Tests
1st tests to order
nasal decongestant test
Test
Involves using a topical nasal decongestant on alternate nights over a 1-week period and comparing the severity of snoring. If the decongestant results in improved symptoms, it may be worth treating nasal abnormalities to improve the snoring.[29]
Result
reduced snoring
Epworth sleepiness score (ESS)
Test
A measurement of excessive daytime somnolence (EDS) may subjectively be made by the ESS patient questionnaire. Patients are asked to rate on a scale of 0 to 3 the likelihood of falling asleep in 8 specific situations. A score above 10 (out of 24) indicates EDS, but the ESS lacks sensitivity and specificity as a screening tool for obstructive sleep apnea (OSA); therefore, in an individual, the ESS may not on its own be very useful and is only a guide.[12] Epworth Sleepiness Scale Opens in new window
Result
score above 10 indicates excessive daytime somnolence
Tests to consider
snoring scale score
Test
This patient questionnaire indicates the severity of snoring by asking three questions looking at the loudness, frequency, and periodicity of the snoring, with four possible responses (0 to 3) giving a score out of 9.[26]
Result
score between 0 and 9, with higher scores indicating greater severity
TFTs
Test
If clinically suspected, thyroid function testing can confirm or exclude hypothyroidism that may be contributing to snoring.
Result
elevated serum TSH and low serum free T4 may indicate hypothyroidism
growth hormone level
Test
If clinically suspected, growth hormone testing may support a diagnosis of acromegaly that may have resulted in weight gain and enlargement of the tongue.
Result
may be elevated in acromegaly
skin-prick tests/serum allergen-specific IgE tests
Test
Used in rhinology clinics for the diagnosis of allergic rhinitis.
Result
positive in patients with allergic rhinitis
sleep study
Test
If there is concern the patient may have OSA, then an overnight sleep study is necessary. The simplest sleep study is overnight pulse oximetry. This device measures oxygen saturation and provides pulse rate data. It assumes that when an individual has an apnea or hypopnea, the oxygen saturation falls. Once the apnea or hypopnea is relieved, the oxygen desaturation recovers. The falls and increases are regarded as oxygen dips.[12]
Some clinicians use oximetry alone as a screen for OSA. Unfortunately, studies using overnight oximetry as a screening tool for OSA have shown good specificity and positive predictive value, but poor sensitivity and negative predictive value.[30] This means overnight oximetry may miss subjects with OSA who do not desaturate. It may also miss patients with upper airway resistance syndrome (UARS).
Full polysomnography remains the definitive method for diagnosing OSA.[12] An apnea-hypopnea index of over 5 indicates OSA.
Result
may identify OSA
acoustic analysis
Test
Acoustic analysis of snoring is helpful in objectively determining the volume and duration of snoring but is only of limited use in detecting the site of snoring.[33]
It may also be a useful research tool to evaluate the impact of various environmental and patient factors on the severity of snoring.[34][35]
Result
indicates volume and duration of snoring
pharyngeal manometry
Test
Pressure probes inserted per nasally into the upper airway, with an overnight sleep study, may help identify whether the snoring is occurring at the palate or tongue base level.[31]
Result
snoring at palate or tongue-base level
sleep nasendoscopy
Test
Used to evaluate the site of snoring. It involves sedating the patient with propofol to a level of sleep sufficient to induce snoring. With the patient in the supine position, the operator then examines the upper aerodigestive tract with a flexible nasendoscope to determine the level(s) of obstruction.
This may help in selecting which patients are suitable for palate surgery.[32]
Result
shows origin of snoring
Emerging tests
head and neck 3-dimensional CT
Test
Three-dimensional CT may be useful to evaluate upper airway patency in patients with sleep-disordered breathing.[12]
Result
sites of narrowing or other abnormal anatomy
head and neck MRI
Test
Ultrafast MRI can be used in awake and asleep patients to assess the site of upper airway obstruction, but it is not available at all centers and short periods of sleep in an MRI machine may not be representative of normal sleep patterns.[12]
Result
sites of narrowing or other abnormal anatomy
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