Neuropathic pain, mood, and stress-related disorders: A literature review of comorbidity and co-pathogenesis.

Neuropathic pain can be caused by multiple factors, and its prevalence can reach 10% of the global population. It is becoming increasingly evident that limited or short-lasting response to treatments for neuropathic pain is associated with psychological factors, which include psychiatric comorbidities known to affect quality of life. It is estimated that 60% of patients with neuropathic pain also experience depression, anxiety, and stress symptoms. Altered mood, including stress, can be a consequence of several painful conditions but can also favor pain chronicization when preexisting. Despite the apparent tight connection between clinical pain and mood/stress disorders, the exact physiological mechanisms remain unclear. This review aims to provide an overview of state-of-the-art research on the mechanisms of pain related to the pathophysiology of depression, anxiety, and stress disorders.

Is brain perfusion correlated to switching mood states and cognitive impairment in bipolar disorder type I? A longitudinal study using perfusion imaging approach.

Type I Bipolar disorder (BD-I) is a neuropsychiatric disorder characterized by manic or mixed-featured episodes, impaired cognitive functioning, and persistent work and social functioning impairment. This study aimed to investigate within-subject; (i) differences in brain perfusion using Single-photon emission computed tomography (SPECT) between manic and euthymic states in BD-I patients; (ii) explore potential associations between altered brain perfusion and cognitive status; and (iii) examine the relationship between cerebral perfusion and mania symptom ratings. Seventeen adult patients diagnosed with BD-I in a manic episode were recruited, and clinical assessments, cognitive tests, and brain perfusion studies were conducted at baseline (mania state) and a follow-up visit 6 months later. The results showed cognitive impairment during the manic episode, which persisted during the euthymic state at follow-up. However, no significant changes in brain perfusion were observed between the manic and euthymic states. During mania, trends toward decreased perfusion in the left cerebellum and right superior parietal lobule were noted. Additionally, trends indicated a higher perfusion imbalance in the left superior and middle frontal gyrus during mania and the right superior and middle frontal gyrus during euthymia. No significant correlations existed between brain perfusion, mania symptom ratings, and cognitive performance, indicating that symptomatology might represent more than neural hemodynamics. These findings suggest that cognitive impairment may persist in BD-I patients and highlight the need for therapeutic interventions targeting cognitive deficits. More extensive studies with extended follow-up periods are warranted further to investigate brain perfusion and cognitive functioning in BD-I patients.

Digitalized transcranial electrical stimulation: A consensus statement.

OBJECTIVE: Although relatively costly and non-scalable, non-invasive neuromodulation interventions are treatment alternatives for neuropsychiatric disorders. The recent developments of highly-deployable transcranial electric stimulation (tES) systems, combined with mobile-Health technologies, could be incorporated in digital trials to overcome methodological barriers and increase equity of access. The study aims are to discuss the implementation of tES digital trials by performing a systematic scoping review and strategic process mapping, evaluate methodological aspects of tES digital trial designs, and provide Delphi-based recommendations for implementing digital trials using tES. METHODS: We convened 61 highly-productive specialists and contacted 8 tES companies to assess 71 issues related to tES digitalization readiness, and processes, barriers, advantages, and opportunities for implementing tES digital trials. Delphi-based recommendations (>60% agreement) were provided. RESULTS: The main strengths/opportunities of tES were: (i) non-pharmacological nature (92% of agreement), safety of these techniques (80%), affordability (88%), and potential scalability (78%). As for weaknesses/threats, we listed insufficient supervision (76%) and unclear regulatory status (69%). Many issues related to methodological biases did not reach consensus. Device appraisal showed moderate digitalization readiness, with high safety and potential for trial implementation, but low connectivity. CONCLUSIONS: Panelists recognized the potential of tES for scalability, generalizability, and leverage of digital trials processes; with no consensus about aspects regarding methodological biases. SIGNIFICANCE: We further propose and discuss a conceptual framework for exploiting shared aspects between mobile-Health tES technologies with digital trials methodology to drive future efforts for digitizing tES trials.

Transcranial Pulsed-Current Stimulation versus Transcranial Direct Current Stimulation in Patients with Disorders of Consciousness: A Pilot, Sham-Controlled Cross-Over Double-Blind Study.

Transcranial direct-current stimulation (tDCS) over the prefrontal cortex can improve signs of consciousness in patients in a minimally conscious state. Transcranial pulsed-current stimulation (tPCS) over the mastoids can modulate brain activity and connectivity in healthy controls. This study investigated the feasibility of tPCS as a therapeutic tool in patients with disorders of consciousness (DoC) and compared its neurophysiological and behavioral effects with prefrontal tDCS. This pilot study was a randomized, double-blind sham-controlled clinical trial with three sessions: bi-mastoid tPCS, prefrontal tDCS, and sham. Electroencephalography (EEG) and behavioral assessments were collected before and after each stimulation session. Post minus pre differences were compared using Kruskal-Wallis and Wilcoxon signed-rank tests. Twelve patients with DoC were included in the study (eight females, four traumatic brain injury, 50.3 ± 14 y.o., 8.8 ± 10.5 months post-injury). We did not observe any side-effects following tPCS, nor tDCS, and confirmed their feasibility and safety. We did not find a significant effect of the stimulation on EEG nor behavioral outcomes for tPCS. However, consistent with prior findings, our exploratory analyses suggest that tDCS induces behavioral improvements and an increase in theta frontal functional connectivity.

The Use of Conditioning Open-Label Placebo in Opioid Dose Reduction: A Case Report and Literature Review.

Introduction: Adequate pain management for inpatients in rehabilitation units is essential for achieving therapeutic goals. Opioid treatments are commonly prescribed, but these are associated with numerous adverse effects, including the risk of addiction and decreased quality of life. Conditioning an open-label placebo is a promising approach to extend the analgesic effect of the opioid while reducing its overall dosage. Objectives: To describe a patient's experience in using conditioning open-label placebo (COLP) as a pharmaco-behavioral intervention to decrease opioid intake and its side effects after inpatient rehabilitation discharge, and to perform a literature review about the use of open-label placebo in pain. Methods: This case study has been extracted from a clinical trial initiated in 2018. A 61-year-old male was recruited at a tertiary rehabilitation hospital after suffering a traumatic sport-related injury and orthopedic surgery. Pain management included prescription of non-steroidal anti-inflammatory drugs (NSAIDs) and short-acting oxycodone. After trial participation, the patient requested off-label COLP treatment to help him decrease outpatient opioid utilization. Results: After COLP treatment, the patient could discontinue oxycodone intake (a reduction from 15 morphine equivalents/day) after rehabilitation discharge. Moreover, opioid side effects decreased from 46 to 9 points on the numerical opioid side-effects scale. A literature review identified five clinical trials using "honest" open-label placebo (OLP) or COLP as an experimental intervention for pain control. From these studies, two were in the area of chronic lower back pain, one in post spine surgery, one in irritable bowel syndrome, and another in spinal cord injury and polytrauma. Four studies reported positive outcomes related to pain control, while one study showed no significant differences in pain management between treatment-as-usual and the COLP group. Conclusion: The case report illustrates how a pharmaco-behavioral intervention can facilitate downward opioid titration safely after inpatient rehabilitation. It initiates a discussion about new approaches for opioid management using conditioning and the patient's expectation of pain relief.

EEG modulation by different transcranial direct current stimulation (tDCS) montages: a randomized double-blind sham-control mechanistic pilot trial in healthy participants.

Background: Based on our Phantom study on transcranial direct current stimulation (tDCS), we hypothesized that EEG band power and field confinement would be greater following left dorsolateral prefrontal cortex (DLPFC - F3) tDCS using circular vs. rectangular electrodes.Methods: Double-blind-randomized trial comparing tDCS with anode over left DLPFC (groups: rectangular electrodes, circular electrodes, sham) and 2 active subgroup references (right shoulder vs. right DLPFC).Results: Twenty-four randomized participants were assessed. We indeed found higher average EEG power spectral density (PSD) across bands for circular vs. rectangular electrodes, largely confined to F3 and there was a significant increase at AF3 for low alpha (p = 0.037). Significant differences included: increased PSD in low beta (p = 0.024) and theta bands (p = 0.021) at F3, and in theta (p = 0.036) at FC5 for the right DLPFC vs. shoulder with no coherence changes. We found PSD differences between active vs. sham tDCS at Fz for alpha (p = 0.043), delta (p = 0.036), high delta (p = 0.030); and at FC1 for alpha (p = 0.031), with coherence differences for F3-Fz in beta (p = 0.044), theta (p = 0.044), delta (p = 0.037) and high delta (p = 0.009).Conclusion: This pilot study despite low statistical power given its small sample size shows that active left DLPFC tDCS modulates EEG frontocentrally and suggests that electrode shapes/reference locations affect its neurophysiological effects, such as increased low alpha power at AF3 using circular vs. rectangular electrodes. Further research with more participants is warranted.

Stimuli Characteristics and Psychophysical Requirements for Visual Training in Amblyopia: A Narrative Review.

Active vision therapy using perceptual learning and/or dichoptic or binocular environments has shown its potential effectiveness in amblyopia, but some doubts remain about the type of stimuli and the mode and sequence of presentation that should be used. A search was performed in PubMed, obtaining 143 articles with information related to the stimuli used in amblyopia rehabilitation, as well as to the neural mechanisms implied in such therapeutic process. Visual deficits in amblyopia and their neural mechanisms associated are revised, including visual acuity loss, contrast sensitivity reduction and stereopsis impairment. Likewise, the most appropriate stimuli according to the literature that should be used for an efficient rehabilitation of the amblyopic eye are described in detail, including optotypes, Gabor's patches, random-dot stimuli and Vernier's stimuli. Finally, the properties of these stimuli that can be modified during the visual training are discussed, as well as the psychophysical method of their presentation and the type of environment used (perceptual learning, dichoptic stimulation or virtual reality). Vision therapy using all these revised concepts can be an effective option for treating amblyopia or accelerating the treatment period when combining with patching. It is essential to adapt the stimuli to the patient's individual features in both monocular and binocular training.

Conditioning open-label placebo: a pilot pharmacobehavioral approach for opioid dose reduction and pain control.

Opioid consumption for those in comprehensive inpatient rehabilitation units is high because of the complexity of their injuries. Notably, pain in rehabilitation leads to worsened clinical outcomes because of maladaptive behaviors and poor engagement during therapies. It is critical to developing evidence-based pharmacobehavioral interventions. Based on principles of classical conditioning, conditioning open-label placebo (COLP) is a promising approach for reducing opioid use in comprehensive inpatient rehabilitation, and this technique takes advantage of the possibility of association learning and opioid pharmacology to promote evoked placebo-driven analgesia. OBJECTIVES: In this brief report, we evaluate the feasibility of COLP as a pharmacobehavioral intervention to decrease total opioid consumption in patients with pain hospitalized at Spaulding Rehabilitation Hospital. METHODS: Inpatients with spinal cord injury and polytrauma (n = 20) with moderate to severe pain were randomized to receive COLP (n = 10) or treatment-as-usual for 6 consecutive days. Opioid utilization was measured by morphine equivalents using the morphine equivalent dose conversion; pain severity was assessed using the numerical visual analog scale. RESULTS: Conditioning open-label placebo significantly reduced total opioid consumption by the end of the intervention period (P ≤ 0.001). Pain reduction was also significant for the COLP group (P = 0.005), whereas the treatment-as-usual group demonstrated a trend towards pain reduction (P = 0.05). CONCLUSIONS: This study presents the first data in the use of a pharmacobehavioral intervention that capitalize on the benefits of open-label placebo and classical drug conditioning for opioid dose reduction in a population with moderate to severe pain exposed to intensive inpatient rehabilitation.

Comparing focused attention meditation to meditation with mobile neurofeedback for persistent symptoms after mild-moderate traumatic brain injury: a pilot study.

PRIMARY OBJECTIVE: This study evaluated whether a meditation practice incorporating mobile neurofeedback (mNF) offers any advantage over a more traditional form of focused attention (FA) meditation in managing persistent symptoms after traumatic brain injury (TBI) (clinicaltrials.gov NCT02615535). RESEARCH DESIGN: Pilot randomized clinical trial, exploring feasibility of mNF in TBI. METHODS AND PROCEDURES: Participants included adults with chronic mood and/or cognitive complaints following mild-moderate TBI. Subjects practiced either FA (n = 10) or mNF (n = 10) meditation 12 minutes daily for 6 weeks. Pre-post intervention difference on the Neurobehavioral Symptom Inventory (NSI) was the primary outcome variable. Secondary outcomes included the Beck Anxiety Inventory (BAI), Beck Depression Inventory-II (BDI-II), amongst other scales and neurocognitive tests. MAIN OUTCOMES AND RESULTS: No significant pre-post between-group differences were found on the NSI (p = .838) nor other assessments. In an exploratory analysis combining FA and mNF data, meditation was associated with significant improvements on the NSI (p = .04), BAI (p = .012) and BDI (p = .037). CONCLUSIONS: Meditating with neurofeedback does not appear to provide an advantage over meditating on one's own for chronic post-TBI symptoms. Further research on home-based meditation following TBI, whether self-directed or technologically facilitated, is warranted.

Brain perfusion during manic episode and at 6-month follow-up period in bipolar disorder patients: Correlation with cognitive functions.

BACKGROUND: Patterns of altered cerebral perfusion and cognitive dysfunction have been described in Bipolar Disorder (BD) acute episodes and euthymia. Knowledge of the relationship between cognitive function and perfusion in a manic state and status when followed up is still limited. OBJECTIVE: To describe brain perfusion alterations and its relationship with cognitive impairment in patients with BD during manic episodes and after 6 months. METHODS: Observational-prospective study in 10 type I BD adults during moderate-severe manic episodes. We assessed sociodemographic data and clinical variables as well as cognitive function through Screening for Cognitive Impairment in Psychiatry (SCIP-S). Finally, we performed a Brain Perfusion SPECT using a Tc99m-ethyl cysteine dimer. RESULTS: During manic episodes, patients showed cognitive impairment with a mean SCIP-S score of 63.8 ± 17.16. This was positively correlated with perfusion measured as relative reuptake index (RRI) at the right temporal pole (ρ = 0.65 p = .0435) and negatively correlated with right the orbitofrontal cortex (ρ = -0.70 p = .0077) and the right subgenual cingulate cortex (ρ = -0.70 p = .0256). Episode severity measured by the Young Mania Rating Scale (YMRS) positively correlated with RRI at the right temporal pole (ρ = 0.75, p = .01). At follow-up, six patients were taking treatment and were euthymic, we found a negative correlation with the YMRS and RRI at the bilateral orbitofrontal cortex (ρ = -0.8827, p = .019). They did not show significant improvement in cognitive performance at SCIP-S, and there was negative correlation with the following of the SCIP-S subscales; processing speed with the bilateral dorsolateral prefrontal, the bilateral medial prefrontal, the left temporal pole cortex RRI, and verbal fluency with the bilateral anterior cingulate cortex RRI. CONCLUSION: Cognitive impairment was correlated with brain perfusion patterns at baseline and follow-up. Large sample size studies with longer follow-up are needed to describe the changes in perfusion and cognitive functions in BD.

Nocebo Effects in Concussion: Is All That Is Told Beneficial?

Nocebo effects refer to new or worsening symptoms that develop in response to negative health-related information, beliefs, and/or experiences. In recent years, research on concussion pathophysiology has significantly advanced. Through health campaigns and media coverage, emerging knowledge on the risks of this injury has been quickly disseminated to the public, and nowadays, the public perceives concussions as more hazardous to health than ever before. Although advancements in concussion-related research and care are of great importance and value, we ask in this article whether the increasing negative publicity regarding concussion also carries any latent costs. Are additional nocebo effects being fostered? To do so, we will review the literature on the psychological and neurobiological processes underlying nocebo effects, present a series of clinical studies demonstrating the ways in which nocebos may impact concussion outcomes both clinically and societally, then speculate on further potential mechanisms for nocebo effects in concussion. We conclude with an outline of the specific efforts one may take to minimize nocebo effects in concussion-related care.

Neurofeedback impacts cognition and quality of life in pediatric focal epilepsy: An exploratory randomized double-blinded sham-controlled trial.

OBJECTIVE: Children with epilepsy experience cognitive deficits and well-being issues that have detrimental effects on their development. Pharmacotherapy is the standard of care in epilepsy; however, few interventions exist to promote cognitive development and to mitigate disease burden. We aimed to examine the impact of two different modalities of neurofeedback (NFB) on cognitive functioning and quality-of-life (QOL) measurements in children and adolescents with controlled focal epilepsy. The study also explored the effects of NFB on clinical outcomes and electroencephalography (EEG) quantitative analysis. METHODS: Participants (n = 44) with controlled focal epilepsy were randomized to one of three arms: sensorimotor rhythm (SMR) NFB (n = 15), slow cortical potentials (SCP) NFB (n = 16), or sham NFB (n = 13). All participants received 25 sessions of intervention. The attention switching task (AST), Liverpool Seizure Severity Scale (LSSS), seizure frequency (SF), EEG power spectrum, and coherence were measured at baseline, postintervention, and at 3-month follow-up. RESULTS: In children and adolescents with controlled focal epilepsy, SMR training significantly reduced reaction time in the AST (p = 0.006), and this was correlated with the difference of change for theta power on EEG (p = 0.03); only the SMR group showed a significant decrease in beta coherence (p = 0.03). All groups exhibited improvement in QOL (p = <0.05). CONCLUSIONS: This study provides the first data on two NFB modalities (SMR and SCP) including cognitive, neurophysiological, and clinical outcomes in pediatric epilepsy. Sensorimotor rhythm NFB improved cognitive functioning, while all the interventions showed improvements in QOL, demonstrating a powerful placebo effect in the sham group.

Transcranial Direct Current Stimulation Optimization - From Physics-Based Computer Simulations to High-Fidelity Head Phantom Fabrication and Measurements.

BACKGROUND: Transcranial direct current stimulation (tDCS) modulates neural networks. Computer simulations, while used to identify how currents behave within tissues of different conductivity properties, still need to be complemented by physical models. OBJECTIVE/HYPOTHESIS: To better understand tDCS effects on biology-mimicking tissues by developing and testing the feasibility of a high-fidelity 3D head phantom model that has sensing capabilities at different compartmental levels. METHODS: Models obtained from MRI images generated 3D printed molds. Agar phantoms were fabricated, and 18 monitoring electrodes were placed on specific phantom brain areas. RESULTS: When using rectangular electrodes, the measured and simulated voltages at the monitoring electrodes agreed reasonably well, except at excitation locations. The electric field distribution in different phantom layers appeared better confined with circular electrodes compared to rectangular electrodes. CONCLUSION: The high-fidelity 3D head model was found to be feasible and comparable with computer-based electrical simulations, with high correlation between simulated and measured brain voltages. This feasibility study supports testing to further assess the reliability of this model.

Combining Fluoxetine and rTMS in Poststroke Motor Recovery: A Placebo-Controlled Double-Blind Randomized Phase 2 Clinical Trial.

Background. Although recent evidence has shown a new role of fluoxetine in motor rehabilitation, results are mixed. We conducted a randomized clinical trial to evaluate whether combining repetitive transcranial magnetic stimulation (rTMS) with fluoxetine increases upper limb motor function in stroke. Methods. Twenty-seven hemiparetic patients within 2 years of ischemic stroke were randomized into 3 groups: Combined (active rTMS + fluoxetine), Fluoxetine (sham rTMS + fluoxetine), or Placebo (sham rTMS + placebo fluoxetine). Participants received 18 sessions of 1-Hz rTMS in the unaffected primary motor cortex and 90 days of fluoxetine (20 mg/d). Motor function was assessed using Jebsen-Taylor Hand Function (JTHF) and Fugl-Meyer Assessment (FMA) scales. Corticospinal excitability was assessed with TMS. Results. After adjusting for time since stroke, there was significantly greater improvement in JTHF in the combined rTMS + fluoxetine group (mean improvement: -214.33 seconds) than in the placebo (-177.98 seconds, P = 0.005) and fluoxetine (-50.16 seconds, P < 0.001) groups. The fluoxetine group had less improvement than placebo on both scales (respectively, JTHF: -50.16 vs -117.98 seconds, P = 0.038; and FMA: 6.72 vs 15.55 points, P = 0.039), suggesting that fluoxetine possibly had detrimental effects. The unaffected hemisphere showed decreased intracortical inhibition in the combined and fluoxetine groups, and increased intracortical facilitation in the fluoxetine group. This facilitation was negatively correlated with motor function improvement (FMA, r2 = -0.398, P = 0.0395). Conclusion. Combined fluoxetine and rTMS treatment leads to better motor function in stroke than fluoxetine alone and placebo. Moreover, fluoxetine leads to smaller improvements than placebo, and fluoxetine's effects on intracortical facilitation suggest a potential diffuse mechanism that may hinder beneficial plasticity on motor recovery.

Distinct behavioral response of primary motor cortex stimulation in itch and pain after burn injury.

It is still unclear whether chronic neuropathic pain and itch share similar neural mechanisms. They are two of the most commonly reported challenges following a burn injury and can be some of the most difficult to treat. Transcranial direct current stimulation (tDCS) has previously been studied as a method to modulate pain related neural circuits. Therefore, we aimed to test the effects of tDCS on post-burn neuropathic pain and itch as to understand whether this would induce a simultaneous modulation of these two sensory manifestations. We conducted a pilot randomized controlled clinical trial comprised of two phases of active or sham M1 tDCS (Phase I: 10 sessions followed by a follow-up period of 8 weeks; Phase II: additional 5 sessions followed by a follow-up period of 8 weeks, and a final visit 12 months from baseline). Pain levels were assessed with the Brief Pain Inventory (BPI) and levels of itch severity were assessed with the Visual Analogue Scale (VAS). Measurements were collected at baseline, after the stimulation periods, at 2, 4 and 8-week follow up both for Phase I and II, and at the final visit. Sixteen patients were assigned to the active group and 15 to the sham group. Ten sessions of active tDCS did not reduce the level of pain or itch. We identified that itch levels were reduced at 2-week follow-up after the sham tDCS session, while no placebo effect was found for the active group. No difference between active and sham groups was observed for pain. We did not find any treatment effects during Phase II. Based on these findings, it seems that an important placebo effect occurred during sham tDCS for itch, while active M1 tDCS seems to disrupt sensory compensatory mechanisms. We hypothesize that pain and itch are complementary but distinct mechanisms of adaptation after peripheral sensory injury following a burn injury and need to be treated differently.

Ceftriaxone Treatment Preserves Cortical Inhibitory Interneuron Function via Transient Salvage of GLT-1 in a Rat Traumatic Brain Injury Model.

Traumatic brain injury (TBI) results in a decrease in glutamate transporter-1 (GLT-1) expression, the major mechanism for glutamate removal from synapses. Coupled with an increase in glutamate release from dead and dying neurons, this causes an increase in extracellular glutamate. The ensuing glutamate excitotoxicity disproportionately damages vulnerable GABAergic parvalbumin-positive inhibitory interneurons, resulting in a progressively worsening cortical excitatory:inhibitory imbalance due to a loss of GABAergic inhibitory tone, as evidenced by chronic post-traumatic symptoms such as epilepsy, and supported by neuropathologic findings. This loss of intracortical inhibition can be measured and followed noninvasively using long-interval paired-pulse transcranial magnetic stimulation with mechanomyography (LI-ppTMS-MMG). Ceftriaxone, a ß-lactam antibiotic, is a potent stimulator of the expression of rodent GLT-1 and would presumably decrease excitotoxic damage to GABAergic interneurons. It may thus be a viable antiepileptogenic intervention. Using a rat fluid percussion injury TBI model, we utilized LI-ppTMS-MMG, quantitative PCR, and immunohistochemistry to test whether ceftriaxone treatment preserves intracortical inhibition and cortical parvalbumin-positive inhibitory interneuron function after TBI in rat motor cortex. We show that neocortical GLT-1 gene and protein expression are significantly reduced 1 week after TBI, and this transient loss is mitigated by ceftriaxone. Importantly, whereas intracortical inhibition declines progressively after TBI, 1 week of post-TBI ceftriaxone treatment attenuates the loss of inhibition compared to saline-treated controls. This finding is accompanied by significantly higher parvalbumin gene and protein expression in ceftriaxone-treated injured rats. Our results highlight prospects for ceftriaxone as an intervention after TBI to prevent cortical inhibitory interneuron dysfunction, partly by preserving GLT-1 expression.

Placebo Effects in Traumatic Brain Injury.

In recent years, several randomized controlled trials evaluating pharmaceutical treatments for traumatic brain injury (TBI) have failed to demonstrate efficacy over placebo, with both active and placebo arms improving at comparable rates. These findings could be viewed in opposing ways, suggesting on the one hand failure of the tested outcome, but on the other, representing evidence of robust placebo effects in TBI. In this article, we examine several of the primary psychological processes driving placebo effects (verbal suggestion, cognitive re-framing, interpersonal interactions, conditioning, therapeutic alliance, anxiety reduction) as well as placebo neurobiology (top-down cortical regulation, reward system activation, dopaminergic and serotonergic neurotransmission). We then extrapolate from the literature to explore whether something inherent in TBI makes it particularly responsive to placebos. Viewed as such here, placebos may indeed represent a powerful and effective treatment for a variety of post-TBI complaints.

A Preliminary Study on qEEG in Burn Patients With Chronic Pruritus.

OBJECTIVE: To explore and determine the reorganizational changes in the cortical neural circuits associated with pruritis, this study was undertaken to compare the electroencephalography (EEG) changes in burn patients having primary symptoms of chronic itching (pruritis) and their paired healthy subjects. METHODS: Eight subjects were recruited for this exploratory pilot study: 4 patients with pruritus after burn injury matched by gender and age with 4 healthy subjects. EEG recordings were analyzed for absolute alpha, low beta, high beta, and theta power for both groups. RESULTS: The mean age of the burn patients was 41.75 years; while the mean age for the matched healthy subjects was 41.5 years. All subjects were male. A decreased alpha activity was observed in the occipital channels (0.82 vs. 1.4; p=0.01) and a decreased low beta activity in the frontal area (0.22 vs. 0.4; p=0.049) in eyes closed conditions. An overall decreased theta trend was observed in both the eyes open and eyes closed conditions in burn patients, compared to healthy individuals. CONCLUSION: This preliminary study presents initial evidence that chronic pruritus in burn subjects may be associated with brain reorganizational changes at the cortical level characterized by an EEG pattern.

Noninvasive Brain Stimulation, Maladaptive Plasticity, and Bayesian Analysis in Phantom Limb Pain.

Introduction: Phantom limb pain (PLP) is a common and poorly understood pathology of difficult medical control that progressively takes place after amputation occurs. Objective: This article discusses the multifactorial bases of PLP. These bases involve local changes at the stump level, spinal modifications of excitability, deafferentation, and central sensitization, leading to the development of maladaptive plasticity, and consequentially, defective processing of sensory information by associative neural networks. These changes can be traced by neurophysiology and imaging topographical studies, indicating a degree of cortical reorganization that perpetuates pain and discomfort. Intervention: Noninvasive brain stimulation can be an alternative way to manage PLP. This article discusses two techniques-transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS)-that have shown promising results for controlling PLP. The modulation that both techniques rely on is based on synaptic mechanisms linked to long-term potentiation and long-term depression phenomena. By applying tDCS or rTMS, clinicians can target processes associated with central sensitization and maladaptive plasticity, while promoting adequate sensory information processing by integrative cognitive behavioral techniques in a comprehensive rehabilitation program. Conclusions: Understanding PLP from a dynamic neurocomputational perspective will help to develop better treatments. Furthermore, Bayesian analysis of sensory information can help guide and monitor therapeutic interventions directed toward PLP resolution.