P260 Spindle-shaped high frequency (±100 Hz) oscillatory activity in scalp EEG of children

• Published in: Clinical neurophysiology 2017-09, Vol.128 (9), p.e261-e262
• Main Authors: Mooij, Anne, Raijmann, Renee, Jansen, Floor, Braun, Kees, Zijlmans, Maeike
• Format: Article
• Language: English
• Subjects: High frequency oscillations; surface EEG
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2017.07.268

To describe a spindle-shaped ripple observed in normal scalp EEG of children and to describe its correlation with age. We included 22 patients from age 1 to 14years. All children had a wake and sleep EEG without spikes. We marked ripples in sleep EEG, filtered between 80 and 250Hz, in bipolar montage. We determined mean frequency, duration and root mean square amplitude. We counted the number of events per channel and calculated ripple rate over a period of 10min. We categorised patients according to three groups: (1) no neurological diagnosis; (2) no epilepsy, but brain disorder; (3) diagnosis of epilepsy. In the ten children without a neurological diagnosis, we ran a lineal regression model with 10log transformed cumulative ripple rate as dependent variable and age as predictor. We found this spindle-shaped ripple in 19 out of 22 children across diagnostic groups. Ripples occurred mostly on central channels (Cz-Pz). Mean frequency was 102Hz, mean duration 70ms, mean root mean square amplitude 0.95μV. Ripple rate was negatively correlated with age (F(1,8)=6.74; p=0.03). The occurrence of these spindle-shaped ripples in normal EEGs and in healthy children indicates that this ripple activity is physiological. The negative correlation with age suggests its occurrence might be related to brain development. Scalp EEGs without spikes can reveal physiological ripples in children. This is the first study to describe physiological high frequency oscillations recorded in human neocortex with scalp EEG.