The polymorphism Val158Met in the COMT gene: disrupted dopamine system in fibromyalgia patients?

ABSTRACT: The single-nucleotide polymorphism (SNP) rs4680 in the catechol-O-methyltransferase gene ( COMT ) is a missense variant (Val158Met) associated with altered activity of the COMT enzyme and suggested as a predictive feature for developing some chronic pain conditions. However, there are controversial results on its role in fibromyalgia (FM). Here, the SNP Val158Met was analyzed in 294 FM patients (without comorbidities) and 209 healthy controls (without chronic pain). The concurrent impact of Val158Met genotypes and FM comorbid disorders (depression and sleep impairment) on FM risk were tested. In addition, the genotypic distribution of FM patients in relation to pain intensity was evaluated. The G allele (Val) resulted in being more represented in the FM group (57.8%) compared with the control group (48.8%; P = 0.037). Logistic regression highlighted that having the G/G (Val/Val) homozygous genotype was associated with 2 times higher risk of having FM compared with the A/A (Met/Met) carriers ( P = 0.038), whereas depression and sleep impairment increased FM risk by 12 and 8 times, respectively ( P < 0.001). However, considering only the FM patient group, the A/A homozygous genotype was significantly associated with severe pain intensity ( P = 0.007). This study highlighted associations between the SNP Val158Met and both FM and pain intensity, suggesting a link between dopaminergic dysfunction and vulnerability to chronic pain. Further studies should explore this SNP in FM patients in conjunction with COMT enzymatic activity and other symptoms connected with the dopaminergic system such as depression or sleep impairment.

Translation, validity, and reliability of the European Portuguese version of the Touch Experiences and Attitudes Questionnaire.

Background: Positive touch experiences have proved to be extremely important throughout our lifespan, with cascading effects on our social life. However, few questionnaires are available to measure attitudes and experiences of touch in the Portuguese population. This study aimed to translate and validate the European Portuguese version of the Touch Experiences and Attitudes Questionnaire (TEAQ), as a reliable and valid instrument to measure different aspects of affective touch experiences and attitudes. Methods: Therefore, an online sample of 384 (299 females and 85 males) participants, aged between 18 and 75 years (M = 24.59; SD = 9.56) was collected. Multidimensional Rasch model and confirmatory factor analysis were carried out, and also reliability and convergent and discriminant validity were determined. In addition, we examined sex differences in attitudes and experiences of touch. Results: Results showed good fit indexes for the 52-item six-factor model structure (friends and family touch, current intimate touch, childhood touch, attitudes to self-care, attitudes to intimate touch, and attitudes to unfamiliar touch). This instrument also showed good reliability and acceptable convergent and discriminant validity. Significant sex differences were found, with female participants reporting more positive touch experiences (including childhood touch, friends and family touch, and current intimate touch) and a more favourable attitude to self-care, with males showing a more positive attitude towards unfamiliar touch. Regarding attitudes towards the intimate touch, scores for both groups were comparable. Conclusion: Overall, the European Portuguese version of the TEAQ presented good psychometric properties and appears to be a reliable and valid self-report measure, being a useful and beneficial instrument in research and clinical settings.

A Machine Learning Approach in Autism Spectrum Disorders: From Sensory Processing to Behavior Problems.

Atypical sensory processing described in autism spectrum disorders (ASDs) frequently cascade into behavioral alterations: isolation, aggression, indifference, anxious/depressed states, or attention problems. Predictive machine learning models might refine the statistical explorations of the associations between them by finding out how these dimensions are related. This study investigates whether behavior problems can be predicted using sensory processing abilities. Participants were 72 children and adolescents (21 females) diagnosed with ASD, aged between 6 and 14 years (M = 7.83 years; SD = 2.80 years). Parents of the participants were invited to answer the Sensory Profile 2 (SP2) and the Child Behavior Checklist (CBCL) questionnaires. A collection of 26 supervised machine learning regression models of different families was developed to predict the CBCL outcomes using the SP2 scores. The most reliable predictions were for the following outcomes: total problems (using the items in the SP2 touch scale as inputs), anxiety/depression (using avoiding quadrant), social problems (registration), and externalizing scales, revealing interesting relations between CBCL outcomes and SP2 scales. The prediction reliability on the remaining outcomes was "moderate to good" except somatic complaints and rule-breaking, where it was "bad to moderate." Linear and ridge regression achieved the best prediction for a single outcome and globally, respectively, and gradient boosting machine achieved the best prediction in three outcomes. Results highlight the utility of several machine learning models in studying the predictive value of sensory processing impairments (with an early onset) on specific behavior alterations, providing evidences of relationship between sensory processing impairments and behavior problems in ASD.

Neural correlates of unpredictable Stop and non-Stop cues in overt and imagined execution.

The ability to inhibit incorrect behaviors is crucial for survival. In real contexts, cues that require stopping usually appear intermixed with indications to continue the ongoing action. However, in the classical Stop-signal task (SST), the unpredictable stimuli are always signals that require inhibition. To understand the neural mechanisms activated by low-probability nonstop cues, we recorded the electroencephalography from 23 young volunteers while they performed a modified SST where the unpredictable stimuli could be either Stop or confirmatory Go signals (CGo). To isolate the influence of motor output, the SST was performed during overt and covert execution. We found that, paradoxically, CGo stimuli activated motor inhibition processes, and evoked patterns of brain activity similar to those obtained after Stop signals (N2/P3 event-related potentials and midfrontal theta power increase), though in lesser magnitude. These patterns were also observed during the imagined performance. Finally, applying machine learning procedures, we found that the brain activity evoked after CGo versus Stop signals can be classified above chance during both, overt and imagined execution. Our results provide evidence that unpredictable signals cause motor inhibition even when they require to continue an ongoing action.

Transcranial direct current stimulation of 3 cortical targets is no more effective than placebo as treatment for fibromyalgia: a double-blind sham-controlled clinical trial.

ABSTRACT: Transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) and the dorsolateral prefrontal cortex seem to improve pain and other symptoms of fibromyalgia (FM), although the evidence on the effectiveness of tDCS and the optimal stimulation target is not robust enough. Our main objective was to establish the optimal area of stimulation, comparing the 2 classical targets and a novel pain-related area, the operculo-insular cortex, in a sham-controlled trial. Using a double-blind design, we randomly assigned 130 women with FM to 4 treatment groups (M1, dorsolateral prefrontal cortex, operculo-insular cortex, and sham), each receiving fifteen 20-minute sessions of 2 mA anodal tDCS over the left hemisphere. Our primary outcome was pain intensity. The secondary outcomes were the other core symptoms of FM (fatigue, mood, cognitive and sleep disorders, and hyperalgesia measured by the pressure pain threshold). We performed the assessment at 3 time points (before, immediately after treatment, and at 6 months follow-up). The linear mixed-model analysis of variances showed significant treatment effects across time for clinical pain and for fatigue, cognitive and sleep disturbances, and experimental pain, irrespective of the group. In mood, the 3 active tDCS groups showed a significantly larger improvement in anxiety and depression than sham. Our findings provide evidence of a placebo effect, support the use of tDCS for the treatment of affective symptoms, and challenge the effectiveness of tDCS as treatment of FM.

DNA Methylation Changes in Fibromyalgia Suggest the Role of the Immune-Inflammatory Response and Central Sensitization.

Fibromyalgia (FM) has been explained as a result of gene-environment interactions. The present study aims to verify DNA methylation differences in eleven candidate genome regions previously associated to FM, evaluating DNA methylation patterns as potential disease biomarkers. DNA methylation was analyzed through bisulfite sequencing, comparing 42 FM women and their 42 healthy sisters. The associations between the level of methylation in these regions were further explored through a network analysis. Lastly, a logistic regression model investigated the regions potentially associated with FM, when controlling for sociodemographic variables and depressive symptoms. The analysis highlighted significant differences in the GCSAML region methylation between patients and controls. Moreover, seventeen single CpGs, belonging to other genes, were significantly different, however, only one cytosine related to GCSAML survived the correction for multiple comparisons. The network structure of methylation sites was different for each group; GRM2 methylation represented a central node only for FM patients. Logistic regression revealed that depressive symptoms and DNA methylation in the GRM2 region were significantly associated with FM risk. Our study encourages better exploration of GCSAML and GRM2 functions and their possible role in FM affecting immune, inflammatory response, and central sensitization of pain.

DNA methylation changes in genes involved in inflammation and depression in fibromyalgia: a pilot study.

OBJECTIVES: The present pilot study aims to investigate DNA methylation changes of genes related to fibromyalgia (FM) development and its main comorbid symptoms, including sleep impairment, inflammation, depression and other psychiatric disorders. Epigenetic modifications might trigger or perpetuate complex interplay between pain transduction/transmission, central pain processing and experienced stressors in vulnerable individuals. METHODS: We conducted DNA methylation analysis by targeted bisulfite NGS sequencing testing differential methylation in 112 genomic regions from leukocytes of eight women with FM and their eight healthy sisters as controls. RESULTS: Tests for differentially methylated regions and cytosines brought focus on the GRM2 gene, encoding the metabotropic glutamate receptor2. The slightly increased DNA methylation observed in the GRM2 region of FM patients may confirm the involvement of the glutamate pathway in this pathological condition. Logistic regression highlighted the simultaneous association of methylation levels of depression and inflammation-related genes with FM. CONCLUSIONS: Altogether, the results evidence the glutamate pathway involvement in FM and support the idea that a combination of methylated and unmethylated genes could represent a risk factor to FM or its consequence, more than single genes. Further studies on the identified biomarkers could contribute to unravel the causative underlying FM mechanisms, giving reliable directions to research, improving the diagnosis and effective therapies.

A family-based study to identify genetic biomarkers of fibromyalgia: consideration of patients' subgroups.

OBJECTIVES: Evidence from genome-wide and candidate gene association studies, familial aggregation and linkage analyses demonstrate the genetic contribution to fibromyalgia (FM) disease. This study aimed to identify genetic biomarkers of FM and its related comorbid disorders, by exploring 41 polymorphisms potentially involved in FM pathogenesis in families with at least one patient with FM. METHODS: Core symptoms were assessed, and blood samples collected from 556 patients with FM and 395 healthy relatives. For the genetic study, a final sample of 401 FM patients and 232 healthy controls was selected, discarding patients with concomitant pathologies and controls with chronic pain. A family-based approach using DFAM test (Plink) and SNPs (single nucleotide polymorphisms) combination analyses to compare FM patients vs. controls were first applied. Second, the genotypic distribution of subgroups of FM patients, stratified by severe vs. mild symptoms of pain, depression and sleep impairment, was considered. RESULTS: No evidence of associations with FM per se were detected, using either a family-based approach or SNPs combination analyses. However, considering the subgroups of FM patients, the SNP rs6454674 (CNR1, cannabinoid receptor 1 gene) was found as a potential genetic marker of FM correlated with depression (p<.001). CONCLUSIONS: No significant associations using either the family-based analysis or the SNPs combination tests dissociated FM patients and their healthy relatives. FM patients with and without depression showed a significant difference in the genotypic distribution related to the SNP rs6454674 in the cannabinoid receptor 1 gene (CNR1) indicating that FM is not a homogenous disorder.

Effects of the COVID-19 pandemic on chronic pain in Spain: a scoping review.

The COVID-19 outbreak has been a great challenge in the management of chronic pain patients. We have conducted a rapid scoping review to assess the impact of the pandemic (and the associated public health measures) on the health status and management practices of chronic pain patients in Spain. To this end, we performed a bibliographic search in LitCOVID and PubMed, and reviewed official websites and documents, and expert reports. The review showed that (1) the studies consistently indicate that the pandemic has had a very negative impact on the physical and psychological health of chronic pain patients; (2) there are scarce data on how the pandemic affected pain unit consultations and a lack of protocols to organize health care in the face of future waves of contagion, with little implementation of telehealth. We make proposals to improve management of chronic pain patients in pandemic situations, which should pivot around 3 axes: (1) a coordinated response of all the relevant stakeholders to define a future roadmap and research priorities, (2) a biopsychosocial approach in pain management, and (3) development and implementation of novel telemedicine solutions.

Patients with fibromyalgia show increased beta connectivity across distant networks and microstates alterations in resting-state electroencephalogram.

Fibromyalgia (FM) is a chronic condition characterized by widespread pain of unknown etiology associated with alterations in the central nervous system. Although previous studies demonstrated altered patterns of brain activity during pain processing in patients with FM, alterations in spontaneous brain oscillations, in terms of functional connectivity or microstates, have been barely explored so far. Here we recorded the EEG from 43 patients with FM and 51 healthy controls during open-eyes resting-state. We analyzed the functional connectivity between different brain networks computing the phase lag index after group Independent Component Analysis, and also performed an EEG microstates analysis. Patients with FM showed increased beta band connectivity between different brain networks and alterations in some microstates parameters (specifically lower occurrence and coverage of microstate class C). We speculate that the observed alterations in spontaneous EEG may suggest the dominance of endogenous top-down influences; this could be related to limited processing of novel external events and the deterioration of flexible behavior and cognitive control frequently reported for FM. These findings provide the first evidence of alterations in long-distance phase connectivity and microstate indices at rest, and represent progress towards the understanding of the pathophysiology of fibromyalgia and the identification of novel biomarkers for its diagnosis.

Brain Electrical Activity Associated With Visual Attention and Reactive Motor Inhibition in Patients With Fibromyalgia.

OBJECTIVE: Fibromyalgia (FM) is a generalized chronic pain condition associated with multiple cognitive impairments, including altered inhibitory processes. Inhibition is a key component of human executive functions and shares neural substrate with pain processing, which may explain the inhibitory deficits in FM. Here, we investigated the integrity of brain inhibitory mechanisms in these patients. METHODS: We recorded the electroencephalographic activity of 27 patients with FM and 27 healthy controls (HCs) (all women) while they performed a reactive motor inhibition task (the stop-signal paradigm). We analyzed task-induced modulations in electrophysiological markers related to inhibition (N2, P3, and midfrontal theta oscillations) and visual attention (posterior alpha oscillations). RESULTS: The FM group performed the task correctly, with no differences relative to HCs at the behavioral level. We did not find any between-group differences in N2 amplitude (F(1,52) = 0.01, p = .93), P3 amplitude (F(1,52) = 3.46; p = .068), or theta power (F(1,52) = 0.05; p = .82). However, modulation of posterior alpha power after presentation of either the go or stop stimuli was lower in patients than in HCs (F(1,52) = 7.98; p = .007). CONCLUSIONS: N2, P3, theta power, and behavioral results indicate that the mechanisms of motor inhibition are sufficiently preserved to enable correct performance of the stop-signal task in patients with FM. Nevertheless, the lower modulation of alpha suggests greater difficulty in mobilizing and maintaining visual attentional resources, a result that may explain the cognitive dysfunction observed in FM.

The Think/No-Think Alcohol Task: A New Paradigm for Assessing Memory Suppression in Alcohol-Related Contexts.

BACKGROUND: Research with the Think/No-Think (TNT) task has shown that voluntary suppression of an unwanted memory may lead to its later forgetting. To date, however, no study has assessed the memory suppression abilities in alcohol-related contexts despite the potential implications that it might have for alcohol research. With this aim, we developed a new version of the TNT paradigm, the TNT Alcohol (TNTA) task, which consists of 36 neutral pictures paired with 36 alcohol/no-alcohol images that are instructed to be suppressed or recollected. METHODS: Electroencephalographic activity was recorded from 64 electrodes while 20 young healthy females performed the TNTA task. The event-related potentials (ERPs) typically involved in memory suppression/recollection were analyzed, namely the fronto-central N2, the late parietal positivity (LPP), and the frontal slow wave (FSW). RESULTS: Findings revealed reduced recall for previously learned images that were subsequently instructed to be suppressed (No-Think) relative to those instructed to be retrieved (Think) and those not cued to be suppressed or retrieved (Baseline). This reduction seemed to be more prominent for alcohol-related memories. In addition, ERP analysis showed that compared to attempts of recollection, attempts of memory suppression were associated with attenuated LPP amplitude-more pronounced for alcohol-related memories-(indicating reduced conscious recollection for No-Think images) as well as with increased FSW (suggesting strategic control aiming at decrease accessibility of unwanted memories). CONCLUSIONS: These results replicate and extend previously reported behavioral and ERP findings in the TNT paradigm and suggest that the TNTA task may be a useful instrument to measure the ability to suppress alcohol-related memories.

Broad cognitive complaints but subtle objective working memory impairment in fibromyalgia patients.

BACKGROUND: Cognitive dysfunction in fibromyalgia (FM) encompasses objective cognitive difficulties, as measured in neuropsychological tests, and self-reported cognitive complaints. Although it has been suggested that FM patients display problems in working memory, the data are inconsistent, and the overall working memory status of the patients is unclear. It is also not clear whether the working memory problems are related to cognitive complaints or how the dyscognition is affected by the characteristic clinical symptoms of FM. METHODS: To clarify these aspects, we explored the neuropsychological performance for different components of working memory and the subjective self-perception of cognitive status in a sample of 38 women with FM. They were compared with a matched group of 32 healthy women. RESULTS: Our findings suggested that the FM patients do not differ from healthy controls in their overall working memory functioning. Only a poor performance was found in a single task of visuospatial working memory, mediated by the presence of depressive symptoms, fatigue and pain. The FM patients also displayed a higher level of perception of cognitive difficulties than healthy controls, and this difference was mediated by depression and fatigue. Furthermore, cognitive complaints in FM patients were only associated with a lower verbal WM capacity. DISCUSSION: FM patients have a subtle specific impairment in their working memory functioning, as well as elevated concern about their cognitive status. These findings suggest a disconnection between neuropsychological performance and subjective complaints. In FM patients, clinical variables such as pain, fatigue, and depression play an important role in dyscognition, as assessed by both objective and subjective measures, and should be taken into account in future research.

Electroencephalographic Evidence of Altered Top-Down Attentional Modulation in Fibromyalgia Patients During a Working Memory Task.

Fibromyalgia (FM) is a chronic syndrome involving widespread pain of unclear pathophysiology. FM patients frequently complain about cognitive symptoms that interfere with their daily life activities. Several studies have reported attentional deficits and working memory impairment in FM patients. Nevertheless, the mechanisms involved in these alterations are still poorly understood. In this study we recorded electroencephalographic activity in 32 women with FM and 30 matched controls while they performed a 2-back working memory task. We analyzed behavioural data, posterior alpha and midfrontal theta frequency power, and theta phase synchronization between midfrontal locations and the remaining scalp-recorded areas. Task performance was similar in patients and controls; however, time-frequency analysis showed a smaller decrease in the amplitude of the posterior alpha (related to attentional processing) and a smaller increase in midfrontal theta power (related to mental effort) in FM patients than in healthy controls. The FM patients also showed lower functional connectivity between midfrontal locations and rest of the scalp-recorded areas in the theta band (related to information transfer across distant brain regions when top-down control is required). To our knowledge, this is the first study relating alterations in oscillatory activity and impaired connectivity to attentional working memory complaints in FM patients. Reduced power in the theta band during performance of the task suggests that the medial frontal cortex may play an important role in the attentional deficits reported in FM.

Brain electrical activity signatures during performance of the Multisource Interference Task.

The Multisource Interference Task (MSIT) was developed to test cognitive control in normal and pathological conditions and has become a reliable tool for exploring the integrity of cingulo-frontal-parietal cognitive/attentional networks in fMRI studies. Analysis of EEG recordings made during performance of the MSIT may provide additional information about the temporal dynamics of cognitive control. However, this has not yet been investigated in depth. In this study, we analyzed the ERPs and carried out time-frequency decomposition of EEG recorded during control and interference conditions of the MSIT. The N2 ERP component and midfrontal theta power (both considered neural signatures of conflict processing) were significantly larger in interference than in control trials. Theta also showed higher phase synchronization between midfrontal and right frontolateral scalp locations in the interference condition, supporting the view that this frequency band entrains additional brain resources when a need for greater control arises. In interference trials, we also observed longer P3 latency, larger P3 amplitude, and greater reduction of posterior alpha (modulations related to allocation of attentional resources), in addition to a greater reduction of central beta power (related to motor preparation). In conclusion, the MSIT reliably modulated brain electrical activity related to cognitive control and attention. The EEG indices obtained during the performance of this task may be useful for exploring the functioning of cognitive/attentional networks in healthy and clinical populations.

Binge drinking affects brain oscillations linked to motor inhibition and execution.

INTRODUCTION: Neurofunctional studies have shown that binge drinking patterns of alcohol consumption during adolescence and youth are associated with anomalies in brain functioning. Recent evidence suggests that event-related oscillations may be an appropriate index of neurofunctional damage associated with alcoholism. However, there is no study to date that has evaluated the effects of binge drinking on oscillatory brain responses related to task performance. The purpose of the present study was to examine brain oscillations linked to motor inhibition and execution in young binge drinkers (BDs) compared with age-matched controls. METHODS: Electroencephalographic activity was recorded from 64 electrodes while 72 university students (36 controls and 36 BDs) performed a visual Go/NoGo task. Event-related oscillations along with the Go-P3 and NoGo-P3 event-related potential components were analysed. RESULTS: While no significant differences between groups were observed regarding event-related potentials, event-related oscillation analysis showed that BDs displayed a lower oscillatory response than controls in delta and theta frequency ranges during Go and NoGo conditions. CONCLUSIONS: Findings are congruent with event-related oscillation studies showing reduced delta and/or theta oscillations in alcoholics during Go/NoGo tasks. Thus, BDs appear to show disruptions in neural oscillations linked to motor inhibition and execution similar to those observed in alcohol-dependent subjects. Finally, these results are the first to evidence that oscillatory brain activity may be a sensitive indicator of underlying brain anomalies in young BDs, which could complement standard event-related potential measures.

Functional Equivalence of Imagined vs. Real Performance of an Inhibitory Task: An EEG/ERP Study.

Early neuroimaging and electrophysiological studies suggested that motor imagery recruited a different network than motor execution. However, several studies have provided evidence for the involvement of the same circuits in motor imagery tasks, in the absence of overt responses. The present study aimed to test whether imagined performance of a stop-signal task produces a similar pattern of motor-related EEG activity than that observed during real performance. To this end, mu and beta event-related desynchronization (ERD) and the Lateralized Readiness Potential (LRP) were analyzed. The study also aimed to clarify the functional significance of the Stop-N2 and Stop-P3 event-related potential (ERPs) components, which were also obtained during both real and imagined performance. The results showed a common pattern of brain electrical activity, and with a similar time course, during covert performance and overt execution of the stop-signal task: presence of LRP and Stop-P3 in the imagined condition and identical LRP onset, and similar mu and beta ERD temporal windows for both conditions. These findings suggest that a similar inhibitory network may be activated during both overt and covert execution of the task. Therefore, motor imagery may be useful to improve inhibitory skills and to develop new communicating systems for Brain-Computer Interface (BCI) devices based on inhibitory signals.

When the brain simulates stopping: Neural activity recorded during real and imagined stop-signal tasks.

It has been suggested that mental rehearsal activates brain areas similar to those activated by real performance. Although inhibition is a key function of human behavior, there are no previous reports of brain activity during imagined response cancellation. We analyzed event-related potentials (ERPs) and time-frequency data associated with motor execution and inhibition during real and imagined performance of a stop-signal task. The ERPs characteristic of stop trials-that is, the stop-N2 and stop-P3-were also observed during covert performance of the task. Imagined stop (IS) trials yielded smaller stop-N2 amplitudes than did successful stop (SS) and unsuccessful stop (US) trials, but midfrontal theta power similar to that in SS trials. The stop-P3 amplitude for IS was intermediate between those observed for SS and US. The results may be explained by the absence of error-processing and correction processes during imagined performance. For go trials, real execution was associated with higher mu and beta desynchronization over motor areas, which confirms previous reports of lower motor activation during imagined execution and also with larger P3b amplitudes, probably indicating increased top-down attention to the real task. The similar patterns of activity observed for imagined and real performance suggest that imagination tasks may be useful for training inhibitory processes. Nevertheless, brain activation was generally weaker during mental rehearsal, probably as a result of the reduced engagement of top-down mechanisms and limited error processing.

Evaluation of the accuracy of several symptoms and domains in distinguishing patients diagnosed with fibromyalgia from healthy controls.

OBJECTIVES: To assess the discriminative power of several symptoms and domains that may assist in the diagnosis of subjects with Fibromyalgia (FM). METHODS: 79 individuals with FM and 66 healthy controls participated in the study. The potential domains proposed by the American College of Rheumatology (ACR) criteria were considered (Wolfe et al., 1990). Binary logistic regression and area under a ROC curve (AUC) were used to rank the importance of the variables in distinguishing patients from pain-free controls. Z values were then calculated to compare the AUC values obtained for each variable with that which yielded the highest AUC (reference standard). For each measure, the cut-offs that maximise sensitivity and specificity were also calculated. RESULTS: The mean pressure pain threshold (PPT) yielded the highest discriminative power (AUC, 0.991) and was therefore chosen as the reference standard; considering an optimal cut- off ≤3.97, it correctly classified 95% of patients and 97% of controls. The discriminative powers of tender point count (cut-off ≥9), health-related quality of life (cut-off ≤63.27) and vitality (cut-off ≤46.97) were as good as that of the reference standard. Finally, items related to physical role and function, body pain, fatigue and memory loss showed adequate discriminative power, although slightly lower than that of the reference. CONCLUSIONS: In addition to pain, health-related quality of life and fatigue/vitality were confirmed as the best predictors of individuals with FM. The study findings indicate that tender point count and especially pressure pain threshold (measured with an algometer) continue to be key issues in the clinical assessment of subjects with FM relative to pain-free controls.

Suicidality in chronic pain: predictors of suicidal ideation in fibromyalgia.

OBJECTIVES: Fibromyalgia (FM) has been associated with a higher prevalence of suicidal behavior. Nevertheless, much remains unknown about suicide risk factors for this chronic pain disorder. In the present study, the relationship of suicidal ideation in FM with a number of sociodemographic, clinical, and psychological variables was analyzed. METHODS: One hundred seventeen women with Fibromyalgia were assessed. The procedure included the exploration of sleep problems (Pittsburgh Sleep Quality Index), depression (Beck Depression Inventory [BDI]), health-related quality of life (SF-36 and Fibromyalgia Impact Questionnaire), the core symptoms of FM (visual analogue scales), and algometry of tender points. Suicidal ideation was evaluated by item 9 of the BDI. Patients with presence vs. absence of suicidal ideation were compared in all the variables studied. RESULTS: The prevalence of suicidal ideation among FM patients was 32.5%. Significant differences between patients with vs. without suicidal ideas emerged mainly for the various indices of depression. Patients with suicidal ideation also reported higher levels of anxiety, more day dysfunction due to sleepiness and more limitations due to emotional and physical problems. Logistic regression analysis revealed that cognitive depression symptoms such as BDI Self-Blame cluster are the more closely related to suicide ideation. CONCLUSIONS: The presence of suicidal ideation in FM patients is closely related to comorbid depression, anxiety and to a higher impact of the disease in daily life.