Diagnostic Value of Psychomotor Vigilance Task for Severe Sleep Inertia in Idiopathic Hypersomnia Versus Other Sleep Disorders Without Sleep Inertia

Sleep inertia impairs performance upon awakening and may be assessed using the psychomotor vigilance task (PVT). This study aimed to determine optimal PVT lapse cut-offs at awakening to objectively measure sleep inertia by comparing patients with idiopathic hypersomnia (IH) and severe sleep inertia to patients with other sleep disorders (OSD) without sleep inertia, to assess the discriminative performance of these thresholds in OSD patients with sleep inertia; and to explore factors associated with PVT lapses. 350 drug-free consecutive patients (227 females, 30.7 ± 11.0 y.o.) were included: 131 IH and 219 OSD (75 non-specified hypersomnolence, 54 narcolepsy, 50 obstructive sleep apnea, 40 others). All patients performed two 5-min PVTs at 07:00 pm and 07:00 am upon awakening. Sleep inertia was self-reported with the Idiopathic Hypersomnia Severity Scale. Receiver operating characteristic analyses were used to determine optimal cut-offs for 7:00 am PVT lapses and the change between 07:00 am and 07:00 pm in IH patients with severe sleep inertia (n = 73) and OSD patients without sleep inertia (n = 84). Optimal PVT cut-offs were ≥ 4 for 7 am-Lapses (sensitivity 72.6%, specificity 69.1%) and ≥ 4 for Delta 7 am-7 pm-Lapses (sensitivity 50.9%, specificity 83.3%). Across all 350 participants, 56.9% exhibited 7 am-Lapses ≥ 4, while 39.7% had Delta 7 am-7 pm Lapses ≥ 4. In conclusion, a threshold of ≥ 4 PVT lapses at 07:00 am, along with an increase of ≥ 4 lapses from 07:00 pm to 07:00 am best capture sleep inertia-related performance impairment in IH, supporting their use as objective markers in clinical practice and research settings.