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Biomedical subjects

R R Edwards

Publications and source records attributed to R R Edwards.

14 recordsLinked to original sources
PubMed2001

The association of hormone replacement therapy with experimental pain responses in postmenopausal women.

Considerable experimental research suggests that ovarian hormones can influence pain perception, and recent epidemiologic and clinical research suggests that exogenous hormone use may influence the prevalence and severity of clinical pain among women. However, to date no studies have examined the influence of hormone replacement therapy (HRT) on experimental pain responses and recent pain complaints among postmenopausal women. In this study, self-reported recent pain and general health were obtained, and thermal pain responses were assessed in three groups of healthy older adults: (1) women on HRT, (2) women not on HRT (No-HRT), and (3) men. Results indicated no group differences in recent pain complaints or self-reported health, but differences emerged for measures of thermal pain perception. Specifically, HRT women showed lower pain thresholds and tolerances than No-HRT women and men, and the latter two groups did not differ from each other. The potential explanations and limitations of the observed findings are discussed.

Aged↗
PubMed2001

Effects of age on temporal summation and habituation of thermal pain: clinical relevance in healthy older and younger adults.

Although the effects of aging on the experience of clinical pain seem relatively clear, investigations of age-related changes in pain perception using laboratory-based pain assessment procedures have yielded contradictory findings. One potential source of variability in this literature is the type of experimental noxious stimulus that is used. Although thermal pain thresholds are the most commonly reported measure of pain sensitivity, use of suprathreshold stimuli in pain assessment procedures may yield additional, more clinically relevant information concerning the effects of aging on the experience of pain. The present study examined the effects of age on temporal summation of both the intensity and unpleasantness of thermal pain at multiple stimulus temperatures. Specifically, responses to repetitive thermal stimuli delivered to the volar forearm at 47 degrees C, 50 degrees C, and 53 degrees C were assessed in 34 younger (mean age, 22.4 years) and 34 older (mean age, 62.2 years) healthy volunteers. Results suggested that for the 47 degrees C and 50 degrees C stimulus trains, older adults exhibited higher ratings of the intensity and unpleasantness of thermal pain and enhanced temporal summation of thermal pain relative to younger adults. Moreover, thermal pain sensitivity was inversely related to perceptions of general health and to reports of recent clinical pain among younger, but not older, subjects. Collectively these findings may indicate small, although potentially significant, age-related alterations in the plasticity of the central nervous system or endogenous pain-modulatory capacities.

Journal Article↗
PubMed2001

Age-associated differences in responses to noxious stimuli.

BACKGROUND: Although population-based studies typically report age-associated increases in clinical pain, laboratory-based pain assessment procedures generally indicate diminished pain sensitivity with age. The majority of these studies have utilized noxious thermal stimuli as the method of pain induction. However, other pain assessment methodologies, including ischemic pain induction, may have a more meaningful relationship to clinical pain. The present study examined the effects of age on responses to a variety of experimental noxious stimuli. In addition, relationships between cardiovascular measures and pain responses were investigated in both older and younger subjects. METHODS: Responses to thermal, mechanical, and ischemic pain were assessed in 34 younger (mean age, 22.4 years) and 34 older adults (mean age, 62.2 years). In addition, relationships between resting blood pressure and pain responses were assessed separately for older and younger participants. RESULTS: Although group differences in thermal and mechanical pain responses did not achieve statistical significance, older individuals demonstrated substantially lower ischemic pain thresholds and tolerances assessed via the modified submaximal effort tourniquet procedure (ps < .01). Overall, higher resting arterial blood pressures were associated with increased pain thresholds and tolerances, although relationships between blood pressure and ischemic pain variables were evident only for the younger group. CONCLUSIONS: These findings indicate that age-related differences in responses to experimental noxious stimuli vary as a function of the pain induction task, with older individuals showing greater sensitivity to clinically relevant stimuli. In addition, the absence of a relationship between blood pressure and ischemic pain responses in older adults may suggest potential functional decrements in at least one endogenous pain-modulatory system.

Adult↗
PubMed2000

Sex-dependent effects of reported familial pain history on recent pain complaints and experimental pain responses.

Previous research has demonstrated that both sex and familial pain history can influence clinical pain, and sex is known to affect experimental pain responses. However, the potential interactive effects of sex and family history on pain-related symptoms and experimental pain have not been investigated. This experiment examined recent pain complaints and laboratory pain responses as a function of sex and reported family history of pain in 212 (122 female, 90 male) young adults. All subjects completed questionnaires regarding family history of pain, recent pain experiences, and psychological measures of hypervigilance. Then, warmth detection thresholds, heat pain thresholds and heat pain tolerances were determined. Results revealed sex-dependent influences of familial pain history on recent pain complaints and experimental pain responses. Specifically, a positive family history of pain was associated with increased reports of pain over the previous month and poorer general health as well as enhanced sensitivity to thermal stimuli among females but not males. Higher levels of hypervigilance accounted for some of the family history effects on recent pain complaints but not experimental pain measures. Potential mechanisms underlying these effects of family history among females are discussed.

Adult↗
PubMed1999

Effects of gender and acute dental pain on thermal pain responses.

OBJECTIVE: Considerable research suggests that females exhibit greater sensitivity to laboratory pain procedures than do males; however, whether the presence of acute clinical pain influences this sex difference in pain sensitivity has not been investigated. The present experiment investigated the effects of sex and acute dental pain on laboratory pain responses. DESIGN: Thermal pain onset and tolerance were determined in 46 dental patients (15 male, 31 female) experiencing pain due to acute irreversible pulpitis and in 33 healthy controls (13 male, 20 female). In addition, measures of mood and coping were obtained in all participants. All subjects participated in two experimental sessions. The first session took place immediately before the patients underwent endodontic treatment for relief of pulpal pain. The second session took place approximately 1-2 weeks later, when pulpitis patients were pain free after treatment. During each session, thermal pain onset and tolerance were assessed with a 1-cm2 contact thermode applied to the right volar forearm using an ascending method of limits. RESULTS: During both sessions, thermal pain onset and tolerance were lower in control females than in control males; however, male and female pulpitis patients did not differ in their thermal pain responses during either session. Pulpitis patients also showed greater affective distress than controls. CONCLUSIONS: These data suggest that the sex difference in thermal pain sensitivity frequently reported in pain-free subjects appears to be absent in patients presenting with acute dental pain. However, this effect cannot be explained solely based on the presence of clinical pain because the effect on pain threshold and tolerance persisted into session 2, when pulpitis patients were pain free. Potential explanations for these results are discussed.

Acute Disease↗
PubMed1996

The effects of aging on information-processing channels in the sense of touch: III. Differential sensitivity to changes in stimulus intensity.

Detection thresholds and difference limens were measured for 16 subjects ranging from 19 to 91 years of age. The stimuli were 250-Hz bursts of vibration applied through a 3.0-cm2 contactor to the thenar eminence of the right hand. Detection thresholds were higher in older than in younger subjects, as were the absolute values of difference limens. When the difference limen was expressed in relative terms as the proportion by which two stimuli had to differ in amplitude to be discriminated (delta alpha/alpha), discriminative capacities were unaffected by aging except for stimuli slightly above the detection threshold, in which case the limens of older subjects were significantly higher than those of younger subjects. The results are consistent with the hypothesis that elevations in the detection thresholds of older subjects are the results of reduced afferent input to central brain centers that, with regard to their capacity to detect the presence of threshold-level stimuli and to discriminate differences among suprathreshold stimuli, are relatively unaffected by aging.

Adult↗
PubMed1990

Use of the signal-averaged ECG to predict maximum ventricular tachycardia rate.

Rapid ventricular tachycardia is poorly tolerated, and estimation of maximum ventricular tachycardia rate prior to programmed ventricular stimulation is difficult. A method to estimate maximum ventricular tachycardia rate using late potential duration from the signal-averaged ECG and ventricular functional refractory period is described. Late potentials recorded in patients with ventricular tachycardia may represent delayed conduction through arrhythmogenic ventricular myocardium. This delay may be rate limiting in determining the minimum cycle length of reentrant ventricular tachycardia originating from these areas. Using the ratio of ventricular activation time (VAT), which equals QRS plus late potential duration, to unfiltered QRS duration (QRS) as estimate of this delay, the following relationship is proposed: Minimum ventricular tachycardia cycle length = (FRP 400 - 12.5 ms) (VAT/QRS). Twenty patients with late potentials who had sustained, monomorphic ventricular tachycardia at programmed stimulation were evaluated. Predicted cycle lengths ranged from 326 to 214 ms. Predicted and observed cycle lengths were significantly correlated (r = 0.91, SEE = 11.9 ms, p less than 0.0005), with predicted and observed cycle lengths differing by less than 3.5%. Predicted cycle lengths were more accurate than cycle lengths estimated using FRP alone (p less than 0.01). Accurate prediction of minimum ventricular tachycardia cycle length using this relationship suggests that late potential duration is proportional to the conduction delay occurring in arrhythmogenic ventricular myocardium.

Cardiac Pacing, Artificial↗
PubMedDate not supplied

Ethnic differences in thermal pain responses.

OBJECTIVE: Although numerous studies have reported ethnic differences in the prevalence and severity of clinical pain, little is known about how these differences affect the perception of experimental pain. The present experiment examined the effects of ethnicity (African American vs. white) on thermal pain responses in a healthy undergraduate population. METHODS: Thirty white subjects (16 women and 14 men) and 18 African Americans (10 women and 8 men) participated in the study. Thermal testing included evaluation of the following: warmth thresholds, thermal pain thresholds, thermal pain tolerances, and magnitude estimates of both the intensity and unpleasantness of thermal pain (at 46 degrees, 47 degrees, 48 degrees, and 49 degrees C). RESULTS: Although no group differences emerged for warmth thresholds, thermal pain thresholds, or pain intensity ratings, African Americans demonstrated lower thermal pain tolerances than whites. In addition, African Americans had smaller slopes and larger intercepts than whites for ratings of pain unpleasantness. Additional analyses suggested that these findings were a consequence of group differences in thermal pain unpleasantness ratings at the lowest temperatures assessed (46 degrees and 47 degrees C); at these temperatures, African Americans rated the stimuli as more unpleasant than whites. Finally, group differences in thermal pain tolerance and thermal pain unpleasantness ratings seemed to partially account for greater self-reported daily pain symptoms among African Americans. CONCLUSIONS: Collectively, these findings seem to suggest ethnic differences in the perception of the affective-motivational dimension of thermal pain.

Adolescent↗
PubMedDate not supplied

Ethnic differences in pain tolerance: clinical implications in a chronic pain population.

OBJECTIVE: Although numerous studies have independently examined ethnic differences in clinical and experimental pain, few have investigated differences in both sensitivity to controlled noxious stimuli and clinical pain reports in the same sample. The present experiment examined the effects of ethnicity (African American vs. white) on experimental pain tolerance and adjustment to chronic pain. METHODS: Three hundred thirty-seven (68 African American and 269 white) patients with chronic pain referred to a multidisciplinary treatment center participated in the study. In addition to completing a number of standardized questionnaires assessing adjustment to chronic pain, participants underwent a submaximal effort tourniquet procedure. This experimental pain procedure yields a measure of tolerance for a controlled noxious stimulus (ie, arm ischemia). RESULTS: African American subjects reported higher levels of clinical pain as well as greater pain-related disability than white participants. In addition, substantial group differences were observed for ischemic pain tolerance, with African Americans demonstrating less tolerance than whites. Correlational analyses revealed a small but significant inverse relationship between ischemic pain tolerance and the reported severity of chronic pain. CONCLUSIONS: Collectively these findings support previous research revealing ethnic differences in responses to both clinical and experimental pain. Moreover, the present results suggest that enhanced sensitivity to noxious stimuli on the part of African Americans may be associated with ethnic differences in reported clinical pain, although the magnitude of ethnic differences was much greater for ischemic pain tolerance than for clinical pain measures.

Adult↗