{"schemaVersion":"1.0","title":"Lullasure research explainer evidence index","description":"Curated article summaries and source references. Not original participant data, laboratory measurements, or a systematic review.","publisher":{"name":"Lullasure editorial team","url":"https://lullasure.com/about"},"clinicalReview":"Not independently clinically reviewed","articles":[{"url":"https://lullasure.com/research/white-noise-newborns-1990-study","title":"The 1990 newborn white noise study, explained","question":"What did the 1990 white noise study actually show?","summary":"In a 1990 randomized trial, 16 of 20 newborns hearing white noise fell asleep within five minutes, compared with 5 of 20 controls. The babies were 2–7 days old. This is evidence about settling in a small newborn sample; it does not establish all-night benefit or long-term safety. Original abstract.","limits":"A short-term sleep result does not establish that longer, louder, or repeated exposure is better.","published":"2026-09-06","modified":"2026-09-06","sourcesChecked":"2026-09-06","sources":[{"id":"spencer-1990","title":"Spencer et al. (1990): White noise and sleep induction","url":"https://pubmed.ncbi.nlm.nih.gov/2405784/","note":"Original trial abstract reviewed; full paper not reviewed."},{"id":"messineo-2017","title":"Messineo et al. (2017): Broadband sound and sleep onset","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC5742584/","note":"Original adult trial; included for method context, not as infant evidence."},{"id":"aap-noise-2023","title":"AAP (2023): Preventing Excessive Noise Exposure","url":"https://publications.aap.org/pediatrics/article/152/5/e2023063752/194468/Preventing-Excessive-Noise-Exposure-in-Infants","note":"Current contextual guidance checked on the date above."}]},{"url":"https://lullasure.com/research/infant-sleep-machines-2014-study","title":"The 2014 infant sound machine study, explained","question":"Did the 2014 study show that sound machines cause hearing loss?","summary":"The 2014 Hugh study tested the maximum sound output of 14 infant sleep machines. At 30 cm, all exceeded a 50 dBA hospital-nursery reference, and three exceeded 85 dBA. These were equipment measurements, not observed hearing injuries in infants; they identify a potential exposure concern. Original abstract.","limits":"A machine’s maximum output is neither a diagnosis for a child nor a measurement of every family’s usual setup.","published":"2026-09-06","modified":"2026-09-06","sourcesChecked":"2026-09-06","sources":[{"id":"hugh-2014","title":"Hugh et al. (2014): Infant sleep machines and hazardous sound pressure levels","url":"https://pubmed.ncbi.nlm.nih.gov/24590753/","note":"Original equipment-study abstract reviewed; no model-level table reproduced."},{"id":"niosh-limits","title":"NIOSH: Occupational versus general environmental exposure limits","url":"https://www.cdc.gov/niosh/bulletin/2016/noise.html","note":"Authority’s explanation of the occupational comparison."},{"id":"aap-noise-2023","title":"AAP (2023): Preventing Excessive Noise Exposure","url":"https://publications.aap.org/pediatrics/article/152/5/e2023063752/194468/Preventing-Excessive-Noise-Exposure-in-Infants"}]},{"url":"https://lullasure.com/research/white-noise-devices-2021-study","title":"The 2021 white noise devices study, explained","question":"What did the 2021 white noise devices study find?","summary":"Hong and colleagues tested eight white noise machines and six iPhone apps in 2021. At maximum volume and 10 cm, nine exceeded 85 dBA. None did so at 30 or 100 cm. Those results compare device output with an occupational reference; they do not establish a safe infant distance. Original abstract.","limits":"Below an adult workplace comparison is not the same as demonstrated suitability for infant sleep.","published":"2026-09-06","modified":"2026-09-06","sourcesChecked":"2026-09-06","sources":[{"id":"hong-2021","title":"Hong et al. (2021): Hazardous sound outputs of white noise devices intended for infants","url":"https://www.sciencedirect.com/science/article/pii/S0165587621001506","note":"Publisher abstract and accessible excerpts reviewed; complete article and product tables not reviewed. DOI: 10.1016/j.ijporl.2021.110757."},{"id":"niosh-limits","title":"NIOSH: Occupational versus general environmental exposure limits","url":"https://www.cdc.gov/niosh/bulletin/2016/noise.html"},{"id":"niosh-app","title":"NIOSH: Sound Level Meter App","url":"https://www.cdc.gov/niosh/noise/about/app.html","note":"Current instrument and calibration context."},{"id":"aap-noise-2023","title":"AAP (2023): Preventing Excessive Noise Exposure","url":"https://publications.aap.org/pediatrics/article/152/5/e2023063752/194468/Preventing-Excessive-Noise-Exposure-in-Infants"}]},{"url":"https://lullasure.com/research/night-waking-1979-study","title":"The 1979 infant night-waking study, explained","question":"Why does the 1979 infant night-waking study still matter?","summary":"Thomas Anders’s 1979 study used home video to observe one night in groups of 2- and 9-month-old infants. Original abstract. Read alongside his later account, it illustrates how a camera and a parent can capture different aspects of waking. It does not establish a sleep-training rule. Researcher’s history.","limits":"Observation of sleep behavior cannot, by itself, show that one parenting response causes another sleep outcome.","published":"2026-09-06","modified":"2026-09-06","sourcesChecked":"2026-09-06","sources":[{"id":"anders-1979","title":"Anders (1979): Night-Waking in Infants During the First Year of Life","url":"https://publications.aap.org/pediatrics/article/63/6/860/49331/Night-Waking-in-Infants-During-the-First-Year-of","note":"Original abstract reviewed; no sample count or outcome percentages inferred."},{"id":"anders-2023","title":"Anders (2023): From ontogenesis to clinical practice: waking up to infant sleep","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC10104392/","note":"First-person history used for context; later findings are not attributed to the 1979 paper."},{"id":"sleep-through-nights","title":"Sleeping through the night or through the nights?","url":"https://www.sciencedirect.com/science/article/pii/S1389945720304469","note":"Original 13-night diary study abstract; a different method and cohort."},{"id":"nichd-sleep-environment","title":"NICHD: Safe Sleep Environment for Baby","url":"https://safetosleep.nichd.nih.gov/reduce-risk/safe-sleep-environment","note":"Current sleep-environment context checked on the date above."}]},{"url":"https://lullasure.com/research/white-noise-child-development-2024-review","title":"The 2024 white noise development review, explained","question":"What does the 2024 white noise review tell parents?","summary":"The 2024 white noise review examined existing animal and pediatric research on prolonged noise exposure. It raised developmental concerns and called for further research on intensity and duration. This mixed evidence does not prove that a particular baby’s sound machine caused harm. Original abstract.","limits":"A review’s publication date and study count do not tell you how directly its evidence applies to your question.","published":"2026-09-06","modified":"2026-09-06","sourcesChecked":"2026-09-06","sources":[{"id":"de-jong-2024","title":"De Jong et al. (2024): Continuous white noise exposure during sleep and childhood development","url":"https://pubmed.ncbi.nlm.nih.gov/38663282/","note":"Original review abstract; DOI: 10.1016/j.sleep.2024.04.006."},{"id":"prisma-scoping","title":"PRISMA: Scoping reviews and reporting guidance","url":"https://www.prisma-statement.org/scoping"},{"id":"spencer-context","title":"Spencer (1990), original trial abstract","url":"https://pubmed.ncbi.nlm.nih.gov/2405784/"},{"id":"hugh-context","title":"Hugh (2014), original equipment-study abstract","url":"https://pubmed.ncbi.nlm.nih.gov/24590753/"},{"id":"hong-context","title":"Hong (2021), original publisher abstract","url":"https://www.sciencedirect.com/science/article/pii/S0165587621001506"}]}]}