Sleep apnea syndrome comorbid with and without restless legs syndrome: differences in insomnia specific symptoms

OBJECTIVE: Sleep Apnea Syndrome (SAS) is frequently comorbid with Restless Legs Syndrome (RLS). Both disorders are associated with disturbed sleep. However, data about insomnia specific symptoms in patients suffering from both sleep disorders (SAS-RLS) are rare. METHODS: In a restrospective design, we investigated 202 patients suffering from SAS and SAS-RLS. All patients underwent polysomnography, performed a vigilance test (Quatember-Maly), and completed the Regensburg Insomnia Scale (RIS), Epworth Sleepiness Scale (ESS), Beck Depression Inventory-II (BDI-II), and a Morning Questionnaire (FZN). Differences in insomnia specific symptoms between SAS and SAS-RLS were calculated using ANOVA. In a secondary analysis, the differences in daytime sleepiness and depression were analyzed. RESULTS: Of 202 patients, 42 (21%) had SAS-RLS. The proportion of women (60%) with SASRLS was higher than for men (40%) while men had had a higher proportion (71%) of SAS alone compared to women (29%), p < 0.0005. The RIS score was higher in SAS-RLS than in SAS. No differences were found in PSG data, ESS, BDI-II, or vigilance tests. CONCLUSIONS: Patients with both disorders SAS and RLS show a higher degree of insomnia-specific symptoms than for SAS alone and may profit from additional insomnia specific treatment.