title: Can observers link dream content to behaviours in rapid eye movement sleep behaviour disorder? A cross-sectional experimental pilot study.
abstract: Motor activity in rapid eye movement (REM) sleep behaviour disorder (RBD) has been linked to dream content. Systematic and controlled sleep laboratory studies directly assessing the relation between RBD behaviours and experienced dream content are, however, largely lacking. We aimed to investigate whether a link can be established between RBD behaviours and dream content when both are systematically sampled in a controlled setting. We investigated six patients with Parkinson syndrome and RBD who underwent 2-3 nights of video-polysomnographic recording during which they were awakened from REM sleep (10 min after the onset of the second and successive REM periods). Spontaneous free-worded dream reports and a structured dream questionnaire were obtained. Video recordings of motor manifestations were each combined with four dream reports, and seven judges had to match the video clip with the correctly reported dream content from a choice of four possibilities. Of the 35 REM sleep awakenings performed, a total of 17 (48.6%) motor-behavioural episodes with recalled dream content were obtained. The mean of correctly identified video-dream pairs was 39.5% (range 0-100%). Our data showed that reported dream content can be linked to motor behaviours above chance level. Matching accuracy was affected mainly by the clarity of dream reports and the specific nature of movements manifest in video recordings.
authors.affiliation: Centre for Cognitive Neuroscience, Department of Behavioral Sciences and Philosophy, University of Turku, Turku, Finland.
authors.forename: Katja
authors.initials: K
authors.lastname: Valli
authors.forename: Birgit
authors.initials: B
authors.lastname: Frauscher
authors.forename: Viola
authors.initials: V
authors.lastname: Gschliesser
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Wolf
authors.forename: Tina
authors.initials: T
authors.lastname: Falkenstetter
authors.forename: Suzana V
authors.initials: SV
authors.lastname: Schönwald
authors.forename: Laura
authors.initials: L
authors.lastname: Ehrmann
authors.forename: Anja
authors.initials: A
authors.lastname: Zangerl
authors.forename: Isabelle
authors.initials: I
authors.lastname: Marti
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Boesch
authors.forename: Antti
authors.initials: A
authors.lastname: Revonsuo
authors.forename: Werner
authors.initials: W
authors.lastname: Poewe
authors.forename: Birgit
authors.initials: B
authors.lastname: Högl
mesh_terms: D003430:Cross-Sectional Studies; D004325:Dreams / Q000523:psychology*; D005149:Facial Expression; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D020734:Parkinsonian Disorders / Q000150:complications / Q000503:physiopathology* / Q000523:psychology; D010865:Pilot Projects; D017286:Polysomnography; D020187:REM Sleep Behavior Disorder / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology; D012895:Sleep, REM / Q000502:physiology*; D011795:Surveys and Questionnaires; D014741:Video Recording