(171) Evaluating the Pain and Discomfort Scale to Assess Spasticity-Related Pain in Cerebral Palsy

S18 The Journal of Pain (167) Subjective Age is Associated with Temporal Summation of Mechanical Pain B. Boring, N. Nanavaty, and V. Mathur; Texas A&M University, College Station,TX Subjective age is a multifaceted self-perception of the age one feels relative to one’s chronological age, and is conceptualized as a reflection of one’s physical, mental, and social health. Markers of poor health are correlated with discrepancies between subjective age and actual chronological age, and individuals with poor overall health, lower grip strength, memory problems, weight gain, and trouble sleeping all report elevated subjective ages relative to healthy populations of similar chronological age. Subjective age may in fact reflect an introspective awareness that takes biopsychosocial factors into account. As such, subjective age has been suggested to be a more robust predictor of overall health and function than chronological age. Therefore, subjective age may be a simple and useful assessment item that corresponds to overall pain sensitivity. To date though, no studies have been conducted to examine whether subjective age can predict pain response in a laboratory setting. Here, among 67 healthy young adults (53.7% female, Mage = 21.66, SD = 3.64 years), subjective age r = .28, p = .02, but not chronological age r = .11, p = .37, was associated with greater mechanical temporal summation. This relationship remained significant after controlling for chronological age in a partial correlation, r = .26, p = .03. The results of the current study suggest that subjective age may be a better predictor of pain sensitization than chronological age, although additional research is needed to probe this relationship across the lifespan.

(168) Clinical Correlates of All-Cause Mortality among Veterans Initiating Pain Care L. Ashrafioun and T. Bishop; VA Center of Excellence for Suicide Prevention, Canandaigua, NY The current study assessed associations of clinical characteristics and all-cause mortality among a cohort of Veterans initiating pain services. Analyses were also stratified by age to examine potential variations. Demographic (male, age), medical comorbidities (diabetes, myocardial infarction, chronic pulmonary conditions, cancer, renal disease, liver disease), pain characteristics (pain intensity, opioid analgesic prescription), and mental health characteristics (depression, opioid use disorder, opioid poisoning/suicide attempts) were extracted from Veterans Health Administration records. Veterans initiating pain services were identified using a billing code for painrelated services (N=221,817). In the year following the initiation of pain services, there was a total of 4,877 deaths. Adjusted logistic regression analyses among whole cohort revealed that cancer (aOR=3.98), renal disease (aOR=2.08), and liver disease (aOR=2.16) were associated with a more than doubling of odds of dying in the year following the initiation of pain services. Although less robust, severe pain (aOR=1.19), opioid analgesic prescriptions (aOR=1.63), opioid use disorders (aOR=1.45), and self-injury (aOR=1.41) were significantly associated with increased odds of death. When stratified by age, having an opioid analgesic prescription was significantly associated with increased odds of death across each age group with increasing odds ratios with decreasing age. Depression, opioid use disorders, and non-fatal self-injury was associated with higher odds of death among 18-39 year-olds. While those aged 75+ years were only other age group that depression was associated with death, they were the only group that opioid use disorders was not associated with death. Cancer was associated with highest odds of death across age groups. Opioids use, characterized by opioid analgesic prescriptions and opioid use disorder, is a key clinical factor that increased odds of all-cause mortality following the initiation of pain services in context of other conditions that contribute to the leading causes of death.

(169) Comparison of Temporal Stability of Conditioned Pain Modulation and Temporal Summation of Pain in Healthy Older and Younger Adults T. Ohlman, L. Miller, and K. Naugle; Indiana University − Purdue University Indianapolis, Indianapolis, IN The temporal stability (test-retest reliability) of temporal summation of pain (TS) and conditioned pain modulation (CPM) has yet to be established in healthy older adults. The current study intended to compare the temporal stability of TS and CPM in healthy older and

Abstracts younger adults, as well as investigate factors that might impact TS and CPM stability. In a test-retest study, 40 healthy older adults and 18 healthy younger adults completed two sessions of quantitative sensory testing within a 2-week period that included: 1) TS of heat pain, 2) TS of mechanical pain, 3) CPM with pressure pain thresholds (CPM-PPT) and suprathreshold heat pain (CPM-Heat) as test stimuli and a cold water bath as conditioning stimulus. During each session participants completed the pain catastrophizing scale and the State Trait Anxiety Scale − state version. The relative stability (Interclass correlation coefficients: ICCs) and intra-individual stability coefficients (ISC) were examined for each variable. Bivariate correlations examined the association of psychological variables and age with the ISCs of TS and CPM. Younger adults showed good to excellent stability for TS (ICC’s: 0.64-0.89), except for mechanical TS on the hand (ICC: 0.34). Older adults showed moderate to good stability for TS (ICC’s: 0.48-0.79). Stability of CPM-PPT was poor for younger and older adults, whereas stability of CPM-Heat was good for younger adults but poor for older adults. Correlational analyses indicated greater ISC’s for CPM were associated with greater stability of the pre-test stimuli. State anxiety was significantly associated with stability of CPM-Heat and TS. These findings suggest that 1) TS and CPM may be more reliable in younger compared to older adults and 2) state anxiety is an important factor influencing the stability of CPM and TS in healthy adults. This study was funded by the IUPUI Developing Diverse Researchers with Investigative Experience Grant.

(170) Diagnostic Criteria for Idiopathic Small Fiber Neuropathy − A Systematic Literature Review M. Todorovic, S. Haroutounian, R. Dworkin, and R. Freeman; Washington University School of Medicine, St. Louis, MO Small fiber neuropathy (SFN) is increasingly recognized as an important cause of distal symmetric pain and sensory symptoms, but its diagnosis remains elusive. We sought to systematically assess the published screening and diagnostic criteria for painful idiopathic small fiber neuropathy (SFN). A systematic literature review was performed using the PubMed database from inception to January 9, 2018, excluding studies where SFN was of known or well-established etiology. Study characteristics and diagnostic criteria for idiopathic SFN were extracted and analyzed. 67 clinical studies and 9 guideline/review publications met the inclusion criteria. Among the clinical studies, 13 studied patients with exclusively idiopathic SFN, and 54 studies enrolled subjects with SFN of mixed etiology. The results demonstrate that diagnostic criteria for idiopathic SFN substantially vary in regard to inclusion of pain, specific sensory and autonomic symptoms and signs, nerve conduction studies, quantification of cutaneous innervation, quantitative sensory testing, or special investigations. The most common sets of criteria included the combination of 1) SFN symptoms, 2) neurological signs or nerve conduction studies to rule out large fiber involvement, and 3) results of skin biopsy quantifying intraepidermal innervation. Given the wide variation in diagnostic approaches, there is urgent need for evidence-based guidelines for this oftenunderdiagnosed condition.

(171) Evaluating the Pain and Discomfort Scale to Assess Spasticity-Related Pain in Cerebral Palsy A. Merbler, C. Barney, K. Frenn, B. Byiers, and F. Symons; University of Minnesota, Minneapolis, MN Assessing pain among individuals with communicative impairments and developmental disabilities is a clinical challenge. In this preliminary study, we addressed, in part, the issue of the association between chronic pain and spasticity in cerebral palsy (CP). Specifically, we evaluated the measurement performance of a proxy-reported spasticity rating scale (Multiple Sclerosis Spasticity Scale−MSSS) and the feasibility of a range of motion examination procedure (Pain Examination Procedure−PEP) using direct-observation to code behavioral reactivity during the exam (Pain and Discomfort Scale − PADS). Fifteen individuals with CP (mean age=10.9 years, range=6.2-17.2 years; GMFCS=3-5; male=46%) were evaluated pre- (T1) and post- (T2) intrathecal baclofen pump (ITB) surgical implant to treat spasticity. The PEP protocol was successfully completed for all participants in the clinical setting. Cronbach’s alpha for the MSSS was 0.96. PADS change scores (T1 to T2) were significantly correlated with MSSS change scores (r=0.80, p=0.006). The strong positive correlation suggests the PADS/PEP protocol may be measuring spasticity-related pain

Abstracts and discomfort, providing initial construct validity evidence between an objective/direct and subjective/indirect assessment method for pain and spasticity in CP. T1 PADS scores were also highly positively correlated with both PADS change and MSSS change scores (r=-0.72, p=0.006; r=-0.85, p=0.002), providing preliminary evidence of the predictive utility of a pre-ITB surgery PADS/PEP protocol. This was not a random sample, therefore the results are specific to the sample and may not hold for the population of individuals living with CP. Given the absence of self-report, we cannot be certain and do not claim to have measured the pain experience of the individuals in the sample. Future work should continue to examine the PADS as a potential pain behavior assessment tool to provide a direct assessment option for the study of pain among individuals with CP and related developmental disabilities. Supported by NICHD Grant No. 73126

(172) Factors that Affect Analgesic Prescriptions in African Americans with Cancer Pain N. Singh and A. Vallerand; Wayne State University, Detroit, MI The experience of cancer pain is poorly understood from the perspective of African Americans, who experience higher levels of pain, more pain-related distress, and poorer function than Caucasians. Perceived control over pain has been shown to lead to decreased pain and distress and improved functional status. Perceived control over pain may play a role in the adequacy of prescriptions received by African American patients with cancer pain. The purpose of this study is to investigate the relationship between factors affecting analgesic prescriptions and perceived control over pain in African Americans with cancer pain. This investigation will be done through a secondary analysis of analgesic prescriptions from of a larger study testing an intervention to improve pain, pain-related distress, and functional status through increasing perceived control over pain. Participants (n=310) who met the criteria of being adult cancer patients and self-identified as African American and reported moderate to severe pain (>4 on a 0-10 scale) within the past two weeks were recruited from the waiting room of an urban comprehensive cancer center. Baseline data will be used for this analysis to characterize the adequacy of pain management, as measured by the Pain Management Index (PMI), in African American adults with cancer pain. Further analysis will examine the extent of adequate pain control (as measured by the PMI) and its correlation with education, marital status, gender, perceived control over pain, and presence of a caregiver as measured by the demographic questionnaire. The study seeks to gain an understanding of the factors which increase the likelihood of a patients receiving adequate analgesia from their providers. Findings from this study will enlighten patient factors and potential areas of intervention leading to adequate analgesia and explore disparities experienced by this population. This work was supported by the National Cancer Institute 1 RO1 CA149432-01A1.

(173) Information Theory and Headache Triggers D. Turner and T. Houle; Massachusetts General Hospital, Boston, MA Approximately 90% of individuals with headache believe there is at least one trigger, or causal factor, of their headache attacks. The list of headache triggers is extensive, but little is known about how individuals develop such beliefs. The aim of this secondary analysis was to evaluate the degree of information, measured using Shannon entropy, that headache triggers contain and to examine the relationship between joint entropy (i.e., triggers and headache activity) and trigger beliefs. We hypothesized that as information about a headache trigger increased (i.e., an individual was exposed to more states of the trigger), the strength of belief about the trigger also would increase. In a computer-based task, N = 300 participants rated the strength of the relationship between triggers and headaches. For each trigger, participants were asked to rate how often they encountered the trigger and how likely it was to cause a headache on a 0 to 10 scale. Headache triggers contained a wide range of information with binary (i.e., presence or absence) triggers containing between 0.01 and 1 bit of information while continuously scaled triggers (e.g., stress) contained more than 10 bits of information. Each bit of joint information was associated with an 18.4% (95CI: 10.9% to 25.9%) increase in perceived potency of the trigger. However, there was a statistically significant trigger x information interaction (p < 0.001) such that some triggers (e.g., red wine, cinnamon,

The Journal of Pain

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fruits, and nuts) were associated with decreased potency beliefs when individuals had more trigger-headache pairing information. Certain triggers hold little information for individuals in that they are either largely absent (e.g., MSG) or always present (e.g., air conditioning). Quantifying how much actual information an individual could possess about specific headache triggers appears to be an important aspect of the assessment process.

(174) Let’s Talk about it: Daily Associations between Shame and Pain and Sexual Distress in Couples Coping with Vulvodynia M. Paquet, N. Rosen, M. Steben, and S. Bergeron; University of Montreal, Montreal, QC Vulvodynia is a chronic vulvovaginal pain condition with a prevalence of 8% in population samples. It is associated with significant negative psychological and sexual consequences for affected women and their partners. Unfortunately, vulvodynia is often misdiagnosed or ignored by health professionals. Epidemiological studies indicate that only 60% of women with vulvovaginal pain seek medical help and among those, 40% never receive a diagnosis. The lack of support from the health care system may contribute to feelings of invalidation and stigmatization often experienced by women with vulvodynia. Qualitative studies have reported that many of them feel inadequate, are apprehensive to speak about their pain, and fear this condition spells the end of their romantic relationship. Thus, many women come to blame themselves and internalise feelings of shame, as well do the partners for being the potential cause of the pain. However, it remains unclear how daily feelings of shame may impact the pain and its associated distress for the couple. Using a dyadic daily experience method, 71 women diagnosed with vulvodynia and their partners reported on painrelated shame, pain intensity, and sexual distress over a period of eight weeks. Multilevel structural equation modeling was used to examine how daily deviations in shame from a participant’s own mean were associated with pain and sexual distress. On days of sexual activity, when women reported feeling more pain-related shame (compared to their average), they reported greater pain and both women and partners reported greater levels of sexual distress. On days of sexual activity, when partners reported feeling more pain-related shame, they reported greater levels of sexual distress. Addressing feelings of shame in therapy and providing women with information about vulvodynia could facilitate communication within their relationships as well as with health care professionals, and break their narratives to remain silent about their pain.

(175) Mechanisms between Sleep and Pain − What Do We Know from Studies of Mediation? D. Whibley, N. AlKandari, K. Kristensen, M. Barnish, M. Rzewuska, K. Druce, and N. Tang; University of Aberdeen, Aberdeen, UK Evidence supports a bidirectional relationship between characteristics of sleep and pain, however prospective and microlongitudinal studies suggest that sleep has a stronger effect on pain rather than vice versa. To develop an understanding of how changes in aspects of sleep may influence pain intensity, studies which support causal inference are required. Results from such studies may provide evidence to inform the design and evaluation of hybrid interventions for pain patients that include a sleep improvement intervention. Mediation analysis is a statistical approach that enables the effect of an exposure on outcome through an intermediary variable to be assessed and quantified. Since its inception this type of analysis has been applied to a range of healthcare-related questions. Over time, methods of mediation analysis have evolved to support stronger arguments for causality, and criteria have been developed to enable the assessment of the quality of studies applying the approach. While studies of mediation applied to the sleep-pain relationship have been undertaken, to date synthesis of the evidence and an appraisal of the application of the methodologies used has yet to be published. The aim of this systematic review was, therefore, to identify studies that have investigated mechanisms underpinning the sleep-pain relationship, summarise their findings, and appraise their methodologies. Our search yielded nine papers, eight of which investigated the sleep-to-pain relationship (11 models), and two of which investigated the pain-to-sleep relationship (two models). Identified mediators included affect and mood, symptoms of depression and anxiety, attention to pain, pain