Table 2.

Inclusion and exclusion criteria.

Inclusion Criteria	Exclusion Criteria
• Intervention studies of white noise* or pink noise** alone or in combination with other auditory stimulation with a sleep-related outcome (objective or self-reported) • Any intervention design type or sample size • Adult participants • English language	• Fetuses, infants, children, or adolescents • Correlational studies, narrative reviews, editorials, letters to the editor, books, book chapters, dissertations, lay magazine articles • Published study protocol • Auditory intervention that is a heartbeat simulator, metronome, music, lullaby, binaural tones, or that uses synchronization • Non-English language

*White noise includes sound generators that mimic television static, steam hissing from a radiator or humidifier, or the whir of a fan. **Pink noise includes nature sounds such as waves lapping on the beach, leaves rustling in the trees, or a steady rainfall.