Neuroscientific and clinical approach for the study and treatment of nightmares

This thesis unveils the study we accomplished with patients suffering from nightmare disorder, a psychiatric disorder characterized by dreams with strong negative emotions occurring in rapid-eye-movement sleep. Nightmares can be conceived as dysfunctional dreams, a phenomenon deprived from efficient adaptive emotional processes. A common treatment for nightmare disorder is imagery rehearsal therapy, a cognitive-behavioral technique that consists in changing the storyline of a nightmare towards a less negative scenario. Previous work has shown that imagery rehearsal therapy is most efficient for individuals having nightmares in which distress can be monitored and further regulated. In the present clinical study, we further investigated the effects of targeted memory reactivation technique, as a new tool empowering IRT for an accelerated remission of nightmare disorder. The goal of the present clinical study is to train our patients for better emotion regulation through fear extinction, using targeted memory reactivation in rapid-eye-movement sleep to facilitate such process. In total, thirty-six patients with nightmare disorder were recruited; half of them received imagery rehearsal therapy as a main treatment (control group), while the other half benefitted from imagery rehearsal therapy associated with targeted memory reactivation (targeted memory reactivation group). Every night for two weeks, both groups practiced imagery rehearsal therapy before sleep, during which the targeted memory reactivation group received a sound, whereas the control group didn’t associate any sound to the imagery. Both groups then received the auditory stimulus during rapid-eye movement sleep over two weeks. Our results show that the targeted memory reactivation group had significantly less frequent nightmares, as well as a greater proportion of positive emotions in their dreams compared to the control group. Such improvement was sustained three months after intervention. Targeted memory reactivation potentiated nightmare disorder treatment by boosting the imagery rehearsal therapy effects. To date, no other study used imagery rehearsal therapy associated with targeted memory reactivation to treat nightmares. Our results encourage future studies to test the efficacy of this treatment on different patient populations, namely on patients suffering from post-traumatic stress disorder</p

Enhancing imagery rehearsal therapy for nightmares with targeted memory reactivation

Nightmare disorder (ND) is characterized by dreams with strong negative emotions occurring during rapid eye movement (REM) sleep. ND is mainly treated by imagery rehearsal therapy (IRT), where the patients are asked to change the negative story line of their nightmare to a more positive one. We here used targeted memory reactivation (TMR) during REM sleep to strengthen IRT-related memories and accelerate remission of ND. Thirty-six patients with ND were asked to perform an initial IRT session and, while they generated a positive outcome of their nightmare, half of the patients were exposed to a sound (TMR group), while no such pairing took place for the other half (control group). During the next 2 weeks, all patients performed IRT every evening at home and were exposed to the sound during REM sleep with a wireless headband, which automatically detected sleep stages. The frequency of nightmares per week at 2 weeks was used as the primary outcome measure. We found that the TMR group had less frequent nightmares and more positive dream emotions than the control group after 2 weeks of IRT and a sustained decrease of nightmares after 3 months. By demonstrating the effectiveness of TMR during sleep to potentiate therapy, these results have clinical implications for the management of ND, with relevance to other psychiatric disorders too. Additionally, these findings show that TMR applied during REM sleep can modulate emotions in dreams