Table 1. Characteristics of trials included in the systematic review and meta-analysis*,†.
| Study (country, study) | Participants | Treatment | Outcomes | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| TBI level | Prominent symptoms | % Female | Mean age (years) | Initial GCS | Mean duration after TBI | Experimental | Control | Administration | Treatment duration (days) | ||
| Sinclair 2014 (Australia) | Mild to severe | sleepiness, sleep disturbance, or fatigue | 20.0 | 42.0 | N/A | 36.9 months | BWLT (λmax = 465 nm) (n = 10) | ALT (λmax = 574 nm) or NLT (n = 20) | Lightbox for 45 minutes daily in the morning | 28 | • Sleepiness: ESS (Experimental > Control) • Sleep disturbance: PSQI (Experimental ≈ Control) • Depressive symptoms: BDI-II (Experimental ≈ Control) • Fatigue: FSS (Experimental > Control) • Dropout rate: (N/A) |
| Quera Salva 2020 (France) | Severe | sleepiness, sleep disturbance, or fatigue | 45.0 | 36.6 | 5.94 | 9.03 years | BWLT (λmax = 468 nm) (n = 10) | NLT (n = 10): | Face-mounted device resembling glasses for 30 minutes daily after waking | 28 | • Sleepiness: ESS (Experimental ≈ Control) • Sleep disturbance: PSQI (Experimental ≈ Control) • Depressive symptoms: HRSD-17 (Experimental > Control) • Fatigue: FSS (Experimental > Control) • Dropout rate: (N/A) |
| Killgore 2020 (USA) | Mild | sleepiness and sleep disturbance | 53.1 | 23.3 | N/A | 6.75 months | BWLT (λmax = 469 nm) (n = 16) | ALT (λmax = 578 nm) (n = 16) | Lightbox for 30 minutes daily in the morning. | 42 | • Sleepiness: ESS (Experimental > Control) • Sleep disturbance: PSQI (Experimental > Control) • Depressive symptoms: BDI-II (N/A) • Dropout rate: (N/A) |
| Raikes 2020 (USA) | Mild | sleep disturbance | 62.8 | 25.9 | N/A | 9.20 months | BWLT (λmax = 480 nm) (n = 17) | ALT (λmax = 530 nm) (n = 18) | lightbox for 30 minutes daily in the morning | 42 | • Sleepiness: ESS (Experimental > Control) • Sleep disturbance: PSQI (Experimental > Control) • Depressive symptoms: BDI-I: (Experimental > Control) • Dropout rate: (N/A) |
| Bell 2021 (USA) | Moderate to severe | sleep disturbance | 31.0 | 40.9 | 3.12 | 29 days | BWLT (λmax = 440–480 nm) (n = 65) | RLT (λmax > 650 nm) (n = 66) | lightbox for 30 minutes daily in the morning | 10 | • Sleepiness: KSS (Experimental ≈ Control) • Fatigue: BNI-FS (Experimental ≈ Control) • Dropout rates (N/A) |
| Connolly 2021 (Australia) | Mild to severe | fatigue | 41.7 | 44.3 | N/A | 10.2 years | BWLT (n = 17) | Sham control condition (n = 13) | House-based light therapy installed in the room that the participants spent most time | 60 | • Sleepiness: ESS (Experimental ≈ Control) • Sleep disturbance: PSQI (Experimental > Control) • - Fatigue: BFI (Experimental ≈ Control |
* The symbols of > and ≈ indicate significant superiority (p < 0.05) and no significant difference (p ≥ 0.05) as being reported by the authors, respectively.
† N/A indicates no statistical analysis of the difference between groups.
ALT: Amber Light Therapy; BWLT: Blue-Wavelength Light Therapy; NLT: No Light Therapy; RLT: Red Light Therapy.
BDI-I: Beck Depression Inventory; BDI-II: Beck Depression Inventory, 2nd edition; BFI: Brief Fatigue Inventory; BNI-FS: Barrow Neurological Institute Fatigue Scale; ESS: Epworth Sleepiness Scale; FSS: Fatigue Severity Scale; GCS: Glasgow Coma Scale; HRSD-17: 17-item Hamilton Rating Scale for Depression; KSS: Karolinska Sleepiness Scale; PSQI: Pittsburgh Sleep Quality Index; TBI: Traumatic brain injury.