Polysomnography reveals unexpectedly high rates of organic sleep disorders in patients with prediagnosed primary insomnia
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It is a matter of debate whether patients with primary insomnia require a polysomnographic examination in order to exclude specific sleep disorders such as sleep apnea syndrome (SAS) or periodic limb movements (PLM). Using a prospective design, we investigated the prevalence of organic sleep disorders by means of polysomnography (PSG) in a series of patients who were previously diagnosed with primary insomnia. This diagnosis was based on a clinical exam and an ambulatory monitoring device or previous PSG.
Seventy-seven women and 16 men (mean age 55.12 ± 13.21 years) who were admitted for cognitive behavioral therapy for insomnia were evaluated by PSG including cardiorespiratory parameters and tibialis EMG. Among them, 50 patients had undergone a clinical exam by a sleep specialist; in 18 patients, actigraphy or portable monitoring had been performed to exclude SAS or PLM; 25 patients had undergone PSG in another sleep lab previously.
In 32 patients (34% of the sample), a PSG revealed a specific sleep disorder (SAS 16; PLMD 11; both 5), resulting in therapeutic consequences for 21 patients (SAS 10; PLMD 9; both 2). SAS and PLM patients were older and SAS patients had a higher body mass index than insomnia patients without additional findings.
Indications for a PSG should be handled less restrictively in the diagnostic workup of older insomnia patients since they have a higher risk of comorbid sleep disorders even in the absence of the clinical signs of SAS or PLM.
KeywordsPolysomnography Sleep apnea Psychophysiological insomnia Women
Beck Depression Inventory
Body mass index
Cognitive behavior therapy for insomnia
Continuous positive airway pressure
Epworth Sleepiness Scale
Insomnia patients without any new findings in PSG
Insomnia patients with unexpected PLMs in PSG
Insomnia patients with unexpected SAS in PSG
- I-SAS + PLM
Insomnia patients with unexpected SAS and PLMs in PSG
Periodic limb movements in sleep
Pittsburgh Sleep Quality Index
Sleep apnea syndrome