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(304) Brain Mediators of Handholding Analgesia
S50 The Journal of Pain pain catastrophizing measure. Between visits, participants wore an actigraphy watch (Actiwatch II, Philips Respironics) for seven days from which the following sleep-derived variables were averaged: latency, total sleep time, efficiency, and wake after sleep onset (WASO). Results revealed that people with TMJD had worse subjective sleep than HCs (all p’s< .02) but did not differ on objective sleep variables. Only subjective ratings of sleep correlated with pain intensity and situational pain catastrophizing (r’s=.27-.37). PSQI Score (=.30), PROMIS Sleep Impairment (=.37), and PROMIS Fatigue (=.29) predicted pain intensity during the CPT. Similarly, PSQI Score (=.29), ISI (=.27), PROMIS Sleep Impairment (=.36), and PROMIS fatigue (=.30) predicted situational pain catastrophizing following the CPT, but these effects were mediated by pain intensity. There were no significant group interactions predicting intensity or catastrophizing. Results suggest that subjective measures of sleep are better predictors of pain intensity and catastrophizing than objective predictors and highlight the importance of assessing sleep subjectively.
(303) Does Pain-Inducing Massage Produce Pain Sensitivity Changes Similar to a Conditioned Pain Modulation Paradigm? A Double-Blinded Randomized Controlled Trial A. Wilson, J. Riley, M. Bishop, Y. Cruz-Almeida, J. Beneciuk, M. Godza, and J. Bialosky; University of Florida, Gainesville, FL Massage is analgesic for some people with pain-inducing massage (PIM) resulting in greater pain sensitivity changes compared to pain-free massage (PFM). However, the underlying neurobiological mechanisms are not well-understood. Given that the experience of pain and analgesia rely on the functioning of pain inhibitory systems, PIM may exert analgesia via mechanisms consistent with conditioned pain modulation (CPM). Thus, we aimed to determine if PIM used as a conditioning stimulus would result in comparable self-reported and experimental pain sensitivity changes as a cold pressor task or a PFM control. Fifty healthy participants (68% female, mean age 22 years (SD=4.72)) were randomly assigned to four, one-minute exposures to a cold pressor to the hand, a PIM or PFM to the neck. Pressure pain thresholds (PPT) were assessed on the contralateral foot before and after each intervention period. Cold pressor pain ratings (M=39.78, SD=24.43)) exceeded PIM pain reports (M=22.04, SD= 14.54, p<0.01) and both exceeded the PFM (M=0.02, SD=0.11, p<0.01). A 2-way repeated measures ANCOVA with baseline PPT as a covariate indicated a group by time interaction in PPT (p<0.01). Cold pressor resulted in increased PPT compared to PFM after 1, 2, and 3 minutes (p’s<0.05) but not following the fourth minute (p=0.09). PIM resulted in higher PPT compared to PFM after 3 and 4 minutes (p’s<0.05). PIM and cold pressor did not differ at any time point (p>0.05). Pearson correlation revealed that greater intervention-related pain was associated with increases in PPT (r=0.29, p=0.04). Although PIM resulted in less selfreported pain than a cold pressor task, both resulted in similar magnitude of the CPM response suggesting shared underlying mechanisms. Future studies are needed to elucidate the neurobiological substrates of PIM that can help identify therapeutic outcomes.
(304) Brain Mediators of Handholding Analgesia M. Lopez Sola, L. Koban, S. Geuter, J. Coan, and T. Wager; Cincinnati Children’s Hospital, Cincinnati, OH Touch can have remarkable benefits in childbirth and during painful medical procedures. But does social touch influence pain neurophysiology, i.e., the brain processes linked to nociception and primary pain experience? And what other brain processes beyond primary pain systems mediate their analgesic effects? In this study, thirty women experienced thermal pain while holding their romantic partner’s hand or an inert pneumatic device. Handholding reduced pain and attenuated fMRI activity in the Neurologic Pain Signature (NPS)—a multivariate brain pattern sensitive and specific to somatic pain—and increased connectivity between the NPS and both somatosensory and ‘default mode’ regions. Brain correlates of touch-induced analgesia included reduced activity in (a) regions targeted by primary nociceptive afferents (e.g., posterior insula, and anterior cingulate cortex (ACC); and (b) changes in regions associated with affective value, meaning and attentional regulation, including lateral and medial prefrontal (PFC) and orbitofrontal cortices. Activation reductions significantly mediated reductions in pain intensity and unpleasantness, which were in turn correlated
Abstracts with greater emotional comfort during handholding and higher perceived relationship quality. The strongest mediators of analgesia were activity reductions in a brain circuit traditionally associated with stress and defensive behavior in mammals as well as pain modulation, including ventromedial and dorsomedial PFC, rostral ACC, amygdala/hippocampus, hypothalamus and PAG. In conclusion, social touch affects core brain processes that contribute to pain and pain-related affective distress, and should be considered alongside other treatments in medical and caregiving contexts.
(305) The Contribution of Experimental Pain to the Sex Differences in Exercise-Induced Hypoalgesia A. Awali, R. Nevsimal, S. O’Melia, A. Alsouhibani, and M. Hoeger Bement; Marquette University, Milwaukee, WI The aim of this study was to investigate the effect of baseline (preexercise) temporal summation (TS) on the change of TS following submaximal isometric exercise in young healthy men (M) and women (W). Fifty-seven participants (20.75 § 1.81 years; 29 women) completed two randomized sessions (exercise or quiet rest session). Isometric exercise consisted of sustained contraction of the knee extensors at 30% of maximum voluntary contraction performed until task failure. TS was assessed by applying a mechanical noxious stimulus equivalent to either 1kg (Low group) or 1.5 kg (High group) on the index finger. The mechanical noxious stimulus was applied for one minute beyond pain threshold, and subjects were instructed to rate their pain every 15 seconds on a numerical pain rating scale (0-10). TS was evaluated before and after exercise and quiet rest. The magnitude of TS was calculated as: [last pain rating − first pain rating]. The change of TS was compared between the two groups within each sex (M-High, M-Low, W-High, and W-Low). Sex differences in exercise-induced hypoalgesia (EIH) occurred among the high TS stimulus intensity group (session X trial X sex X group; p= 0.01); only W-High group experienced EIH while M-High experienced no change (session X trial X sex; p=0.039). Among women, the W-High had greater EIH than W-Low (session X trial X group; p= 0.049). In addition, pre-exercise TS was positively correlated with the magnitude of EIH (r= 0.34, p= 0.01). These results suggest that baseline experimental pain may contribute to the magnitude of EIH and to the sex differences in EIH.
(306) The Unique and Interactive Effects of Patient Race, Patient Weight, and Provider Implicit Attitudes on Chronic Pain Treatment Decisions T. Anastas, K. Walsh, M. Miller, Z. Trost, L. Goubert, L. De Ruddere, and A. Hirsh; Indiana University − Purdue University Indianapolis, Indianapolis, IN Prior work suggests that providers are influenced by patient race and weight when making pain-related decisions. Providers with stronger implicit (automatic) attitudes about race and weight may be more likely to be influenced by these patient-level characteristics when making treatment decisions. In this multi-part study, we (a) examined the influence of patient race and weight on providers’ pain treatment decisions, (b) measured providers’ implicit attitudes about race and weight with two separate Implicit Association Tests, and (c) explored the extent to which providers’ attitudes predicted their treatment decisions. Ninety medical students (“providers”) viewed four videos of women with chronic low back pain completing a standardized sit-to-stand task who varied by race (Black/White) and weight (overweight/obese). Text vignettes with additional patient information accompanied the videos. For each patient, providers rated their likelihood of recommending opioids, a psychology referral, and disability compensation. Repeated measures ANOVAs indicated no main effects of patient race or weight on providers’ opioid decisions; however, providers were more likely to recommend a psychology referral for patients with obesity versus overweight [F(1,89)=9.79, p<.01] and disability compensation for Black versus White patients [F(1,89)=4.64, p=.03]. Providers demonstrated a moderate implicit preference for White over Black people (M=.29, SD=.40) and people with normal weight over obesity (M=.30, SD=.44). Providers with a stronger implicit preference for people with normal weight were less likely to recommend disability compensation to patients with obesity versus overweight (b=.28, p=.02). Providers’ implicit attitudes about race and weight did not significantly predict the other treatment items. These results suggest that patient race and weight and providers’ implicit attitudes about weight influence some, but not all, pain treatment decisions. Future
(303) Does Pain-Inducing Massage Produce Pain Sensitivity Changes Similar to a Conditioned Pain Modulation Paradigm? A Double-Blinded Randomized Controlled Trial A. Wilson, J. Riley, M. Bishop, Y. Cruz-Almeida, J. Beneciuk, M. Godza, and J. Bialosky; University of Florida, Gainesville, FL Massage is analgesic for some people with pain-inducing massage (PIM) resulting in greater pain sensitivity changes compared to pain-free massage (PFM). However, the underlying neurobiological mechanisms are not well-understood. Given that the experience of pain and analgesia rely on the functioning of pain inhibitory systems, PIM may exert analgesia via mechanisms consistent with conditioned pain modulation (CPM). Thus, we aimed to determine if PIM used as a conditioning stimulus would result in comparable self-reported and experimental pain sensitivity changes as a cold pressor task or a PFM control. Fifty healthy participants (68% female, mean age 22 years (SD=4.72)) were randomly assigned to four, one-minute exposures to a cold pressor to the hand, a PIM or PFM to the neck. Pressure pain thresholds (PPT) were assessed on the contralateral foot before and after each intervention period. Cold pressor pain ratings (M=39.78, SD=24.43)) exceeded PIM pain reports (M=22.04, SD= 14.54, p<0.01) and both exceeded the PFM (M=0.02, SD=0.11, p<0.01). A 2-way repeated measures ANCOVA with baseline PPT as a covariate indicated a group by time interaction in PPT (p<0.01). Cold pressor resulted in increased PPT compared to PFM after 1, 2, and 3 minutes (p’s<0.05) but not following the fourth minute (p=0.09). PIM resulted in higher PPT compared to PFM after 3 and 4 minutes (p’s<0.05). PIM and cold pressor did not differ at any time point (p>0.05). Pearson correlation revealed that greater intervention-related pain was associated with increases in PPT (r=0.29, p=0.04). Although PIM resulted in less selfreported pain than a cold pressor task, both resulted in similar magnitude of the CPM response suggesting shared underlying mechanisms. Future studies are needed to elucidate the neurobiological substrates of PIM that can help identify therapeutic outcomes.
(304) Brain Mediators of Handholding Analgesia M. Lopez Sola, L. Koban, S. Geuter, J. Coan, and T. Wager; Cincinnati Children’s Hospital, Cincinnati, OH Touch can have remarkable benefits in childbirth and during painful medical procedures. But does social touch influence pain neurophysiology, i.e., the brain processes linked to nociception and primary pain experience? And what other brain processes beyond primary pain systems mediate their analgesic effects? In this study, thirty women experienced thermal pain while holding their romantic partner’s hand or an inert pneumatic device. Handholding reduced pain and attenuated fMRI activity in the Neurologic Pain Signature (NPS)—a multivariate brain pattern sensitive and specific to somatic pain—and increased connectivity between the NPS and both somatosensory and ‘default mode’ regions. Brain correlates of touch-induced analgesia included reduced activity in (a) regions targeted by primary nociceptive afferents (e.g., posterior insula, and anterior cingulate cortex (ACC); and (b) changes in regions associated with affective value, meaning and attentional regulation, including lateral and medial prefrontal (PFC) and orbitofrontal cortices. Activation reductions significantly mediated reductions in pain intensity and unpleasantness, which were in turn correlated
Abstracts with greater emotional comfort during handholding and higher perceived relationship quality. The strongest mediators of analgesia were activity reductions in a brain circuit traditionally associated with stress and defensive behavior in mammals as well as pain modulation, including ventromedial and dorsomedial PFC, rostral ACC, amygdala/hippocampus, hypothalamus and PAG. In conclusion, social touch affects core brain processes that contribute to pain and pain-related affective distress, and should be considered alongside other treatments in medical and caregiving contexts.
(305) The Contribution of Experimental Pain to the Sex Differences in Exercise-Induced Hypoalgesia A. Awali, R. Nevsimal, S. O’Melia, A. Alsouhibani, and M. Hoeger Bement; Marquette University, Milwaukee, WI The aim of this study was to investigate the effect of baseline (preexercise) temporal summation (TS) on the change of TS following submaximal isometric exercise in young healthy men (M) and women (W). Fifty-seven participants (20.75 § 1.81 years; 29 women) completed two randomized sessions (exercise or quiet rest session). Isometric exercise consisted of sustained contraction of the knee extensors at 30% of maximum voluntary contraction performed until task failure. TS was assessed by applying a mechanical noxious stimulus equivalent to either 1kg (Low group) or 1.5 kg (High group) on the index finger. The mechanical noxious stimulus was applied for one minute beyond pain threshold, and subjects were instructed to rate their pain every 15 seconds on a numerical pain rating scale (0-10). TS was evaluated before and after exercise and quiet rest. The magnitude of TS was calculated as: [last pain rating − first pain rating]. The change of TS was compared between the two groups within each sex (M-High, M-Low, W-High, and W-Low). Sex differences in exercise-induced hypoalgesia (EIH) occurred among the high TS stimulus intensity group (session X trial X sex X group; p= 0.01); only W-High group experienced EIH while M-High experienced no change (session X trial X sex; p=0.039). Among women, the W-High had greater EIH than W-Low (session X trial X group; p= 0.049). In addition, pre-exercise TS was positively correlated with the magnitude of EIH (r= 0.34, p= 0.01). These results suggest that baseline experimental pain may contribute to the magnitude of EIH and to the sex differences in EIH.
(306) The Unique and Interactive Effects of Patient Race, Patient Weight, and Provider Implicit Attitudes on Chronic Pain Treatment Decisions T. Anastas, K. Walsh, M. Miller, Z. Trost, L. Goubert, L. De Ruddere, and A. Hirsh; Indiana University − Purdue University Indianapolis, Indianapolis, IN Prior work suggests that providers are influenced by patient race and weight when making pain-related decisions. Providers with stronger implicit (automatic) attitudes about race and weight may be more likely to be influenced by these patient-level characteristics when making treatment decisions. In this multi-part study, we (a) examined the influence of patient race and weight on providers’ pain treatment decisions, (b) measured providers’ implicit attitudes about race and weight with two separate Implicit Association Tests, and (c) explored the extent to which providers’ attitudes predicted their treatment decisions. Ninety medical students (“providers”) viewed four videos of women with chronic low back pain completing a standardized sit-to-stand task who varied by race (Black/White) and weight (overweight/obese). Text vignettes with additional patient information accompanied the videos. For each patient, providers rated their likelihood of recommending opioids, a psychology referral, and disability compensation. Repeated measures ANOVAs indicated no main effects of patient race or weight on providers’ opioid decisions; however, providers were more likely to recommend a psychology referral for patients with obesity versus overweight [F(1,89)=9.79, p<.01] and disability compensation for Black versus White patients [F(1,89)=4.64, p=.03]. Providers demonstrated a moderate implicit preference for White over Black people (M=.29, SD=.40) and people with normal weight over obesity (M=.30, SD=.44). Providers with a stronger implicit preference for people with normal weight were less likely to recommend disability compensation to patients with obesity versus overweight (b=.28, p=.02). Providers’ implicit attitudes about race and weight did not significantly predict the other treatment items. These results suggest that patient race and weight and providers’ implicit attitudes about weight influence some, but not all, pain treatment decisions. Future