Idiopathic REM sleep behavior disorder in the elderly Spanish community: a primary care center study with a two-stage design using video-polysomnography

Objective: To examine the presence and characteristics of idiopathic REM sleep behavior disorder (IRBD) in a representative Caucasian sample from the elderly community of Lleida, Spain, attending primary care centers.

Methods: Participants were individuals aged 60 years or older who underwent routine visits in two primary care centers. They underwent a two-stage study; a validated screening single question for IRBD diagnosis (RBD1Q) followed by, in those who endorsed positive answer, clinical assessment by a neurologist plus video-polysomnography (V-PSG).

Results: Of 539 individuals (56.4% women, mean age 72.86 ± 8.20 years), 28 (5.2%) endorsed positively the RBD1Q. Four of these 28 refused further assessments. Four of the 24 remaining subjects underwent clinical assessment but refused V-PSG. Of the 20 who underwent clinical assessment plus V-PSG, REM sleep was not recorded in four (20%, all four taking antidepressants). V-PSG ruled out RBD in 12 subjects who had obstructive sleep apnea (n = 9), periodic limb movement disorder in sleep (n = 2) and normal sleep (n = 1). IRBD was diagnosed in four individuals giving an estimated prevalence of 0.74% (95% CI = 0.29-1.89). They were three men and one woman between 74 and 82 years of age who never reported dream-enacting behaviors to their doctors because they thought they represented a normal phenomenon despite suffering sleep-related injuries. These patients had history of violent sleep behaviors with an interval between estimated RBD onset and V-PSG of 4.5 ± 4.2 years.

Conclusions: IRBD is not uncommon in the elderly community and its demographic and clinical profile is similar to those diagnosed in sleep centers.