Sense of effort associated with exercise in the chronic fatigue syndrome

Investigations into the mediators of effort sensation have indicated that central mechanisms related to corollary discharges may be responsible for an increased sense of effort during fatiguing isometric exercise. The role for central mediators for sense of effort have been objectively demonstrated through use of contralateral limb matching tasks. Subjects diagnosed with chronic fatigue syndrome (CFS) often report prevalent fatigue associated with a greater sense of effort when involved in exercise. This study employed a fatiguing contralateral limb-matching task in order to determine if CFS subjects (n == 6) experienced an altered sense of effort associated with the task when compared to control group (n = 6). The task involved subjects performing an intermittent sub-maximal contraction in their reference (non-dominant) arm for a 45 minute period. Subjects attempted to match the force in their reference arm (30% MVC) with their dominant arm every minute, except for every fifth minute, when a maximal voluntary contraction (MVC) was performed in the reference arm. Associated electromyography (EMG), force, and rate of perceived exertion (RPE) were recorded on a regular basis. Results indicated that while there were no significant difference between groups for matching force, rmsEMG amplitude, and MVC force, there was a significant difference in reported RPE scores (P \u3c 0.05) during the fatiguing task, as well as during baseline measurements. Elevated RPE scores, combined with trends indicating that a longer protocol may have produced a significant difference in matching force, provide evidence demonstrating thdt CFS subjects experienced a greater sense of effort relative to controls. This study demonstrates that the symptom of fatigue experienced in CFS may be better defined employing mediators for sense of effort than the regular application of a neurophysiological definition of fatigue concerned with the loss of force generating capacity

Sense of effort associated with exercise in the chronic fatigue syndrome

Investigations into the mediators of effort sensation have indicated that central mechanisms related to corollary discharges may be responsible for an increased sense of effort during fatiguing isometric exercise. The role for central mediators for sense of effort have been objectively demonstrated through use of contralateral limb matching tasks. Subjects diagnosed with chronic fatigue syndrome (CFS) often report prevalent fatigue associated with a greater sense of effort when involved in exercise. This study employed a fatiguing contralateral limb-matching task in order to determine if CFS subjects (n == 6) experienced an altered sense of effort associated with the task when compared to control group (n = 6). The task involved subjects performing an intermittent sub-maximal contraction in their reference (non-dominant) arm for a 45 minute period. Subjects attempted to match the force in their reference arm (30% MVC) with their dominant arm every minute, except for every fifth minute, when a maximal voluntary contraction (MVC) was performed in the reference arm. Associated electromyography (EMG), force, and rate of perceived exertion (RPE) were recorded on a regular basis. Results indicated that while there were no significant difference between groups for matching force, rmsEMG amplitude, and MVC force, there was a significant difference in reported RPE scores (P \u3c 0.05) during the fatiguing task, as well as during baseline measurements. Elevated RPE scores, combined with trends indicating that a longer protocol may have produced a significant difference in matching force, provide evidence demonstrating thdt CFS subjects experienced a greater sense of effort relative to controls. This study demonstrates that the symptom of fatigue experienced in CFS may be better defined employing mediators for sense of effort than the regular application of a neurophysiological definition of fatigue concerned with the loss of force generating capacity

Nonnegative subtheories and quasiprobability representations of qubits

Negativity in a quasiprobability representation is typically interpreted as an indication of nonclassical behavior. However, this does not preclude states that are non-negative from exhibiting phenomena typically associated with quantum mechanics - the single qubit stabilizer states have non-negative Wigner functions and yet play a fundamental role in many quantum information tasks. We seek to determine what other sets of quantum states and measurements for a qubit can be non-negative in a quasiprobability representation, and to identify nontrivial unitary groups that permute the states in such a set. These sets of states and measurements are analogous to the single qubit stabilizer states. We show that no quasiprobability representation of a qubit can be non-negative for more than four bases and that the non-negative bases in any quasiprobability representation must satisfy certain symmetry constraints. We provide an exhaustive list of the sets of single qubit bases that are non-negative in some quasiprobability representation and are also permuted by a nontrivial unitary group. This list includes two families of three bases that both include the single qubit stabilizer states as a special case and a family of four bases whose symmetry group is the Pauli group. For higher dimensions, we prove that there can be no more than 2^{d^2} states in non-negative bases of a d-dimensional Hilbert space in any quasiprobability representation. Furthermore, these bases must satisfy certain symmetry constraints, corresponding to requiring the bases to be sufficiently complementary to each other.Comment: 17 pages, 8 figures, comments very welcome; v2 published version. Note that the statement and proof of Theorem III.2 in the published version are incorrect (an erratum has been submitted), and this arXiv version (v2) presents the corrected theorem and proof. The conclusions of the paper are unaffected by this correctio

Pacing as a strategy to improve energy management in myalgic encephalomyelitis/chronic fatigue syndrome: a consensus document

Purpose: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition characterized by a number of symptoms which typically worsen following minimal exertion. Various strategies to manage the limited energy levels have been proposed. Of these, pacing has been consistently rated as one of the most helpful in surveys conducted by patient groups. This review is a response to the paucity of the information on pacing in the scientific literature. Method: We describe the principle of pacing and how this can be adapted to meet individual abilities and preferences. A critical evaluation of the research was conducted to ascertain the benefits and limitations of this strategy. Results: Based on various studies, it is proposed that pacing can help to stabilize the condition and avoid post-exertional malaise. Conclusion: Pacing offers practitioners an additional therapeutic option which is acceptable to the majority of patients and can reduce the severity of the exertion-related symptoms of ME/CFS

Acute physical-activity related increases in interoceptive ability are not enhanced with simultaneous interoceptive attention.

Interoception, the sense of the internal body, is proposed to support self-regulation, and consequently influence mental health. Researchers have therefore shown interest in improving the ability to accurately monitor internal signals (i.e., interoceptive accuracy, IAcc). Research suggests that cardiac IAcc is modifiable by both manipulations of interoceptive attention (guided attention towards the internal body), and interoceptive exposure (strategically inducing somatic signals e.g., via physical activity). Whilst successful in isolation, it is unclear whether a combined approach (i.e., directing attention towards the internal body when signals are more salient) could elicit greater benefits. In a 2 × 2 within-subject design, 48 healthy adults (Mage = 25.98 ± 4.73 years, 50% female) completed four 20-min conditions varying in both attentional focus (interoceptive vs exteroceptive) and physical activity (active vs rest), with cardiac IAcc measured immediately after. Results revealed a main effect for physical activity (p < 0.001), however, there was no effect for attentional focus (p = 0.397), and no interaction effect (p = 0.797). Differential analyses showed that a higher sporting background increased sensitivity to physical activity-related increases in cardiac IAcc (p = 0.031). Findings indicate that (irrespective of attentional focus) moderate-vigorous physical activity-based interventions have the potential to increase cardiac IAcc, with certain individuals potentially benefiting more

Generalized Bell Inequality Experiments and Computation

We consider general settings of Bell inequality experiments with many parties, where each party chooses from a finite number of measurement settings each with a finite number of outcomes. We investigate the constraints that Bell inequalities place upon the correlations possible in a local hidden variable theories using a geometrical picture of correlations. We show that local hidden variable theories can be characterized in terms of limited computational expressiveness, which allows us to characterize families of Bell inequalities. The limited computational expressiveness for many settings (each with many outcomes) generalizes previous results about the many-party situation each with a choice of two possible measurements (each with two outcomes). Using this computational picture we present generalizations of the Popescu-Rohrlich non-local box for many parties and non-binary inputs and outputs at each site. Finally, we comment on the effect of pre-processing on measurement data in our generalized setting and show that it becomes problematic outside of the binary setting, in that it allows local hidden variable theories to simulate maximally non-local correlations such as those of these generalised Popescu-Rohrlich non-local boxes.Comment: 16 pages, 2 figures, supplemental material available upon request. Typos corrected and references adde

Miscellaneous Problems

Contains reports on two research projects

Positive patient experiences in an Australian integrative oncology centre

Background: The purpose of this study was to explore the experiences of cancer patients\u27 utilising complementary and integrative therapies (CIT) within integrative oncology centres across Western Australia.Methods: Across four locations 135 patients accessed CIT services whilst undergoing outpatient medical treatment for cancer. Of the 135 patients, 66 (61 ± 12 y; female n = 45; male n = 21) agreed to complete a personal accounts questionnaire consisting of open-ended questions designed to explore patients\u27 perceptions of CIT. All results were transcribed into nVivo (v9) and using thematic analysis, key themes were identified.Results: Of the 66 participants, 100% indicated they would recommend complementary therapies to other patients and 92% stated CIT would play a significant role in their future lifestyle . A mean score of 8 ± 1 indicated an improvement in participants\u27 perception of wellbeing following a CIT session. Three central themes were identified: empowerment, support and relaxation. Fourteen sub-themes were identified, with all themes clustered into a framework of multifaceted views held by cancer patients in relation to wellbeing, role of significant others and control.Conclusions: Exploration of patients\u27 experiences reveals uniformly positive results. One of the key merits of the environment created within the centres is patients are able to work through their cancer journey with an increased sense of empowerment, without placing them in opposition to conventional medical treatment. In order to effectively target integrative support services it is crucial to explore the experiences of patients in their own words and use those forms of expression to drive service delivery

Characteristics and quality of life of patients presenting to cancer support centres: Patient rated outcomes and use of complementary therapies

Background: In order to effectively target and provide individualised patient support strategies it is crucial to have a comprehensive picture of those presenting for services. The purpose of this study was to determine the characteristics and patient rated outcomes of individuals presenting to SolarisCare cancer support centres and their choices regarding complementary and integrated therapies (CIT).Methods: A cohort with a current or previous cancer diagnosis aged 18 - 87 years presenting to a SolarisCare centre during a 5-day period completed a questionnaire. Four SolarisCare centres participated in the trial including regional and metropolitan locations. Outcomes included medical and demographic characteristics, CIT variables and patient rated outcomes (PROs) including quality of life (QoL).Results: Of the 95 participants (70.3%) who completed the survey, the mean age was 60.5 years with 62% currently receiving treatment. Eighty percent of the sample had at least one other comorbid condition, with the most popular CIT being relaxation massage. Of the PROs, QoL was significantly lower than norms for the Australian population and other mixed cancer populations. No notable differences were seen between genders, however significantly poorer outcomes were found for the younger age group. Fifty percent of the population did not meet physical activity recommendations, and musculoskeletal symptoms explained between 25-27% of variance in QoL.Conclusions: A greater understanding of the health profiles of patients presenting to supportive care centres and their use of CIT, provides Western Australian health professionals with key information to ensure the safety of supportive care practices, as well as fosters optimal patient outcomes and enhances the integration of supportive care strategies within mainstream medical care