{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,27]],"date-time":"2026-09-27T15:56:41Z","timestamp":1790524601366,"version":"4.1.0"},"reference-count":16,"publisher":"BMJ","issue":"5","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["Pract Neurol"],"accepted":{"date-parts":[[2025,12,24]]},"published-print":{"date-parts":[[2026,10]]},"abstract":"<jats:p>Functional seizures are one of the most common presentations of functional neurological disorder and frequently generate diagnostic uncertainty in emergency settings. We are experiencing increasing reports of oxygen desaturation during functional seizures, particularly with widespread use of consumer oximeters and wearable devices. We describe a case of recurrent functional seizures with documented desaturation that prompted cardiopulmonary investigations and repeat video-electroencephalogram evaluation. In a controlled setting, apparent desaturations were attributable to artefact and brief breath-holding, with saturations remaining within the expected physiological range. We review common artefactual causes of low oxyhaemoglobin saturation in functional seizures, including motion, excessive pressure due to clenched fingers, excessive ambient light, poor probe placement and low perfusion, as well as the potential role of posthyperventilation apnoea. Recognising these pitfalls is essential to avoid misinterpretation, unnecessary investigations and anxiety for patients and clinicians. Understanding oximetry waveform quality and artefact sources is key to distinguishing true hypoxia from misleading readings.<\/jats:p>","DOI":"10.1136\/pn-2025-004868","type":"journal-article","created":{"date-parts":[[2026,1,27]],"date-time":"2026-01-27T18:20:32Z","timestamp":1769538032000},"page":"464-467","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":1,"title":["Oxygen desaturation in patients with functional seizures: pitfalls for the unwary"],"prefix":"10.1136","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6948-6040","authenticated-orcid":false,"given":"Takamichi","family":"Kanbayashi","sequence":"first","affiliation":[{"name":"Department of Neurology, Teikyo University School of Medicine, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kirsteen","family":"Brown","sequence":"additional","affiliation":[{"name":"Department of Anaesthetics, Royal Infirmary of Edinburgh, Edinburgh, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9829-8092","authenticated-orcid":false,"given":"Jon","family":"Stone","sequence":"additional","affiliation":[{"name":"Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,1,27]]},"reference":[{"key":"2026092100401140000_26.5.464.1","doi-asserted-by":"publisher","DOI":"10.1016\/S1474-4422(21)00422-1"},{"key":"2026092100401140000_26.5.464.2","doi-asserted-by":"publisher","DOI":"10.1111\/ene.16003"},{"key":"2026092100401140000_26.5.464.3","doi-asserted-by":"publisher","DOI":"10.1111\/epi.17038"},{"key":"2026092100401140000_26.5.464.4","doi-asserted-by":"publisher","DOI":"10.1213\/01.ane.0000278134.47777.a5"},{"key":"2026092100401140000_26.5.464.5","doi-asserted-by":"publisher","DOI":"10.1186\/s13054-015-0984-8"},{"key":"2026092100401140000_26.5.464.6","doi-asserted-by":"crossref","first-page":"126","DOI":"10.4103\/nsn.nsn_4_22","article-title":"Comparison of Semiologic Characteristics of Psychogenic Nonepileptic Seizures and Frontal and Temporal Lobe Seizures","volume":"39","author":"Isik","year":"2022","journal-title":"Neurological Sciences and Neurophysiology"},{"key":"2026092100401140000_26.5.464.7","doi-asserted-by":"crossref","first-page":"432","DOI":"10.11622\/smedj.2019031","article-title":"The effects of gel-based manicure on pulse oximetry","volume":"60","author":"Yek","year":"2019","journal-title":"Singapore Med J"},{"key":"2026092100401140000_26.5.464.8","doi-asserted-by":"publisher","DOI":"10.1016\/S0952-8180(97)00039-1"},{"key":"2026092100401140000_26.5.464.9","doi-asserted-by":"publisher","DOI":"10.1016\/j.rmed.2013.02.004"},{"key":"2026092100401140000_26.5.464.10","doi-asserted-by":"publisher","DOI":"10.1016\/S0735-6757(99)90019-0"},{"key":"2026092100401140000_26.5.464.11","doi-asserted-by":"crossref","first-page":"961","DOI":"10.1007\/s10877-021-00797-8","article-title":"Accuracy of pulse oximeters in measuring oxygen saturation in patients with poor peripheral perfusion: a systematic review","volume":"36","author":"Poorzargar","year":"2022","journal-title":"J Clin Monit Comput"},{"key":"2026092100401140000_26.5.464.12","doi-asserted-by":"crossref","DOI":"10.1186\/s12912-018-0283-1","article-title":"Accuracy of pulse oximetry in detection of oxygen saturation in patients admitted to the intensive care unit of heart surgery: comparison of finger, toe, forehead and earlobe probes","volume":"17","author":"Seifi","year":"2018","journal-title":"BMC Nurs"},{"key":"2026092100401140000_26.5.464.13","doi-asserted-by":"crossref","first-page":"727","DOI":"10.4187\/respcare.07520727","article-title":"The ear as an alternative site for a pulse oximeter finger clip sensor","volume":"52","author":"Haynes","year":"2007","journal-title":"Respir Care"},{"key":"2026092100401140000_26.5.464.14","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1016\/j.seizure.2022.10.007","article-title":"Utility of serum lactate on differential diagnosis of seizure-like activity: A systematic review and meta-analysis","volume":"102","author":"Patel","year":"2022","journal-title":"Seizure"},{"key":"2026092100401140000_26.5.464.15","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1016\/j.seizure.2020.01.008","article-title":"Plasma-lactate levels in simulated seizures - 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