Spontaneous Eye-Blink Rate: A Non-Invasive, Behavioral Index of Brain Activity Relevant to Emotion, Self-Regulation, and Addiction

Background: Chronic pain is one of the most prevalent health problems in the US, for which opioids remain the primary treatment. Opioids act through numerous pathways, including a system in the brain heavily implicated in emotional experience, self-regulatory capacity, and the reward circuitry undergirding addiction. Protracted use of opioids is thought to have deleterious effects on this pathway. Spontaneous eye-blink rate (EBR)—the number of times a person blinks over a set period of time—is a non-invasive, behavioral index of activity in this brain system. Accordingly, EBR can be used as an inferential measure of dysregulated emotion, impaired self-regulation, and susceptibility to opioid dependence. This behavioral index of brain activity may contribute to social workers’ ability to more accurately assess and treat addictions and mental health problems stemming from emotion dysregulation and impaired self-regulation. Methods: This cross-sectional, secondary analysis examined data obtained from a sample of chronic pain patients (N=52) who participated in a randomized controlled trial (Garland et al., 2014). Blinks were captured via electrooculography (EOG) while participants completed an emotional Go-No-Go (GNG) task—a computerized test used to assess inhibitory control. Spontaneous EBR was calculated as number of blinks divided by number of minutes in two GNG blocks: one with drug cues (e.g., pills), and one with naturally rewarding cues (e.g., a beautiful sunset). Results: Results indicate that, compared to chronic patients without opioid dependence, opioid-dependent patients have significantly lower EBR during attention to naturally pleasant cues alone, as well as relative to drug cues. Implications: Results suggest opioid dependence contributes to the presence of differential relationships between spontaneous EBR and emotionally-valenced cues representing natural reward and drug reward. Blunted EBR among opioid-dependent individuals may represent dysregulated activity in a brain system implicated in emotion, self-regulation, and addiction. Social work research may benefit from this non-invasive, behavioral measure of physiological aspects relevant to the downward spiral from chronic pain to opioid misuse.