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(969)
Abstracts
S91
(967) Categorizing pain intensity for veterans with severe and intractible chronic pain
(969) Refer to Oral Paper Session 324
G Tan; Michael E. DeBakey VA Medical Center, Houston, TX The incorporation of pain as a fifth vital sign within the Veterans Affairs Medical Centers has heightened interest in the search for a meaningful way of measuring and categorizing pain. Previous research has attempted to classify pain intensity into discrete categories in terms of its relative interference with function (Serlin et al., 1995; Jensen et al., 2001;Zelman et al., 2003; Paul et al., 2005). However, while some consistencies are found across some studies, the research performed to date has failed to identify consistent cutoffs that are optimal for classifying responses to 0 – 10 scales into mild, moderate, and severe categories. It appears necessary to identify the cutoffs that are most useful in specific populations and settings. Previous research has shown that veterans do display characteristics of more severe pathology and disability, and are more severe in self-reported pain severity, and measures of depression and disability (Tan et al., 2005). In the current study, Serlin et al.’s (1995) procedures were used to identify the optimal cutoffs for classifying pain intensity among 355 veterans from the Michael E. DeBakey Va Medical Center who were referred to the Pain Clinic for chronic pain assessment and treatment. A multivariate regression analysis of variance (MANOVA) using pain interference, depression, and disability as dependent variables found that cutoff points at 4 and 7 were superior to other alternatives for worst pain intensity, but not for average pain ratings, where the differences between the different cutoff points were not significant. The findings suggest that in this sample of veterans with chronic pain, worst pain ratings demonstrate a non-linear association with measures of pain impact (and can therefore be classified), but that average pain ratings cannot be reliably classified into mild, moderate, and severe pain using an ANOVA approach.
G30 - Other
(968) Information recall bias in chronic pain and depression S Cho, C Lam, J Wesch; Swedish Covenant Hospital, Chicago, IL The purpose of this study was to investigate 1) the effect of pain and depression upon un-cued recall of words that have a pain sensory or affective component and 2) the effect of self-schema on un-cued recall. The sample included four groups: 16 non-depressed chronic pain patients (P), 15 depressed chronic pain patients (PD), 15 depressed nonchronic pain patients (D) and 15 non-depressed non-chronic pain medical patients (NPND). Groups were identified by medical records and scores on the Beck Depression Inventory Fast Screen for Medical Patients, and the Visual Analogue Scales for pain. The results showed that in terms of between-group comparisons, there were no significant differences in recall of pain-sensory words across the four groups, and the D group and NPND group significantly recalled more negative words and positive words respectively. In terms of within-group comparisons, the P group significantly recalled more both pain-sensory and positive words, and NPND group significantly recalled more positive words. On the other hand, the PD group and the D group showed no significant difference in a recall of any word-type. In addition, all groups significantly recalled more self-referential words than non-self-referential words. Implications include the following: 1) pain and depression are related to selective memory bias, 2) the effect of depression on memory was not significantly different in chronic pain patients, compared to depressed patients without chronic pain, and 3) self-schema plays an important role in enhancing memory. This study also suggested investigation of differential clinically approaches to depressed chronic pain patients compared to non-depressed chronic pain patients. For example, it might be shown that pain tolerance may be enhanced among depressed chronic pain patients by focusing on changing negative emotional responses to their pain experience.
(970) Relationships among anxious symptomology, anxiety sensitivity and laboratory pain response in children J Tsao, Q Lu, S Kim, L Zeltzer; UCLA Pediatric Pain Program, Los Angeles, CA Anxiety sensitivity (AS) refers to the specific tendency to interpret arousal sensations (e.g., shortness of breath, rapid heart beat) as leading to harmful physical, psychological or social consequences. Previous work in adults has suggested that AS increases an individual’s propensity to experience pain-related anxiety which in turn enhances laboratory pain responsivity. Such relationships have not been examined in younger populations. Thus, the present study used structural equation modeling (SEM) to test a conceptual model in which AS would evidence an indirect relationship with pain intensity via its contribution to state-specific anticipatory anxiety in relation to a variety of laboratory pain tasks (cold pressor, thermal heat, and pressure pain) in 234 healthy children (116 girls; mean age ⫽ 12.6 years, range ⫽ 8-18 years). The model further hypothesized that existing anxious symptomology would demonstrate a direct relationship with pain intensity. The proposed conceptual model fit the data well (Satorra-Bentler Scaled chi-square (15, N⫽234) ⫽ 17.60, p⫽0.28, CFI⫽ 0.97, NNFI⫽0.94, RMSEA⫽0.027). As expected, AS did not evidence a direct relationship with pain intensity but instead demonstrated a significant indirect effect on pain intensity through pain-related anticipatory anxiety. The total indirect effect of AS accounted for 29% of the variance in laboratory pain intensity via its effects on anticipatory anxiety. Anxious symptomology on the other hand, demonstrated a significant direct effect on pain intensity, accounting for 15% of variance. The combined effects of AS, anxiety symptoms, and anticipatory anxiety together explained 62% of the variance in pain intensity. These relationships did not differ for boys and girls indicating no moderating effect of sex in the conceptual model. The present results support the potential benefit of assessing both AS and anxiety symptoms in children prior to undergoing painful stimulation such as that induced by routine medical procedures.
(971) Psychometric item response theory (IRT) analysis of the Short-Form McGill Pain Questionnaire for chronic pain assessment K Schmidt, A Cook, D Roberts, B Clark, B Parker; Barron Associates, Inc., Charlottesville, VA The Short-Form McGill Pain Questionnaire (SF-MPQ) is one of the most commonly used measures of the sensory, affective, and intensity dimensions of chronic pain. Like most pain measures, its psychometric validation is based on classical test theory methods. Little is known about the performance and scaling properties of the individual items that comprise the SF-MPQ, or of relative response patterns for chronic pain subgroups based upon age, gender, and pain duration. Item response theory (IRT) provides a basis for calibrating test items and trait scores on a common underlying scale, detecting varying response option interpretations, and evaluating potential differences in item function between subgroups. Item responses for N ⫽ 855 chronic pain patients (65% female; M age ⫽ 47; M pain duration ⫽ 77 months) on the 17 SF-MPQ items were examined using the Rasch partial credit model. Subgroups based on age, gender, and pain duration were analyzed using differential item functioning (DIF) procedures. Results indicated that few participants used “mild” pain classifications for many of the pain rating index (PRI) items, indicating that a reduction in response categories may enhance scale usefulness in some samples of chronic pain patients. DIF comparisons revealed some statistically significant subgroup response differences, such as greater likelihood for females to endorse a severe level of tender pain than males, and for younger participants (⬍40 yrs) to endorse a severe level of fearful pain than older patients. Implications for use of the SF-MPQ in chronic pain samples and patient subgroups are discussed, as well as future applications such as computerized adaptive testing (CAT). This work was supported by NIH NINDS grant R43 NS49945-01.
S91
(967) Categorizing pain intensity for veterans with severe and intractible chronic pain
(969) Refer to Oral Paper Session 324
G Tan; Michael E. DeBakey VA Medical Center, Houston, TX The incorporation of pain as a fifth vital sign within the Veterans Affairs Medical Centers has heightened interest in the search for a meaningful way of measuring and categorizing pain. Previous research has attempted to classify pain intensity into discrete categories in terms of its relative interference with function (Serlin et al., 1995; Jensen et al., 2001;Zelman et al., 2003; Paul et al., 2005). However, while some consistencies are found across some studies, the research performed to date has failed to identify consistent cutoffs that are optimal for classifying responses to 0 – 10 scales into mild, moderate, and severe categories. It appears necessary to identify the cutoffs that are most useful in specific populations and settings. Previous research has shown that veterans do display characteristics of more severe pathology and disability, and are more severe in self-reported pain severity, and measures of depression and disability (Tan et al., 2005). In the current study, Serlin et al.’s (1995) procedures were used to identify the optimal cutoffs for classifying pain intensity among 355 veterans from the Michael E. DeBakey Va Medical Center who were referred to the Pain Clinic for chronic pain assessment and treatment. A multivariate regression analysis of variance (MANOVA) using pain interference, depression, and disability as dependent variables found that cutoff points at 4 and 7 were superior to other alternatives for worst pain intensity, but not for average pain ratings, where the differences between the different cutoff points were not significant. The findings suggest that in this sample of veterans with chronic pain, worst pain ratings demonstrate a non-linear association with measures of pain impact (and can therefore be classified), but that average pain ratings cannot be reliably classified into mild, moderate, and severe pain using an ANOVA approach.
G30 - Other
(968) Information recall bias in chronic pain and depression S Cho, C Lam, J Wesch; Swedish Covenant Hospital, Chicago, IL The purpose of this study was to investigate 1) the effect of pain and depression upon un-cued recall of words that have a pain sensory or affective component and 2) the effect of self-schema on un-cued recall. The sample included four groups: 16 non-depressed chronic pain patients (P), 15 depressed chronic pain patients (PD), 15 depressed nonchronic pain patients (D) and 15 non-depressed non-chronic pain medical patients (NPND). Groups were identified by medical records and scores on the Beck Depression Inventory Fast Screen for Medical Patients, and the Visual Analogue Scales for pain. The results showed that in terms of between-group comparisons, there were no significant differences in recall of pain-sensory words across the four groups, and the D group and NPND group significantly recalled more negative words and positive words respectively. In terms of within-group comparisons, the P group significantly recalled more both pain-sensory and positive words, and NPND group significantly recalled more positive words. On the other hand, the PD group and the D group showed no significant difference in a recall of any word-type. In addition, all groups significantly recalled more self-referential words than non-self-referential words. Implications include the following: 1) pain and depression are related to selective memory bias, 2) the effect of depression on memory was not significantly different in chronic pain patients, compared to depressed patients without chronic pain, and 3) self-schema plays an important role in enhancing memory. This study also suggested investigation of differential clinically approaches to depressed chronic pain patients compared to non-depressed chronic pain patients. For example, it might be shown that pain tolerance may be enhanced among depressed chronic pain patients by focusing on changing negative emotional responses to their pain experience.
(970) Relationships among anxious symptomology, anxiety sensitivity and laboratory pain response in children J Tsao, Q Lu, S Kim, L Zeltzer; UCLA Pediatric Pain Program, Los Angeles, CA Anxiety sensitivity (AS) refers to the specific tendency to interpret arousal sensations (e.g., shortness of breath, rapid heart beat) as leading to harmful physical, psychological or social consequences. Previous work in adults has suggested that AS increases an individual’s propensity to experience pain-related anxiety which in turn enhances laboratory pain responsivity. Such relationships have not been examined in younger populations. Thus, the present study used structural equation modeling (SEM) to test a conceptual model in which AS would evidence an indirect relationship with pain intensity via its contribution to state-specific anticipatory anxiety in relation to a variety of laboratory pain tasks (cold pressor, thermal heat, and pressure pain) in 234 healthy children (116 girls; mean age ⫽ 12.6 years, range ⫽ 8-18 years). The model further hypothesized that existing anxious symptomology would demonstrate a direct relationship with pain intensity. The proposed conceptual model fit the data well (Satorra-Bentler Scaled chi-square (15, N⫽234) ⫽ 17.60, p⫽0.28, CFI⫽ 0.97, NNFI⫽0.94, RMSEA⫽0.027). As expected, AS did not evidence a direct relationship with pain intensity but instead demonstrated a significant indirect effect on pain intensity through pain-related anticipatory anxiety. The total indirect effect of AS accounted for 29% of the variance in laboratory pain intensity via its effects on anticipatory anxiety. Anxious symptomology on the other hand, demonstrated a significant direct effect on pain intensity, accounting for 15% of variance. The combined effects of AS, anxiety symptoms, and anticipatory anxiety together explained 62% of the variance in pain intensity. These relationships did not differ for boys and girls indicating no moderating effect of sex in the conceptual model. The present results support the potential benefit of assessing both AS and anxiety symptoms in children prior to undergoing painful stimulation such as that induced by routine medical procedures.
(971) Psychometric item response theory (IRT) analysis of the Short-Form McGill Pain Questionnaire for chronic pain assessment K Schmidt, A Cook, D Roberts, B Clark, B Parker; Barron Associates, Inc., Charlottesville, VA The Short-Form McGill Pain Questionnaire (SF-MPQ) is one of the most commonly used measures of the sensory, affective, and intensity dimensions of chronic pain. Like most pain measures, its psychometric validation is based on classical test theory methods. Little is known about the performance and scaling properties of the individual items that comprise the SF-MPQ, or of relative response patterns for chronic pain subgroups based upon age, gender, and pain duration. Item response theory (IRT) provides a basis for calibrating test items and trait scores on a common underlying scale, detecting varying response option interpretations, and evaluating potential differences in item function between subgroups. Item responses for N ⫽ 855 chronic pain patients (65% female; M age ⫽ 47; M pain duration ⫽ 77 months) on the 17 SF-MPQ items were examined using the Rasch partial credit model. Subgroups based on age, gender, and pain duration were analyzed using differential item functioning (DIF) procedures. Results indicated that few participants used “mild” pain classifications for many of the pain rating index (PRI) items, indicating that a reduction in response categories may enhance scale usefulness in some samples of chronic pain patients. DIF comparisons revealed some statistically significant subgroup response differences, such as greater likelihood for females to endorse a severe level of tender pain than males, and for younger participants (⬍40 yrs) to endorse a severe level of fearful pain than older patients. Implications for use of the SF-MPQ in chronic pain samples and patient subgroups are discussed, as well as future applications such as computerized adaptive testing (CAT). This work was supported by NIH NINDS grant R43 NS49945-01.