Table 1.

Methodological details of the identified articles.

Study	Ripple, fast ripple	Sampling rate (kHz)	Time	Threshold	Detection	Outcome	Follow-up
Ochi et al., 2007	R	1	pre-/ ictal	No	Visual	Engel	17.4 (11–23)
Jacobs et al., 2010b	R, FR	2	SWS	No	Visual	Engel	22.7 (6.8)
Akiyama et al., 2011	R, FR	1	NREM	Yes	Auto	ILAE	24
van't Klooster et al., 2011	R, FR	2	e-stim	Yes	Visual	Engel	>12
Modur et al., 2011	R	1	ictal	Yes	Visual	Engel	26.5 (6.57)
Usui et al., 2011	FR	1	inter-/ ictal	No	Visual	Engel	12–54
Fujiwara et al., 2012	R (FR)	2	ictal	No	Visual	Seizure free	n.a.
Cho et al., 2014	R, FR	2	SWS	Yes	Auto	Engel	26.33 (4.76)
Kerber et al., 2014b	R (FR)	1	SWS	No	Visual	Engel	52.94 (18.27)
van Klink et al., 2014	R, FR	2	io	No	Auto	Engel	12
Okanishi et al., 2014	R, FR	1–2	NREM	Yes	Auto	Engel	58 (19–76)

The columns indicate whether R, Ripples; and/or FR, Fast Ripples were assessed, the kind of EEG/the time when HFOs were searched in the EEG; i.e., during SWS, interictal slow wave sleep; NREM, interictal non-rapid eye movement sleep; io, intra-operative EEG; or during e-stim, electrical stimulation; further, the columns indicate whether the study used a threshold (thresh) so that channels were considered as containing HFOs only if the rate of HFO-occurrence/time interval exceeded a defined threshold, whether the study used auto: automated, or visual detection of HFOs, and which outcome classification was used. Finally, follow-up is indicated as general follow-up time for all patients or in average months along and/or with the range or standard deviation, depending on what information was given in the original paper. n.a., not available.