Mild Traumatic Brain Injury Chronically Impairs Sleep- and Wake-Dependent Emotional Processing

Area of Science:

• Neuroscience
• Psychology
• Sleep Science

Background:

• Mild traumatic brain injury (TBI), even a single concussion, can lead to long-term consequences.
• Individuals with a history of chronic mild TBI (>1 year prior) exhibit increased risks of mood disturbances and persistent sleep alterations, including poor sleep quality and changes in sleep architecture.

Purpose of the Study:

• To investigate whether sleep-dependent emotional memory consolidation is impaired in individuals with a history of chronic mild TBI.
• To compare emotional memory processing between mild TBI survivors and an uninjured control group under conditions of sleep and wakefulness.

Main Methods:

• Participants (mild TBI group and non-TBI control group) viewed negative and neutral images before and after a 12-hour sleep or wake period.
• Emotional memory consolidation was assessed by testing recognition of images and participants' subjective ratings of valence and arousal.

Main Results:

• The mild TBI group experienced reduced REM sleep and increased sleep complaints compared to controls.
• While sleep-dependent consolidation of neutral images occurred in all participants, consolidation of negative emotional images was observed only in the non-TBI group.
• The TBI group showed impaired emotional memory consolidation, with poor performance in the sleep condition and unexpectedly enhanced performance in the wake condition, unlike the non-TBI group which habituated to negative images.

Conclusions:

• Disrupted sleep- and wake-dependent emotional processing following chronic mild TBI may contribute to adverse emotional outcomes.
• These findings highlight the significant impact of mild TBI on emotional regulation and memory consolidation, with implications for approximately one-third of the US population who experience mild TBI.