{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,8,2]],"date-time":"2025-08-02T16:23:37Z","timestamp":1754151817504,"version":"3.41.2"},"reference-count":39,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,7,21]],"date-time":"2025-07-21T00:00:00Z","timestamp":1753056000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Sleep"],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>This methodological report draws conclusions about a study that aimed to investigate the biological function of dreams. The main hypothesis in the study 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.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>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, and thrombolysis) were conducted to assess recruitment challenges.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>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.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>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).<\/jats:p><\/jats:sec><jats:sec><jats:title>Trial registration<\/jats:title><jats:p><jats:ext-link>clinicaltrials.gov<\/jats:ext-link> (ID: NCT04749992).<\/jats:p><\/jats:sec>","DOI":"10.3389\/frsle.2025.1585263","type":"journal-article","created":{"date-parts":[[2025,7,21]],"date-time":"2025-07-21T05:22:59Z","timestamp":1753075379000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Exploring the biological function of dreaming: lessons learned from recruitment challenges in a pilot study with PCA stroke patients"],"prefix":"10.3389","volume":"4","author":[{"given":"Tamara","family":"Fischmann","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Luisa","family":"Peters","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vanessa","family":"Rieker","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael","family":"Koslowski","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2025,7,21]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"128","DOI":"10.1161\/01.STR.25.1.128","article-title":"Stroke rehabilitation outcome. A potential use of predictive variables to establish levels of care","volume":"25","author":"Alexander","year":"1994","journal-title":"Stroke"},{"key":"B2","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1037\/h0094375","article-title":"The \u201ccommittee of sleep\u201d: a study of dream incubation for problem solving","volume":"3","author":"Barrett","year":"1993","journal-title":"Dreaming"},{"key":"B3","doi-asserted-by":"publisher","first-page":"156","DOI":"10.1016\/j.sleep.2008.06.006","article-title":"The restless legs syndrome diagnostic index (RLS-DI). Validation of an algorithm for the diagnosis of the restless legs syndrome (RLS)","volume":"6","author":"Benes","year":"2005","journal-title":"Sleep Med."},{"key":"B4","doi-asserted-by":"publisher","first-page":"663","DOI":"10.1177\/1747493016641963","article-title":"Methods to improve patient recruitment and retention in stroke trials","volume":"11","author":"Berge","year":"2016","journal-title":"Int. J. Stroke"},{"key":"B5","doi-asserted-by":"publisher","first-page":"583","DOI":"10.1002\/ana.20246","article-title":"Total dream loss: a distinct neuropsychological dysfunction after bilateral PCA stroke","volume":"56","author":"Bischof","year":"2004","journal-title":"Ann. Neurol."},{"key":"B6","doi-asserted-by":"publisher","first-page":"102957","DOI":"10.1016\/j.concog.2020.102957","article-title":"Attempted induction of signalled lucid dreaming by transcranial alternating current stimulation","volume":"83","author":"Blanchette-Carri\u00e8re","year":"2020","journal-title":"Conscious. Cogn"},{"key":"B7","doi-asserted-by":"publisher","first-page":"632","DOI":"10.1161\/STROKEAHA.122.040071","article-title":"Recruitment in acute stroke trials: challenges and potential solutions","volume":"54","author":"Broderick","year":"2023","journal-title":"Stroke"},{"key":"B8","doi-asserted-by":"publisher","first-page":"864","DOI":"10.1161\/01.STR.20.7.864","article-title":"Measurements of acute cerebral infarction: a clinical examination scale","volume":"20","author":"Brott","year":"1989","journal-title":"Stroke"},{"key":"B9","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1037\/h0036811","article-title":"Problem solving: waking and dreaming","volume":"83","author":"Cartwright","year":"1974","journal-title":"J. Abnormal Psychol"},{"key":"B10","doi-asserted-by":"publisher","first-page":"631","DOI":"10.1378\/chest.15-0903","article-title":"STOP-bang questionnaire: a practical approach to screen for obstructive sleep apnea","volume":"149","author":"Chung","year":"2016","journal-title":"Chest"},{"key":"B11","doi-asserted-by":"publisher","first-page":"14","DOI":"10.1037\/drm0000047","article-title":"The invasion of the concept snatchers: the origins, distortions, and future of the continuity hypothesis","volume":"27","author":"Domhoff","year":"2017","journal-title":"Dreaming"},{"year":"1900","author":"Freud","journal-title":"The Interpretation of Dreams","key":"B12"},{"volume-title":"Wechsler Ged\u00e4chtnis Test-Revidierte Fassung (WMS-R)","year":"2000","author":"H\u00e4rting","key":"B13"},{"key":"B14","doi-asserted-by":"publisher","first-page":"e14634","DOI":"10.1111\/cns.14634","article-title":"Advancing stroke therapy: a deep dive into early phase of ischemic stroke and recanalization","volume":"30","author":"He","year":"2024","journal-title":"CNS Neurosci. Therapeut."},{"key":"B15","doi-asserted-by":"publisher","first-page":"74","DOI":"10.1016\/j.jpsychores.2011.01.005","article-title":"Normative values for the hospital anxiety and depression scale (HADS) in the general German population","volume":"71","author":"Hinz","year":"2011","journal-title":"J. Psychosom. Res."},{"key":"B16","doi-asserted-by":"publisher","first-page":"57","DOI":"10.1016\/j.sleep.2016.03.008","article-title":"Sleep quality in the general population: psychometric properties of the Pittsburgh Sleep Quality Index, derived from a German community sample of 9284 people","volume":"30","author":"Hinz","year":"2017","journal-title":"Sleep Med."},{"key":"B17","doi-asserted-by":"crossref","first-page":"1335","DOI":"10.1176\/ajp.134.12.1335","article-title":"The brain as a dream state generator: an activation-synthesis hypothesis of the dream process","volume":"134","author":"Hobson","year":"1977","journal-title":"Am. J. Psychiatry"},{"volume-title":"Mini Mental Status Examination MMSE: German Version","year":"1990","author":"Kessler","key":"B18"},{"key":"B19","doi-asserted-by":"publisher","first-page":"1612","DOI":"10.1161\/STROKEAHA.118.023553","article-title":"Sleep and stroke","volume":"50","author":"Khot","year":"2019","journal-title":"Stroke"},{"key":"B20","doi-asserted-by":"publisher","first-page":"479","DOI":"10.1093\/ageing\/25.6.479","article-title":"Predicting disability in stroke\u2014a critical review of the literature","volume":"25","author":"Kwakkel","year":"1996","journal-title":"Age Ageing"},{"year":"2008","author":"Lang","journal-title":"International affective picture system (IAPS): affective ratings of pictures and instruction manual","key":"B21"},{"key":"B22","first-page":"61","article-title":"Functional evaluation: the Barthel index. A simple index of independence useful in scoring improvement in the rehabilitation of the chronically ill","volume":"14","author":"Mahoney","year":"1965","journal-title":"Md. State Med. J."},{"key":"B23","doi-asserted-by":"publisher","first-page":"71","DOI":"10.1016\/j.genhosppsych.2005.07.003","article-title":"Validity of the brief patient health questionnaire mood scale (PHQ-9) in the general population","volume":"28","author":"Martin","year":"2006","journal-title":"Gen. Hosp. Psychiatry"},{"volume-title":"Insomnia: Psychological Assessment and Management","year":"1993","author":"Morin","key":"B24"},{"key":"B25","doi-asserted-by":"publisher","first-page":"1286","DOI":"10.1038\/nature04288","article-title":"What are the memory sources of dreaming?","volume":"437","author":"Nielsen","year":"2005","journal-title":"Nature"},{"year":"2008","author":"Niemann","journal-title":"CVLT California verbal learning test","key":"B26"},{"key":"B27","doi-asserted-by":"publisher","first-page":"88","DOI":"10.1016\/j.tics.2009.12.001","article-title":"Dreaming and the brain: from phenomenology to neurophysiology","volume":"14","author":"Nir","year":"2010","journal-title":"Trends Cogn. Sci."},{"key":"B28","doi-asserted-by":"publisher","first-page":"6735","DOI":"10.1038\/s41598-020-63479-6","article-title":"Modulating dream experience: noninvasive brain stimulation over the sensorimotor cortex reduces dream movement","volume":"10","author":"Noreika","year":"2020","journal-title":"Sci. Rep"},{"key":"B29","doi-asserted-by":"publisher","first-page":"671","DOI":"10.1101\/lm.77104","article-title":"Sleep, dreams, and memory consolidation: the role of the stress hormone cortisol","volume":"11","author":"Payne","year":"2004","journal-title":"Learn. Memory"},{"year":"2012","author":"Petermann","journal-title":"Wechsler Adult Intelligence ScaleFourth Edition (WAIS-IV)","key":"B30"},{"volume-title":"Clinical Neuropsychology: Current Status and Applications","year":"1974","author":"Reitan","key":"B31"},{"key":"B32","doi-asserted-by":"publisher","first-page":"S4","DOI":"10.1093\/neuros\/nyz042","article-title":"Epidemiology, natural history, and clinical presentation of large vessel ischemic stroke","volume":"85","author":"Rennert","year":"2019","journal-title":"Neurosurgery"},{"key":"B33","doi-asserted-by":"publisher","first-page":"877","DOI":"10.1017\/S0140525X00004015","article-title":"The reinterpretation of dreams: an evolutionary hypothesis of the function of dreaming","volume":"23","author":"Revonsuo","year":"2000","journal-title":"Behav. Brain Sci."},{"key":"B34","doi-asserted-by":"publisher","first-page":"220","DOI":"10.3390\/brainsci11020220","article-title":"Investigation on neurobiological mechanisms of dreaming in the New Decade","volume":"11","author":"Scarpelli","year":"2021","journal-title":"Brain Sci."},{"key":"B35","doi-asserted-by":"publisher","first-page":"141","DOI":"10.1037\/t67062-000","article-title":"The Mannheim Dream questionnaire (MADRE): retest reliability, age and gender effects","volume":"7","author":"Schredl","year":"2014","journal-title":"Int. J. Dream Res."},{"key":"B36","doi-asserted-by":"crossref","first-page":"386","DOI":"10.1002\/1097-4679(196707)23:3<386::AID-JCLP2270230328>3.0.CO;2-S","article-title":"A shortened Form of BETTS'questionnaire upon mental imagery","volume":"23","author":"Sheehan","year":"1967","journal-title":"J. Clin. Psychol."},{"key":"B37","doi-asserted-by":"publisher","first-page":"843","DOI":"10.1017\/S0140525X00003988","article-title":"Dreaming and REM sleep are controlled by different brain mechanisms","volume":"23","author":"Solms","year":"2000","journal-title":"Behav. Brain Sci."},{"key":"B38","doi-asserted-by":"crossref","DOI":"10.4324\/9781315806440","author":"Solms","year":"2014","journal-title":"The Neuropsychology of Dreams: A Clinico-Anatomical Study"},{"key":"B39","doi-asserted-by":"publisher","first-page":"810","DOI":"10.1038\/nn.3719","article-title":"Induction of self awareness in dreams through frontal low current stimulation of gamma activity","volume":"17","author":"Voss","year":"2014","journal-title":"Nat. Neurosci."}],"container-title":["Frontiers in Sleep"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/frsle.2025.1585263\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,7,21]],"date-time":"2025-07-21T05:23:01Z","timestamp":1753075381000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/frsle.2025.1585263\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,21]]},"references-count":39,"alternative-id":["10.3389\/frsle.2025.1585263"],"URL":"https:\/\/doi.org\/10.3389\/frsle.2025.1585263","relation":{},"ISSN":["2813-2890"],"issn-type":[{"type":"electronic","value":"2813-2890"}],"subject":[],"published":{"date-parts":[[2025,7,21]]},"article-number":"1585263"}}