Biomedical subjects

Kenneth M Prkachin

Publications and source records attributed to Kenneth M Prkachin.

At least 19 recordsLinked to original sources

PubMed2006

Validation of the Dimensions of Tobacco Dependence Scale for adolescents.

The purpose of this study was to refine the Dimensions of Tobacco Dependence Scale (DTDS) - a measure of tobacco dependence for adolescents - by removing poorly discriminating items, testing the measurement structure of the remaining items and examining the predictive utility of the resulting scale in terms of its ability to explain the average number of cigarettes smoked per day (CPD). A total of 1425 current smokers (mean age 16 years) completed the questionnaire. Confirmatory factor analyses of the DTDS items supported a 4-factor model composed of social, emotional, nicotine and sensory related dimensions of tobacco dependence. Predictive utility and incremental validity of the DTDS was evident in the many sizable correlations between the DTDS and CPD as well as measures of self-rated addiction after controlling for scores on several other commonly used measures of nicotine dependence. The results indicate that the DTDS is a reliable and valid measure of tobacco dependence for adolescents that has the potential to enhance our understanding of the complex processes driving the emergence of tobacco dependence and cigarette smoking.

Adolescent↗

PubMed2006

Temperament and pain reactivity predict health behavior seven years later.

OBJECTIVE: Minor illnesses and major diseases are affected by individual, environmental, and social factors. We sought to determine if children's temperament and pain reactivity (individual response styles) measured in kindergarten are related to future health behavior. METHODS: Seven-year follow-up measures of health behavior were gathered in 42 children (mean age M = 11 years) who participated in a previous study of pain reactivity and somatization. Current health behavior was compared with children's pain reactivity and temperament measured in kindergarten. RESULTS: Pain reactivity in kindergarten was associated with children's self-reports of somatization 7 years later, independent of their temperament. Temperament was related to children's self-reports of somatization and to maternal reports of health care utilization and psychosocial health status. CONCLUSIONS: Early response styles (i.e., heightened pain reactivity and difficulty adjusting) may indicate risk for increased health care utilization and poorer health and well-being later in childhood.

Child↗

PubMed2006

Is pain the price of empathy? The perception of others' pain in patients with congenital insensitivity to pain.

Empathy is a complex form of psychological inference that enables us to understand the personal experience of another person through cognitive/evaluative and affective processes. Recent findings suggest that empathy for pain may involve a 'mirror-matching' simulation of the affective and sensory features of others' pain. Despite such evidence for a shared representation of self and other pain at the neural level, the possible influence of the observer's own sensitivity to pain upon his perception of others' pain has not been investigated yet. The aim of this study was to explore how patients with congenital insensitivity to pain (CIP), who are largely deprived of common stimulus-induced pain experiences, perceive the pain of others. Ratings of verbally presented imaginary painful situations showed that CIP patients' semantic knowledge regarding the pain of others did not differ from control subjects. Moreover, the propensity to infer pain from facial expressions was very similar between CIP patients and control subjects. On the other hand, when asked to rate pain-inducing events seen in video clips in the absence of visible or audible pain-related behaviour, CIP patients showed more variable and significantly lower pain ratings, as well as a reduction in aversive emotional responses, compared with control subjects. Interestingly, pain judgements, inferred either from facial pain expressions or from pain-inducing events, were strongly related to inter-individual differences in emotional empathy among CIP patients, while such correlation between pain judgement and empathy was not found in control subjects. The results suggest that a normal personal experience of pain is not necessarily required for perceiving and feeling empathy for others' pain. In the absence of functional somatic resonance mechanisms shaped by previous pain experiences, others' pain might be greatly underestimated, however, especially when emotional cues are lacking, unless the observer is endowed with sufficient empathic abilities to fully acknowledge the suffering experience of others in spite of his own insensitivity.

Adolescent↗

PubMed2006

Testing two accounts of pain underestimation.

Two important influences on pain underestimation by health care professionals were investigated by varying specific cues with reference to underestimation of patients' pain: when observers are not allowed to talk to patients and when observers expect social cheating. One hundred and twenty health care professionals watched videotaped facial expressions of pain patients and estimated their pain. The first group only saw the faces, the second group was given patients' self-reports in addition and the last group was given a context cue priming them to expect cheating in addition to faces and patients' ratings. Health care professionals generally underestimated patients' pain, but this varied depending on the cues given. Those viewing the face without patients' ratings underestimated pain to a greater extent than health care professionals provided with patients' ratings. Health care professionals primed to expect cheating underestimated pain as much as those seeing only patients' faces. Therefore, both accounts, verbal report as important but missing cue as well as an alerted cheating detection device, could account for underestimation.

Adult↗

PubMed2005

Viewing facial expressions of pain engages cortical areas involved in the direct experience of pain.

Recent neuroimaging and neuropsychological work has begun to shed light on how the brain responds to the viewing of facial expressions of emotion. However, one important category of facial expression that has not been studied on this level is the facial expression of pain. We investigated the neural response to pain expressions by performing functional magnetic resonance imaging (fMRI) as subjects viewed short video sequences showing faces expressing either moderate pain or, for comparison, no pain. In alternate blocks, the same subjects received both painful and non-painful thermal stimulation. Facial expressions of pain were found to engage cortical areas also engaged by the first-hand experience of pain, including anterior cingulate cortex and insula. The reported findings corroborate other work in which the neural response to witnessed pain has been examined from other perspectives. In addition, they lend support to the idea that common neural substrates are involved in representing one's own and others' affective states.

Adult↗

PubMed2005

Development of a multidimensional measure of tobacco dependence in adolescence.

The objective of this research was to develop a multidimensional measure of tobacco dependence, sensitive to signs of incipient dependence and relevant to adolescents. A cross-sectional survey was conducted of students attending randomly selected high schools in two regions of British Columbia, Canada. Of the 3280 adolescents who completed the survey, 17% (n=562) indicated that they had smoked at least once in the month preceding the survey and were classified as "smokers." Ninety-one percent of the smokers (n=513) completed all or most of the items and comprised the sample for the analysis. The survey included a number of items related to smoking status and nicotine dependence, including the newly developed Dimensions of Tobacco-Dependence Scale (DTDS), a 54-item multidimensional measure of tobacco dependence. Exploratory factor analyses using MINRES was used to examine the dimensions of the DTDS. The measure was found to include four dimensions: social reinforcement, emotional reinforcement, sensory reinforcement, and physical reinforcement. All subscales had adequate reliability (Cronbach's alpha coefficients >.70).

Adolescent↗

PubMed2005

Effects of deliberate control on verbal and facial expressions of pain.

The 'facial feedback hypothesis' suggests that inhibiting or exaggerating pain displays produces parallel effects on subjective experience. Research on the regulation of emotional expressions suggests that the act of self-regulation may be detectable in the properties of facial behavior. Both issues were examined in this study. Healthy young volunteers were videotaped while they were exposed to electric shocks varying in intensity. Participants in the Augment group were instructed to exaggerate their facial reactions to the shocks. Participants in the Attenuate group were instructed to inhibit their reactions. Controls simply responded to the shocks. All groups rated the pain of each shock on numeric, sensory and affective scales. In subsequent phases, judges rated the intensity of pain displays for all participants, and facial reactions were measured with the Facial Action Coding System. Results provided no support for the facial feedback hypothesis. Judges' ratings of participants' pain indicated that the augment instructions produced distinct alterations in pain expression. The control and inhibit groups showed linear increases in pain expression with increasing pain intensity, which did not differ significantly. Fine-grained analysis of participants' facial behavior provided evidence that pain augmentation was accompanied by topographic changes in pain expression. Parallels with existing studies, methodological issues and practical implications of the findings are discussed.

Adult↗

PubMed2005

Processing of facial expressions of negative emotion in alexithymia: the influence of temporal constraint.

Alexithymia, a characteristic involving a limited affective vocabulary appears to involve three components: difficulty identifying feelings, difficulty describing feelings, and externally oriented thinking. There is evidence that alexithymic characteristics are associated with differences in emotion information-processing. We examined the role of temporal factors in alexithymic emotion-processing deficits, taking into account the confound between alexithymic characteristics and positive and negative affectivity. One hundred forty-six participants completed the 20-item Toronto Alexithymia Scale and the Positive and Negative Affect Schedule. In a signal-detection paradigm, participants judged facial expressions depicting neutral or negative emotions under slow and rapid presentation conditions. The alexithymia component of difficulty in describing feelings was inversely related to the ability to detect expressions of negative emotion in the speeded condition. This relationship was independent of positive and negative affectivity. Alexithymic components positive and negative affectivity were unrelated to response bias. The results emphasize the influence of difficulty describing feelings within the alexithymia construct and its difference from positive and negative affectivity. They suggest that an alexithymic deficit in describing feelings is associated with a deficit in processing negative emotions that is most apparent when processing capacity is challenged. Theoretical and methodological implications are discussed.

Adult↗

PubMed2004

Effects of exposure on perception of pain expression.

The present study evaluated the effects of exposure to facial expression of pain, on observers' perceptions of pain expression. Thirty-one male and 49 female observers judged 1-s video excerpts in a signal detection paradigm. The excerpts showed facial expressions of shoulder-pain patients displaying no pain or moderate pain. Participants were randomly allocated to one of four groups, which varied in the number of prior exposures of a 1 s display of strong pain. On each test trial, participants indicated whether the test stimulus showed no pain or pain. Data were analyzed using signal detection theory methods. There was a linear relationship between the density of exposure to strong pain and observers' response criteria: greater exposure was associated with more conservative decisions. On average, participants showed very high levels of sensitivity to pain expression, with women significantly outperforming men. Results are discussed in terms of their implications for pain judgments of health care professionals, adaptation-level theory, and the psychophysical method of selective adaptation.

Adaptation, Physiological↗

PubMed2004

Development of sensitivity to facial expression of pain.

The ability to perceive pain in others is an important human capacity. Its development has not been studied. The present study examined the development of sensitivity to evidence of pain from childhood to early adulthood. One hundred and thirty-four males and females from four age groups (5-6, 8-9, 11-12 years and young adult) took part. They judged the amount of pain displayed on videotaped excerpts of the facial expressions of pain patients. Excerpts were selected to display no pain, some pain and strong pain, based on facial measurements, and were displayed to participants in a signal-detection paradigm. All participant groups were more sensitive to evidence of strong than some pain. The ability to detect pain expressions increased across the young, middle and older groups of children, but older children did not differ from adults. Increasing age was generally associated with increasing sensitivity to more subtle facial signs of pain. The results indicate that the ability to perceive pain in others is already significantly developed by the ages of five to six, but refinements in the ability continue through to early adulthood. These findings represent the first description of the development of the ability to perceive pain in others. Important areas for future research into the neurobiological, personal and social determinants of this ability are highlighted.

Adolescent↗

PubMed2002

Real-time assessment of pain behavior during clinical assessment of low back pain patients.

The development of procedures for assessing factors that contribute to pain and disability is crucial for clinical and epidemiologic studies. The present paper describes a system for in vivo, real-time assessment of pain behaviors integrated with a standardized physical examination for low back pain patients. The principles for measuring five categories of pain behavior--guarding, touching/rubbing, words, sounds and facial expressions--and for parsing the physical examination are described. The system was learned by five observers who then applied it during the physical examinations of 176 patients classified as suffering from sub-acute or chronic pain. The system was also applied to 77 patients in a test-retest consistency study. Measures of guarding, words, sounds and facial expression showed adequate psychometric properties. The test-retest consistency of guarding, sounds and facial expression was moderate-to-good, suggesting that these behaviors were consistent over the test-retest interval and promising for future study. The advantages and limitations of the technique are discussed and ways of modifying it to simplify coding and enhance the accuracy and reliability of its application are suggested. Overall, the technique shows promise for clinical and epidemiologic research.

Adolescent↗

PubMed2002

Hostility and facial expression in young men and women: is social regulation more important than negative affect?

Behavioral differences may clarify the link between hostility and health. This study examined facial expression. Seventy-two low- and high-hostile undergraduates underwent the Type A Structured Interview (SI) and a test of social anxiety. Facial behavior was measured with the Facial Action Coding System. Low-hostile participants displayed non-Duchenne smiles more frequently than high-hostile participants during the SI. There were no group differences in the expression of disgust. The results identify differences in the nonverbal behavior of hostile people. Restricted use of non-Duchenne smiles may reflect limited use of appeasement, contributing to uncomfortable interpersonal relations and limited social support. The findings are consistent with a behavioral ecology perspective and suggest that social regulation may be as important as negative affect in determining the consequences of hostility.

Affect↗

PubMed1994

Encoding and decoding of pain expressions: a judgement study.

The communication of pain requires a sufferer to encode and transmit the experience and an observer to decode and interpret it. Rosenthal's (1982) model of communication was applied to an analysis of the role of facial expression in the transmission of pain information. Videotapes of patients with shoulder pain undergoing a series of movements of the shoulder were shown to a group of 5 judges. Observers and patients provided ratings of the patients' pain on the same verbal descriptor scales. Analyses addressed relationships among patients' pain reports, observers' judgements of patients' pain and measures of patients' facial expressions based on the Facial Action Coding System. The results indicated that although observers can make coarse distinctions among patients' pain states, they (1) are not especially sensitive, and (2) are likely to systematically downgrade the intensity of patients' suffering. Moreover, observers appear to make insufficient use of information that is available in patients' facial expression. Implications of the findings for pain patients and for training of health-care workers are discussed as are directions for future research.

Adult↗

PubMed1992

Dissociating spontaneous and deliberate expressions of pain: signal detection analyses.

Neuro-anatomical and behavioral findings suggest that spontaneous and deliberate facial expressions are regulated by separate systems. The present study examined whether spontaneous and deliberate expressions of pain could be distinguished and, if so, the dimensions on which they differ. Forty subjects were exposed to electric shocks that varied from painless to strong pain. They also simulated facial reactions to the same levels. Observers rated the apparent pain in subjects' expressions and whether they were feigned or genuine. Signal detection analyses indicated that the intensity of deliberate expressions was greater than spontaneous expressions at levels below strong pain. Observers were able to distinguish between deliberate and spontaneous expressions to a modest degree. The intensity of deliberate expressions was related to role-playing ability. The results suggest that deliberate and spontaneous expressions of pain probably differ in intensity, topography and temporal features. They suggest that facial expressions of pain have different determinants than other forms of pain behavior.

Adult↗

PubMed1992

The consistency of facial expressions of pain: a comparison across modalities.

A number of facial actions have been found to be associated with pain. However, the consistency with which these actions occur during pain of different types has not been examined. This paper focuses on the consistency of facial expressions during pain induced by several modalities of nociceptive stimulation. Forty-one subjects were exposed to pain induced by electric shock, cold, pressure and ischemia. Facial actions during painful and pain-free periods were measured with the Facial Action Coding System. Four actions showed evidence of a consistent association with pain, increasing in likelihood, intensity or duration across all modalities: brow lowering, tightening and closing of the eye lids and nose wrinkling/upper lip raising. Factor analyses suggested that the facial actions reflected a general factor with a reasonably consistent pattern across modalities which could be combined into a sensitive single measure of pain expression. The findings suggest that the 4 actions identified carry the bulk of facial information about pain. They also provide evidence for the existence of a universal facial expression of pain. Implications of the findings for the measurement of pain expression are discussed.

Adult↗

PubMed1989

Pain expression in patients with shoulder pathology: validity, properties and relationship to sickness impact.

This study dealt with the validity and correlates of facial expressions of pain. Twenty-four patients seeking treatment for gleno-humeral joint pain and 12 controls underwent a standardized physiotherapy assessment protocol involving active and passive arm movements, and experimental pain induced by pressure. Subjects rated pain intensity on each trial using categorical, sensory and affective scales. Independent of testing, they completed a questionnaire measure of sickness impact. Facial behavior was measured by an abbreviated version of the Facial Action Coding System. Facial actions that related to pain indices included eyebrow lowering, narrowing and closing of the eyes, lip pulling, nose wrinkling and mouth opening. Facial actions during clinical tests showed consistent relationships with sensory and affective pain scales. Greater physical disability was associated with more intense pain actions on active, but not passive, tests. The results support the validity and generality of facial measures of pain, show that they yield graded sensitive information and suggest that they encode information about the psychosocial context of pain problems. Theoretical implications of these findings are discussed.

Adult↗

PubMed1985

Influencing non-verbal expressions of pain: signal detection analyses.

Non-verbal expressive behaviour may provide important information about pain not available through verbal report. Nevertheless, it has received little attention in pain research. In the present study, changes in expressive behaviour resulting from electric shock were related to shock intensity, self-report of discomfort, observers' judgements of subjects' distress and social modelling influences. Subjects were videotaped while they rated low-, medium- and high-intensity shocks. Simultaneously, they were exposed to a tolerant social model or an inactive companion. Observers then viewed videotapes of subjects and judged the level of shock being delivered on the basis of non-verbal behaviour. Observers' judgements were analysed by signal detection methods to quantify expressive behaviour. Change in expressive reactions to the shocks was directly related to stimulus intensity, self-report of pain, and observers' judgements of subjects' distress. Expressive behaviour resulting from high shocks was diminished by exposure to a tolerant model. These findings establish the feasibility of pain measurement based on expressive behaviour, suggest that expressive behaviour provides a sensitive and valid index of pain, and indicate that tolerant modelling reduces evidence of pain across multiple measures.

Discrimination, Psychological↗

PubMed1977

Factors of the langugage of pain in patient and volunteer groups.

An empirical determination of the nature and minimum number of dimension necessary to describe responses to the McGill Pain Questionnaire, and a comparison of groups, experiencing clinical or experimentally induced pain, on the dimensions were carried out. Eighty-five patients referred to a low back pain diagnostic clinic and groups of 129 volunteer students exposed to electric shock to pain threshold and pain tolerance levels described their pain using the McGill Pain Questionnaire's descriptive words. An incomplete principle component factor analysis of subjects' ratings suggested that 5 factors should be retained. These factors were judged to reflect: (I) immediated anxiety, (II) perception of harm, (III) somesthetic pressure, (IV) cutaneous sensitivity, and (V) sensory information. Canonical Analysis of Variance and univariate comparisons of back pain, threshold, and tolerance groups on these dimensions were conducted and implications for clinical and laboratory research discussed.

Adult↗