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The underlying pathophysiology of OSA is complex as there are a range of causes of partial collapse of the upper airway.

With OSA there is a partial collapse of the upper airway (at palato and/or oropharyngeal level) leading to repeated episodes of obstruction. This is a complex event with different gradations involving both anatomical and non-anatomical factors including loss of muscle tone.1, 2 External factors include compression of the upper airway by fat or craniofacial abnormalities (e.g. retrognathia), reduced longitudinal traction on the upper airway due to reduced lung volumes, and interactions between the upper airway and control of ventilation in respiration centres in the brain.3

OSA can be accompanied by fluctuations in intrathoracic pressure, arousals, hypoxemia hypercapnia, and fluctuations in blood pressure and heart rhythm. These effects vary greatly from patient to patient and are associated with cardiometabolic disorders (See Comorbidities & Complications). The effects are not directly related to the severity of the OSA. There is, for example, no linear relation between apnoea-hypopnoea index (AHI) and the degree of hypoxemia. Hypoxemia parameters (e.g. desaturation index and the sleep duration with an SpO2 value < 90%), when compared to AHI, may have a better predictive value for clinical outcomes and prognosis.4The biological impact of hypoxemia at the organ level, e.g. the sensitivity (vulnerability) and tolerance (resistance) for the same degree of hypoxemia, also varies greatly from patient to patient – underlying factors are yet unknown, and may include genetics.5, 6


AHI - Apnoea-Hypopnoea Index
BBTi - Brief Behavioural Therapy for Insomnia
BMI - Body Mass Index (kg/m2)
BQ - Berlin Questionnaire
CBTi - Cognitive Behavioural Therapy for Insomnia
CELL - Coblation Endoscopic Lingual Lightening
COPD - Chronic Obstructive Pulmonary Disease
CVA - Cerebrovascular Accident
CPAP - Continuous Positive Airway Pressure
CSA - Central Sleep Apnoea
DASS - Depression Anxiety Stress Scale
DBAS - Dysfunctional Beliefs and Attitudes about Sleep
DBP - Diastolic Blood Pressure
DIMS - Difficulties Initiating and/or Maintaining Sleep
DISE - Drug-Induced Sleep Endoscopy
DISS - Daytime Insomnia Symptom Scale
ENT - Ear Nose and Throat
ESS - Epworth Sleepiness Scale
FOSQ - Functional Outcomes of Sleep Questionnaire
FSH - Follicle-Stimulating Hormone
FTP - Friedman Tong Position
GP - General Practitioner
HANDI - RACGP Handbook of Non-Drug Interventions
HGNS - Hypoglossal Herve Htimulation
ISI - Insomnia Severity Index
K10 - Kessler Psychological Distress Scale
MAD - Mandibular Advancement Device
MAS - Mandibular Advancement Rplint
MBS - Medicare Benefits Schedule
MMA - Maxillomandibular Advancement Surgery
MRA - Mandibular Repositioning Appliance
ODI - Oxygenation Desaturation Index
OSA - Obstructive Sleep Apnoea
PLMD - Periodic Limb Movement Disorder
PT - Positional Therapy
PTSD - Post-Traumatic Stress Disorder
PSG - Polysomnography
QSQ - Quebec Sleep Questionnaire
REM - Rapid Eye Movement
RFTB - Radiofrequency Thermotherapy of the Tongue Base
SBP - Systolic Blood Pressure
SCI - Sleep Condition Indicator
SE - Sleep Efficiency
SF36 - Short-Form (36) Health Survey
SMILE - Submucosal Minimally Invasive Lingual Excision
SNRIs - Serotonin-Norepinephrine Reuptake Inhibitors
SOL - Sleep Onset Latency
SSRI - Selective Serotonin Reuptake Inhibitors
TFTs - Thyroid Function Tests
TIB - Time In Bed
TORS - Transoral Robotic Surgery
TST - Total Sleep Time
UPPP - Uvulopalatopharyngoplasty
WASO - Wake After Sleep Onset

Quick links


  1. Zinchuk AV, et al. Phenotypes in obstructive sleep apnea: a definition, examples and evolution of approaches. Sleep Med Rev 2017;35(10):113-23
  2. Eckert DJ, et al. Defining phenotypic causes of obstructive sleep apnea. Identification of novel therapeutic targets. Am J Respir Crit Care Med 2013;188(8):996-1004
  3. Malhotra A, et al. Obstructive sleep apnoea. The Lancet 2002; 360:237-45
  4. Rosenzweig I, et al. Sleep apnoea and the brain: a complex relationship. Lancet Respir Med 2015;3(5):404-14
  5. Khalyfa A, et al. The Challenges of Precision Medicine in Obstructive Sleep Apnea. Sleep Med Clin 2016;11(2):213-26
  6. De Luca Canto G et al. Diagnostic capability of biological markers in assessment of obstructive sleep apnea: a systematic review and meta-Analysis. J Clin Sleep Med 2015;11(1):27-36