Other suspected sleep disorders that commonly warrant testing in a sleep lab include obesity hypoventilation syndrome, upper airway resistance syndrome and limb movement disorders, said Dr. Weaver.
Explore This IssueJuly 2008
Finally, those with negative home monitoring results might warrant in-lab testing if a sleep disorder is still suspected or if technical problems arose with home testing, said Dr. Weaver.
Cognitive Impairments and Comorbidities
Individuals suspected of having sleep apnea but who are cognitively impaired may require in-lab testing so an attendant can monitor and adjust monitors as needed, said Dr. Davidson.
In addition, patients with suspected sleep apnea but with significant comorbidities are best tested in a sleep lab, said Dr. Weaver. These include serious cardiovascular, pulmonary, or neurological disease or any other condition that might affect sleep testing quality or complicate the sleep apnea, he explained.
Those with significant cardiac disease or pulmonary problems are generally not good candidates for home testing because if blood oxygen drops, the machine cannot detect whether it is due to sleep apnea or there other underlying conditions, explained Dr. Wardrop.
Also of consideration are the diagnostic capabilities of home testing and PSG for sleep apnea. Overall, the literature indicates both approaches provide equally good diagnostic data and test results, said Dr. Davidson.
For example, a recent randomized, controlled, open-label study of 68 patients with a high probability of obstructive sleep apnea found that PSG has no advantage over home testing in making a diagnosis (Ann Intern Med 2007;146(3):157-66).
However, home monitoring can be conducted over several nights, which could potentially provide more reliable results than PSG, noted Dr. Weaver. Home monitoring also reduces unnecessary measurements for routine sleep apnea, he said.
A potential drawback of home monitoring is that it may underestimate the severity of sleep apnea, said Dr. Weaver. Additionally, because a technician isn’t on hand to monitor whether lines become unhooked, home testing can result in unusable data or data loss, he said. Moreover, standardizing the quality of testing is difficult and some scoring algorithms may be inadequate, he added.
Whatever the diagnostic capabilities of the tests or the recommendations of the physician are, patients may prefer home monitoring to diagnose suspected sleep apnea, noted Dr. Davidson.
Senior citizens, for example, are less likely to opt for PSG, one reason often being that they don’t like to drive at night, he said. Older people don’t sleep as well and would rather test at home in their own bed, he added. As many as 50% of older patients don’t go to PSG when recommended to do so by their physicians, he explained.