Cortico-cortical connectivity is influenced by levodopa in tremor-dominant Parkinson's disease

Resting tremor is the most common presenting motor symptom in Parkinson's disease (PD). The supplementary motor area (SMA) is a main target of the basal-ganglia-thalamo-cortical circuit and has direct, facilitatory connections with the primary motor cortex (M1), which is important for the execution of voluntary movement. Dopamine potentially modulates SMA and M1 activity, and both regions have been implicated in resting tremor. This study investigated SMA-M1 connectivity in individuals with PD ON and OFF dopamine medication, and whether SMA-M1 connectivity is implicated in resting tremor. Dual-site transcranial magnetic stimulation was used to measure SMA-M1 connectivity in PD participants ON and OFF levodopa. Resting tremor was measured using electromyography and accelerometry. Stimulating SMA inhibited M1 excitability OFF levodopa, and facilitated M1 excitability ON levodopa. ON medication, SMA-M1 facilitation was significantly associated with smaller tremor than SMA-M1 inhibition. The current findings contribute to our understanding of the neural networks involved in PD which are altered by levodopa medication and provide a neurophysiological basis for the development of interventions to treat resting tremor.

Cognitive and neuroscientific perspectives of healthy ageing

With dementia incidence projected to escalate significantly within the next 25 years, the United Nations declared 2021-2030 the Decade of Healthy Ageing, emphasising cognition as a crucial element. As a leading discipline in cognition and ageing research, psychology is well-equipped to offer insights for translational research, clinical practice, and policy-making. In this comprehensive review, we discuss the current state of knowledge on age-related changes in cognition and psychological health. We discuss cognitive changes during ageing, including (a) heterogeneity in the rate, trajectory, and characteristics of decline experienced by older adults, (b) the role of cognitive reserve in age-related cognitive decline, and (c) the potential for cognitive training to slow this decline. We also examine ageing and cognition through multiple theoretical perspectives. We highlight critical unresolved issues, such as the disparate implications of subjective versus objective measures of cognitive decline and the insufficient evaluation of cognitive training programs. We suggest future research directions, and emphasise interdisciplinary collaboration to create a more comprehensive understanding of the factors that modulate cognitive ageing.

Anticipating noxious stimulation rather than afferent nociceptive input may evoke pupil asymmetry

Unilateral nociceptive stimulation is associated with subtle signs of pupil asymmetry that may reflect lateralized activity in the locus coeruleus. To explore drivers of this pupil asymmetry, electrical stimuli, delivered alone or 200 ms before or after an acoustic startle stimulus, were administered to one ankle under four experimental conditions: with or without a 1.6 s anticipatory period, or while the forearm ipsilateral or contralateral to the electrical stimulus was heated tonically to induce moderate pain (15 healthy participants in each condition). Pupil diameter was measured at the start of each trial, at stimulus delivery, and each second for 5 s after stimulus delivery. At the start of the first trial, the pupil ipsilateral to the side on which electric shocks were later delivered was larger than the contralateral pupil. Both pupils dilated robustly during the anticipatory period and dilated further during single- and dual-stimulus trials. However, pupil asymmetry persisted throughout the experiment. Tonically-applied forearm heat-pain modulated the pupillary response to phasic electrical stimuli, with a slight trend for dilatation to be greater contralateral to the forearm being heated. Together, these findings suggest that focusing anxiously on the expected site of noxious stimulation was associated with dilatation of the ipsilateral pupil whereas phasic nociceptive stimuli and psychological arousal triggered bilateral pupillary dilatation. It was concluded that preparatory cognitive activity rather than phasic afferent nociceptive input is associated with pupillary signs of lateralized activity in the locus coeruleus.

Inflammation induces α1-adrenoceptor expression in peripheral blood mononuclear cells of patients with complex regional pain syndrome

Persistent regional and systemic inflammation may promote pain and hyperalgesia in complex regional pain syndrome (CRPS). In this study, we investigated whether stimulation of α1-adrenoceptors (α1-AR) on peripheral blood mononuclear cells (PBMC) might contribute to this inflammatory state. PBMC were isolated from venous blood collected from 21 CRPS patients and 21 sex and age-matched controls. Lipopolysaccharide (LPS), a bacterial toxin, was administered to cultured PBMC for 24 h to trigger inflammation. Exposure to LPS resulted in heightened gene expression of α1-AR subtype B (α1B-AR) in PBMC of CRPS patients relative to controls. Interleukin (IL)-1β and IL-6 levels did not change when the α1-AR agonist phenylephrine was administered to naïve PBMC. However, α1-AR stimulation following LPS treatment increased IL-6 mRNA and protein levels in PBMC of patients and controls. To investigate the possible consequence of heightened IL-6 levels on immunoglobulin G antibody production, PBMC were stimulated with CD40 ligand and IL-21 to generate plasmablasts (B cells that secrete antibodies). This response was similar in patients and controls. Adding IL-6 to the cell culture medium increased plasmablast differentiation in controls and antibody production both in patients and controls. These findings suggest that the inflammatory cascade associated with elevated levels of IL-6 may generate α1B-AR expression in CRPS PBMC. A reciprocal interaction between heightened α1-AR expression in PBMC and IL-6 secretion may contribute to systemic inflammation and antibody production in CRPS.

A Macroscopic Quantum Three-Box Paradox: Finding Consistency with Weak Macroscopic Realism

The quantum three-box paradox considers a ball prepared in a superposition of being in any one of three boxes. Bob makes measurements by opening either box 1 or box 2. After performing some unitary operations (shuffling), Alice can infer with certainty that the ball was detected by Bob, regardless of which box he opened, if she detects the ball after opening box 3. The paradox is that the ball would have been found with certainty by Bob in either box if that box had been opened. Resolutions of the paradox include that Bob's measurement cannot be made non-invasively or else that realism cannot be assumed at the quantum level. Here, we strengthen the case for the former argument by constructing macroscopic versions of the paradox. Macroscopic realism implies that the ball is in one of the boxes prior to Bob or Alice opening any boxes. We demonstrate the consistency of the paradox with macroscopic realism, if carefully defined (as weak macroscopic realism, wMR) to apply to the system at the times prior to Alice or Bob opening any boxes but after the unitary operations associated with preparation or shuffling. By solving for the dynamics of the unitary operations and comparing with mixed states, we demonstrate agreement between the predictions of wMR and quantum mechanics: the paradox only manifests if Alice's shuffling combines both local operations (on box 3) and nonlocal operations, on the other boxes. Following previous work, the macroscopic paradox is shown to correspond to a violation of a Leggett-Garg inequality, which implies failure of non-invasive measurability if wMR holds.

Midpoint projection algorithm for stochastic differential equations on manifolds

Stochastic differential equations projected onto manifolds occur in physics, chemistry, biology, engineering, nanotechnology, and optimization, with interdisciplinary applications. Intrinsic coordinate stochastic equations on the manifold are sometimes computationally impractical, and numerical projections are therefore useful in many cases. In this paper a combined midpoint projection algorithm is proposed that uses a midpoint projection onto a tangent space, combined with a subsequent normal projection to satisfy the constraints. We also show that the Stratonovich form of stochastic calculus is generally obtained with finite bandwidth noise in the presence of a strong enough external potential that constrains the resulting physical motion to a manifold. Numerical examples are given for a wide range of manifolds, including circular, spheroidal, hyperboloidal, and catenoidal cases, higher-order polynomial constraints that give a quasicubical surface, and a ten-dimensional hypersphere. In all cases the combined midpoint method has greatly reduced errors compared to other methods used for comparison, namely, a combined Euler projection approach and a tangential projection algorithm. We derive intrinsic stochastic equations for spheroidal and hyperboloidal surfaces for comparison purposes to verify the results. Our technique can handle multiple constraints, which allows manifolds that embody several conserved quantities. The algorithm is accurate, simple, and efficient. A reduction of an order of magnitude in the diffusion distance error is found compared to the other methods and an up to several orders of magnitude reduction in constraint function errors.

Stimulation of alpha-1 adrenoceptors may intensify cutaneous inflammation in complex regional pain syndrome

ABSTRACT

Alpha-1 adrenoceptors are overexpressed in the epidermis of a subgroup of patients with complex regional pain syndrome (CRPS). Activating α 1 -adrenoceptors in epidermal cells increases production of the proinflammatory cytokine interleukin-6 (IL-6), a mediator of inflammation. To investigate whether this might exacerbate inflammation in CRPS, primary keratinocytes or dermal fibroblasts were cultured from skin biopsies obtained from the affected limb of 25 patients and a similar site in 28 controls. The fundamental proinflammatory cytokine, tumor necrosis factor alpha, was administered for 24 hours to initiate inflammation. After this, cells were incubated for 6 hours with the α 1 -adrenoceptor agonist phenylephrine. Exposure to tumor necrosis factor alpha induced proinflammatory cytokine mRNA production and protein secretion in keratinocytes and fibroblasts and enhanced α 1B -adrenoceptor mRNA expression in keratinocytes. Additional stimulation of α 1 adrenoceptors with phenylephrine increased the production of IL-6 mRNA and protein secretion in both cell types. Under all conditions, gene and protein α 1 -adrenoceptor levels and cytokine gene expression and protein secretion were similar, overall, in patients and controls, except for abnormally high α 1 -adrenoceptor protein levels in the keratinocytes of 3 of 17 patients. These findings suggest that persistent inflammation in CRPS is not due to dysfunction of skin cells but is a normal response to extrinsic signals. After α 1 -adrenoceptor stimulation of keratinocytes, increases in IL-6 mRNA but not protein were proportional to basal α 1 -adrenoceptor protein levels. Skin cells play an important role in persistent inflammation in CRPS. Potentially, a positive feedback loop between α 1 -adrenoceptors and IL-6 production in skin cells contributes to this inflammatory state.

Auditory disturbances in patients with complex regional pain syndrome

ABSTRACT

Complex regional pain syndrome (CRPS) is often associated with reduced sound tolerance (hyperacusis) on the affected side, but the mechanism of this symptom is unclear. As compensatory increases in central auditory activity after cochlear injury may trigger hyperacusis, hearing and discomfort thresholds to pure tones (250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz) were assessed in 34 patients with CRPS and 26 pain-free controls. In addition, in 31 patients and 17 controls, auditory-evoked potentials to click stimuli (0.08 ms duration, 6 Hz, 60 dB above the hearing threshold) were averaged across 2000 trials for each ear. Auditory discomfort thresholds were lower at several pitches on the CRPS-affected than contralateral side and lower at all pitches on the affected side than in controls. However, ipsilateral hyperacusis was not associated with psychophysical or physiological signs of cochlear damage. Instead, neural activity in the ipsilateral brainstem and midbrain was greater when repetitive click stimuli were presented on the affected than contralateral side and greater bilaterally than in controls. In addition, click-evoked potentials, reflecting thalamo-cortical signal transfer and early cortical processing, were greater contralaterally in patients than controls. Together, these findings suggest that hyperacusis originates in the ipsilateral brainstem and midbrain rather than the peripheral auditory apparatus of patients with CRPS. Failure of processes that jointly modulate afferent auditory signalling and pain (eg, inhibitory influences stemming from the locus coeruleus) could contribute to ipsilateral hyperacusis in CRPS.

Effects of a polyphenol-rich grape and blueberry extract (Memophenol™) on cognitive function in older adults with mild cognitive impairment: A randomized, double-blind, placebo-controlled study

Background

Polyphenols are naturally occurring organic compounds found in plants. Research suggests that their intake reduces the risk of cognitive decline and related dementias. Grapes and blueberries are polyphenol-rich foods that have attracted attention for their potential cognitive-enhancing effects.

Purpose

Examine the effects of supplementation with a standardized and patented polyphenol-rich grape and blueberry extract (Memophenol™) on cognitive function in older adults with mild cognitive impairment.

Study design

Two-arm, 6 month, parallel-group, randomized, double-blind, placebo-controlled trial.

Methods

One hundred and forty-three volunteers aged 60 to 80 years with mild cognitive impairment were supplemented with either 150 mg of Memophenol™, twice daily or a placebo. Outcome measures included computer-based cognitive tasks, the Behavior Rating Inventory of Executive Function (BRIEF-A), the Cognitive Failures Questionnaire, and the CASP-19.

Results

Compared to the placebo, Memophenol™ supplementation was associated with greater improvements in the speed of information processing (p = 0.020), visuospatial learning (p = 0.012), and the BRIEF-A global score (p = 0.046). However, there were no other statistically significant between-group differences in the performance of other assessed cognitive tests or self-report questionnaires. Memophenol™ supplementation was well-tolerated with no reports of significant adverse reactions.

Conclusion

The promising results from this trial suggest that 6-months of supplementation with Memophenol™ may improve aspects of cognitive function in adults with mild cognitive impairment. Further research will be important to expand on the current findings and identify the potential mechanisms of action associated with the intake of this polyphenol-rich extract.

Temple cooling increases parasympathetic activity and decreases pressure pain on the hand

BACKGROUND

Applying an ice cube to the temple (the conditioning stimulus) inhibits electrically evoked pain in the forearm. The present study aimed to determine whether temple cooling also inhibits pressure- and heat-pain test stimuli in the upper limb and, if so, to investigate the intra-session test-retest reliability of this response. Additional aims were to establish whether pain inhibition evoked by temple cooling was associated with parasympathetic activity; and to explore sex differences in response.

METHODS

The sample consisted of 40 healthy adults (24 females). Heart rate was recorded continuously throughout the session. An ice cube (3 × 4 cm contact area) was applied for 1 min to the temple on the dominant side. Before and immediately afterwards, the pressure pain threshold was measured from the dorsal hand and sensitivity to heat (individually adjusted at baseline to elicit moderate pain) was measured from the ventral forearm. The procedures were repeated 15 min later.

RESULTS

Temple cooling inhibited pressure pain on the hand but not heat pain on the forearm. However, test-retest reliability of pressure pain inhibition was poor. Heart rate decreased during temple cooling, consistent with a "diving" reflex. Males had stronger pressure pain inhibition, lower heart rate and higher overall autonomic activity than females. However, cardiac parasympathetic activation during temple cooling was comparable in both sexes and was unrelated to pain inhibition.

CONCLUSIONS

These findings indicate that temple cooling evokes pain inhibition that is stronger in males than in females. Cardiac parasympathetic activity does not appear to mediate this response.

SIGNIFICANCE

The conditioning stimulus in the conditioned pain modulation paradigm is often applied to the upper or lower limbs. This may confound pain-inhibitory effects in people with peripheral neuropathy who typically have enhanced or diminished sensation in the extremities. Applying an ice cube at the temple area induces pain-inhibitory effects on the upper limb after the ice is removed. Future research examining pain modulation in people with peripheral neuropathy may consider adopting temple cooling as the conditioning stimulus.

High Blood Glucose and Excess Body fat Enhance Pain Sensitivity and Weaken Pain Inhibition in Healthy Adults: A Single-blind Cross-over Randomized Controlled Trial

To investigate links between blood glucose, body fat mass and pain, the effects of acute hyperglycaemia on pain sensitivity and pain inhibition were examined in healthy adults with normal (n = 24) or excess body fat (n = 20) determined by dual-energy X-ray absorptiometry. Effects of hyperglycaemia on heart rate variability and reactive hyperaemia were also explored. For the overall sample, ingesting 75-g glucose enhanced pain sensitivity during 1-minute cold-water immersion of both feet (conditioning stimulus) and weakened the pain inhibitory effect of cold water on pressure pain thresholds (test stimulus). Exploratory subgroup analyses not adjusted for multiple comparisons suggested that this effect was limited to people with excess fat mass. In addition, acute hyperglycaemia suppressed resting heart rate variability only in people with excess fat mass. Furthermore, regardless of blood glucose levels, people with excess fat mass had weaker pain inhibition for pinprick after cold water and reported more pain during 5-minutes of static blood flow occlusion. Neither high blood glucose nor excess body fat affected pinprick-temporal summation of pain or reactive hyperaemia. Together, these findings suggest that hyperglycaemia and excess fat mass interfere with pain processing and autonomic function. PERSPECTIVE: Ingesting 75-g glucose (equivalent to approximately 2 standard cans of soft drink) interfered with pain-processing and autonomic function, particularly in people with excess body fat mass. As both hyperglycaemia and overweight are risk factors for diabetes, whether these are sources of pain in people with diabetes should be further explored.

Olfaction in complex regional pain syndrome

Objective

Complex regional pain syndrome (CRPS) is associated with a range of sensory disturbances on the symptomatic side of the body but whether this includes olfaction is uncertain. To clarify this, the aims of this study were to compare ratings of intensity and hedonic appeal of household odorants in CRPS patients and controls, and to determine whether ratings differed between the symptomatic and contralateral sides within the sample of patients.

Methods

Six odorants (vanilla, fish sauce, vinegar, eucalyptus, almond essence and acetone) were presented sequentially in random order on cottonwool buds held in the midline approximately 1 cm from both nostrils in 37 CRPS patients and 21 pain-free controls. Each odour was rated for intensity and hedonic appeal, and participants reported whether the odour was stronger and/or smelt different on one side than the other.

Results

The odorants smelt worse for patients than controls (p < 0.05 for the symptomatic and contralateral sides) but neither the intensity nor the unpleasantness of the odorants was greater on the symptomatic than contralateral side in the group as-a-whole.

Conclusion

These findings suggest that the trigeminal component of olfaction interacts bilaterally with pain-sensitized circuits in the thalamus or higher cortical centres to distort odour perception in patients with CRPS. This aberrant process appears to differ from the mechanism that underlies hemilateral hyperalgesia in other sensory modalities.

Defining pain-validation: The importance of validation in reducing the stresses of chronic pain

Purpose

To validate an individual's feelings or behaviour is to sanction their thoughts or actions as worthy of social acceptance and support. In contrast, rejection of the individual's communicated experience indicates a denial of social acceptance, representing a potential survival threat. Pain-invalidation, though ill-defined, appears to be a fundamental component of psychosocial stress for people with chronic pain. As such, the aim of this paper was to define pain-validation and outline its importance for those with chronic pain.

Methods

The pain-validation construct was defined using themes inherent in the narratives of those with chronic pain, as identified in a previously published systematic search and thematic analysis, together with examination of additional literature on pain-validation in the clinical context.

Results

We present a construct definition, proposing that pain-validation must necessarily include: (i) belief that the pain experience is true for the individual, (ii) acceptability of the individual's expressions of pain, and (iii) communication of belief and acceptability to the individual experiencing pain. Further, we outline the importance of pain-validation as a protective factor and means of reducing many of the psychosocial stresses of chronic pain; for example, by indicating social support for pain-coping, buffering negative emotions, and re-enforcing unity and shared identity.

Implications

The role of pain-validation in the current era of pain management intervention is discussed. Adhering to interventions that involve cognitive and behavioural change is often difficult. Acknowledging and validating the acceptability of the patient's pain experience in the early stages of pain management may, therefore, be a key component of intervention that encourages compliance to the treatment plan and achieving therapeutic goals.

A randomized, double-blind, placebo-controlled trial investigating the effects of an Ocimum tenuiflorum (Holy Basil) extract (HolixerTM) on stress, mood, and sleep in adults experiencing stress

Background

In Ayurveda, Ocimum tenuiflorum (Holy Basil) is referred to as “the elixir of life” and is believed to promote longevity and general wellbeing. Although limited, there are clinical trials to suggest Ocimum tenuiflorum has anti-stress effects.

Purpose

Examine the effects of a standardized Ocimum tenuiflorum extract (Holixer^TM) on subjective and objective measures of stress and sleep quality in adults experiencing stress.

Study design

Two-arm, parallel-group, 8-week, randomized, double-blind, placebo-controlled trial. Australian and New Zealand Clinical Trials Registry trial registration number ACTRN12621000609853.

Methods

One hundred volunteers aged 18–65 years received either 125 mg of Ocimum tenuiflorum twice daily or a placebo. Outcome measures included the Perceived Stress Scale (PSS) (primary outcome measure), Profile of Mood States, Athens Insomnia Scale (AIS), Restorative Sleep Questionnaire, and the Patient-Reported Outcomes Measurement Information System-29. Sleep quality was also assessed using a wrist-worn sleep tracker (Fitbit), and stress changes were examined by measuring between-group differences in hair cortisol and stress responses after exposure to an experiment stress procedure known as the Maastricht Acute Stress Test (MAST).

Results

Compared to the placebo, Ocimum tenuiflorum supplementation was associated with greater improvements in PSS (p = 0.003) and AIS (p = 0.025) scores; and at week 8, concentrations in hair cortisol were also lower (p = 0.025). Moreover, Ocimum tenuiflorum supplementation was associated with a buffered stress responses after exposure to the MAST as demonstrated by significantly lower concentrations in salivary cortisol (p = 0.001), salivary amylase (p = 0.001), systolic (p = 0.010) and diastolic (p = 0.025) blood pressure, and subjective stress ratings (p < 0.001). Ocimum tenuiflorum supplementation was well-tolerated with no reports of major adverse effects.

Conclusion

The results from this trial suggest that 8 weeks of supplementation with an Ocimum tenuiflorum extract (Holixer^TM) may reduce objective and subjective measures of stress, and improve subjective measures of sleep quality. However, further research using gold-standard objective sleep measures will be required to substantiate the sleep-related findings.

Clinical trial registration

https://www.anzctr.org.au/ACTRN12621000609853p.aspx, identifier: ACTRN12621000609853p.

The Pain-Invalidation Scale: Measuring Patient Perceptions of Invalidation Toward Chronic Pain

Increasing evidence reveals the damaging impact of having one's chronic pain symptoms invalidated through disbelief, discrediting, and critical judgement. In other instances, a caregiver's over-attentiveness to the daily tasks of individuals with pain can be problematic, potentially undermining rehabilitation. The aim of this study was to develop an instrument to measure different aspects of invalidation perceived by people with chronic pain. Item generation was informed through literature review and a thematic analysis of narratives from 431 peer-reviewed articles. The crowdsourcing platform Prolific was used to distribute survey items to participants. In Study 1A, Principal Component Analysis was performed on data from 302 respondents, giving rise to 4 subscales, including: Invalidation by the Self, Invalidation by Immediate Others, Invalidation by Healthcare Professionals, and Invalidation by Over-attentive Others. Confirmatory Factor Analysis of data collected from aonther 308 individuals in Study 1B supported the 4-factor model of the Pain-Invalidation Scale (Pain-IS) and identified a best-fit model with 24 items. The Pain-IS was further validated in another 300 individuals in Study 2. The Pain-IS demonstrates sound psychometric properties and may serve as a valuable tool for use by clinicians in the detection of pain-invalidation issues, as a first step in patient pain management. Perspective. Links between pain-invalidation and pain levels, as well as functional detriment, highlight the importance of having one's chronic pain experience heard, believed and accepted. The Pain-Invalidation Scale is designed to identify domains where invalidation of the patient's pain should be addressed to promote emotional processing, treatment adherence and improved outcomes.

The Effects of Lutein and Zeaxanthin Supplementation on Cognitive Function in Adults With Self-Reported Mild Cognitive Complaints: A Randomized, Double-Blind, Placebo-Controlled Study

Background

Lutein and zeaxanthin are fat-soluble, dietary carotenoids with high concentrations in human brain tissue. There have been a number studies confirming an association between lutein and zeaxanthin and cognitive function.

Purpose

Examine the effects of lutein and zeaxanthin supplementation on cognitive function in adults with self-reported cognitive complaints.

Study Design

Two-arm, parallel-group, 6-month, randomized, double-blind, placebo-controlled trial.

Methods

Ninety volunteers aged 40–75 years received either 10 mg of lutein and 2 mg of zeaxanthin, once daily or a placebo. Outcome measures included computer-based cognitive tasks, the Cognitive Failures Questionnaire, Behavior Rating Inventory of Executive Function, Profile of Mood States, and the Patient-Reported Outcomes Measurement Information System-29.

Results

Compared to the placebo, lutein and zeaxanthin supplementation was associated with greater improvements in visual episodic memory (p = 0.005) and visual learning (p = 0.001). However, there were no other statistically-significant differences in performance on the other assessed cognitive tests or self-report questionnaires. Lutein and zeaxanthin supplementation was well-tolerated with no reports of significant adverse effects.

Conclusion

The results from this trial suggest that 6-months of supplementation with lutein and zeaxanthin may improve visual memory and learning in community-dwelling adults with self-reported cognitive complaints. However, it had no other effect on other computer-based measures of cognitive performance or self-report measures of cognition, memory, mood, or physical function.

Phase-space simulations of feedback coherent Ising machines

A new, to the best of our knowledge, technique is demonstrated for carrying out exact positive-P phase-space simulations of the coherent Ising machine quantum computer. By suitable design of the coupling matrix, general hard optimization problems can be solved. Here, computational quantum simulations of a feedback type of photonic parametric network are carried out, which is the implementation of the coherent Ising machine. Results for success rates are obtained using this scalable phase-space algorithm for quantum simulations of quantum feedback devices.

Painful diabetic peripheral neuropathy: Role of oxidative stress and central sensitisation

AIMS

Diabetic peripheral neuropathy (DPN) occurs in about half of people with diabetes, of whom a quarter may develop chronic pain. Pain may remain for years yet be difficult to treat because the underlying mechanisms remain unclear. There is consensus that processing excessive glucose leads to oxidative stress, interfering with normal metabolism. In this narrative review, we argue that oxidative stress may also contribute to pain.

METHODS

We reviewed literature in PubMed published between January 2005 and August 2021.

RESULTS AND CONCLUSIONS

In diabetes, hyperglycaemia and associated production of reactive species can directly increase pain signalling and activate sensory neurons; or the effects can be indirect, mediated by mitochondrial damage and enhanced inflammation. Furthermore, pain processing in the central nervous system is compromised in painful DPN. This is implicated in central sensitisation and dysfunctional pain modulation. However, central pain modulatory function is understudied in diabetes. Future research is required to clarify whether central sensitisation and/or disturbances in central pain modulation contribute to painful DPN. Positive results would facilitate early detection and future treatment.

Co-morbidity between trigeminal autonomic cephalalgias and complex regional pain syndrome: Two case reports

BACKGROUND

Trigeminal autonomic cephalalgias and complex regional pain syndrome are rare conditions, and their co-occurrence has not been reported previously.Clinical findings: In two patients, ipsilateral trigeminal autonomic cephalalgias developed after the onset of upper limb complex regional pain syndrome. Hyperalgesia to thermal and mechanical stimuli extended beyond the affected limb to encompass the ipsilateral forehead, and was accompanied by ipsilateral hyperacusis and photophobia. In addition, examination of the painful limb and bright light appeared to aggravate symptoms of trigeminal autonomic cephalalgias. Detailed examination of the association between facial and upper limb pain indicated that both sources of pain cycled together. Furthermore, in one case, stellate ganglion blockade inhibited pain for an extended period not only in the affected limb but also the face.

CONCLUSIONS

These findings suggest some overlap in the pathophysiology of complex regional pain syndrome and trigeminal autonomic cephalalgias. Specifically, central sensitization and/or disruption of inhibitory pain modulation on the affected side of the body in complex regional pain syndrome might trigger ipsilateral cranial symptoms and increase vulnerability to trigeminal autonomic cephalalgias.

A Summary of Current Findings on Quality of Life Domains and a Proposal for Their Inclusion in Clinical Interventions

Whilst the assessment of quality of life (QoL) and well-being has burgeoned in the past 50 years, there still remains relatively little research into its treatment in psychology, in spite of the launching of such approaches as positive psychology to widen the ambit of interventions to promote well-being. We posit that there are a number of outstanding QoL areas that could be integrated into standard therapeutic procedures, and that this would this result in an increase in well-being as a therapeutic outcome. To investigate this an exploratory search of the literature was undertaken of associations between improvements in a life domain and increased well-being or QoL. Ten domains (relationships, work, money, health, and leisure, mindfulness, self-esteem, resolution of past life events, mental style and life management skills) were identified. In view of the substantial evidence of the cumulative impact of these domains upon well-being, it is proposed that conducting a unidimensional clinical intervention that focuses only on the presenting issue is not sufficient. Implications and possible therapeutic pathways are discussed and it is recommended that practitioners include such QoL domains in their assessment, case formulation, and intervention planning.

Denying the Truth Does Not Change the Facts: A Systematic Analysis of Pseudoscientific Denial of Complex Regional Pain Syndrome

Purpose

Several articles have claimed that complex regional pain syndrome (CRPS) does not exist. Although a minority view, it is important to understand the arguments presented in these articles. We conducted a systematic literature search to evaluate the methodological quality of articles that claim CRPS does not exist. We then examined and refuted the arguments supporting this claim using up-to-date scientific literature on CRPS.

Methods

A systematic search was conducted in MEDLINE, EMBASE and Cochrane CENTRAL databases. Inclusion criteria for articles were (a) a claim made that CRPS does not exist or that CRPS is not a distinct diagnostic entity and (b) support of these claims with subsequent argument(s). The methodological quality of articles was assessed if possible.

Results

Nine articles were included for analysis: 4 narrative reviews, 2 personal views, 1 letter, 1 editorial and 1 case report. Seven points of controversy were used in these articles to argue that CRPS does not exist: 1) disagreement with the label “CRPS”; 2) the “unclear” pathophysiology; 3) the validity of the diagnostic criteria; 4) CRPS as a normal consequence of immobilization; 5) the role of psychological factors; 6) other identifiable causes for CRPS symptoms; and 7) the methodological quality of CRPS research.

Conclusion

The level of evidence for the claim that CRPS does not exist is very weak. Published accounts concluding that CRPS does not exist, in the absence of primary evidence to underpin them, can harm patients by encouraging dismissal of patients’ signs and symptoms.

Effects of an Oroxylum indicum Extract (Sabroxy®) on Cognitive Function in Adults With Self-reported Mild Cognitive Impairment: A Randomized, Double-Blind, Placebo-Controlled Study

Background: Oroxylum indicum has been used in traditional Ayurvedic medicine for the prevention and treatment of several diseases and may have neuroprotective effects.

Purpose: Examine the effects of Oroxylum indicum on cognitive function in older adults with self-reported cognitive complaints.

Study Design: Two-arm, parallel-group, 12-week, randomized, double-blind, placebo-controlled trial.

Methods: Eighty-two volunteers received either 500 mg, twice daily of a standardized Oroxylum indicum extract or placebo. Outcome measures included several computer-based cognitive tasks, the Control, Autonomy, Self-Realization, and Pleasure scale (CASP-19), Cognitive Failures Questionnaire (CFQ), and the Montreal Cognitive Assessment (MoCA). Changes in the concentration of brain-derived neurotrophic factor (BDNF) were also examined.

Results: Compared to the placebo, Oroxylum indicum was associated with greater improvements in episodic memory, and on several computer-based cognitive tasks such as immediate word recall and numeric working memory, and a faster rate of learning on the location learning task. However, there were no other significant differences in performance on the other assessed cognitive tests, the MoCA total score, or other self-report questionnaires. BDNF concentrations increased significantly in both groups, with no statistically-significant between-group differences. Oroxylum indicum was well tolerated except for an increased tendency for mild digestive complaints and headaches.

Conclusion: The results of this first human trial on the cognitive-enhancing effects of Oroxylum indicum suggest that it is a promising herbal candidate for the improvement of cognitive function in older adults with self-reported cognitive complaints.

Anodal Transcranial Direct Current Stimulation Reduces Secondary Hyperalgesia Induced by low Frequency Electrical Stimulation in Healthy Volunteers

The aim of the study was to determine whether transcranial direct current stimulation (tDCS) reduced pain and signs of central sensitization induced by low frequency electrical stimulation in healthy volunteers. Thirty-nine participants received tDCS stimulation under 4 different conditions: anodal tDCS of the primary motor cortex (M1), anodal tDCS of the dorsolateral prefrontal cortex (DLPFC), anodal tDCS over M1 and DLPFC concurrently, and sham tDCS. Participants were blind to the tDCS condition. The order of the conditions was randomized among participants. Pain ratings to pinpricks, the current level that evoked moderate pain, and pain induced by low frequency electrical stimulation were assessed in the forearm by an experimenter who was blind to the tDCS conditions. Anodal tDCS at M1 increased the current level that evoked moderate pain compared to sham and other conditions. Anodal tDCS of DLPFC completely abolished secondary hyperalgesia. Unexpectedly, however, concurrent anodal tDCS over M1 and DLPFC did not reduce pain or hyperalgesia more than M1 alone or DLPFC alone. Overall, these findings suggest that anodal tDCS over M1 suppresses pain, and that anodal tDCS over DLPFC modulates secondary hyperalgesia (a sign of central sensitization) in healthy participants. PERSPECTIVE: Anodal transcranial current stimulation (atDCS) at the left motor cortex and the dorsolateral prefrontal cortex increased the electrically-evoked pain threshold and reduced secondary hyperalgesia in healthy participants. Replication of this study in chronic pain populations may open more avenues for chronic pain treatment.

Reduced SMA-M1 connectivity in older than younger adults measured using dual-site TMS

With advancing age comes a decline in voluntary movement control. Growing evidence suggests that an age-related decline in effective connectivity between the supplementary motor area and primary motor cortex (SMA-M1) might play a role in an age-related decline of bilateral motor control. Dual-site transcranial magnetic stimulation (TMS) can be used to measure SMA-M1 effective connectivity. In the current study, we aimed to (1) replicate previous dual-site TMS research showing reduced SMA-M1 connectivity in older than younger adults and (2) examine whether SMA-M1 connectivity is associated with bilateral motor control in independent samples of younger (n = 30) and older adults (n = 30). SMA-M1 connectivity was measured using dual-site TMS with interstimulus intervals of 6, 7 and 8 ms, and bilateral motor control was measured using the Purdue Pegboard, Four Square Step Test and the Timed Up and Go task. Findings from this study showed that SMA-M1 connectivity was reduced in older than in younger adults, suggesting that the direct excitatory connections between SMA and M1 had reduced efficacy in older than younger adults. Furthermore, greater SMA-M1 connectivity was associated with better bimanual motor control in older adults. Thus, SMA-M1 connectivity in older adults might underpin, in part, the age-related decline in bilateral motor control. These findings contribute to our understanding of age-related declines in motor control and provide a physiological basis for the development of interventions to improve bimanual and bilateral motor control.

An investigation into an evening intake of a saffron extract (affron®) on sleep quality, cortisol, and melatonin concentrations in adults with poor sleep: a randomised, double-blind, placebo-controlled, multi-dose study

OBJECTIVE/BACKGROUND

To validate and extend on previous positive findings of the sleep-enhancing effects of saffron supplementation in adults with unsatisfactory sleep.

PATIENTS/METHODS

In this 28-day, 3-arm, parallel-group, double-blind, randomised controlled trial, 120 adults with unsatisfactory sleep received either a placebo, 14 mg, or 28 mg of a standardised saffron extract (affron®), 1 h before bed. Outcome measures included the Pittsburgh Sleep Diary (with sleep quality ratings as the primary outcome measure), Insomnia Symptom Questionnaire (ISQ), Profile of Mood States, Restorative Sleep Questionnaire, the Functional Outcomes of Sleep Questionnaire, and evening salivary melatonin and cortisol concentrations.

RESULTS

Compared to the placebo, saffron supplementation was associated with greater improvements in sleep quality ratings (primary outcome measure), mood ratings after awakening, the ISQ total score, and ISQ-insomnia classifications. However, there were no significant differences between the saffron and placebo groups in other questionnaire and sleep diary outcome measures. Sleep improvements were similar for the two administered saffron doses. Compared to the placebo, saffron supplementation was associated with increases in evening melatonin concentrations but did not affect evening cortisol. Saffron supplementation was well-tolerated with no reported significant adverse effects.

CONCLUSIONS

These results provide further validation of the sleep-enhancing effects of 28-days of saffron supplementation in adults with unsatisfactory sleep. Further research is required to examine the efficacy and safety of saffron supplementation using objective sleep measures, over a longer duration, in people presenting with a diagnosed insomnia disorder and other psychogenic and demographic characteristics, and into its potential sleep-enhancing mechanisms of action.

Pupillary Reflexes in Complex Regional Pain Syndrome: Asymmetry to Arousal Stimuli Suggests an Ipsilateral Locus Coeruleus Deficit

Converging lines of evidence suggest that autonomic and nociceptive pathways linked with the locus coeruleus are disrupted in complex regional pain syndrome (CRPS). To investigate this, pupillary dilatation to arousal stimuli (which reflects neural activity in the locus coeruleus) and pupillary reflexes to light were assessed in a cross-sectional study of 33 patients with CRPS. Moderately painful electrical shocks were delivered to the affected or contralateral limb and unilateral 110 dB SPL acoustic startle stimuli were delivered via headphones. To determine whether the acoustic startle stimuli inhibited shock-induced pain, startle stimuli were also administered bilaterally 200 ms before or after the electric shock. The pupils constricted briskly and symmetrically to bright light (500 lux) and dilated symmetrically in dim light (5 lux). However, the pupil on the CRPS-affected side was smaller than the contralateral pupil before and after the delivery of painless and painful arousal stimuli. Auditory sensitivity was greater on the affected than unaffected side but acoustic startle stimuli failed to inhibit shock-induced pain. Together, these findings suggest that neural activity in pathways linked with the locus coeruleus is compromised on the affected side in patients with CRPS. This may contribute to autonomic disturbances, auditory discomfort and pain. Perspective: The locus coeruleus is involved not only in modulation of pain but also regulates sensory traffic more broadly. Hence, fatigue of neural activity in the ipsilateral locus coeruleus might not only exacerbate pain and hyperalgesia in CRPS but could also contribute more generally to hemilateral disturbances in sensory processing.

Test Re-test Reliability of Dual-site TMS Measures of SMA-M1 Connectivity Differs Across Inter-stimulus Intervals in Younger and Older Adults

Dual-site transcranial magnetic stimulation (TMS) is a promising tool to measure supplementary motor area and primary motor cortex (SMA-M1) connectivity in younger and older adults, and could be used to understand the pathophysiology of movement disorders. However, test re-test reliability of dual-site TMS measures of SMA-M1 connectivity has not been established. We examined the reliability of SMA-M1 connectivity using dual-site TMS in two sessions in 30 younger and 30 older adults. For dual-site TMS, a conditioning pulse delivered to SMA (140% of active motor threshold) preceded a test pulse delivered to M1 (intensity that elicited MEPs of ~1 mV) by inter-stimulus intervals (ISI) of 6 ms, 7 ms, and 8 ms. Moderate intraclass correlation coefficients (ICC) were found for SMA-M1 connectivity at an ISI of 7 ms in younger (ICC: 0.69) and older adults (ICC: 0.68). Poor ICCs were found for SMA-M1 connectivity at ISIs of 6 ms and 8 ms in both age groups (ICC range: 0.01-0.40). We report evidence for stable measures of SMA-M1 connectivity at an ISI of 7 ms in both age groups. These findings are foundational for future research developing evidence-based interventions to strengthen SMA-M1 connectivity to improve bilateral motor control in older adults and populations with movement disorders.

"Big girls don't cry": the effect of the experimenter's sex and pain catastrophising on pain

OBJECTIVES

The expression of pain in males and females involves complex socio-psychological mechanisms. Males may report lower pain to a female experimenter to appear strong, whereas females may report higher pain to a male experimenter to appear weak and to seek protection. However, evidence to support these stereotypes is inconclusive. Individuals who catastrophise about pain rate higher pain than those who do not. How pain catastrophising interacts with the effect of the experimenter's sex on pain reports is yet to be explored. Thus, the aim of this study was to determine whether pain catastrophising moderated the effect of the experimenter's sex on pain reports in healthy males and females.

METHODS

Participants (n=60, 30 males) were assigned to one of four experimental conditions: males tested by male experimenters, males tested by female experimenters, females tested by male experimenters, and females tested by female experimenters. Participants completed the Pain Catastrophising Scale, and then sensitivity to heat and to blunt (pressure-pain threshold) and sharp stimuli was assessed on both forearms, and to high frequency electrical stimulation (HFS) administered to one forearm.

RESULTS

Females reported lower pressure-pain thresholds than males irrespective of the experimenters' sex. Females reported lower sharpness ratings to male than female experimenters only when the test stimuli were moderately or intensely sharp. Higher pain catastrophising scores were associated with higher sharpness ratings in females but not males. Additionally, higher pain catastrophising scores were associated with greater temporal summation of pain to HFS, and with lower pressure-pain thresholds in females who were tested by male experimenters.

CONCLUSIONS

These findings indicate that the experimenters' sex and the participant's pain catastrophising score influence pain reports, particularly in females. Awareness of these psychosocial factors is important in order to interpret pain responses in a meaningful way, especially when females are tested by male experimenters. A greater awareness of sex/gender role biases and their potential interaction with pain catastrophising may help researchers and clinicians to interpret pain reports in meaningful ways. In turn, this may help to improve delivery of treatments for patients with chronic pain.

Effects of saffron on sleep quality in healthy adults with self-reported poor sleep: a randomized, double-blind, placebo-controlled trial

STUDY OBJECTIVES

Herbal medicines are frequently used by adults with sleep difficulties. However, evidence of their efficacy is limited. Therefore, the goal of this study was to examine the sleep-enhancing effects of a standardized saffron extract (affron).

METHODS

This was a 28-day, parallel-group, double-blind, randomized controlled trial. Sixty-three healthy adults aged 18-70 with self-reported sleep problems were recruited and randomized to receive either saffron extract (affron; 14 mg twice daily) or a placebo. Outcome measures included the Insomnia Severity Index (ISI; primary outcome measure) collected at baseline and days 7, 14, 21, and 28 and the Restorative Sleep Questionnaire (RSQ) and the Pittsburgh Sleep Diary (PSD) collected on days -1, 0, 3, 7, 14, 27, and 28.

RESULTS

Based on data collected from 55 participants, saffron was associated with greater improvements in ISI total score (P = .017), RSQ total score (P = .029), and PSD sleep quality ratings (P = .014) than the placebo. Saffron intake was well tolerated with no reported adverse effects.

CONCLUSIONS

Saffron intake was associated with improvements in sleep quality in adults with self-reported sleep complaints. Further studies using larger samples sizes, treatment periods, objective outcome measures, and volunteers with varying demographic and psychographic characteristics are required to replicate and extend these findings.

CLINICAL TRIAL REGISTRATION

Registry: Australian New Zealand Clinical Trials Registry; Name: Effects of Saffron on Sleep Quality in Healthy Adults with Self-Reported Unsatisfactory Sleep; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377781; Identifier: ACTRN12619000863134.

Alpha 1 adrenoceptor expression in skin, nerves and blood vessels of patients with painful diabetic neuropathy

Diabetic neuropathy (dNP) patients often suffer from severe neuropathic pain. It was suggested that alpha-1 adrenoceptor (α₁-AR) hyperresponsiveness contributes to pain in dNP. The aim of our study was to quantify α₁-AR expression using immunohistochemistry in skin biopsies of nine patients with painful diabetic neuropathy compared to 10 healthy controls. Additionally, the association between α₁-AR expression and activation with spontaneous and sympathetically maintained pain (SMP) induced by intradermal injection of the α₁-agonist phenylephrine was investigated. For control purposes the α₂-agonist clonidine was injected in a different session. We found that dermal nerve density was significantly lower in dNP than in controls. However, α₁-AR expression was significantly greater on cutaneous blood vessels and keratinocytes of dNP patients than controls. A similar trend, which failed to reach significance, was observed for dermal nerves. Intradermal injection of phenylephrine induced only minor pain, which resolved after a few minutes. Adrenergically evoked pain persisted for more than 15 min in only one patient, but none of the patients fulfilled the criteria for SMP (pain increase after injection of phenylephrine and decrease after clonidine). In conclusion, our results imply that SMP does not occur in dNP. However, elevated expression of α₁-AR on keratinocytes and dermal blood vessels is an important finding, since this could contribute to dNP progression and supports the theory of receptor up-regulation of denervated structures. The implications of this α₁-upregulation should be examined in further studies.

Reduced Cerebellar Brain Inhibition Measured Using Dual-Site TMS in Older Than in Younger Adults

Dual-site transcranial magnetic stimulation (TMS) can be used to measure the cerebellar inhibitory influence on the primary motor cortex, known as cerebellar brain inhibition (CBI), which is thought to be important for motor control. The aim of this study was to determine whether age-related differences in CBI (measured at rest) were associated with an age-related decline in bilateral motor control measured using the Purdue Pegboard task, the Four Square Step Test, and a 10-m walk. In addition, we examined test re-test reliability of CBI measured using dual-site TMS with a figure-of-eight coil in two sessions. There were three novel findings. First, CBI was less in older than in younger adults, which is likely underpinned by an age-related loss of Purkinje cells. Second, greater CBI was associated with faster 10-m walking performance in older adults, but slower 10-m walking performance in younger adults. Third, moderate intraclass correlation coefficients (ICCs: 0.53) were found for CBI in younger adults; poor ICCs were found for CBI (ICC: 0.40) in older adults. Together, these results have important implications for the use of dual-site TMS to increase our understanding of age- and disease-related changes in cortical motor networks, and the role of functional connectivity in motor control.

Modulation of the hypothalamic-pituitary-adrenal (HPA) axis by plants and phytonutrients: a systematic review of human trials

INTRODUCTION

The hypothalamic-pituitary-adrenal (HPA) axis plays a central role in the stress response. Plants, herbs, spices, and plant-based nutrients may influence HPA-axis activity.

OBJECTIVE

To evaluate randomised controlled, human trials assessing the effects of single plants or phytonutrients on HPA-axis related hormones.

METHODS

A systematic review of PubMed, Cochrane library, and the Cumulative Index to Nursing and Allied Health Literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria comprised of human, randomised controlled studies with a control intervention examining the effects of a single herb, spice, plant, or extract on pre- and post-changes in blood, saliva, urine, or hair concentrations of cortisol, cortisone, corticotrophin-releasing hormone, or adrenocorticotropic hormone. Databases were searched from inception until October 2020.

RESULTS

Fifty-two studies were identified examining the effects of ashwagandha, Korean ginseng, St John's Wort, cannabidiol, Rhodiola rosea, curcumin, cherry juice, asparagus, Jiaogulan, Black cohosh, Siberian ginseng, Bacopa monnieri, blueberries, green tea, Caralluma fimbriata, cashew apple juice, melon, American ginseng, Ginkgo biloba, grape juice, grapefruit juice, rosella, hops, mangosteen, holy basil, and pomegranate juice. Due to significant variability in study designs, the effect of phytonutrients on HPA-axis activity in humans was unclear. The most consistent finding was a morning, cortisol-lowering effect from ashwagandha supplementation.

CONCLUSION

For most phytonutrients, the effects of supplementation on HPA-axis activity in humans is unclear. Before more definitive conclusions about the effects of phytonutrients on the HPA-axis can be made, further research is required.

Acoustic startle stimuli inhibit pain but do not alter nociceptive flexion reflexes to sural nerve stimulation

Acoustic startle stimuli inhibit pain, but whether this is due to a cross-modal inhibitory process or some other mechanism is uncertain. To investigate this, electrical stimulation of the sural nerve either preceded or followed an acoustic startle stimulus (by 200 ms) or was presented alone in 30 healthy participants. Five electrical stimuli, five acoustic startle stimuli, 10 startle + electrical stimuli, and 10 electrical + startle stimuli were presented in mixed order at intervals of 30-60 s. Effects of the startle stimulus on pain ratings, pupillary dilatation and nociceptive flexion reflexes to the electric shock were assessed. The acoustic startle stimulus inhibited electrically evoked pain to the ensuing electric shock (p < .001), and the electrical stimulus inhibited the perceived loudness of a subsequent acoustic startle stimulus (p < .05). However, the startle stimulus did not affect electrically evoked pain when presented 200 ms after the electric shock, and electrically evoked pain did not influence the perceived loudness of a prior startle stimulus. Furthermore, stimulus order did not influence the pupillary responses or nociceptive flexion reflexes. These findings suggest that acoustic startle stimuli transiently inhibit nociceptive processing and, conversely, that electrical stimuli inhibit subsequent auditory processing. These inhibitory effects do not seem to involve spinal gating as nociceptive flexion reflexes to the electric shock were unaffected by stimulus order. Thus, cross-modal interactions at convergence points in the brainstem or higher centers may inhibit responses to the second stimulus in a two-stimulus train.

The Feasibility and Efficacy of a Brief Integrative Treatment for Adults With Depression and/or Anxiety: A Randomized Controlled Trial

The aim of this study was to investigate the efficacy and suitability of a brief integrative intervention, Personalized Integrative Therapy (PI Therapy), for the treatment of adult depression and/or anxiety. In this 6-week, 3-arm, parallel-group, randomized trial, PI Therapy delivered alone or with nutritional supplements (PI Therapy + Supps) was compared to cognitive behavior therapy (CBT) in 48 adults with depression and/or anxiety. All treatments were delivered as a 1-day workshop plus 6 weeks of reminder phone text messages to reinforce topics and skills covered in the workshop. Affective symptoms decreased significantly and to the same extent in all 3 conditions. At the end of treatment, 33% to 58% of participants reported levels of depressive symptoms in the normal range, and 50% to 58% reported nonclinical levels of anxiety. Compared to CBT and PI Therapy, PI Therapy + Supps was associated with significantly greater improvements in sleep quality. These findings suggest that a brief integrative intervention with or without supplements was comparable to CBT in reducing affective symptoms in adults with depression and/or anxiety. However, sleep quality improved only in the PI Therapy + Supps condition. These findings will require replication with a larger cohort.

Expression of Cutaneous Beta-2 Adrenoceptors Is Similar in Patients with Complex Regional Pain Syndrome and Pain-Free Controls

OBJECTIVE

Studies in rodents suggest that cutaneous beta-2 adrenoceptors (β2-ARs) mediate inflammation and pain after tissue injury and that inflammation and peripheral nerve injury trigger increases in neuronal β2-AR expression. Hence, the aim of this study was to investigate the expression of β2-ARs on keratinocytes and dermal nerves in patients with complex regional pain syndrome (CRPS).

DESIGN, SETTING, AND SUBJECTS

Fifty-eight patients with CRPS were recruited for this study. In addition, skin biopsies were obtained from 13 pain-free women and three pain-free men of similar age and sex distribution as the patients.

METHODS

Quantitative sensory tests for assessing sensitivity to pressure, pinprick, light touch, heat, and cold were administered, and skin biopsies were obtained from the affected and contralateral limbs. Skin biopsies were also obtained from a similar site on the dorsal hand or foot of pain-free controls. Immunohistochemistry and confocal microscopy were used to identify β2-ARs on keratinocytes, dermal nerves, and blood vessels in the skin samples.

RESULTS

The distribution of β2-ARs in keratinocytes and nerves was similar in the affected and contralateral limbs of patients and was similar for target cells in patients and controls. However, elevated β2-AR expression in reticular nerve bundles was associated with heightened sensitivity to heat pain.

CONCLUSIONS

These findings do not support a major role of cutaneous β2-ARs in CRPS. However, activation of neuronal β2-ARs may contribute to thermal hyperalgesia in a subgroup of patients. Whether activation of β2-ARs on keratinocytes mediates inflammation early in the course of CRPS requires further investigation.

A Randomized, Double-Blind, Placebo-Controlled, Crossover Study Examining the Hormonal and Vitality Effects of Ashwagandha ( Withania somnifera) in Aging, Overweight Males

Ashwagandha ( Withania somnifera) is a herb commonly used in Ayurvedic medicine to promote youthful vigor, enhance muscle strength and endurance, and improve overall health. In this 16-week, randomized, double-blind, placebo-controlled, crossover study, its effects on fatigue, vigor, and steroid hormones in aging men were investigated. Overweight men aged 40-70 years, with mild fatigue, were given a placebo or an ashwagandha extract (Shoden beads, delivering 21 mg of withanolide glycosides a day) for 8 weeks. Outcome measures included the Profile of Mood States, Short Form (POMS-SF), Aging Males' Symptoms (AMS) questionnaire, and salivary levels of DHEA-S, testosterone, cortisol, and estradiol. Fifty-seven participants were enrolled, with 50 people completing the first 8-week period of the trial and 43 completing all 16 weeks. Improvements in fatigue, vigor, and sexual and psychological well-being were reported over time, with no statistically significant between-group differences. Ashwagandha intake was associated with an 18% greater increase in DHEA-S ( p = .005) and 14.7% greater increase in testosterone ( p = .010) compared to the placebo. There were no significant between-group differences in cortisol and estradiol. In conclusion, the intake of a standardized ashwagandha extract (Shoden beads) for 8 weeks was associated with increased levels of DHEA-S and testosterone, although no significant between-group differences were found in cortisol, estradiol, fatigue, vigor, or sexual well-being. Further studies with larger sample sizes are required to substantiate the current findings.

Reduction in Migraine and Headache Frequency and Intensity With Combined Antioxidant Prophylaxis (N-acetylcysteine, Vitamin E, and Vitamin C): A Randomized Sham-Controlled Pilot Study

OBJECTIVE

To investigate the preventive effects of a combined antioxidant drug (N-acetylcysteine, vitamin E, and vitamin C [NEC]) on migraine outcomes. Migraine is characterized by increased oxidative stress and neurogenic inflammation in the brain; therefore, antioxidants may have a migraine preventive effect.

DESIGN

Randomized, double-blind, sham-controlled pilot study.

SETTING

Australian community.

SUBJECTS

Adults reporting 2 to 8 migraines per month for at least a year.

METHODS

After a 1-month baseline period, 35 subjects completed 3 months of treatment with NEC (n = 19) or sham (n = 16) capsules. The primary outcome was the difference in mean number of headaches per month between baseline and final month of the trial for NEC and sham groups; secondary outcomes are listed below.

RESULTS

For NEC there was a significant decrease in mean number of headaches by 3.0 per month (P = 0.004) compared with 1.4 for sham (P = 0.073); there was no significant difference in these changes between the 2 groups (P = 0.052). Average monthly headache (P = 0.041) and migraine frequency (P = 0.018) were significantly less for NEC vs. sham. In NEC subjects, there was a significant decrease in average monthly migraine days (-3.1), moderate/severe headache days (-3.2), migraine duration, headache pain scores, and acute headache medication use.

CONCLUSIONS

This is the first randomized controlled trial to find that combined antioxidant therapy with NEC reduces headaches and migraines in adult migraineurs. Given the limitations of this pilot study, an adequately powered randomized controlled trial is planned to further investigate antioxidant prophylaxis in migraine.

A positive feedback loop between alpha1-adrenoceptors and inflammatory cytokines in keratinocytes

A positive feedback loop between inflammatory cytokines and alpha₁-adrenoceptors (α₁-AR) (a target of the sympathetic nervous system neurotransmitter norepinephrine) influences inflammatory responses in immune cells. This cross-talk between the sympathetic nervous system and immune system may play a role in promoting chronic inflammation. Emerging evidence shows that α₁-AR interact with inflammatory cytokines in keratinocytes, and this epidermal adrenergic signalling may contribute to skin inflammatory responses following injury, disease or stress. In this study, utilizing an in vitro approach, we hypothesized that α₁-AR interact in a positive feedback loop with inflammatory mediators in keratinocytes. The pro-inflammatory cytokine tumor necrosis factor α (TNFα) was used to induce an inflammatory state in cultured keratinocytes. TNFα increased interleukin (IL)-1β, IL-6, IL-8 and nerve growth factor (NGF) production and gene expression levels of α₁-AR subtype B (α_1B-AR). Additional stimulation of α₁-AR further increased IL-6 levels, while maintaining high levels of IL-8 and decreasing levels of IL-1β and NGF. Our results suggest that reciprocal influences between α₁-ARs and inflammatory cytokines may play a role in normal inflammatory responses. However, if unchecked, this cycle could contribute to pathology (e.g. chronic inflammatory diseases, chronic pain conditions, and stress-induced cancer progression).

Expression of the noradrenaline transporter in the peripheral nervous system

The noradrenaline transporter (NAT) transfers noradrenaline released into the synaptic cleft back into the presynaptic terminal, thus terminating neurotransmission. Although the distribution of NAT within the central nervous system has been well-characterized, less is known about its distribution elsewhere in the peripheral nervous system and in organs such as the skin. To address this in the present study, NAT expression was investigated using immunohistochemistry in the hind paw skin and more proximally in the sciatic nerve, dorsal root ganglia and spinal cord of five male Wistar rats. It was hypothesised that NAT would be expressed exclusively on nerve fibres labelled by dopamine beta hydroxylase (DβH), an enzyme involved in the conversion of dopamine to noradrenaline. NAT co-localised with DβH in neurons in the spinal cord, dorsal root ganglia and sciatic nerve. Unexpectedly, however, NAT-like immunoreactivity was not observed in DβH immuno-reactive fibres that innervated dermal blood vessels, suggesting that a mechanism other than presynaptic re-uptake of noradrenaline through NAT regulates transmission at neurovascular junctions in the skin. Furthermore, a novel association between NAT-like immunoreactivity and the myelin marker myelin basic protein (MBP) was identified in peripheral nerves. Specifically, NAT and MBP appeared to congregate around primary afferent nerve fibres labelled by neurofilament 200, a marker of neurons with medium- and large-diameter axons. NAT-like immunoreactivity was also detected in cultured Schwann cells immunohistochemically and at the mRNA level. Together, these findings imply a hitherto unrecognised role of Schwann cells in clearance of noradrenaline in the peripheral nervous system.

Efficacy of a standardised saffron extract (affron®) as an add-on to antidepressant medication for the treatment of persistent depressive symptoms in adults: A randomised, double-blind, placebo-controlled study

BACKGROUND

As a stand-alone intervention, saffron has efficacy for the treatment of mild-to-moderate depression. However, research as an adjunct agent is limited.

AIMS

The effects of saffron as an adjunct to pharmaceutical antidepressants in adults with persistent depression was investigated.

METHODS

In this eight-week, randomised, double-blind, placebo-controlled study, adults with persistent depression, currently taking a pharmaceutical antidepressant were given a placebo or a saffron extract (affron®, 14 mg b.i.d.). Primary outcome measures included the clinician-rated Montgomery-Åsberg Depression Rating Scale (MADRS) and self-rated MADRS (MADRS-S). Secondary outcome measures included the Antidepressant Side-Effect Checklist (ASEC) and Short Form-36 Health Survey (SF-36).

RESULTS

Of the 160 participants enrolled, 139 provided usable data. Based on the MADRS, depressive symptoms decreased more in participants taking saffron compared with a placebo, with reductions of 41 and 21%, respectively (p = 0.001). However, scores on the MADRS-S decreased 27 and 26% in the saffron and placebo conditions, respectively (p = 0.831). Saffron was associated with a greater reduction in adverse effects of antidepressants (p = 0.019), although this was non-significant after covarying for baseline values (p = 0.449). Quality of life improved in both groups with no significant between-group differences (p = 0.638).

CONCLUSION

Adjunctive administration of a standardised saffron extract (affron®) for eight weeks was associated with a greater improvement in depressive symptoms as measured by the clinician-rated MADRS but not the self-report MADRS-S. Given the conflicting results, further research is needed to clarify the clinical benefits of saffron as an adjunctive treatment for adults with persistent depressive symptoms despite antidepressant drug treatment.

Tumor necrosis factor α induces α1B-adrenergic receptor expression in keratinocytes

Keratinocytes produce cytokines and nerve growth factor (NGF) as part of a repair response to injury, disease or stress, and express alpha₁-adrenoceptors (α₁-AR). The expression of these receptors is elevated in some inflammatory diseases and chronic pain conditions. In this study, we investigated whether inflammatory signalling affects α₁-AR expression in keratinocytes in vitro. Tumor necrosis factor α (TNFα) was administered to human keratinocytes, after which the levels of other key pro-inflammatory cytokines and NGF were measured. The production of these cytokines and NGF increased in cells treated with TNFα compared to untreated cells. Furthermore, exposure to TNFα increased gene expression of the α₁-AR subtype B in keratinocytes. Our results suggest that inflammatory cytokines released during injury stimulate α₁-AR expression in keratinocytes. The up-regulation of α₁-AR may amplify the adrenergic sensitivity of these cells to catecholamines released during sympathetic nervous system activation after injury which, in turn, could heighten the inflammatory response.

Bilaterally Reduced Intraepidermal Nerve Fiber Density in Unilateral CRPS-I

Objective

Findings regarding small nerve fiber damage in complex regional pain syndrome type I (CRPS-I) are not uniform, and studies have not included a matched healthy control group. The aim was to assess intraepidermal nerve fiber density (IENFD) in relation to thermal sensitivity of the same skin areas in CRPS-I patients and a gender- and age-matched healthy control group.

Methods

IENFD was investigated in skin biopsies from the CRPS-affected and contralateral limbs of eight CRPS-I patients and from an equivalent site in eight gender- and age-matched healthy controls (HCs). Thermal thresholds (cold/warm detection, cold- and heat-pain detection) were assessed on the affected limb, the matching contralateral limb, and on the equivalent limbs of HCs, and participants rated the intensity of cold/heat and pain to static thermal stimuli (5 °C and 40 °C).

Results

IENFD was significantly lower in both the affected and contralateral limbs of CRPS-I patients than HCs, but IENFD did not differ between the affected and contralateral limbs of patients. The heat pain threshold was lower in the affected CRPS-I limb than in HCs, but all other thermal thresholds were similar in both groups. CRPS-I patients rated the cold stimulus as colder and more painful in the affected limb, and the warm stimulus as hotter, bilaterally, than the HCs.

Conclusions

CRPS-I may be associated with bilateral small fiber damage, and perhaps small fiber neuropathy and bilateral disturbances in thermo-sensory perception. These disturbances could stem from a systemic response to injury or might increase the risk of developing CRPS-I after physical trauma.

Quantum fidelity measures for mixed states

Applications of quantum technology often require fidelities to quantify performance. These provide a fundamental yardstick for the comparison of two quantum states. While this is straightforward in the case of pure states, it is much more subtle for the more general case of mixed quantum states often found in practice. A large number of different proposals exist. In this review, we summarize the required properties of a quantum fidelity measure, and compare them, to determine which properties each of the different measures has. We show that there are large classes of measures that satisfy all the required properties of a fidelity measure, just as there are many norms of Hilbert space operators, and many measures of entropy. We compare these fidelities, with detailed proofs of their properties. We also summarize briefly the applications of these measures in teleportation, quantum memories and quantum computers, quantum communications, and quantum phase-space simulations.

Nonlocal Pair Correlations in a Higher-Order Bose Gas Soliton

The truncated Wigner and positive-P phase-space representations are used to study the dynamics of a one-dimensional Bose gas. This allows calculations of the breathing quantum dynamics of higher-order solitons with 10^{3}-10^{5} particles, as in realistic Bose-Einstein condensation experiments. Although classically stable, these decay quantum mechanically. Our calculations show that there are large nonlocal correlations and nonclassical quantum entanglement.

A Human Sensory Pathway Connecting the Foot to Ipsilateral Face That Partially Bypasses the Spinal Cord

Human sensory transmission from limbs to brain crosses and ascends through the spinal cord. Yet, descriptions exist of ipsilateral sensory transmission as well as transmission after spinal cord transection. To elucidate a novel ipsilateral cutaneous pathway, we measured facial perfusion following painfully-cold water foot immersion in 10 complete spinal cord-injured patients, 10 healthy humans before and after lower thigh capsaicin C-fiber cutaneous conduction blockade, and 10 warm-immersed healthy participants. As in healthy volunteers, ipsilateral facial perfusion in spinal cord injured patients increased significantly. Capsaicin resulted in contralateral increase in perfusion, but only following cold immersion and not in 2 spinal cord-injured patients who underwent capsaicin administration. Supported by skin biopsy results from a healthy participant, we speculate that the pathway involves peripheral C-fiber cross-talk, partially bypassing the cord. This might also explain referred itch and jogger's migraine and it is possible that it may be amenable to training spinal-injured patients to recognize lower limb sensory stimuli.

Robustness of quantum Fourier transform interferometry

We analyze the effect of decoherence and noise on quantum Fourier transform interferometry, in which a boson sampling photonic network is used to measure optical phase gradients. This novel type of metrology is shown to be robust against phase decoherence. One can also measure gradients using lower-order correlations without substantial degradation. Our results involve the estimation of up to a 100×100 matrix permanent.

Loratadine augments emotional blushing

The aim of this study was to determine whether loratadine, a selective inverse agonist of peripheral histamine H₁ receptors, would reduce emotional blushing. Loratadine (10 mg) or placebo was administered orally one hour before 31 healthy participants sang a children's nursery rhyme to evoke embarrassment and blushing. Skin blood flow was monitored via a laser Doppler probe attached to the cheek. Increases in facial blood flow while participants sang were greater in the loratadine than the placebo group (mean increase ± standard deviation 71 ± 52% in the loratadine group versus 35 ± 37%, p = .036). However, perceptions of blushing were similar in both groups. These findings suggest that loratadine augmented blushing rather than inhibiting it. Thus, histamine released during blushing may inhibit acute increases in facial blood flow by evoking H₁ receptor-mediated vasoconstriction.

RAPID INDUCTION ANALGESIA FOR CAPSAICIN-INDUCED PAIN IN UNIVERSITY STUDENTS: A Randomized, Controlled Trial

The effect of rapid-induction analgesia (RIA) hypnosis on capsaicin-induced pain was tested in 60 healthy volunteers allocated randomly to 1 of 3 conditions: listening to an RIA recording several times before and then during the session, only the in-session RIA intervention, or listening to relaxing music (the control condition). Participants who had listened to the RIA recording beforehand were significantly more relaxed than controls when differences between the groups were identified for pain intensity. These findings suggest that relaxation induced by RIA recordings can alleviate the affective component of pain. In addition, benefits of RIA may strengthen with practice.