Occult sleep apnea in a recruited sample of older adults with insomnia.

Although costly polysomnography (PSG) is not routinely performed with people with insomnia, it may be more necessary with recruited older adults with insomnia because this population may pose a greater risk of veiled sleep disorders compared with younger age groups and with referred samples. The present PSG screening of a recruited sample of older adults with insomnia found a 29%-43% rate of undiagnosed sleep apnea (SA), depending on whether an apnea-hypopnea index of 15 or 5 was used, after interviews had already screened out obvious cases of SA. Also, PSGs revealed a 4% rate of occult periodic limb movements. A discriminant analysis identified overweight men reporting dry mouth at highest risk for occult SA, with an apnea-versus-insomnia classification success rate of 78%. Using PSG evaluations in research on insomnia in recruited older adults is requisite to preclude substantial representation of occult SA.