Veterans may be at higher risk of idiopathic rapid eye movement sleep behavior disorders, particularly if they have traumatic brain injury (TBI) or posttraumatic stress disorder (PTSD) according to a paper published in Sleep.

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In a prospective, cross-sectional study, researchers recruited 394 veterans – 94% of whom were male – who underwent in-lab video-polysomnography and questionnaires about REM sleep behavior disorder (RBD), as well as assessment of their trauma status and medical history.

Overall, 9% of subjects had RBD, a figure considerably higher than has been estimated in the general population (prevalence of 0.38%-1.0%). Seven percent had REM sleep without atonia, 31% had other parasomnias such as a history of dream enactment behavior, and 53% were classified as normal.

The majority of subjects determined to have RBD (n = 34) had either PTSD or comorbid TBI+PTSD (n = 19, 56%). The combined overall crude prevalence of RBD in subjects with either PTSD alone or TBI+PTSD was 16.8% (n = 19 out of 113).

The individuals with PTSD had a 2.81-fold greater odds of RBD and 3.13-fold greater odds of other parasomnias compared with those without PTSD.

Those with both traumatic brain injury and PTSD had 3.43-fold greater odds of RBD and 3.22-fold greater odds of other parasomnias compared with individuals without.

“Interestingly, the neuropathology underpinning PTSD shares common features with RBD, raising the question as to whether or not PTSD has a causal role in the development of RBD, or if a single pathophysiologic process generates two clinical entities,” wrote Jonathan E. Elliott, PhD, of the VA Portland Health Care System, and coauthors.

The researchers also looked for evidence of trauma-associated sleep disorder (TASD), a recently proposed phenomenological sleep disorder whose diagnostic criteria overlaps with REM sleep behavior disorder but includes subjects reporting having an inciting traumatic experience and a history of dreaming related to this experience as well as evidence of autonomic hyperarousal.

The researchers found 22 of the subjects with REM behavior disorder had a traumatic brain injury and/or PTSD, and 9 of these subjects reported evidence of altered dream mentation related to that prior traumatic experience. However, none showed evidence of autonomic nervous system hyperarousal that coincided with abnormal REM sleep activity.

The investigators noted that although the sample of 394 subjects with in-lab video-polysomnography is large, the study is underpowered to draw broader conclusions about prevalence of RBD among veterans. In addition, the study did not establish whether or not trauma exposure preceded, and contributed to, the development of parasomnias and this question should be pursued in further studies.

“Given the purported relationships between TBI, PTSD, RBD, and neurodegeneration, we sought to determine the crude prevalence and related associations of RBD following TBI and PTSD among veterans. Our data show that the prevalence of RBD and related parasomnias is significantly higher in veterans with PTSD and TBI+PTSD compared to veterans without a history of neuropsychiatric trauma,” the authors wrote.

No funding or conflicts of interest were declared.

SOURCE: Elliott JE et al. Sleep 2019 Oct 7. doi: 10.1093/sleep/zsz237.