FAQs

Access a library of clinical resources, guides, and reference materials to support sleep diagnostics. From setup instructions and interpretation protocols to research insights and training tools, the Knowledge Base helps clinicians and technicians get the most from Stowood technologies.

Clinical FAQs – Sleep Diagnostics

Answers to commonly asked questions in sleep and respiratory studies

This page brings together frequently asked clinical questions and evidence-based responses related to oximetry, polygraphy, and polysomnography (PSG). All references are from published clinical literature.

Important: Stowood provides this page for information only and accepts no responsibility for its clinical accuracy or application. Always consult a qualified clinician or sleep specialist before acting on any advice. If you have a suggestion for a topic to add, please contact us.

Sleep Recording for Personal Use

Q: Can I buy a sleep recorder and use it on myself if I think I have a sleep disorder?
A: While there is no legal restriction in the UK on individuals purchasing a sleep recorder, we strongly discourage this. A diagnosis and treatment plan can only be provided if your study is performed and interpreted by a recognised clinician. We recommend contacting your local NHS or private sleep clinic. For more information, visit the Sleep Apnoea Trust Association (SATA).

Oximetry Studies

Q: Can oximetry alone diagnose sleep apnoea?

  • Thorax: Oximetry alone allows recognition of moderate or severe OSA.

  • AJRCCM: Home oximetry is as predictive of CPAP response as full PSG.

  • Western Journal of Medicine: Oximetry is useful, but additional channels (respiratory effort, leg movement) improve diagnostic accuracy.

Q: Does the choice of oximeter matter?

  • Chest: Oximeter type can affect AHI calculation and diagnostic thresholds.

Explore Stowood’s oximetry range | Visi-Download software

Polygraphy (PG) / Ambulatory Studies

Q: Is PSG better than polygraphy for diagnosing OSA?

  • Ann Intern Med.: No significant advantage of PSG over ambulatory PG for OSA diagnosis and CPAP titration.

Q: Are nasal prongs better than thermistors?

  • Chest: Nasal prongs provide better resolution and diagnostic accuracy than thermistors.

Q: How does Respiratory Inductive Plethysmography (RIP) compare to oesophageal pressure for UARS?

  • Chest: RIP offers high sensitivity and specificity, especially pre-arousal.

Q: Are sleep studies helpful in children with suspected upper airway obstruction?

  • Archives of Disease in Childhood: Yes – useful for surgery decisions and postoperative risk assessment.

Q: Are there reference values for PG in children?

  • See Pediatric Research for normative data.

Q: How can obstructive events in children be measured?

  • Pediatric Research: Pulse Transit Time (PTT) is more sensitive than EEG arousals.

  • Arch Otolaryngol: PTT useful in moderate/severe OSAHS, not in mild cases.

Q: What can photoplethysmography (PPG) signals tell us?

  • J Clin Sleep Med. & Medicine (Baltimore): PPG changes reflect arousals and sympathetic activity, correlating well with PSG.

Explore Stowood’s ambulatory monitors

Polysomnography (PSG)

Currently no FAQs listed.
Explore Stowood’s PSG and lab-based systems
Have a question? Let us know and we may include it here.

Osler Tests (Daytime Sleepiness Assessment)

Q: How many Osler tests are needed in one day?

  • J Sleep Res.: Up to four tests/day shows consistent results.

  • Am J Respir Crit Care Med (2001): Two tests may be sufficient.

  • Am J Respir Crit Care Med (2002): A single 9 am test is comparable to the four-test average in detecting vigilance fluctuation.