BRIEF RESEARCH REPORT article

Front. Sleep

Sec. Sleep, Behavior and Mental Health

Volume 4 - 2025 | doi: 10.3389/frsle.2025.1585263

This article is part of the Research TopicUnderstanding conscious experiences during sleepView all articles

Exploring the Biological Function of Dreaming: Lessons Learned from Recruitment Challenges in a Pilot Study with PCA Stroke Patients

Provisionally accepted
Tamara  FischmannTamara Fischmann1*Luisa  PetersLuisa Peters1Vanessa  RiekerVanessa Rieker1Michael  KoslowskiMichael Koslowski2
  • 1International Psychoanalytic University Berlin, Berlin, Germany
  • 2Charité University Medicine Berlin, Berlin, Baden-Wurttemberg, Germany

The final, formatted version of the article will be published soon.

Background: This methodological report draws conclusions about a study that aimed to investigate the biological function of dreams. The main hypothesis posited that dreams serve to maintain sleep by hallucinatory wish fulfillment in response to affect-laden impulses. A secondary hypothesis was whether dreams contribute to the consolidation of non-declarative memory. Neurological patients with ischemic stroke of the posterior cerebral artery (PCA stroke) served as a pragmatic lesion model for loss of dreaming ability, following evidence on the importance of parieto-occipital cortical areas for dream formation.Methods: This quasi-experimental, two-arm controlled study intended to assess sleep quality and non-verbal memory consolidation in participants with PCA stroke who lost dreaming ability, compared to PCA stroke patients with preserved dreaming. Descriptive statistics using morbidity variables (e.g. NIHSS, Barthel-Index, thrombolysis) were conducted to assess recruitment challenges.Results: Recruitment was significantly constrained due to inclusion criteria and multimorbidity of the study population. Of 255 patients screened, 14 were included, and 6 completed the study. Descriptive data from the 14 inclusions as well as reasons for exclusion and dropouts are reported. Morbidity variables varied substantially between completers and non-completers, indicating that PCA stroke might not be an appropriate lesion model for dream research.Conclusion: This methodological report highlights the difficulties in recruiting adequate patient samples for dream research within a stroke lesion model, in order to gain valuable insights into methodological obstacles in this field. Solutions to these challenges are proposed, e.g. using functional lesion models in healthy controls with transcranial alternating current stimulation (tACS).

Keywords: dreaming, REM sleep, Posterior stroke, PCA stroke, Recruitment challenges, non declarative memory consolidation

Received: 28 Feb 2025; Accepted: 18 Jun 2025.

Copyright: © 2025 Fischmann, Peters, Rieker and Koslowski. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Tamara Fischmann, International Psychoanalytic University Berlin, Berlin, 60325, Germany

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