tone, and/or a changed breathing pattern, was collected by questionnaires at the ages of 2, 6, and 12 months. Information on possible prenatal and perinatal determinants was obtained by measurements and questionnaires during pregnancy and after birth. RESULTS: Information about paroxysmal events in the first year of life was available in 2860 participants (1410 males, 1450 females). We found an incidence of paroxysmal disorders of 8.9% (n=255) in the first year of life. Of these participants, 17 were diagnosed with febrile seizures and two with epilepsy. Non-epileptic events included physiological events, apnoeic spells, loss of consciousness by causes other than epileptic seizures or apnoeic spells, parasomnias, and other events. Preterm birth (p<0.001) and low Apgar score at 1 minute (p<0.05) were significantly associated with paroxysmal disorders in the first year of life. Continued maternal smoking during pregnancy and preterm birth were significantly associated with febrile seizures in the first year of life (p<0.05). INTERPRETATION: Paroxysmal disorders are frequent in infancy. They are associated with preterm birth and a low Apgar score. Epileptic seizures only form a minority of the paroxysmal events in infancy. In this study, children whose mothers continued smoking during pregnancy had a higher reported incidence of febrile seizures in the first year of life. These findings may generate various hypotheses for further investigations.