Figure 1.

Graphical illustration of the acoustic stimulation. During the night, slow waves were detected online in real time and tones were presented according to a 3 × 5-min-block design. One stimulation cycle consisted of 5 min no stimulation (NoStim_pre), 5 min stimulation (DOWN or UP) followed by 5 min no stimulation [(NoStim_after), shown for DOWN (left) and UP stimulation (right) enlarged on the bottom]. In patients diagnosed with benign epilepsy with centro-temporal spikes (BECTS) or generalized spike waves in sleep (n = 3) tones onset during the stimulation blocks were played precisely time-locked either to the down-phase (DOWN, reddish color) or up-phase (UP, bluish color) of the detected slow wave, alternately in every other stimulation cycle (top panel). In patients diagnosed with ESES (n = 2), only the DOWN stimulation (reddish color) was applied (middle panel). Stimulation was applied throughout the night when subjects were in deep sleep (i.e., N2 and N3, for further details see “Materials and Methods” section).