{
  "registry": "KnowYourPrime Evidence Registry",
  "license": {
    "name": "CC BY 4.0",
    "url": "https://creativecommons.org/licenses/by/4.0/",
    "attribution": "Credit KnowYourPrime and link to the finding URL."
  },
  "fields": {
    "devices": "Devices this finding names, including models it says it does not cover. What was actually tested is in scope.applies_to; exclusions are in scope.does_not_cover.",
    "evidence": "Studies by role: anchor (the rating rests on it), conflicting, null_result, supporting.",
    "industry_ties": "Device-maker ties listed in Europe PMC metadata: author_affiliations names makers an author lists as an affiliation, funders names makers listed as funding. stated_ties holds ties a paper states only in its own conflict, funding or acknowledgement text, each read from that statement and worded to say only what it says. Sources are Europe PMC metadata, funding printed in the abstract, and those reviewed statements. An empty list means no tie was found there, not that the study is independent: many papers have no open full text to read. Metadata, not a judgment of the study. checked false means no Europe PMC metadata was available."
  },
  "id": "KYP-ER-0008",
  "version": "1.0",
  "reviewed": "2026-10-24",
  "url": "https://knowyourprime.com/evidence-under-mattress-sleep-sensor-accuracy",
  "title": "Under-Mattress Sleep Sensor Accuracy",
  "question": "Does an under-mattress sleep sensor agree with polysomnography?",
  "measurement": "Sleep",
  "devices": [
    "Withings Sleep Analyzer"
  ],
  "rating": {
    "label": "Uncertain",
    "code": "uncertain",
    "definition": "Evidence is conflicting, inconsistent, or difficult to interpret.",
    "rule_version": "1.6",
    "rule_reasons": [
      "An anchor study was assessed but its own reported finding supports this claim only weakly, so the evidence is treated as unsettled rather than affirming.",
      "An anchor study was assessed but its own reported finding supports this claim only weakly, so the evidence is treated as unsettled rather than affirming."
    ]
  },
  "conclusion": "It finds sleep almost every time and misses most waking time, so it overstates how long you slept. In a sleep lab the Withings Sleep Analyzer overstated sleep by 48 minutes; at home the gap was smaller, and its sleep stage estimates were further off than its sleep and wake calls.",
  "reasoning": [
    "An under-mattress sensor reads breathing and body movement through the mattress. Lying still awake looks much like sleep to it, which is why its errors run in one direction.",
    "Two studies of the same device, one in a lab and one at home, both reach the same mixed result: strong at detecting sleep, weak at detecting wake. Neither cleanly affirms agreement with polysomnography, so the rule rates the claim Uncertain."
  ],
  "key_results": [
    {
      "text": "In 183 participants over more than 400 lab nights, the Withings Sleep Analyzer classified sleep and wake with 83 percent accuracy, caught 95 percent of sleep and 37 percent of wake, and overestimated total sleep time by 48 minutes while underestimating wake after sleep onset by 54 minutes.",
      "source": "doi:10.1111/jsr.14480",
      "source_url": "https://doi.org/10.1111/jsr.14480",
      "source_citation": "Manners et al., Journal of Sleep Research, 2025"
    },
    {
      "text": "At home in 117 healthy adults, accuracy was 87 percent with 93 percent sensitivity to sleep and 73 percent to wake, while sleep stage accuracy fell to 63 percent (kappa 0.49), overestimating light sleep by 1 hour 21 minutes and underestimating deep sleep by 46 minutes.",
      "source": "doi:10.2196/77033",
      "source_url": "https://doi.org/10.2196/77033",
      "source_citation": "Stefanos et al., JMIR Human Factors, 2026"
    }
  ],
  "scope": {
    "applies_to": "The Withings Sleep Analyzer under-mattress sensor compared with simultaneous polysomnography, in a lab with and without sleep disorders and at home in healthy adults.",
    "does_not_cover": "Other under-mattress or smart mattress products; sleep apnea detection; wrist and ring trackers, covered in a separate finding."
  },
  "limitations": [
    "Both studies tested one device; the home study and a grant behind the lab study have Withings funding or support.",
    "Two studies are a small base for a device category."
  ],
  "evidence": {
    "anchor": [
      {
        "key": "doi:10.2196/77033",
        "title": "Evaluation of a Contactless Sleep Monitoring Device for Sleep Stage Detection at Home in a Healthy Population: Prospective Study in Free-Living Conditions.",
        "first_author": "Stefanos",
        "journal": "JMIR human factors",
        "year": 2026,
        "url": "https://doi.org/10.2196/77033",
        "industry_ties": {
          "checked": true,
          "author_affiliations": [
            "Withings"
          ],
          "funders": [],
          "stated_ties": []
        }
      },
      {
        "key": "doi:10.1111/jsr.14480",
        "title": "Performance evaluation of an under-mattress sleep sensor versus polysomnography in > 400 nights with healthy and unhealthy sleep.",
        "first_author": "Manners",
        "journal": "Journal of sleep research",
        "year": 2025,
        "url": "https://doi.org/10.1111/jsr.14480",
        "industry_ties": {
          "checked": true,
          "author_affiliations": [],
          "funders": [],
          "stated_ties": [
            "conflict statement: two authors had a Withings-supported research grant"
          ]
        }
      }
    ],
    "supporting": [
      {
        "key": "doi:10.1007/s11325-025-03544-4",
        "title": "Diagnostic value of wearable and contactless technologies for detecting obstructive sleep apnea: a systematic review and meta-analysis.",
        "first_author": "Hasanain",
        "journal": "Sleep & breathing = Schlaf & Atmung",
        "year": 2025,
        "url": "https://doi.org/10.1007/s11325-025-03544-4",
        "industry_ties": {
          "checked": true,
          "author_affiliations": [],
          "funders": [],
          "stated_ties": []
        }
      }
    ]
  },
  "evidence_last_evaluated": "Oct 17, 2026",
  "rating_history": [
    {
      "date": "2026-09-29",
      "rating": "Uncertain",
      "from": null,
      "rule_version": "1.6"
    }
  ],
  "versions": [
    {
      "version": "1.0",
      "date": "2026-10-24",
      "rating": "Uncertain",
      "change": "First published."
    }
  ],
  "research_desk": "https://knowyourprime.com/research-desk-sleep#nearable_accuracy",
  "related_findings": [
    "https://knowyourprime.com/evidence-wearable-sleep-tracking-accuracy"
  ],
  "related_articles": [
    "https://knowyourprime.com/under-mattress-sleep-tracker-vs-wearable-accuracy"
  ],
  "methodology": "https://knowyourprime.com/methodology",
  "citation": "KnowYourPrime Evidence Registry, Finding KYP-ER-0008, version 1.0, reviewed 2026-10-24. https://knowyourprime.com/evidence-under-mattress-sleep-sensor-accuracy"
}