Homeostatic Regulation of Sleep in Short Sleepers

The decay dynamics will be modeled using an exponential function.

Variation in EEG spectral power within the 0.5-9 Hz frequency range assessed across all channels of a 128-channel EEG system during the 30 minutes following awakening

will be assessed using continuous interstitial glucose monitoring with the FreeStyle Libre® system. Glucose values, expressed in mmol/L (or mg/dL), will be recorded at regular intervals and used to calculate variability metrics, including standard deviation (SD) and coefficient of variation (CV, %).

Lean mass index will be assessed using Bioelectrical Impedance Analysis (BIA).

Fat mass index and fat mass index will be assessed using Bioelectrical Impedance Analysis (BIA).

IPAQ is a seven-question self-report questionnaire that assesses physical activity over the past 7 days and provides a total score expressed in MET-minutes per week and/or categorical activity levels (low, moderate, high)."

The Food Frequency Questionnaire (FFQ) is a self-administered tool used to assess habitual dietary intake over a defined period, providing a quantitative estimate of dietary intake."

ESS is a short 8-item questionnaire designed to assess daytime sleepiness. Participants assign a score from 0 to 3 (0 = never; 1 = weak; 2 = moderate; 3 = strong).The minimum score is 0 and the maximum score is 24

IHSS is a tool used to measure the severity of the symptoms experienced by patients with IH during the previous month. The IHSS includes 2 items (1 and 2) on nighttime sleep duration and quality, 3 items (3, 4, and 5) on sleep inertia and sleep drunkenness after nighttime sleep and 1 (8) after daytime nap, and 3 items (6, 7, and 9) on diurnal symptoms (nap occurrence, daytime sleepiness). Items 10-14 assess daytime functioning alterations due to hypersomnolence. Six items are scored on a 3-point Likert scale and 8 items on a 4-point Likert scale; the Likert scale is a point scale that is used to allow the individual to express how much they agree or disagree with a particular statement. The total IHSS score is the sum of all item scores (range: 0-50), and higher scores indicate more severe symptoms

KSS is a self-reported measure of subjective sleepiness at a specific time point. Participants rate their level of sleepiness over the preceding 10 minutes on a 9-point Likert scale ranging from 1 ('extremely alert') to 9 ('very sleepy, fighting sleep'). The KSS provides a measure of situational sleepiness, with higher scores indicating greater sleepiness

corresponds to the total count of REM sleep episodes occurring within 15 minutes of sleep onset across all nap trials of the Multiple Sleep Latency Test (MSLT). Typically ranging from 0 to 5, this measure reflects abnormal REM intrusion when elevated and is a key diagnostic marker for conditions such as Narcolepsy, particularly when two or more SOREMPs are observed alongside reduced mean sleep latency

is the time from lights-off to the onset of sleep during each nap trial of the Multiple Sleep Latency Test (MSLT), typically conducted across 4 to 5 sessions. Shorter sleep latencies indicate greater daytime sleepiness, while longer latencies reflect higher alertness. This measure is commonly used, alongside SOREMP detection, to help diagnose conditions such as Narcolepsy and excessive daytime sleepiness

it takes a participant to fall asleep across all nap trials of the Multiple Sleep Latency Test (MSLT). It is calculated by averaging the sleep latency values from each nap session (typically 4 to 5 tests). Lower mean sleep latency indicates greater daytime sleepiness, while higher values reflect better alertness. This parameter is a key diagnostic indicator, particularly for conditions such as Narcolepsy and excessive daytime sleepiness

refers to whether REM sleep occurs within 15 minutes after sleep onset during each nap trial of the Multiple Sleep Latency Test (MSLT). This measure is recorded as a binary outcome for each test (present = 1, absent = 0) and reflects abnormal REM intrusion when present. It is used alongside sleep latency to help identify sleep disorders such as Narcolepsy and excessive daytime sleepiness

FOSQ : a self-administered instrument consisting of 10 items evaluating the impact of sleepiness and fatigue on daily activities. Each item is rated on a 4- to 6-point Likert scale according to the frequency or degree of difficulty experienced, with higher scores indicating better functional status

WPAI:GH is a well validated instrument to measure the effect of health conditions on work productivity and daily activities. The WPAI-GH consists of six questions: 1 = currently employed; 2 = hours missed due to health problems; 3 = hours missed other reasons; 4 = hours actually worked; 5 = degree health affected productivity while working (using a 0 to 10 Visual Analogue Scale (VAS)); 6 = degree health affected productivity in regular unpaid activities (VAS).

The Insomnia Severity Index (ISI) is a 7-item self-report questionnaire assessing the nature, severity of both nighttime and daytime components of insomnia, and impact of insomnia. Each item is scored 0 (no problem) - 4 (very big problem) with total between 0-28 (absence of insomnia (0-7); sub-threshold insomnia (8-14); moderate insomnia (15-21); and severe insomnia (22-28)

MEQ : a validated self-reported instrument evaluating individual chronotype. The MEQ provides a total score classifying participants along a continuum from eveningness to morningness, with higher scores indicating a stronger morning-type preference

PVT is a widely utilized as a measure of behavioral alertness, primary due to its high sensitivity to sleep deprivation and its psychometric advantages over other cognitive tests. The standard 10-min PVT measures sustained or vigilant attention by recording response times (RT) to visual (or auditory) stimuli presented at random inter-stimulus intervals

Serum proteins will be collected for future exploratory analyses using the NULISA platform