Subtypes of anhedonia and facial electromyography response to negative affective pictures in non-psychiatric adults.

INTRODUCTION: Flat/constricted affect and anhedonia are symptoms found in several psychiatric disorders such as depression and schizophrenia. However, there are very few studies on the relationships between specific anhedonia subtypes and objectively assessed flat affect, and it appears that none of the existing studies examined potential moderation by sex. METHODS: Forty-seven undergraduate students (60% male) completed self-report questionnaires assessing three subtypes of anhedonia - non-social consummatory (CON) and anticipatory (ANT) anhedonia, and overall social anhedonia. Participants viewed 15 pictures (5 neutral and 10 negative) from the International Affective Picture System, whereas facial muscle reaction was recorded using electromyography (EMG). RESULTS: Male participants reporting a greater level of overall social or non-social CON anhedonia showed a greater EMG activity increase in the corrugator supercilii muscle to negative (vs. neutral) pictures. In females, the relationship was only found with social anhedonia and was opposite in direction, as increased social anhedonia related to less EMG activity change in the corrugator muscle. CONCLUSIONS: The relationship between anhedonia and flat affect varied as a function of sex and anhedonia subtype. These findings may help explain discrepancies in the sparse existing literature examining this relationship in psychiatric populations and have implications for assessment and treatment of these symptoms across psychiatric disorders.

Independent evaluation of a multidisciplinary rehabilitation program for chronic low back pain.

Severe chronic low back pain was diagnosed in 236 patients by one physician and they were referred to the University of Miami Comprehensive Pain and Rehabilitation Center (UMCPRC) over a 5-year period for an intensive 4-week inpatient treatment program. Of these 143 (61%) were able to be contacted by telephone and given a structured interview designed for the study. The average time elapsed at follow-up from referral for all patients was 22.5 months. Outcome was measured in the following terms: current levels of pain, percent decrease in pain, subsequent health care utilization, activities of daily living, and attitudes toward treatment. After completion of the interview, the McGill Pain Questionnaire and the Oswestry Low Back Pain Disability Questionnaire were sent to the patients. The patients fell into five groupings: Group 1--participants in the UMCPRC program (n = 39); Group 2--those whose participation was not approved by insurance (n = 30); Group 3--those who declined participation (n = 46); Group 4--participants in other programs (n = 14); Group 5--dropouts (n = 14). The five groups were not meaningfully different with regard to prereferral demographics. Interestingly, Group 1 patients exhibited significantly greater prereferral pain and unemployment levels. Despite this, at follow-up significantly more Group 1 members were employed and they exhibited a greater percent decrease in pain as compared to the nonparticipant groups. Returned McGill and Oswestry Questionnaires mirrored these findings. Group 1 members also demonstrated significantly lower rates of subsequent health care utilization, i.e., physician visits, hospitalizations, and surgery than the nonparticipant groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Pain, disability, and psychological functioning in chronic low back pain subgroups: myofascial versus herniated disc syndrome.

A series of patients with chronic low back pain evaluated at a tertiary referral center were the subjects for this study. Of 250 consecutive patients, 94 were diagnosed as having myofascial pain and 57 as having herniated disc syndrome. Before evaluation and diagnosis, all patients completed the McGill Pain Questionnaire, ratings of pain and disability, and the Symptom Checklist 90-R. Patients were also grouped on the basis of previous surgical history and workers' compensation benefits. Patients suffering from myofascial pain were significantly less likely to report periods of pain relief than patients with herniated disc syndrome. Those receiving workers' compensation benefits reported significantly greater levels of pain, disability, and psychological distress than those not receiving benefits, irrespective of diagnosis. Patients who underwent previous surgery did not differ significantly from those who never underwent surgery. All patients had elevated scores on the Somatization subscale of the Symptom Checklist 90-R. Patients with myofascial pain and workers' compensation benefits demonstrated the highest levels of somatization and phobia. These findings suggest that the effects of low back pain of myofascial origin have comparable, if not worse, consequences than disc herniation. These findings also reaffirm the importance of workers' compensation in understanding the differences in patients with chronic low back pain.

Trunk strength and lumbar paraspinal muscle activity during isometric exercise in chronic low-back pain patients and controls.

The purpose of this study was to describe trunk strength and lumbar paraspinal muscle activity across five angles of flexion during isometric exercise and rest in chronic low-back pain patients and control subjects. High muscle tension as measured by surface integrated electromyography is predicted by a muscle spasm model, and low muscle tension is predicted by a muscle deficiency model. Prior lumbar surgery had no affect on peak torque or maximum surface integrated electromyography data. Both groups produced greater torque and less surface integrated electromyography in more flexed positions. Chronic low-back pain patients exhibited lower peak torque and lower maximum surface integrated electromyography bilaterally during isometric extension effort across all angles. A muscle deficiency model of chronic low back pain was supported by these data and a muscle spasm model was not supported. Discriminant analyses indicated that monitoring maximum surface integrated electromyography of lumbar muscles during isometric effort facilitates classification of chronic low-back pain patients. Future directions are discussed in terms of applying psychophysiologic methods to pain rehabilitation.

Patellar taping in the treatment of patellofemoral pain. A prospective randomized study.

The purpose of this prospective study was to evaluate the efficacy of a patellar taping program in the conservative management of patellofemoral pain. Twenty-five patients with patellofemoral pain were randomized into two groups. One group underwent a standard physical therapy program for patellofemoral pain. The other group underwent the same physical therapy program, but use of a patellar taping technique was added to this program. Results of a subjective visual analog scale and changes in isokinetic strength and electromyographic activity of the quadriceps muscle were analyzed. Both the tape and no-tape groups experienced a statistically significant decrease in symptoms (P < 0.05), but no difference in improvement of patellofemoral pain was noted between the groups. Likewise, both groups demonstrated significant improvement in quadriceps muscle isokinetic strength (P < 0.05) and activity (P < 0.001), but no difference in improvement was noted between groups. The results of this study suggest no beneficial effect of adding a patellar taping program to a standard physical therapy program in the conservative treatment of patellofemoral pain. Larger prospective studies are warranted to support this opinion.

The effects of impression management demands on heart rate, self-reported social anxiety, and social competence in undergraduate males.

The effects of self-presentation demands were evaluated through conversational probe (CP) role-play tasks. Participants (N = 29) were required to manage their self-presentations (i.e., the impression they made, in each of two conditions). During high impression management (IM) demand, participants were evaluated on their performance. During Low IM demand, participants evaluated a confederate's performance. The High IM demand condition produced significantly higher heart rate (HR) and self-reported anxiety. HR and self-reported anxiety accounted for a significant amount of the variance in criterion measures of social competence. Greater social competence during High IM was associated with higher HR. Greater social competence during Low IM was associated with lower HR and lower self-reported anxiety. Although preliminary, these results suggest that uncontrolled IM demands contributed to mixed results found within and between social anxiety studies in the literature. Implications for the treatment of social anxiety are discussed.

Psychophysiological reactivity to alcohol advertising in light and moderate social drinkers.

Psychophysiological responses to alcohol and nonalcohol advertising slides were compared in light and moderate social drinkers. Each slide presentation was interspersed with a rest period. Before viewing the slides, participants completed a questionnaire to estimate their quantity and frequency of alcohol consumption. Participants were divided into two groups using a median split of alcohol consumption scores. Light social drinkers showed a significant decrease in heart rate response to both alcohol-related and nonalcohol advertisements. Moderate social drinkers showed a significant increase in skin conductance to both alcohol-related and nonalcohol advertisements. The findings of this study have implications for understanding both the influence of alcohol advertisements on behavior and the psychophysiological correlates of cue reactivity.

EMG feedback-assisted postoperative rehabilitation of minor arthroscopic knee surgeries.

This study assessed the effectiveness of surface integrated electromyographic (EMG) biofeedback in the rehabilitation of 51 patients undergoing minor arthroscopic knee surgery. Prior to surgery, both control (n = 23) and treatment (n = 28) groups received verbal and written explanations of postoperative isometric exercises; the treatment group received additional instruction in the use of ambulatory biofeedback equipment during exercise. Isokinetic tests of strength at approximately two weeks post-surgery revealed that patients given EMG biofeedback during postoperative exercise demonstrated significantly greater extensor torque and quadriceps muscle fiber recruitment than controls. Implications for the use of EMG biofeedback in long-term postoperative rehabilitation are discussed.

The detection of malingering and deception with a short form of the MMPI-2 based on the L, F, and K scales.

This project examined the use of a short inventory based on the validity subscales from the MMPI-2. In Study 1, 69 subjects responded to the extracted L, F, and K items and to those items when embedded in the complete MMPI-2. Correlations between administrations were equivalent to the original test-retest reliabilities for these scales. In Study 2, 60 subjects responded to the short-form with instructions to be honest, fake good, or fake bad. The correct classification rate was 77% using the standard MMPI-2 rules of L greater than 7OT for faking good and F greater than 7OT for faking bad. Taken together, these findings suggest that the short-form may be useful alone or when combined with other questionnaires to identify potential problems in self-report.

Ethical and practice considerations for biofeedback therapists in the treatment of urinary incontinence.

The treatment of incontinence presents many unique issues for biofeedback therapists that are routine for professionals in fields such as nursing or medicine. Although all professional practice is guided by ethical standards, the unique circumstances encountered during biofeedback treatments for this disorder warrant the development of specific guidelines. This is true whether insertable or surface EMG devices are used. Therefore, the purpose of this article is to propose a set of ethical guidelines for biofeedback therapists. The intended audience includes professionals such as psychologists, clinical psychophysiologists, and other mental health-care providers who use biofeedback techniques. These are not formally endorsed by any professional organizations (e.g., APA, AAPB) at this time. Ethical considerations include proper medical evaluation, informed consent, patient instruction, disrobing, nonerotic physical contact, patient safety, and patient satisfaction.

Relationships between coping style and PAI profiles in a community sample.

Relationships between coping style and psychological functioning were examined in a heterogeneous community sample (N = 168). Psychological functioning was categorized with the Personality Assessment Inventory (PAI; Morey, 1991). Subjects were assigned to PAI configural profile clusters, using T-scores from PAI clinical scales. Three PAI clusters were prominent in this sample: normal, anxious, and eccentric. Multivariate analysis of covariance revealed that these clusters differed significantly in coping style, as measured by the dispositional format of the COPE Inventory (Carver, Scheier, & Weintraub, 1989). Normals coped through avoidance significantly less than anxious or eccentric subjects. Also, normals engaged in seeking social support and venting more than eccentric but less than anxious subjects. Gender differences also were noted, with women more likely to cope by seeking social support and men more likely to cope through hedonistic escapism.

Validation of surface EMG as a measure of intravaginal and intra-abdominal activity: implications for biofeedback-assisted Kegel exercises.

This study validates surface EMG as a measure of pelvic muscle and abdominal activity by showing its high correlation to internal pressure data. Using standardized scores, between-subjects correlation of perineal EMG and intravaginal pressure was r = .75, and the correlation of abdominal EMG and intra-abdominal pressure was r = .72. Discriminant validity was also demonstrated by showing low correlation between standardized abdominal and perineal EMG measurements (r = .10). A repeated measures multivariate analysis of variance demonstrated that visual and auditory biofeedback of EMG during pelvic floor contractions increases intravaginal pressure when compared with trials without biofeedback. Potential benefits of fabric electrodes include reduced invasiveness and risk and the ease with which patients can utilize this technology for home practice.

EMG-activated feedback alarms for the treatment of nocturnal bruxism: current status and future directions.

This article reviews published research on the use of EMG-activated feedback paradigms to modify nocturnal bruxism. The first three sections review naturalistic trials, laboratory studies, and comparisons of feedback paradigms with alternative treatment/management approaches. The fourth section overviews several sources of theoretical guidance for further research and delineates some substantive directions. The final section identifies major scientific shortcomings that are common in the literature and offers some correctives. The empirical reviews suggest that nocturnal bruxing feedback is beneficial and competitive with other approaches, particularly when the feedback serves to occasion behaviors that require wakefulness. The theoretical overview points to classical learning theories, biofeedback theories, and theories concerning the etiology of bruxism as guideposts for continued research. The methodological narrative calls for adequately detailed scientific reporting, for increased operational commonality across experiments, and for innovative integrations of actuarial and intrasubject research designs.

Effect of instructions to simulate a back injury on torque reproducibility in an isometric lumbar extension task.

The purpose of this study was to investigate the differences in test-retest reliability between maximal and "simulated back injury" efforts in an isometric lumbar extension task and to test the hypothesis that voluntary attempts to "simulate" a back injury would yield less consistent torque production than maximal efforts. Twenty subjects were asked to undergo lumbar extensor testing at seven different positions in a lumbar extension machine. Each subject was tested twice in a maximal effort condition and twice with instructions to "simulate" a back injury. The order of the conditions was counterbalanced across subjects so that half of the subjects performed the maximal effort tests first and half performed the "simulated" effort first. Results indicated high test-retest correlations at all angles in both conditions. There were no differences in test-retest reliability between effort conditions. Therapist ratings of consistency did not differ between conditions and therapists could not discriminate between conditions on the basis of effort consistency. In the "simulated" condition subjects produced reliable, submaximal torque plots consistent with previous data indicating similar reliability at submaximal levels. It was concluded that use of test-retest torque consistency as a measure of sincerity of effort is premature and may be misleading.

Reproducibility of maximal versus submaximal efforts in an isometric lumbar extension task.

The purpose of this study was to investigate the differences in test-retest reliability between maximal and submaximal efforts in an isometric lumbar extension task and to test the hypothesis that submaximal efforts would be less consistent than maximal efforts. Twenty subjects were asked to produce maximum voluntary contractions at seven different positions in a lumbar extension machine. Each subject was tested twice in a maximal-effort condition and twice in a 50% effort condition. The order of the effort conditions was counterbalanced across subjects so that half of the subjects performed the maximal-effort tests first and half performed the submaximal effort first. Results indicated high test-retest correlations at all angles in both conditions. There were no differences in test-retest reliability between effort conditions. Therapist ratings of consistency did not differ between conditions, and therapists could not discriminate between conditions on the basis of effort consistency. Because subjects could reliably reproduce a submaximal effort, it was concluded that consistency interpretations of isometric strength testing may be misleading.

Relationship between confabulation and measures of memory and executive function.

Confabulation has traditionally been attributed to a combination of memory impairment and executive dysfunction, but recent models propose that confabulation can result from executive dysfunction alone. One hundred and ten patients with diverse neurologic and psychiatric diagnoses were subdivided into high-, low-, and non-confabulator groups based upon the ratio of confabulations to total responses produced during story recall. Consistent with the combined deficit model, high-confabulators performed significantly worse than the low- and non-confabulators on measures of memory and measures of executive function that assess sustained attention, mental tracking, and set-shifting ability. However, there were no differences between groups on measures of problem-solving, concept formation, and verbal fluency, suggesting a dissociation in executive functions that contribute to confabulation.

The use of ambulatory EMG monitoring to measure compliance with lumbar strengthening exercise.

This study validates the use of ambulatory EMG monitoring as a measure of exercise compliance. The model rehabilitative exercise used was the Prone Back Extension. Thirty-two undergraduate volunteers were videorecorded as they performed the exercise alone in a closed room. The correlation between a direct observation count of the number of repetitions and an independent EMG-based count was .95. EMG amplitude was examined by repetition and gender with regression and ANOVA. There were significant gender differences in the amplitude of EMG across repetitions. There were no significant differences by gender in the declining slope of amplitude across repetitions. This slope may represent a typical "fatigue" curve. Thus, not only the occurrence but also the intensity of exercise can be quantified.

Lumbar iEMG during isotonic exercise: chronic low back pain patients versus controls.

Two studies investigated the use of lumbar integrated electromyography (iEMG) during flexion-extension exercises of the lumbar spine. The first study compared the iEMG fatigue slopes of 12 pain-free controls during a standardized isotonic workout with a heavy weight and a light weight. Results indicated that the slopes of the iEMG across flexion-extension repetition was negative in both conditions, with the heavy weight producing significantly steeper fatigue slopes. In the second study, iEMG was compared from 16 chronic low back pain (CLBP) patients and 12 asymptomatic controls during isotonic exercise. Integrated EMG was recorded during 18 lumbar extension-flexion cycles (3 min) at a standard pace. Each subject exercised at a weight equal to 60% of his maximum isometric torque produced at the most extended position. Results indicated significantly less iEMG was produced by the CLBP group during both concentric and eccentric exertion. For both groups, eccentric exertion produced significantly less iEMG than concentric exertion. The groups showed significantly different iEMG fatigue slopes, with the control group showing declining iEMG by repetition, while the CLBP group showed flatter, slightly increasing iEMG. This occurred for both eccentric and concentric comparisons. A muscle deficiency model of CLBP is supported and results suggest the importance of endurance factors in addition to strength in rehabilitation efforts. Results also suggest the possibility of using this methodology for detecting insincere efforts in lumbar spine assessment.