Scalp high-frequency oscillation rates are higher in younger children.
High-frequency oscillations in scalp EEG are promising non-invasive biomarkers of epileptogenicity. However, it is unclear how high-frequency oscillations are impacted by age in the paediatric population. We prospectively recorded whole-night scalp EEG in 30 children and adolescents with focal or generalized epilepsy. We used an automated and clinically validated high-frequency oscillation detector to determine ripple rates (80-250 Hz) in bipolar channels. Children < 7 years had higher high-frequency oscillation rates (P = 0.021) when compared with older children. The median test-retest reliability of high-frequency oscillation rates reached 100% (iqr 50) for a data interval duration of 10 min. Scalp high-frequency oscillation frequency decreased with age (r = -0.558, P = 0.002), whereas scalp high-frequency oscillation duration and amplitude were unaffected. The signal-to-noise ratio improved with age (r = 0.37, P = 0.048), and the background ripple band activity decreased with age (r = -0.463, P = 0.011). We characterize the relationship of scalp high-frequency oscillation features and age in paediatric patients. EEG intervals of  10 min duration are required for reliable measurements of high-frequency oscillation rates. This study is a further step towards establishing scalp high-frequency oscillations as a valid epileptogenicity biomarker in this vulnerable age group.
['Cserpan|Dorottya|D|https://orcid.org/0000-0002-7538-1931', 'Boran|Ece|E|', 'Lo Biundo|Santo Pietro|SP|', 'Rosch|Richard|R|https://orcid.org/0000-0002-0316-5818', 'Sarnthein|Johannes|J|https://orcid.org/0000-0001-9141-381X', 'Ramantani|Georgia|G|https://orcid.org/0000-0002-7931-2327']
high-frequency oscillations scalp EEG biomarker reliability paediatric epilepsy