Mechanisms of Isometric Exercise-Induced Hypoalgesia in Young and Older Adults

Pain reduction following exercise (exercise-induced hypoalgesia; EIH) is well-established in young adults. Specific to isometric exercise, the greatest EIH follows low intensity contractions held for long duration. The EIH response of older adults is not known; and the mechanisms for EIH are unclear at any age. This dissertation aimed to address these unknowns through a series of three studies. In study one, repeatability of pressure pain reports (pain threshold and pain ratings) was assessed in healthy older adults, including the impact of psychological factors. Pain reports, measured before and after quiet rest, did not change following quiet rest. Higher state anxiety was associated with greater pain. Study two examined the impact of isometric contractions that varied in intensity and duration on pain relief in healthy older adults. Pressure pain was assessed before and after isometric contractions of the left elbow flexor muscles. Unlike young adults, older adults experienced EIH similarly across different isometric exercise tasks and women experienced greater pain reduction than men. Anxiety did not influence EIH. Conditioned pain modulation (CPM; a reduction in pain to a test stimulus in the presence of a noxious conditioning stimulus) has been hypothesized to augment EIH when exercise is painful. In study three, CPM and EIH were assessed in healthy young and older adults. CPM was measured as the difference in pressure pain with the foot immersed in neutral-temperature water versus noxious ice water. While young adults experienced CPM, older adults experienced a range of responses from hypoalgesia to hyperalgesia with foot immersion in the ice water bath. CPM predicted EIH and was associated with state anxiety; however state anxiety was unrelated to EIH. Results for age and sex-related differences in pain perception varied across studies or sessions. The results of this dissertation suggest anxiety influences pain sensitivity, but not magnitude of EIH. Older adults, particularly women, experience reductions in pain following isometric exercise and are less dependent upon task than young adults. CPM may predict EIH response following isometric exercise in both young and older adults and may be a useful tool in clinical decision making for adults experiencing pai

Conditioned Pain Modulation Predicts Exercise-Induced Hypoalgesia in Healthy Adults

Introduction: Conditioned pain modulation (CPM) is the concept that pain inhibits pain and has potential rehabilitation implications for exercise prescription. The purpose of this study was to determine whether changes in pressure pain perception after a thermal conditioning stimulus (i.e., CPM) was attenuated with aging and whether CPM predicted pain relief after exercise (exercise-induced hypoalgesia (EIH)) in healthy young and older adults. Methods: Twenty young (21.9 ± 3.3 yr, 10 men) and 19 older (72.0 ± 4.5 yr, 10 men) adults participated in three sessions: one familiarization and two experimental (EIH and CPM) sessions. Pressure pain perception was assessed using a weighted Lucite edge placed on the right index finger for 1 min. EIH was determined by measuring pressure pain perception before and after prolonged submaximal isometric contraction of the elbow flexors. CPM was assessed by measuring pressure pain perception at the finger while the foot was immersed in neutral water versus painful ice water. Results: Young, but not older, adults reported a decrease in pressure pain at the finger while their foot was immersed in the ice water bath compared with the neutral bath (i.e., CPM, trial–age: P = 0.001). Pressure pain ratings decreased after exercise (P = 0.03) that was perceived as painful (peak arm pain, 7.0 ± 3.3) for both young and older adults. Regression analysis showed that after controlling for age and baseline pain, CPM predicted EIH (model adjusted R2 = 0.23, P = 0.007). Conclusions: CPM was attenuated in older adults, as measured with a noxious pressure stimulus after a thermal conditioning stimulus, and adults with greater CPM were more likely to report greater EIH

Is Compressed and Limited Synchronous Delivery of Anatomy Content in a Hybrid Delivery Format Effective in Transitional OT Student Learning?

Hybrid occupational therapy (OT) students transitioning from certified OT assistants (COTAs) to OTs can successfully learn graduate-level anatomy in a compressed format with limited synchronous instruction time. The effectiveness of a human anatomy course with limited synchronous instruction time for transitional hybrid occupational therapy students was investigated. A retrospective, non-randomized study was used. A university graduate level human anatomy course for transitional OT students used prosected (previously dissected) cadavers. Students (n=46, 32 instruction hours over 16 weeks) final anatomy course grades for three cohorts were measured retrospectively. There was a 98% first-time pass rate and 100% second time pass rate. Less than 5% of the students needed to either repeat the course (one student) or withdrew from the course prior to course completion (one student). Results suggest that a hybrid learning model with limited synchronous instruction time is effective for transitional OT students learning human anatomy. Programs should consider how instruction time and distribution impacts anatomy learners, and when there is limited time in the classroom, investigate alternative pedagogies for those few students who would benefit from a more immersive-learning environment. Anatomy knowledge is essential in progressing through occupational therapy curriculums and is needed for client management. Understanding what factors impact learning anatomy could assist in creating more effective anatomy courses for occupational therapy students

Pain Relief in Older Adults Following Static Contractions is not Task-Dependent

Pain complaints increase with age. Exercise is frequently utilized for pain relief but the optimal exercise prescription to relieve pain is not clear. Following static contractions, young adults experience the greatest pain relief with low intensity, long duration contractions. The pain response to static contractions in older adults however is unknown. PURPOSE : To compare pain reports in healthy older adults before and after static contractions of varying intensity and duration. METHODS: Pain perception was assessed in 23 healthy older adults (11 men, 12 women; 72.0 ± 6.3 yrs) using a pressure pain device consisting of a 10 N force applied to the right index finger through a Lucite edge (8 x 1.5mm) for two minutes. Subjects pushed a timing device when they first felt pain (i.e., pain threshold) and rated their pain intensity every 20 seconds using a 0-10 numerical rating scale. Pain threshold and pain ratings were measured before and immediately after static contractions of the left elbow flexors at the following three doses: 1) three brief maximal voluntary contractions (MVC); 2) 25% MVC sustained for 2 minutes; and 3) 25% MVC sustained until task failure. Experimental sessions were randomized and separated by one week. RESULTS : Time to task failure for the 25% MVC contraction was 11.8 ± 5.1 minutes. A reduction in pain was found following all three tasks with no difference between tasks (trial x task effect: p \u3e 0.05), despite the duration of the 2 minute low-intensity contraction being ~17% of the contraction held to task failure. Pain thresholds for all doses increased 20% from 51 ± 33 to 61 ± 37 seconds and pain ratings averaged over the six time points decreased 20% from 3.3 ± 2.8 to 2.6 ± 2.5 following static contractions (trial effect: p \u3c 0.001 and p \u3c 0.001, respectively). CONCLUSION : Low and high intensity static contractions of both long and short duration produce similar levels of pain reduction in older adults. These preliminary data suggest that several different types of static contractions can induce significant pain relief in older adults. Age-related changes in the pain response to static contractions must be taken into account when prescribing static exercise for the management of pain

Pain Relief in Older Adults Following Static Contractions is not Task-Dependent

Pain complaints increase with age. Exercise is frequently utilized for pain relief but the optimal exercise prescription to relieve pain is not clear. Following static contractions, young adults experience the greatest pain relief with low intensity, long duration contractions. The pain response to static contractions in older adults however is unknown. PURPOSE : To compare pain reports in healthy older adults before and after static contractions of varying intensity and duration. METHODS: Pain perception was assessed in 23 healthy older adults (11 men, 12 women; 72.0 ± 6.3 yrs) using a pressure pain device consisting of a 10 N force applied to the right index finger through a Lucite edge (8 x 1.5mm) for two minutes. Subjects pushed a timing device when they first felt pain (i.e., pain threshold) and rated their pain intensity every 20 seconds using a 0-10 numerical rating scale. Pain threshold and pain ratings were measured before and immediately after static contractions of the left elbow flexors at the following three doses: 1) three brief maximal voluntary contractions (MVC); 2) 25% MVC sustained for 2 minutes; and 3) 25% MVC sustained until task failure. Experimental sessions were randomized and separated by one week. RESULTS : Time to task failure for the 25% MVC contraction was 11.8 ± 5.1 minutes. A reduction in pain was found following all three tasks with no difference between tasks (trial x task effect: p \u3e 0.05), despite the duration of the 2 minute low-intensity contraction being ~17% of the contraction held to task failure. Pain thresholds for all doses increased 20% from 51 ± 33 to 61 ± 37 seconds and pain ratings averaged over the six time points decreased 20% from 3.3 ± 2.8 to 2.6 ± 2.5 following static contractions (trial effect: p \u3c 0.001 and p \u3c 0.001, respectively). CONCLUSION : Low and high intensity static contractions of both long and short duration produce similar levels of pain reduction in older adults. These preliminary data suggest that several different types of static contractions can induce significant pain relief in older adults. Age-related changes in the pain response to static contractions must be taken into account when prescribing static exercise for the management of pain

Only Women Report Increase in Pain Threshold Following Fatiguing Contractions of the Upper Extremity

Purpose The perception of pain in response to a noxious stimulus can be markedly reduced following an acute bout of exercise [exercise-induced hypoalgesia (EIH)]. Sex differences in EIH frequently occur after exercise but may be confounded by the sex differences in muscle fatigue. The purpose was to determine if sex differences in pain relief occur after an exercise protocol when muscle fatigue is similar for both young and older men and women. Methods Pain perception of 33 men (15 young) and 31 women (19 young) was measured using a pressure pain stimulus on the left index finger before and after maximal velocity concentric contractions of knee extensors or elbow flexors (separate days). During the 2-min pressure pain test, participants verbally indicated the onset of pain (pain threshold) and reported pain intensity (0–10) every 20 s. Results Only women experienced an increase in pain threshold (30 ± 27 to 41 ± 32 s) following elbow flexor exercise (trial × sex: p = 0.03). Neither men nor women experienced an increase in pain threshold following knee extensor exercise, and pain ratings were unchanged after exercise with either limb (p \u3e 0.05). The pain response to exercise was similar in young and older adults (trial × age: p \u3e 0.05), despite older adults demonstrating greater fatigability than young adults for the elbow flexor and knee extensor exercise tasks. Conclusions Under controlled conditions where muscle fatigue is similar, sex differences in EIH occur in young and older adults that is site specific (upper extremity). Only women experience EIH following acute single limb high-velocity contractions

Relation between Pain Catastrophizing and Reporting of Pain Threshold in Healthy Adults

Participants may not consistently report pain threshold under some testing conditions. The purpose of this study was to assess the possible relations of pain catastrophizing and fear of pain to failure to report pain threshold during assessment of conditioned pain modulation (CPM). Twenty young (21.9 ± 3.3 yrs, 10 men) and 19 older (72.0 ± 4.5 yrs, 10 men) adults participated. Pressure pain was assessed using a 1.5 kg weight mounted on a Lucite edge placed on the index finger for one minute. Participants were instructed to say “pain” when the pressure first changed to pain. Pressure pain thresholds were determined with the participant’s foot placed in neutral water (non-noxious control) and in noxious ice water. Fifteen participants [10 older (7 women); 5 young (3 women)] failed to report pain threshold with their foot immersed in the ice water compared with nine [6 older (1 woman); 3 young (1 woman)] in the neutral water. Five participants failed to report pain threshold in either condition (1 older woman, 2 older men, 2 young men). Adults who failed to report pain threshold in the ice water had higher pain catastrophizing (19.2 ± 10.5 vs 10.6 ± 7.6) and greater fear of pain (14.9 ± 5.6 vs 11.5 ± 4.5) than those who said “pain”. No group differences were found for the neutral water condition. Controlling for sex, the logistic regression model containing pain catastrophizing and fear of pain was significant only for the ice water condition [χ2 (3, N=39) = 11.815, p = 0.008] explaining 26.1-35.5% of the variance. Only pain catastrophizing made a unique contribution to the model (Odds Ratio 1.10, 95% C.I. 1.004–1.208). Our data suggest that individuals with higher pain catastrophizing are more likely to fail to report pain threshold for the test stimulus when assessing CPM

K/DOQI clinical practice guidelines for chronic kidney disease: Evaluation, classification, and stratification

Introduction: Chronic kidney disease as a public health problem. Chronic kidney disease is a worldwide public health problem. In the United States, there is a rising incidence and prevalence of kidney failure, with poor outcomes and high cost. There is an even higher prevalence of earlier stages of chronic kidney disease. Increasing evidence, accrued in the past decades, indicates that the adverse outcomes of chronic kidney disease, such as kidney failure, cardiovascular disease, and premature death, can be prevented or delayed. Earlier stages of chronic kidney disease can be detected through laboratory testing. Treatment of earlier stages of chronic kidney disease is effective in slowing the progression toward kidney failure. Initiation of treatment for cardiovascular risk factors at earlier stages of chronic kidney disease should be effective in reducing cardiovascular disease events both before and after the onset of kidney failure. Unfortunately, chronic kidney disease is "under-diagnosed" and "under-treated" in the United States, resulting in lost opportunities for prevention. One reason is the lack of agreement on a definition and classification of stages in the progression of chronic kidney disease. A clinically applicable classification would be based on laboratory evaluation of the severity of kidney disease, association of level of kidney function with complications, and stratification of risks for loss of kidney function and development of cardiovascular disease. Charge to the K/DOQI work group on chronic kidney disease. In 2000, the National Kidney Foundation (NKF) Kidney Disease Outcome Quality Initiative (K/DOQI) Advisory Board approved development of clinical practice guidelines to define chronic kidney disease and to classify stages in the progression of chronic kidney disease. The Work Group charged with developing the guidelines consisted of experts in nephrology, pediatric nephrology, epidemiology, laboratory medicine, nutrition, social work, gerontology, and family medicine. An Evidence Review Team, consisting of nephrologists and methodologists, was responsible for assembling the evidence. Defining chronic kidney disease and classifying the stages of severity would provide a common language for communication among providers, patients and their families, investigators, and policy-makers and a framework for developing a public health approach to affect care and improve outcomes of chronic kidney disease. A uniform terminology would permit: 1. More reliable estimates of the prevalence of earlier stages of disease and of the population at increased risk for development of chronic kidney disease 2. Recommendations for laboratory testing to detect earlier stages and progression to later stages 3. Associations of stages with clinical manifestations of disease 4. Evaluation of factors associated with a high risk of progression from one stage to the next or of development of other adverse outcomes 5. Evaluation of treatments to slow progression or prevent other adverse outcomes. Clinical practice guidelines, clinical performance measures, and continuous quality improvement efforts could then be directed to stages of chronic kidney disease. The Work Group did not specifically address evaluation and treatment for chronic kidney disease. However, this guideline contains brief reference to diagnosis and clinical interventions and can serve as a "road map" linking other clinical practice guidelines and pointing out where other guidelines need to be developed. Eventually, K/DOQI will include interventional guidelines. The first three of these, on bone disease, dyslipidemia, and blood pressure management are currently under development. Other guidelines on cardiovascular disease in dialysis patients and kidney biopsy will be initiated in the Winter of 2001. This report contains a summary of background information available at the time the Work Group began its deliberations, the 15 guidelines and the accompanying rationale, suggestions for clinical performance measures, a clinical approach to chronic kidney disease using these guidelines, and appendices to describe methods for the review of evidence. The guidelines are based on a systematic review of the literature and the consensus of the Work Group. The guidelines have been reviewed by the K/DOQI Advisory Board, a large number of professional organizations and societies, selected experts, and interested members of the public and have been approved by the Board of Directors of the NKF. Framework. The Work Group defined "chronic kidney disease" to include conditions that affect the kidney, with the potential to cause either progressive loss of kidney function or complications resulting from decreased kidney function. Chronic kidney disease was thus defined as the presence of kidney damage or decreased level of kidney function for three months or more, irrespective of diagnosis. The target population includes individuals with chronic kidney disease or at increased risk of developing chronic kidney disease. The majority of topics focus on adults (age ≥18 years). Many of the same principles apply to children as well. In particular, the classification of stages of disease and principles of diagnostic testing are similar. A subcommittee of the Work Group examined issues related to children and participated in development of the first six guidelines of the present document. However, there are sufficient differences between adults and children in the association of GFR with signs and symptoms of uremia and in stratification of risk for adverse outcomes that these latter issues are addressed only for adults. A separate set of guidelines for children will have to be developed by a later Work Group. The target audience includes a wide range of individuals: those who have or are at increased risk of developing chronic kidney disease (the target population) and their families; health care professionals caring for the target population; manufacturers of instruments and diagnostic laboratories performing measurements of kidney function; agencies and institutions planning, providing or paying for the health care needs of the target population; and investigators studying chronic kidney disease. There will be only brief reference to clinical interventions, sufficient to provide a basis for other clinical practice guidelines relevant to the evaluation and management of chronic kidney disease. Subsequent K/DOQI clinical practice guidelines will be based on the framework developed here. Definition of chronic kidney disease. Why "Kidney"? The word "kidney" is of Middle English origin and is immediately understood by patients, their families, providers, health care professionals, and the lay public of native English speakers. On the other hand, "renal" and "nephrology," derived from Latin and Greek roots, respectively, commonly require interpretation and explanation. The Work Group and the NKF are committed to communicating in language that can be widely understood, hence the preferential use of "kidney" throughout these guidelines. The term "End-Stage Renal Disease" (ESRD) has been retained because of its administrative usage in the United States referring to patients treated by dialysis or transplantation, irrespective of their level of kidney function. Why Develop a New Classification? Currently, there is no uniform classification of the stages of chronic kidney disease. A review of textbooks and journal articles clearly demonstrates ambiguity and overlap in the meaning of current terms. The Work Group concluded that uniform definitions of terms and stages would improve communication between patients and providers, enhance public education, and promote dissemination of research results. In addition, it was believed that uniform definitions would enhance conduct of clinical research. Why Base a New Classification System on Severity of Disease? Adverse outcomes of kidney disease are based on the level of kidney function and risk of loss of function in the future. Chronic kidney disease tends to worsen over time. Therefore, the risk of adverse outcomes increases over time with disease severity. Many disciplines in medicine, including related specialties of hypertension, cardiovascular disease, diabetes, and transplantation, have adopted classification systems based on severity to guide clinical interventions, research, and professional and public education. Such a model is essential for any public health approach to disease. Why Classify Severity as the Level of GFR? The level of glomerular filtration rate (GFR) is widely accepted as the best overall measure of kidney function in health and disease. Providers and patients are familiar with the concept that "the kidney is like a filter." GFR is the best measure of the kidneys' ability to filter blood. In addition, expressing the level of kidney function on a continuous scale allows development of patient and public education programs that encourage individuals to "Know your number!" The term "GFR" is not intuitively evident to anyone. Rather, it is a learned term, which allows the ultimate expression of the complex functions of the kidney in one single numerical expression. Conversely, numbers are an intuitive concept and easily understandable by everyone