Maternal care in wild toque macaques (Macaca sinica) involves prolonged lactation and interbirth intervals as adaptations to reduce maternal depletion and infant mortality in harsh environments.

Weaning age in primates has been challenging to measure and new methods, involving molecular biomarkers in feces, tissue, or teeth have contributed to a solution. Here, we used a direct approach by briefly anesthetizing 442 female toque macaques (Macaca sinica) of Sri Lanka (over a 17-year period) and manually testing their mammary tissue for the presence or absence of milk. Milk tests were related to known offspring ages and maternal care behaviors and indicated that older infants suckled milk well past the weaning age of 7 months that is often reported for food-provisioned primates. Mothers strongly rejected their infants' nursing attempts in two phases, the first at 7 months as an honest signal "giving notice" promoting a shift to greater independence from milk to solid food, and when "shutting down" at final weaning after 12-18 months. The shift to supplementary lactation coincided also with the cessation of mothers carrying their infants and a resumption of cycling. All infants up to 7.2 months suckled milk, 91% of them did up to 18 months, this continued for 42% of infants beyond 18 months, and normally none received milk after 22 months. Lactation extended into 2.2% of cycling and 10.7% of pregnant females (up to 50% of gestation). The interbirth interval was prolonged by factors predicted to draw on female metabolic energy reserves and included the duration of lactation, growth among primiparas, and dietary limitations. The last also increased menarche. Females offset the metabolic costs of lactation with increased foraging and catabolism, but infants died when lactation costs seemingly compromised maternal condition. The prolonged lactation and slowed reproduction are considered adaptations to promote infant survival and growth in an environment where the natural food supply limits population growth and competition for food and water impacts the mortality of the youngest the most.

Characteristics and Outcomes of a Community Upper Limb Rehabilitation Group for Adult Stroke Survivors in Australia: A Pre-Post Cohort Study.

This study investigated outcomes of a community-based upper limb rehabilitation group for adult stroke survivors in metropolitan Australia. Pre-post data were extracted from medical records. Participants (n = 27) were predominantly men (n = 22, 81%); mean age 61 years (SD 17) and median time 109 days post stroke. Participants improved on upper limb outcomes, with statistically significant changes on several of the items on the Motor Assessment Scale (item seven mean improvement 0.93 (95% CI 0.48-2.19), p = .016; item eight mean improvement 1.4 (95% CI 0.38-2.42), p = .016) and grip strength (mean improvement 4.5 kg/9 pounds, 14.73 ounces (95% CI 1.5-7.6), p = .006). These results guide occupational therapists implementing community-based upper limb rehabilitation groups.

Using the 2020 global pandemic as a springboard to highlight the need for amphibian conservation in eastern Asia.

Emerging infectious diseases are on the rise in many different taxa, including, among others, the amphibian batrachochytrids, the snake fungal disease and the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) virus, responsible for Coronavirus disease 2019 (COVID-19) in mammals. Following the onset of the pandemic linked to COVID-19, eastern Asia has shown strong leadership, taking actions to regulate the trade of potential vector species in several regions. These actions were taken in response to an increase in public awareness, and the need for a quick reaction to mitigate against further pandemics. However, trade restrictions rarely affect amphibians, despite the risk of pathogen transmission, directly, or indirectly through habitat destruction and the loss of vector consumption. Thus, species that help alleviate the risk of zoonoses or provide biological control are not protected. Hence, in view of the global amphibian decline and the risk of zoonoses, we support the current wildlife trade regulations and support measures to safeguard wildlife from overexploitation. The current period of regulation overhaul should be used as a springboard for amphibian conservation. To mitigate risks, we suggest the following stipulations specifically for amphibians. I) Restrictions to amphibian farming in eastern Asia, in relation to pathogen transmission and the establishment of invasive species. II) Regulation of the amphibian pet trade, with a focus on potential vector species. III) Expansion of the wildlife trade ban, to limit the wildlife-human-pet interface. The resulting actions will benefit both human and wildlife populations, as they will lead to a decrease in the risk of zoonoses and better protection of the environment. SIGNIFICANCE STATEMENT: There is an increasing number of emerging infectious diseases impacting all species, including amphibians, reptiles and mammals. The latest threat to humans is the virus responsible for COVID-19, and the resulting pandemic. Countries in eastern Asia have taken steps to regulate wildlife trade and prevent further zoonoses thereby decreasing the risk of pathogens arising from wild species. However, as amphibians are generally excluded from regulations we support specific trade restrictions: I) Restrictions to amphibian farming; II) regulation of the amphibian pet trade; III) expansion of the wildlife trade ban. These restrictions will benefit both human and wildlife populations by decreasing the risks of zoonoses and better protecting the environment.

Adverse childhood experiences predict autonomic indices of emotion dysregulation and negative emotional cue-elicited craving among female opioid-treated chronic pain patients.

Through autonomic and affective mechanisms, adverse childhood experiences (ACEs) may disrupt the capacity to regulate negative emotions, increasing craving and exacerbating risk for opioid use disorder (OUD) among individuals with chronic pain who are receiving long-term opioid analgesic pharmacotherapy. This study examined associations between ACEs, heart rate variability (HRV) during emotion regulation, and negative emotional cue-elicited craving among a sample of female opioid-treated chronic pain patients at risk for OUD. A sample of women (N = 36, mean age = 51.2 ± 9.5) with chronic pain receiving long-term opioid analgesic pharmacotherapy (mean morphine equivalent daily dose = 87.1 ± 106.9 mg) were recruited from primary care and pain clinics to complete a randomized task in which they viewed and reappraised negative affective stimuli while HRV and craving were assessed. Both ACEs and duration of opioid use significantly predicted blunted HRV during negative emotion regulation and increased negative emotional cue-elicited craving. Analysis of study findings from a multiple-levels-of-analysis approach suggest that exposure to childhood abuse occasions later emotion dysregulation and appetitive responding toward opioids in negative affective contexts among adult women with chronic pain, and thus this vulnerable clinical population should be assessed for OUD risk when initiating a course of extended, high-dose opioids for pain management.

Acquiring diminutive allomorphs: taking item-specific characteristics into account.

Phonological characteristics and frequencies of stems and allomorphs have been explored as possible factors causing differences in production accuracies between allomorphic forms. However, previous findings are not consistent and the relative contributions of these factors are unclear. This study investigated target and erroneous productions of the Dutch diminutive, which has five allomorphs with varying type frequencies and of which the selection depends on the phonological characteristics of the stems. Typically developing children (N = 115, 5;1-10;3) were tested on their production of real and nonce diminutives. Linear mixed effects modelling was used to analyse the data taking nonverbal IQ into account. Type frequencies of the allomorphs and differences in phonological characteristics of the stems were found to be related to differences in production accuracies between the allomorphs. However, phonological characteristics of the stems appeared to have a bigger impact, mainly due to the phonological complexity of these characteristics.

Randomized Controlled Trial of Brief Mindfulness Training and Hypnotic Suggestion for Acute Pain Relief in the Hospital Setting.

BACKGROUND: Medical management of acute pain among hospital inpatients may be enhanced by mind-body interventions. OBJECTIVE: We hypothesized that a single, scripted session of mindfulness training focused on acceptance of pain or hypnotic suggestion focused on changing pain sensations through imagery would significantly reduce acute pain intensity and unpleasantness compared to a psychoeducation pain coping control. We also hypothesized that mindfulness and suggestion would produce significant improvements in secondary outcomes including relaxation, pleasant body sensations, anxiety, and desire for opioids, compared to the control condition. METHODS: This three-arm, parallel-group randomized controlled trial conducted at a university-based hospital examined the acute effects of 15-min psychosocial interventions (mindfulness, hypnotic suggestion, psychoeducation) on adult inpatients reporting "intolerable pain" or "inadequate pain control." Participants (N = 244) were assigned to one of three intervention conditions: mindfulness (n = 86), suggestion (n = 73), or psychoeducation (n = 85). KEY RESULTS: Participants in the mind-body interventions reported significantly lower baseline-adjusted pain intensity post-intervention than those assigned to psychoeducation (p < 0.001, percentage pain reduction: mindfulness = 23%, suggestion = 29%, education = 9%), and lower baseline-adjusted pain unpleasantness (p < 0.001). Intervention conditions differed significantly with regard to relaxation (p < 0.001), pleasurable body sensations (p = 0.001), and desire for opioids (p = 0.015), but all three interventions were associated with a significant reduction in anxiety (p < 0.001). CONCLUSIONS: Brief, single-session mind-body interventions delivered by hospital social workers led to clinically significant improvements in pain and related outcomes, suggesting that such interventions may be useful adjuncts to medical pain management. TRIAL REGISTRATION: Trial Registry: ClinicalTrials.gov ; registration ID number: NCT02590029 URL: https://clinicaltrials.gov/ct2/show/NCT02590029.

A systematic review of evidence for fitness-to-drive among people with the mental health conditions of schizophrenia, stress/anxiety disorder, depression, personality disorder and obsessive compulsive disorder.

BACKGROUND: Limited evidence exists regarding fitness-to-drive for people with the mental health conditions of schizophrenia, stress/anxiety disorder, depression, personality disorder and obsessive compulsive disorder (herein simply referred to as 'mental health conditions'). The aim of this paper was to systematically search and classify all published studies regarding driving for this population, and then critically appraise papers addressing assessment of fitness-to-drive where the focus was not on the impact of medication on driving. METHODS: A systematic search of three databases (CINAHL, PSYCHINFO, EMBASE) was completed from inception to May 2016 to identify all articles on driving and mental health conditions. Papers meeting the eligibility criteria of including data relating to assessment of fitness-to-drive were critically appraised using the American Academy of Neurology and Centre for Evidence-Based Medicine protocols. RESULTS: A total of 58 articles met the inclusion criteria of driving among people with mental health conditions studied, and of these, 16 contained data and an explicit focus on assessment of fitness-to-drive. Assessment of fitness-to-drive was reported in three ways: 1) factors impacting on the ability to drive safely among people with mental health conditions, 2) capability and perception of health professionals assessing fitness-to-drive of people with mental health conditions, and 3) crash rates. The level of evidence of the published studies was low due to the absence of controls, and the inability to pool data from different diagnostic groups. Evidence supporting fitness-to-drive is conflicting. CONCLUSIONS: There is a relatively small literature in the area of driving with mental health conditions, and the overall quality of studies examining fitness-to-drive is low. Large-scale longitudinal studies with age-matched controls are urgently needed in order to determine the effects of different conditions on fitness-to-drive.

Caregiver outcomes and interventions: a systematic scoping review of the traumatic brain injury and spinal cord injury literature.

AIM: To identify factors reported with negative and positive outcomes for caregivers of the traumatic brain injury and spinal cord injury cohorts, to investigate what interventions have been studied to support carers and to report what effectiveness has been found. METHODS: Scoping systematic review. Electronic databases and websites were searched from 1990 to December 2015. Studies were agreed for inclusion using pre-defined criteria. Relevant information from included studies was extracted and quality assessment was completed. Data were synthesised using qualitative methods. RESULTS: A total of 62 studies reported caregiver outcomes for the traumatic brain injury cohort; 51 reported negative outcomes and 11 reported positive outcomes. For the spinal cord injury cohort, 18 studies reported caregiver outcomes; 15 reported negative outcomes and three reported positive outcomes. Burden of care was over-represented in the literature for both cohorts, with few studies looking at factors associated with positive outcomes. Good family functioning, coping skills and social support were reported to mediate caregiver burden and promote positive outcomes. A total of 21 studies further described interventions to support traumatic brain injury caregivers and four described interventions to support spinal cord injury caregivers, with emerging evidence for the effectiveness of problem-solving training. Further research is required to explore the effects of injury severity of the care recipient, as well as caregiver age, on the outcome of the interventions. CONCLUSION: Most studies reported negative outcomes, suggesting that barriers to caregiving have been established, but not facilitators. The interventions described to support carers are limited and require further testing to confirm their effectiveness.

Self-interest may not be entirely in the interest of the self: Association between selflessness, dispositional mindfulness and psychological well-being.

The association between mindfulness and selflessness is firmly grounded in classical Indo-Sino-Tibetan contemplative traditions, but has received limited empirical attention from Western researchers. In Buddhism, the relationship between mindfulness and the self is of central concern to the cultivation of well-being. Mindfulness is believed to encourage insight into the truly insubstantial nature of the self, an understanding that is thought to encourage well-being. The present study explores these relationships, attending to dispositional mindfulness, the self as it exists on a continuum from self-centered to selfless, and psychological well-being. Results indicate a positive relationship between selflessness, dispositional mindfulness, and psychological well-being. It appears that construing the self as interdependent and interconnected with a broader social, natural, and cosmic context is linked with greater psychological well-being and dispositional mindfulness. Path analyses revealed that selflessness mediated the relationship between dispositional mindfulness and psychological well-being.

Megninia ginglymura feather mite infestation in a Hamburg poultry flock in the United Kingdom.

BACKGROUND: A flock of rare breed poultry was heavily infested with small white mites. Although apparently not harming the birds, the mites were identified in order to access data on veterinary/medical significance and to decide upon appropriate treatment. OBJECTIVES: To determine the identity of the mites, assess their potential impact on the host birds and to apply a chemical treatment regime. ANIMALS: Twelve, 5-month-old Hamburg large fowl kept on a UK farm owned by the second author. They were housed together on shavings in an indoor pen with a grass outdoor run. All were hatched on the farm and never left it. METHODS: Mites were identified using taxonomic identification keys and morphological descriptions. Nine birds were treated topically with 0.25% fipronil at 8 mL/kg on one occasion, while three birds were separated and left untreated as a control. RESULTS: The infesting species was the feather mite Megninia ginglymura. Treated birds were mite-free after three weeks, whereas untreated ones were still heavily infested. CONCLUSIONS AND CLINICAL IMPORTANCE: This is the first published report of such a heavy infestation of M. ginglymura in poultry in the UK and the first time topical fipronil has been used to eradicate these mites. The case is highlighted because, although asymptomatic in this instance, such infestations may be injurious to birds in different rearing regimes.

Rapid learning of minimally different words in five- to six-year-old children: effects of acoustic salience and hearing impairment.

This study investigates the role of acoustic salience and hearing impairment in learning phonologically minimal pairs. Picture-matching and object-matching tasks were used to investigate the learning of consonant and vowel minimal pairs in five- to six-year-old deaf children with a cochlear implant (CI), and children of the same age with normal hearing (NH). In both tasks, the CI children showed clear difficulties with learning minimal pairs. The NH children also showed some difficulties, however, particularly in the picture-matching task. Vowel minimal pairs were learned more successfully than consonant minimal pairs, particularly in the object-matching task. These results suggest that the ability to encode phonetic detail in novel words is not fully developed at age six and is affected by task demands and acoustic salience. CI children experience persistent difficulties with accurately mapping sound contrasts to novel meanings, but seem to benefit from the relative acoustic salience of vowel sounds.

What information is provided in Australian emergency departments about fitness-to-drive after mild traumatic brain injury: a national survey.

BACKGROUND/AIM: Occupational therapists work together with their medical and nursing colleagues to ensure that patients are able to return to safe and legal driving upon discharge from the emergency department after a range of illnesses and/or injuries. This study aimed to determine the type of information that is provided nationally in emergency departments to people after mild traumatic brain injury (mTBI), with respect to fitness-to-drive. METHODS: Cross-sectional electronic survey mailed to all emergency departments in Australia (N = 110). Responses were invited from medical, nursing, and allied-health professionals. The survey asked respondents to comment about the existence and use of fitness-to-drive management guidelines, as well as their opinion on when clearance should be given to return to driving post injury. RESULTS: 104 clinicians completed the survey; the majority of respondents were medical staff (n = 46, 51%) followed by allied-health staff (n = 23, 25%), with the highest response rate provided from Victoria (n = 41, 45%). Just over one-third of respondents' emergency departments (n = 34, 36%) recommended a period of 'no driving' after mTBI, and within these departments, this recommendation was usually provided by medical staff (n = 25, 80%). Consensus was not displayed with respect to the safest time to return to driving after mTBI. Opinions from respondents strongly suggested that a review of fitness-to-drive management guidelines was required for mTBI patients (n = 78, 88%). CONCLUSION: No consensus exists in the fitness-to-drive recommendations provided to patients after mTBI, and clinicians have reported the need for a review of fitness-to-drive management guidelines in Australian emergency departments. With their understanding about the complex interplay of the skills required for safe driving, occupational therapists are positioned to help guide the development of protocols in this area.

Relationships between spoken word and sign processing in children with cochlear implants.

The effect of using signed communication on the spoken language development of deaf children with a cochlear implant (CI) is much debated. We report on two studies that investigated relationships between spoken word and sign processing in children with a CI who are exposed to signs in addition to spoken language. Study 1 assessed rapid word and sign learning in 13 children with a CI and found that performance in both language modalities correlated positively. Study 2 tested the effects of using sign-supported speech on spoken word processing in eight children with a CI, showing that simultaneously perceiving signs and spoken words does not negatively impact their spoken word recognition or learning. Together, these two studies suggest that sign exposure does not necessarily have a negative effect on speech processing in some children with a CI.

Enhanced motor network engagement during reward gain anticipation in fibromyalgia.

Reward motivation is essential in shaping human behavior and cognition. Both reward motivation and reward brain circuits are altered in chronic pain conditions, including fibromyalgia. In this study of fibromyalgia patients, we used a data-driven independent component analysis (ICA) approach to investigate how brain networks contribute to altered reward processing. From females with fibromyalgia (N = 24) and female healthy controls (N = 24), we acquired fMRI data while participants performed a monetary incentive delay (MID) reward task. After analyzing the task-based fMRI data using ICA to identify networks, we analyzed 3 networks of interest: motor network (left), value-driven attention network, and basal ganglia network. Then, we evaluated correlation coefficients between each network timecourse versus a task-based timecourse which modeled gain anticipation. Compared to controls, the fibromyalgia cohort demonstrated significantly stronger correlation between the left motor network timecourse and the gain anticipation timecourse, indicating the left motor network was more engaged with gain anticipation in fibromyalgia. In an exploratory analysis, we compared motor network engagement during early versus late phases of gain anticipation. Across cohorts, greater motor network engagement (i.e., stronger correlation between network and gain anticipation) occurred during the late timepoint, which reflected enhanced motor preparation immediately prior to response. Consistent with the main results, patients exhibited greater engagement of the motor network during both early and late phases compared with healthy controls. Visual-attention and basal ganglia networks revealed similar engagement in the task across groups. As indicated by post-hoc analyses, motor network engagement was positively related to anxiety and negatively related to reward responsiveness. In summary, we identified enhanced reward-task related engagement of the motor network in fibromyalgia using a novel data-driven ICA approach. Enhanced motor network engagement in fibromyalgia may relate to impaired reward motivation, heightened anxiety, and possibly to altered motor processing, such as restricted movement or dysregulated motor planning.

Recovery of neurophysiological measures in post-COVID fatigue: a 12-month longitudinal follow-up study.

One of the major consequences of the COVID-19 pandemic has been the significant incidence of persistent fatigue following resolution of an acute infection (i.e. post-COVID fatigue). We have shown previously that, in comparison to healthy controls, those suffering from post-COVID fatigue exhibit changes in muscle physiology, cortical circuitry, and autonomic function. Whether these changes preceded infection, potentially predisposing people to developing post-COVID fatigue, or whether the changes were a consequence of infection was unclear. Here we present results of a 12-month longitudinal study of 18 participants from the same cohort of post-COVID fatigue sufferers to investigate these correlates of fatigue over time. We report improvements in self-perception of the impact of fatigue via questionnaires, as well as significant improvements in objective measures of peripheral muscle fatigue and autonomic function, bringing them closer to healthy controls. Additionally, we found reductions in muscle twitch tension rise times, becoming faster than controls, suggesting that the improvement in muscle fatigability might be due to a process of adaptation rather than simply a return to baseline function.

Verb inflection in monolingual Dutch and sequential bilingual Turkish-Dutch children with and without SLI.

Both children with specific language impairment (SLI) and children who acquire a second language (L2) make errors with verb inflection. This overlap between SLI and L2 raises the question if verb inflection can discriminate between L2 children with and without SLI. In this study we addressed this question for Dutch. The secondary goal of the study was to investigate variation in error types and error profiles across groups. Data were collected from 6-8-year-old children with SLI who acquire Dutch as their first language (L1), Dutch L1 children with a typical development (TD), Dutch L2 children with SLI, and Dutch L1 TD children who were on average 2 years younger. An experimental elicitation task was employed that tested use of verb inflection; context (3SG, 3PL) was manipulated and word order and verb type were controlled. Accuracy analyses revealed effects of impairment in both L1 and L2 children with SLI. However, individual variation indicated that there is no specific error profile for SLI. Verb inflection use as measured in our study discriminated fairly well in the L1 group but classification was less accurate in the L2 group. Between-group differences emerged furthermore for certain types of errors, but all groups also showed considerable variation in errors and there was not a specific error profile that distinguished SLI from TD.

Reduced Spinal Cord Gray Matter in Patients with Fibromyalgia Using Opioids Long-term.

Objective: Chronic pain involves alterations in brain gray matter volume (GMV). Moreover, opioid medications are known to reduce GMV in numerous brain regions involved in pain processing. However, no research has evaluated (1) chronic pain-related GMV alterations in the spinal cord or (2) the effect of opioids on spinal cord GMV. Accordingly, this study evaluated spinal cord GMV in health controls and patients with fibromyalgia who were using and not using opioids long-term. Methods: We analyzed average C5 - C7 GMV of the spinal cord dorsal and ventral horns in separate female cohorts of healthy controls (HC, n = 30), fibromyalgia patients not using opioids (FMN, n = 31), and fibromyalgia patients using opioids long-term (FMO, n = 27). To assess the effect of group on average dorsal and ventral horn GMV, we conducted a one-way multivariate analysis of covariance. Results: After controlling for age, we observed a significant effect of group on ventral horn GMV (p = 0.03, η2 = 0.09), and on dorsal horn GMV (p = 0.05, η2 = 0.08). Tukey's posthoc comparisons showed that, compared to HC participants, FMOs had significantly lower ventral (p = 0.01) and dorsal (p = 0.02) GMVs. Among FMOs only, ventral horn GMV was significantly positively associated with pain severity and interference, and both dorsal and ventral GMVs were significantly positively associated with cold pain tolerance. Conclusion: Long-term opioid use may impact sensory processing in fibromyalgia via gray matter changes within the cervical spinal cord.

Altered Functional Networks during Gain Anticipation in Fibromyalgia.

Reward motivation is essential in shaping human behavior and cognition. Previous studies have shown altered reward motivation and reward brain circuitry in chronic pain conditions, including fibromyalgia. Fibromyalgia is a chronic disorder characterized by widespread musculoskeletal pain, fatigue, cognitive problems, and mood-related symptoms. In this study, we analyzed brain reward networks in patients with fibromyalgia by using a data-driven approach with task-based fMRI data. fMRI data from 24 patients with fibromyalgia and 24 healthy controls were acquired while subjects performed a monetary incentive delay (MID) reward task. Functional networks were derived using independent component analysis (ICA) focused on the gain anticipation phase of the reward task. Functional activity in the motor, value-driven attention, and basal ganglia networks was evaluated during gain anticipation in both patient and healthy control groups. Compared to controls, the motor network was more engaged during gain anticipation in patients with fibromyalgia. Our findings suggest that reward motivation may lead to hyperactivity in the motor network, possibly related to altered motor processing, such as restricted movement or dysregulated motor planning in fibromyalgia. As an exploratory analysis, we compared levels of motor network engagement during early and late timepoints of the gain anticipation phase. Both groups showed greater motor network engagement during the late timepoint (i.e., closer to response), which reflected motor preparation prior to target response. Importantly, compared to controls and consistent with the initial findings described above, patients exhibited greater engagement of the motor network during both early and late timepoints. In summary, by using a novel data-driven ICA approach to analyze task-based fMRI data, we identified elevated motor network engagement during gain anticipation in fibromyalgia.

Interplay between noxious heat sensitivity and temporal summation magnitude in patients with fibromyalgia and long-term opioid use.

Introduction: In chronic pain conditions such as fibromyalgia (FM), pain amplification within the central nervous system, or "central sensitization," may contribute to the development and maintenance of chronic pain. Chronic pain treatments include opioid therapy, and opioid therapy may maladaptively increase central sensitization, particularly in patients who take opioids long-term. However, it has remained unknown how central sensitization is impacted in patients who use opioids long-term. Methods: To investigate how long-term opioid therapy affects central sensitization, we used the validated measure of temporal summation. The temporal summation measurement consists of applying a series of noxious stimuli to a patient's skin and then calculating changes in the patient's pain rating to each stimulus. Using this measurement, we evaluated temporal summation in study participants with fibromyalgia who take opioids long-term (i.e., greater than 90 days duration; n = 24, opioid-FM). We compared opioid-FM responses to 2 control groups: participants with fibromyalgia who do not take opioids (n = 33, non-opioid FM), and healthy controls (n = 31). For the temporal summation measurement, we applied a series of 10 noxious heat stimuli (sensitivity-adjusted temperatures) to the ventral forearm (2s duration of each stimulus, applied once every 3 s). Additionally, we collected responses to standard pain and cognitive-affective questionnaires to assess pain severity and other factors. Results and discussion: Group differences in sensitivity-adjusted stimulus temperatures were observed, with only the non-opioid FM group requiring significantly lower stimulus temperatures (The opioid-FM group also required lower temperatures, but not significantly different from the control group). However, all 3 groups exhibited similar magnitudes of temporal summation. Across combined FM groups, temporal summation negatively correlated with pain severity (r = -0.31, p = 0.021). Within the opioid-FM group, higher pain sensitivity to heat (i.e., lower sensitivity-adjusted temperatures) showed a trend relationship with higher opioid dosage (r = -0.45, p = 0.036), potentially reflective of opioid-related hyperalgesia. Our findings also indicated that heightened pain severity may skew sensitivity-adjusted temporal summation, thereby limiting its utility for measuring central sensitization. Overall, in participants taking opioids, temporal summation may be influenced by hypersensitivity to heat pain, which appeared to vary with opioid dosage.

Neural dysregulation in post-COVID fatigue.

Following infection with SARS-CoV-2, a substantial minority of people develop lingering after-effects known as 'long COVID'. Fatigue is a common complaint with a substantial impact on daily life, but the neural mechanisms behind post-COVID fatigue remain unclear. We recruited 37 volunteers with self-reported fatigue after a mild COVID infection and carried out a battery of behavioural and neurophysiological tests assessing the central, peripheral and autonomic nervous systems. In comparison with age- and sex-matched volunteers without fatigue (n = 52), we show underactivity in specific cortical circuits, dysregulation of autonomic function and myopathic change in skeletal muscle. Cluster analysis revealed no subgroupings, suggesting post-COVID fatigue is a single entity with individual variation, rather than a small number of distinct syndromes. Based on our analysis, we were also able to exclude dysregulation in sensory feedback circuits and descending neuromodulatory control. These abnormalities on objective tests may aid in the development of novel approaches for disease monitoring.