Maturation of EEG oscillations in children with sodium channel mutations
Gregory L Holmes1, Alex C Bender, Edie X Wu
1Department of Neurology, Neuroscience Center at Dartmouth, Dartmouth Medical School, Hanover, NH 03756, USA. Gregory.L.Holmes@Dartmouth.Edu
Insights
Dravet syndrome (DS) involves Scn1a gene mutations, leading to age-dependent changes in brainwave activity. These oscillatory alterations correlate with cognitive impairment in affected children.
Area of Science:
- Neuroscience
- Genetics
- Epilepsy Research
Background:
- Dravet syndrome (DS) is a severe infantile epileptic encephalopathy characterized by intractable seizures and cognitive deficits.
- Mutations in the Scn1a gene, crucial for interneuron function and brain rhythm generation, are found in most DS patients.
- Interneurons play a vital role in cognitive processing through brain rhythm generation.
Purpose of the Study:
- To investigate age-dependent alterations in electroencephalogram (EEG) oscillatory activity in children with Dravet syndrome and Scn1a mutations.
- To determine if specific EEG power spectral differences exist between children with DS and age-matched controls.
Main Methods:
- EEG power spectral analysis was performed on 23 EEGs from 12 children with DS and 18 age-matched controls during wakefulness.
- Frequency and power of brain oscillations were compared between the DS group and controls.
Main Results:
- Few EEG power spectral differences were observed in children under 2 years old.
- Children with DS aged 3-5 years showed significantly decreased alpha power compared to controls.
- Children with DS over 6 years exhibited increased theta and decreased alpha power compared to controls.
- Cognitive impairment severity increased with age in DS children, paralleling EEG findings.
Conclusions:
- Scn1a mutations induce age-dependent alterations in brain oscillatory processes in Dravet syndrome.
- These developmental changes in brain rhythms may contribute to the cognitive deficits observed in children with DS.
- EEG analysis reveals a potential biomarker for cognitive progression in Dravet syndrome.
Abstract:
Dravet syndrome (DS) is a severe epileptic encephalopathy beginning in infancy in which children have difficult to control seizures and cognitive impairment. The majority of children with DS carry mutations of the gene Scn1a, which codes for the alpha subunit of the type 1 voltage-gated sodium channel and is important for the function of interneurons. Interneurons have a critical role in the generation of brain rhythms involved in cognitive processing. We hypothesized that children with DS with Scn1a mutations would have abnormal oscillatory activity. To address this hypothesis, we used EEG power spectral analysis during the wakening to determine if frequency and power are altered in 23 EEGs from 12 children with DS compared to 18 age-matched controls. While there were few differences between the EEG power spectra in DS and controls in children under 2years, in older children group differences were apparent. In DS children between 3 and 5years there were significant decreases in percentage of alpha power compared to controls and in DS children over age 6years there was a marked increase of theta and decrease of alpha compared to controls. Developmental status paralleled the power spectral analysis with an increasing likelihood of having severe cognitive problems with increasing age. These results demonstrate that Scn1a mutations result in an age-dependent alteration in oscillatory process. Such abnormalities in developmental progression of oscillations may play an important role in poor cognitive development in children with DS.
