Ian A. Boggero

The Nature of Self-Regulatory Fatigue and “Ego Depletion” Lessons From Physical Fatigue

Self-regulation requires overriding a dominant response and leads to temporary self-regulatory fatigue. Existing theories of the nature and causes of self-regulatory fatigue highlight physiological substrates such as glucose, or psychological processes such as motivation, but these explanations are incomplete on their own. Historically, theories of physical fatigue demonstrate a similar pattern of useful but incomplete explanations, as recent views of physical fatigue emphasize the roles of both physiological and psychological factors. In addition to accounting for multiple inputs, these newer views also explain how fatigue can occur even in the presence of sufficient resources. Examining these newer theories of physical fatigue can serve as a foundation on which to build a more comprehensive understanding of self-regulatory fatigue that integrates possible neurobiological underpinnings of physical and self-regulatory fatigue, and suggests the possible function of self-regulatory fatigue.

Variability and reliability of diurnal cortisol in younger and older adults: Implications for design decisions

The extant research is inconclusive regarding the best sampling methods to construct reliable measures of between-person differences in derived parameters of diurnal cortisol, and no study provides such recommendations for detecting within-person changes. These studies determined how many days of sampling are necessary to assess between-person differences and within-person changes over multiple occasions in diurnal mean, diurnal slope, and area under the curve (AUC). Generalizability and decision analyses were conducted on diurnal salivary cortisol data from two separate longitudinal studies, one with younger adults (N=124) and one with older adults (N=148). In both studies, results indicated that 3 days of data collection provided the minimal level of reliability in mean cortisol to detect between-person differences; 4-8 days were necessary to reliably assess AUC, and 10 days for cortisol slope. Similarly, in order to reliably characterize within-person changes across occasions, at least 3 days of data collection were needed for mean cortisol and AUC and 5-8 days for slope. Results also indicated that only two samples per day, taken morning and evening, could faithfully reproduce the diurnal slope calculated from 3 or 4 samples (r=.97-.99). Instead of having participants provide many samples per day over the course of a few days, we recommend collecting fewer samples per day over more days.

Fatigue mediates the relationship between pain interference and distress in patients with persistent orofacial pain.

AIMS To test the role of fatigue and its subtypes (general, physical, emotional, mental, and vigor) in mediating the relationship between psychological distress and pain interference. METHODS Retrospective, de-identified records were examined for 431 patients seeking treatment for persistent orofacial pain. Primary diagnoses of participants were muscle pain (29.8%), joint pain (26.0%), neuropathic pain (19.5%), and other (ie, fibromyalgia, centrally mediated myalgia, tendonitis, dental pain, cervical spine displacement, and no diagnosis; 24.7%). Mediation models were tested with distress as the independent variable, interference as the dependent variable, and fatigue or its subtypes as the mediators. RESULTS After controlling for pain duration and average levels of pain, total fatigue mediated the relationship between distress and interference. Fatigue subtypes partially mediated the relationship between distress and interference, but mediation was strongest with the composite fatigue variable. The results, however, should be interpreted cautiously, as data were collected at a single time point and do not imply causality. CONCLUSION These results suggest that interventions targeted specifically at fatigue symptoms may be helpful for reducing interference and improving quality of life in patients with persistent orofacial pain.

Pain Intensity Moderates the Relationship Between Age and Pain Interference in Chronic Orofacial Pain Patients.

Background/Study Context: Chronic pain is associated with increased interference in daily functioning that becomes more pronounced as pain intensity increases. Based on previous research showing that older adults maintain well-being in the face of pain as well as or better than their younger counterparts, the current study examined the interaction of age and pain intensity on interference in a sample of chronic orofacial pain patients. Methods: Data were obtained from the records of 508 chronic orofacial pain patients being seen for an initial evaluation from 2008 to 2012. Collected data included age (range: 18–78) and self-reported measures of pain intensity and pain interference. Bivariate correlations and regression models were used to assess for statistical interactions. Results: Regression analyses revealed that pain intensity positively predicted pain interference (R2 = .35, B = 10.40, SE = 0.62, t(507) = 16.70, p < .001). A significant interaction supported the primary hypothesis that aging was associated with reduced interference at high levels of pain intensity (ΔR2 = .01, B = −1.31, SE = 0.63, t(505) = −2.90, p = .04). Conclusion: At high levels of pain intensity, interference decreased with age, although the age by pain intensity interaction effect was small. This evidence converges with aging theories, including socioemotional selectivity theory, which posits that as people age, they become more motivated to maximize positive emotions and minimize negative ones. The results highlight the importance of studying the mechanisms older adults use to successfully cope with pain.

Sick in the Head? Pathogen Concerns Bias Implicit Perceptions of Mental Illness:

Biases against the mentally ill are historically and cross-culturally pervasive, suggesting they may have an evolutionary basis. The prevailing view is that people seek to distance themselves from the mentally ill because they are perceived as dangerous, violent, and incompetent. However, because of similarities between sickness behaviors and symptoms of some mental disorders, it was hypothesized that mental illness stigma could be partially explained as a function of behavioral immune system biases designed to avoid potential sources of contagion. In two experiments, it was found that mental illness was implicitly associated more with disease than danger. In Experiment 1, this implicit association was exacerbated among people who have had their biological immune system activated by a recent illness. In Experiment 2, experimentally priming disease salience increased implicit association between mental illness and disease. Implications for the evolutionary origins of prejudice and the prevention of mental illness stigma are discussed.

Endogenous Cortisol Exposure and Declarative Verbal Memory: A Longitudinal Study of Healthy Older Adults.

Objective Exposure to endogenous cortisol is associated with hippocampal degeneration and may contribute to problems with declarative memory, but effects of persistent versus phasic cortisol elevations have not been established. The present longitudinal investigation examined persistent individual differences and phasic changes in cortisol as they related to verbal memory, executive functions, and subjective cognitive function. Methods Older adults (n = 132, aged 60–93 years) were followed up for up to 5 years. They were assessed annually for verbal memory and every 6 months for executive functions, subjective cognitive function, and cortisol area under the curve (averaged over 3 days). Results In multilevel models, persistently but not phasically higher cortisol was associated with worse verbal memory in both learning (t(181) = 2.99, p = .003) and recall (t(280) = 3.10, p = .002). This effect withstood adjustment for stress, depression, metabolic health, and age. There was evidence for attenuated primacy in learning with higher persistent cortisol. Phasic increases in cortisol were not associated with changes in memory, and cortisol was not related to executive functions or subjective cognitive function. Conclusions Higher secretion of cortisol may, over time, contribute to memory dysfunction in older adults.

Psychosocial functioning and the cortisol awakening response: Meta-analysis, P-curve analysis, and evaluation of the evidential value in existing studies

Cortisol levels rise immediately after awakening and peak approximately 30-45min thereafter. Psychosocial functioning influences this cortisol awakening response (CAR), but there is considerable heterogeneity in the literature. The current study used p-curve and meta-analysis on 709 findings from 212 studies to test the evidential value and estimate effect sizes of four sets of findings: those associating worse psychosocial functioning with higher or lower cortisol increase relative to the waking period (CARi) and to the output of the waking period (AUCw). All four sets of findings demonstrated evidential value. Psychosocial predictors explained 1%-3.6% of variance in CARi and AUCw responses. Based on these effect sizes, cross-sectional studies assessing CAR would need a minimum sample size of 617-783 to detect true effects with 80% power. Depression was linked to higher AUCw and posttraumatic stress to lower AUCw, whereas inconclusive results were obtained for predictor-specific effects on CARi. Suggestions for future CAR research are discussed.

All Fatigue is Not Created Equal: The Association of Fatigue and its Subtypes on Pain Interference in Orofacial Pain.

Objectives: Fatigue is known to be a pathway through which depression, psychological distress, pain intensity, and sleep disturbance influence pain interference, but the independent effects of fatigue on pain interference after controlling for these variables remains unknown. In addition, no study to date has tested whether fatigue subtypes of general fatigue, mental fatigue, emotional fatigue, physical fatigue, or vigor differentially predict pain interference. Methods: The current study tested these associations using archival medical data of 2133 chronic orofacial pain patients, who completed a battery of psychological questionnaires at the time of their first appointment at an orofacial pain clinic. Results: Hierarchical linear regression analysis revealed that after controlling for depression, psychological distress, sleep disturbance, pain intensity, and demographic variables, fatigue predicted higher pain interference (B=0.70, SE=0.17, P<0.001, &eegr;2=0.01). Physical fatigue (B=1.70, SE=0.48, P<0.001, &eegr;2=0.01) and vigor (B=−3.24, SE=0.47, P<0.001, &eegr;2=0.03) were independently associated with pain interference after controlling for the aforementioned variables. Discussion: The findings suggest that fatigue is an important independent predictor of pain interference and not merely a mediator. These findings also suggest that not all fatigue is created equal. Interventions aimed at reducing pain interference should target specific fatigue symptoms of physical fatigue and vigor. Future research investigating the independent associations of fatigue subtypes on pain outcomes may help clarify the nature of the interrelationships between pain and fatigue.

Smoking and Posttraumatic Stress Disorder Symptomatology in Orofacial Pain

To explore the impact of interactions between smoking and symptoms of posttraumatic stress disorder (PTSD) on pain intensity, psychological distress, and pain-related functioning in patients with orofacial pain, a retrospective review was conducted of data obtained during evaluations of 610 new patients with a temporomandibular disorder who also reported a history of a traumatic event. Pain-related outcomes included measures of pain intensity, psychological distress, and pain-related functioning. Main effects of smoking status and PTSD symptom severity on pain-related outcomes were evaluated with linear regression analyses. Further analyses tested interactions between smoking status and PTSD symptom severity on pain-related outcomes. PTSD symptom severity and smoking predicted worse pain-related outcomes. Interaction analyses between PTSD symptom severity and smoking status revealed that smoking attenuated the impact of PTSD symptom severity on affective distress, although this effect was not found at high levels of PTSD symptom severity. No other significant interactions were found, but the present results identifying smoking as an ineffective coping mechanism and the likely role of inaccurate outcome expectancies support the importance of smoking cessation efforts in patients with orofacial pain. Smoking is a maladaptive mechanism for coping with pain that carries significant health- and pain-related risks while failing to fulfill smokers’ expectations of affect regulation, particularly among persons with orofacial pain who also have high levels of PTSD symptom severity. Addressing smoking cessation is a critical component of comprehensive treatment. Further research is needed to develop more effective ways to help patients with pain and/or PTSD to replace smoking with more effective coping strategies.

Somatosensory and Affective Contributions to Emotional, Social, and Daily Functioning in Chronic Pain Patients

OBJECTIVE The present study tested the independent and interactive contributions of the somatosensory component of pain (pain intensity) and the affective component of pain (pain unpleasantness) on emotional, social, and daily functioning in chronic pain patients. SUBJECTS Participants were 472 patients seeking treatment for chronic orofacial pain. Mean age of the sample was 46.0 years (standard deviation [SD] = 14.67, range 18-78), with 82.2% female. Average pain duration at the time of initial appointment was 75.7 months (SD = 106.66). METHODS Participants completed self-report measures of pain intensity, unpleasantness, and functional outcomes at the time of their first appointment. These data were later extracted from participants de-identified medical records. Multivariate linear regression was used to test the interaction of pain intensity and unpleasantness on outcome measures of emotional, social, and daily functioning. RESULTS Results revealed that pain intensity contributed to poorer functional outcomes but higher levels of social support even after controlling for pain unpleasantness. After controlling for pain intensity, unpleasantness was associated with higher pain interference and affective distress. There was also pain intensity by unpleasantness interaction on pain interference. Specifically, at lower levels of pain unpleasantness, changes in pain intensity produced greater changes in pain interference than they did at higher levels of pain unpleasantness. CONCLUSIONS Results suggest that both intensity and unpleasantness contribute unique variance to functional outcomes. The results highlight the importance of interventions that not only try to reduce pain levels but also reduce levels of pain unpleasantness.