Table 5.
Additional laboratory studies of sleep inertia
| Study | N | Age | Design | Factor | Subj | Obj | Time before testing | Findings |
|---|---|---|---|---|---|---|---|---|
| Asaoka S et al 2010 [31] | 9 | 24.0 | Counter-balanced to one hour nap or rest (14:00–15:00) | nap versus rest | rating of performance | spatial Stroop | 90 s | Objective measures not different, but nappers rated performance better. |
| Kubo T et al 2010 [93] | 12 | 21.6 | Counter-balanced to no nap versus four nap types (60 or 120 min, MN or 0400 am) | nap timing and length | VAS sleepy | VVT | Right away | Late 60 min nap worsened RT and lapses on VVT versus no-nap. No effect of any nap on VAS. |
| Lovato N et al 2009 [94] | 22 | 22.5 | Counter-balanced to 0 vs 30 min nap at 0230; afternoon nap for all | nap versus no nap | SSS, KSS, POMS, VAS sleepiness | SDST, LCT, PVT | 10 min | SSS & KSS worse after nap; no objective differences |
| Matchock RL and Mordkoff JT 2007 [95] | 15 | 21.6 | Counter-balanced to wake times: 2400 (after 1 hour TIB), 0300 (4 hrs TIB), 0600 (7 hours TIB) | Wake time, prior TIB | VAS arousal | Flanker | < 3 min | Energy & tiredness worse after all awakenings. Flanker task RTs worse after waking at 0300 and 0600 |
| Takeyama H et al 2004 [96] | 6 | ages 19–22; men | Counter-balanced to no-nap, 60 or 120 min at MN, 60 or 120 min at 0400 | Nap length & timing | fatigue | logical reason, CRT, VVT | not stated | No sleep inertia after any nap except worsened VVT RT after late 60 min nap. |
| Wakasa M et al 2016 [97] | 14 | 64.5 | Nocturnal sleep of 5 hours | SSS | TUG, FRT, balance | after waking | TUG and SSS worse upon awakening | |
| Wertz AT et al 2006 [98] | 9 | 29.1 | Testing upon am awakening (after 8 hrs sleep) then testing for 26 hours | ADD | mean 73 s | Testing upon awakening worse than during subsequent sleep deprivation. |
Abbreviations: CRT=choice reaction test, FRT=functional reach test, KSS=Karolinska sleepiness scale, LCT=letter cancellation task, min=minutes, MN=midnight, n=number analyzed, obj=objective measures, POMS=profile of mood states, PVT=psychomotor vigilance task, RT=reaction time, SDST=symbol digit substitution task, subj=subjective measures, SSS=Stanford sleepiness scale, TIB=time in bed, TUG=timed up and go, VAS=visual analog scale, VVT=visual vigilance task