SCREENING AND DIAGNOSIS

SCREENING AND DIAGNOSIS OF SLEEP APNEA

Identifying some of the signs and symptoms of sleep apnea is typically the first step toward diagnosis.

There are a number of self-assessment questionnaires such as the Epworth Sleepiness Scale, STOP-BANG or Berlin Questionnaire that can be filled out by patients, parents or healthcare providers. MyApnea.org also provides an online form that can be readily filled out by patients for an automated risk assessment calculation. These screening tools are useful in identifying the relative risk of sleep apnea being present and provide further supporting evidence in determining whether a referral to a sleep physician should be sought out. In addition to the signs and symptoms described above, these screening tools may include questions about neck size, high blood pressure, family history of sleep apnea, insomnia, etc.

These findings should be discussed with the physician and basic education about the risks of OSA should be provided by the health care team. Once a decision has been made to get tested for sleep apnea, a referral from the primary care physician is usually needed to make an appointment with the sleep physician.

The sleep physician will conduct a thorough review of medical history and relevant symptoms, as well as a clinical evaluation in order to determine contributing factors and the possible presence of other disorders such as insomnia, restless leg syndrome, heart failure, medication side effects, etc. Because up to 1/3 of OSA patients have another co-existing sleep disorder, it is important to begin the process with this consultation and to return for re-evaluation once the subjective signs of sleep apnea have been resolved, as residual problems may be present.

Sleep disordered breathing is diagnosed on the basis of an in-lab attended polysomnogram (PSG) or a home sleep test (HST), which can be performed more conveniently in the comfort of one's own bedroom. These tests use specific sensors to continuously record a number of important parameters such as any reduction or cessation of airflow, oxygen desaturations, heart rate, breathing effort, snoring, body position, sleep stage, muscle activity, etc. After analysing the full night recording, the sleep physician is able to determine key indicators (such as the apnea-hypopnea index, severity and duration of oxygen desaturations, or frequency of awakenings) which help him or her arrive at a diagnosis and prescribe the most appropriate treatment.

A second, titration study is typically ordered at a later time to determine the ideal settings on the CPAP (continuous positive airway pressure) machine or oral appliance prescribed for treatment. Sometimes the two studies are combined into one split-night polysomnography protocol.

Home sleep tests have several advantages: they are more convenient for the patient, as there is no need to spend the night away from home; they are less expensive and typically can be scheduled sooner; they may also reflect a more typical night, as there is less interference with the patient's typical routine. However HSTs can not provide the full set of data available from a PSG, due to the limitations of the portable equipment, and sensors may become dislodged during the night due to patient movement. The sleep physician will determine during the initial consult which test is most appropriate and order the study, which should be initiated or supervised by an appropriately trained technician.