Fig. 1: Study design.

Visualization of the 5-week experimental paradigm, a between-person double-blind randomized controlled trial. (I) screening and preparation (days −7 to 1): Participants underwent a screening, and eligible participants attended the first appointment (t0, scheduled 2–5 days before the ImR memory modulation). Two nights before the ImR intervention, participants completed two habituation nights (HN-1 and HN-2) with the wearable EEG. Participants completed an app-based intrusion diary during seven days pre-ImR. (II) Experimental ImR and TMR (days 1 to 7): ImR took place in the evening of day 1, including a pre-ImR (t1) and post-ImR (t2) script driven imagery procedure to assess memory characteristics. Participants then were randomized to cueing conditions and completed two experimental nights (EN-1 and EN-2): cueing with words from the ImR updated memory (experimental group, EG) vs. cueing with neutral words (control group 2, CG-2) or no cueing (control group 1, CG-1). The script-driven imagery procedure to assess memory characteristics was repeated online via videocall each morning 30 min after the habitual wakening time after EN-1 (t3) and EN-2 (t4). Participants in the EG were then asked to complete three additional nights with the MHSL-SB between day 3 and day 7 with participants in EG-1 continue to receive ImR words cueing, whereases participants in EG-2 received three additional sham-EEG nights (without ImR words cueing). All participants continued with the app-based intrusion diary within seven days post-ImR. (II) Follow-up (days 7 to 28): Script-driven imagery to assess emotional memory characteristics at 1-week (t5, in-lab) and 1-month (t6, online via video call) post-ImR.