The association of upper airway resistance with periodic limb movements

Study Objectives: We hypothesized that the upper airway resistance syndrome (UARS), the component event being a respiratory effort related arousal (RE RA), and periodic limb movements in sleep (PLMS), the component event being repetitive, stereotyped extremity movements occurring in a periodic fashio n, were associated in certain patients. Design: Invasive polysomnography using Pes and full facemask pneumotachogra phy was used to identify RERA's in patients, Periodic limb movements (PLM) were scored according to standard criteria and as associated with RERA if t he movement occurred between the Pes nadir and the onset of the arousal. Setting: A university hospital Sleep Disorders Laboratory Participants: Patients consecutively diagnosed with PLMS in our sleep disor ders laboratory over a 1 year period. Interventions: None Measurements and Results: Fourteen of twenty patients demonstrated UARS in addition to PLMS (70%). In those 14, 63% of RERAs were associated with a PL M (mean = 51.7 + 36.2 PLM/RERAs per study vs 5.6 + 6.3 PLM/RERAs per study if the association were random). Patients with UARS had more arousals with their PLMs (P = 0.0006). Conclusions: An association exists between PLMS and UARS on both a group le vel and an event level. A high percentage of PLM with arousals correlated w ith breathing events due to increased effort in UARS; this may be of clinic al utility in the management of PLMS patients.