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14-and-6 Hz positive bursts in childhood encephalopathies
1Department of Neurology, University of Michigan Medical School, Ann Arbor.
Insights
14-and-6 Hz positive bursts, a normal EEG pattern, appear in children with altered mental status, not just Reyes syndrome. Their incidence and features in encephalopathies are similar to those in healthy children.
Area of Science:
- Pediatric Neurology
- Clinical Neurophysiology
- Epileptology
Background:
- 14-and-6 Hz positive bursts are a recognized EEG pattern.
- This pattern has been observed in children with liver disease, particularly Reyes syndrome.
- Its presence in other pediatric encephalopathies requires further investigation.
Purpose of the Study:
- To determine the incidence of 14-and-6 Hz positive bursts in children with stupor or coma.
- To compare the characteristics and incidence of these bursts in encephalopathic children versus a normal control group.
- To assess whether these bursts represent a pathological process or a normal EEG variant in childhood encephalopathies.
Main Methods:
- Review of 154 portable EEGs from 111 children with altered mental status.
- Analysis of EEG patterns, focusing on 14-and-6 Hz positive bursts.
- Comparison with an age-matched control group (75 children) with normal sleep EEGs.
Main Results:
- Seven children with altered mental status exhibited 14-and-6 Hz positive bursts, often with background slowing.
- These bursts were similar in morphology, location, and frequency to those in normal controls but were more readily activated by stimulation.
- No statistically significant difference in incidence was found between the encephalopathic group and the control group (7/111 vs. 5/75).
Conclusions:
- 14-and-6 Hz positive bursts can occur in various childhood encephalopathies, not exclusively in Reyes syndrome.
- The findings suggest these bursts may represent a persistent normal EEG feature rather than a sign of underlying pathology.
- Further research is warranted to understand the implications of these bursts in pediatric neurological conditions.
Abstract:
14-and-6 Hz positive bursts, a benign epileptiform variant, have also been described in comatose children with liver disease, chiefly Reyes syndrome. To determine the incidence of this pattern in children in stupor or coma, 154 portable EEGs in 111 children with mental status changes were reviewed. Seven children showed 14-and-6 Hz bursts in the setting of moderate to marked background slowing. They were similar to positive bursts seen in normals in location, duration, morphology, frequency and repetition rate. They differed in being readily activated by stimulation. The etiology was toxic/metabolic in 4 cases, primary cerebral insult in 2 cases and a combination of the two in 1 case. Amongst an age-matched control population, 5 of 75 showed 14-and-6 Hz positive bursts in stage I or II sleep. There were no statistically significant differences in incidence rates between the 2 groups. 14-and-6 Hz positive bursts may occur in diverse encephalopathies of childhood, not just Reyes syndrome. The similar incidence rate, morphology and topography to normals suggest that the presence of these wave forms in encephalopathies represents persistence of a normal EEG feature rather than an expression of some underlying pathophysiological process.