EEG spectral analysis in children with febrile delirium
Sachiko Onoe1, Toshinori Nishigaki
1Department of Pediatrics, Osaka Police Hospital, 10-31 Kitayama-cho, Tennouji-ku, Osaka 543-0035, Japan.
Insights
Febrile delirium in children is characterized by posterior slowing on electroencephalogram (EEG). Decreased delta wave power in EEG is the best indicator of clinical improvement in these cases.
Area of Science:
- Pediatric Neurology
- Neurophysiology
- Clinical Medicine
Background:
- Febrile delirium, an acute confusional state with fever, is rarely reported despite fever being common in children.
- Previous research indicated posterior slowing in electroencephalogram (EEG) of febrile delirious patients.
Purpose of the Study:
- To evaluate occipital slow wave features using spectral analysis in febrile delirium.
- To identify EEG parameters correlated with clinical improvement.
Main Methods:
- Investigated digital EEG tracings using Fourier analysis (Fast Fourier Transform - FFT) in 20 pediatric patients (2-13 years).
- Performed spectral analysis of EEG, including repeat analysis in 7 patients and comparison with 34 controls.
- Analyzed EEG of a febrile child without delirium.
Main Results:
- Febrile delirium episodes occurred within the first three days of fever, lasting up to 10 minutes.
- Increased relative delta frequency band power was observed in 65% of patients, with preserved occipital alpha rhythm.
- The decrease in relative delta band power emerged as the most reliable parameter for clinical improvement; posterior slowing was also noted in a febrile child without delirium.
Conclusions:
- Febrile delirious children exhibit distinct clinical and spectral EEG features.
- Numerical EEG data aids in comparing serial findings and monitoring recovery.
Unlabelled:
Febrile delirium is defined as an acute and transient confusional state with high fever. There are very few reports on febrile delirium, although fever is one of the commonest symptoms in children. We previously found a posterior slowing in the electroencephalogram (EEG) of delirious patients with fever. The purpose of this study is to evaluate the features of occipital slow waves by spectral analysis and to find a parameter associated with clinical improvement.
Methods:
Digital EEG tracings were investigated by Fourier analysis in 20 patients aged from 2 to 13 years. The fast Fourier transform (FFT) was computed for 20 s tracing from the P3-A1 and P4-A2 derivations. The spectral analysis of EEG was repeated in 7 patients. The tracings of 34 control subjects were also analyzed by FFT. EEG of a febrile, nine-year-old girl without delirium was also studied.
Results:
Febrile delirium was seen during the first three days of fever. The episodes lasted up to 10 min. Four patients showed febrile delirium again after admission but they became conscious a few minutes later. The relative power in the delta frequency band was increased in 65% of patients with preservation of the occipital alpha rhythm. In addition, repeated febrile delirium did not cause worsening of the posterior slowing. The duration of abnormal EEG was only a few days and the decrease of relative power in the delta frequency band was the best parameter of clinical improvement. Posterior slowing was also found in a febrile patient without delirium.
Conclusion:
Febrile delirious children showed the characteristic clinical and spectral analytical features and the numerical data of EEG facilitate the comparison of the serial findings.
