Acoustic Startle Reflex and Its Modulation in Trauma-Exposed Populations and Posttraumatic Stress Disorder: A Systematic Review and Meta-Analysis
Description
This meta-analysis compared electromyographic (EMG), heart rate (HR), and skin conductance response (SCR) measures within acoustic startle reflex (ASR) paradigms among individuals with posttraumatic stress disorder (PTSD), trauma-exposed controls (TECs), and healthy controls (HCs). Trauma exposure alone did not significantly influence psychophysiological responses. For EMG, individuals with PTSD exhibited heightened baseline startle (g = 0.27 vs. TECs; g = 0.31 vs. HCs), slower habituation (g = -0.15 vs. TECs; g = -0.35 vs. HCs), reduced prepulse inhibition (g = -0.32 vs. TECs; g = -0.27 vs. HCs), and elevated fear-potentiated startle (FPS) under fear conditions (g = 0.36 vs. TECs; g = 0.35 vs. HCs). In fear conditioning paradigms, individuals with PTSD further showed impaired fear inhibition to safety cues (g = 0.43 vs. TECs; g = 0.40 vs. HCs) and diminished fear extinction (g = 0.41 vs. TECs; g = 0.43 vs. HCs), whereas threat-safety discrimination did not differ from TECs, as indexed by EMG-based FPS. Individual with PTSD also showed elevated HR during startle elicitation (g = 0.63 vs. TECs; g = 0.62 vs. HCs), hyperreactive baseline startle reactivity (g = 0.30 vs. TECs) and blunted habituation in SCR (g = -0.32 vs. TECs). Longitudinal evidence suggested that alterations in ASR may reflect pre-existing vulnerability or acquired changes following trauma. Future research integrating behavioral, psychophysiological, and neuroimaging data within ASR paradigms may further elucidate the etiology and pathophysiology of PTSD. ASR paradigms represent promising translational tools for identifying PTSD risk, monitoring symptom trajectories, and indexing treatment outcomes.
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CMA software Version 3.0