Self-Reported Sleep Disturbance Mediates the Relationship Between PTSD and Cognitive Outcome in Blast-Exposed OEF/OIF Veterans.
Mieke Verfaellie, Lewina O Lee, Ginette Lafleche and 1 others
PMID 26580692WHAT IT FOUND
In blast-exposed veterans, poor sleep links PTSD symptoms to worse cognitive performance.
Sleep disturbance accounted for most of the association between PTSD and deficits in memory, processing speed, and cognitive control. Clinicians should assess sleep when evaluating cognition in this population.
Key findings
01Sleep disturbance mediated the relationship between PTSD severity and worse performance in processing speed, verbal memory, visual memory, motor speed, and cognitive control.
02For each cognitive factor, a large proportion of the total effect of PTSD was due to the indirect effect of sleep disturbance, ranging from 72.7% to 96%.
03After adjusting for PTSD, mild TBI with loss of consciousness was linked to worse manual dexterity, but this relation could not be explained by sleep disturbance.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs
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What it does not show
The study is cross-sectional, so it cannot prove that treating sleep will improve cognition or that sleep causes the deficits. Sleep was measured by self-report, which may be inaccurate in individuals with PTSD who might overestimate their sleep difficulties. The sample was limited to veterans exposed to blast, so findings may not apply to other populations with PTSD or mTBI. Depression and PTSD scores were highly correlated, making it difficult to separate the specific effects of PTSD from general distress.
Declared interests
No specific conflicts of interest were reported in the provided text.
The easy way to misread this
Do not assume that treating sleep disturbance will directly improve cognitive outcomes. The study is cross-sectional and shows an association, not causation. While sleep disturbance mediated the relationship between PTSD and cognition, the authors explicitly state that it is unknown whether improved sleep leads to cognitive benefits.