Mind-wandering and Predictive Processes in Narcolepsy: a Putative Mechanism Through Covert REM Intrusions
NCT Number: NCT06457945
Acronym: NARCOWANDERING
Status: NOT_YET_RECRUITING
Study Type: INTERVENTIONAL
Phases: NA
Conditions: Narcolepsy Type 1|Hypersomnolence|Idiopathic Hypersomnia
Interventions: BEHAVIORAL: ASRT|BEHAVIORAL: Questionnaires|DEVICE: Electrophysiological recordings
Sponsor: Hospices Civils de Lyon
Sex: ALL
Age: ADULT, OLDER_ADULT
Enrollment: 180
Study Design: Allocation: NON_RANDOMIZED|Intervention Model: PARALLEL|Masking: NONE|Primary Purpose: BASIC_SCIENCE
Start Date: 2024-06-15
Completion Date: 2026-06-15
Locations: Hôpital de la Croix-Rousse, Lyon, 69004, France

Summary:
Mind wandering is a state in which attention turns away from the external environment or current task to focus on internal thoughts (past experiences, future events, planned actions...). Humans are thought to spend at least one third of their waking lives in this state. Mind wandering can be assessed experimentally by investigating mental content during well-controlled tasks. In this case, task-unrelated thoughts likely to arise during tasks of varying cognitive demand are studied. Mind wandering (=task-unrelated thoughts) has a deleterious effect on cognitive performance in most paradigms, particularly those requiring sustained attention and executive control. However, this phenomenon could also have cognitive benefits, although knowledge on this issue remains limited. For example, it has been suggested that mind wandering could promote creativity, anticipation of future scenarios and prospective memory. In a recent behavioural study, we investigated the cost and benefit of mind wandering in an implicit visual-motor probabilistic learning task (ASRT - Alternating Serial Reaction Time Task). ASRT distinguishes between two fundamental processes: visuomotor performance and implicit statistical learning. While the former reflects visuo-spatial discrimination efficiency, the latter refers to the unintentional acquisition of probabilistic regularities of external inputs. Reduced visuo-spatial accuracy and faster but less accurate responses have been observed during periods of mind-wandering. On the other hand, mind-wandering was associated with enhanced statistical learning reflecting improved predictive processing.

Whereas the study of the neural correlates of mind-wandering is constantly growing, the mechanisms triggering mind-wandering are far from being unravelled, but may involve sleep pressure. Thus, the frequency of mind wandering tends to increase after sleep deprivation or during attention-demanding cognitive tasks, during which neurophysiological markers of local sleep appear. These markers of sleep during wakefulness are frequently observed in hypersomnolence disorders. They are generally defined by the appearance of slow waves (typical of slow wave sleep, SWS). Nevertheless, sleep intrusions during wakefulness may not be limited to non-rapid-eye-movement (NREM) sleep but also concern REM sleep. REM sleep is the sleep state when the most intense forms of dreaming occur, and could therefore be phenomenologically similar to the reverie of mind wandering. Thus, daytime mental wandering could be triggered by intrusions of REM sleep during wakefulness.

Patients with narcolepsy type 1 (NT1) exhibit frequent REM sleep onset during daytime wakefulness. The study of ASRT in this population therefore offers a unique opportunity to investigate the role of REM sleep intrusions in mind wandering. The hypothesis is that mind wandering would be observed more frequently during the ASRT task in NT1 patients (with REM sleep intrusions during wakefulness) than in patients with idiopathic hypersomnia (IH) (with NREM sleep intrusions during wakefulness) and patients with subjective hypersomnolence (little or no sleep intrusion). Furthermore, it could be possible that REM sleep-related mind wandering would be associated with impaired visuomotor performance in terms of accuracy, but improved predictive processing (probabilistic learning) compared to NREM sleep intrusions or no sleep intrusion during the task.

Primary Outcome Measures: Difference in accuracy in responses between high-and low- probability trials during the ASRT, Statistical learning will be assessed by the difference in accuracy (percentage of correct location) in responses between high-and low probability trials during the ASRT in the 3 groups (NT1, IH, subjective sleepiness). Mean accuracy scores will be computed for each block for high-and low- probability trials, and the above learning indices will be extracted for each block., At inclusion, during the ASRT|Difference in reaction time in responses between high-and low- probability trials during the ASRT, Statistical learning will be assessed by the difference in reaction time (in ms) in responses between high-and low probability trials during the ASRT in the 3 groups (NT1, IH, subjective sleepiness). Median reaction times will be computed for each block for high-and low- probability trials, and the above learning indices will be extracted for each block., At inclusion, during the ASRT
Secondary Outcome Measures: Subjective states of mind during the ASRT, Distribution of subjective states of mind (mind wandering, mind blanking, focus on task) assessed at the end of each block during the ASRT in the 3 groups (NT1, IH, subjective sleepiness), At inclusion, at the end of each block of ASRT|Neurophysiological patterns during the ASRT, Neurophysiological patterns (EEG, electro-oculography (EOG), electromyography (EMG), ECG to detect sleep intrusion: micro-REM and micro-NREM) will be assessed for each block during the ASRT in all patients and each group of patient (NT1, IH and subjective hypersomnolence) EEG features: spectral power (aperiodic and periodic components, relative and theta-delta/alpha-beta ratio vs pre-task baseline) and specific grapho-elements such as sawtooth waves, alpha bursts and beta oscillations; 2) EMG: muscle tone (% vs pre-task baseline), 3) EOG: presence and % slow vs rapid vs no eye movements, 4) ECG: heart rate, heart rate variability (SDNN, RMSSD), heartbeat evoked potentials), At inclusion, during the ASRT|Spontaneous and Deliberate Mind Wandering Scales (SDMWS) score, At inclusion|Epworth Sleepiness Scale score, Subjective sleepiness will be assessed thnaks to Epworth Sleepiness Scale, At inclusion|Dream recall frequency, Dream recall frequency (n/week, diary the week before the ASRT), At inclusion|Frequency of sleep-related hallucinations, Frequency of sleep-related hallucinations (nb/week, item of the Narcolepsy Severity Scale), At inclusion|Insomnia Severity Index score, Nighttime sleep quality assessed thanks to the Insomnia Severity Index., At inclusion