Nearly half of patients with post-traumatic stress disorder (PTSD) do not respond optimally to standard psychotherapy. Sleep represents a unique time-window to increase treatment effects based on its essential role in the processing of (traumatic) memories. In this project, sponsored by a Hersenstichting grant and a Narsad Young Investigator grant, we will apply a novel technique using EEG-guided acoustic stimulation to reactivate treatment memories and boost slow wave sleep in patients with PTSD during sleep after standard psychotherapy. This is hypothesized to strengthen the storage of treatment memories and generally restore disturbed sleep, together resulting in stronger symptom improvement.