Self-ratings of higher olfactory acuity contrast with reduced olfactory test results of fibromyalgia patients

Deciphering nociplastic pain: clinical features, risk factors and potential mechanisms

Nociplastic pain is a mechanistic term used to describe pain that arises or is sustained by altered nociception, despite the absence of tissue damage. Although nociplastic pain has distinct pathophysiology from nociceptive and neuropathic pain, these pain mechanisms often coincide within individuals, which contributes to the intractability of chronic pain. Key symptoms of nociplastic pain include pain in multiple body regions, fatigue, sleep disturbances, cognitive dysfunction, depression and anxiety. Individuals with nociplastic pain are often diffusely tender - indicative of hyperalgesia and/or allodynia - and are often more sensitive than others to non-painful sensory stimuli such as lights, odours and noises. This Review summarizes the risk factors, clinical presentation and treatment of nociplastic pain, and describes how alterations in brain function and structure, immune processing and peripheral factors might contribute to the nociplastic pain phenotype. This article concludes with a discussion of two proposed subtypes of nociplastic pain that reflect distinct neurobiological features and treatment responsivity.

Feasibility, reliability, and validity of ambulatory cognitive tests in fibromyalgia and matched controls

OBJECTIVE

This observational study examined the feasibility, reliability, and validity of repeated ambulatory cognitive tests in fibromyalgia (FM).

METHOD

Adults with FM (n = 50) and matched controls (n = 50) completed lab-based neuropsychological tests (NIH Toolbox) followed by eight days of smartphone-based ambulatory testing of processing speed (symbol search) and working memory (dot memory) five times daily. Feasibility was assessed based on response rates. Reliability was evaluated using overall average between-person reliabilities for the full assessment period and by determining the number of assessment days necessary to attain reliabilities of >.80 and >.90. To assess convergent validity, correlations were calculated between ambulatory test scores and NIH Toolbox scores. Test performance was contrasted between the FM and non-FM groups to examine known-groups validity.

RESULTS

Average rates of response to the ambulatory cognitive tests were 89.5% in FM and 90.0% in non-FM. Overall average between-person reliabilities were ≥.96. In FM, between-person reliability exceeded .90 after two days for symbol search and three days for dot memory. Symbol search scores correlated with NIH Toolbox processing speed scores in both groups, though there were no significant group differences in symbol search performance. Dot memory scores correlated with NIH Toolbox working memory scores in both groups. FM participants exhibited worse dot memory performance than did non-FM participants.

CONCLUSIONS

Repeated ambulatory tests of processing speed and working memory demonstrate feasibility and reliability in FM, though evidence for construct validity is mixed. The findings demonstrate promise for future research and clinical applications of this approach to assessing cognition in FM.

Symptomatology of Fibromyalgia Syndrome in Men: A Mixed-Method Pilot Study

Fibromyalgia syndrome (FMS) is characterized by generalized chronic musculoskeletal pain, fatigue, and sleep disturbance, as well as cognitive, somatic, and other symptoms. Most people affected by FMS are women, and studies analyzing this condition in men are scarce. In this study, we discuss the physical and psychological symptoms of FMS in men, analyze the possible side effects of pharmacological therapies, and explore the impact of the illness comparing these results between the different classification groups according to sociodemographic variables (marital status, level of education, employment situation and number of people living at home). We used a sequential exploratory mixed method (MM). Qualitative information was obtained from two focus groups (n = 10). Structured questionnaires were administered to 23 men affected by FMS. The mean age of the participants was 51.7 years (SD = 9.64). The most common drugs used were antidepressants and anxiolytics (86.9%), followed by non-steroidal anti-inflammatory drugs (82.6%) and opioids (60.9%). Current level of pain was high (8.2; SD = 1.1), while perceived health and satisfaction with pharmacological treatments were low (4.6; SD = 2.6 and 3.5; SD = 3.2, respectively). The impact of FMS measured using the Fibromyalgia Impact Questionnaire (FIQ) was very high at 88.7 (SD = 8.2). Six categories related with symptoms and side effects of the medication were observed in the qualitative data: (1) main physical symptoms, (2) mood disorders, (3) insomnia and non-restorative sleep, (4) cognitive disturbance, (5) hypersensitivity, and (6) symptoms secondary to opioids. Pain and fatigue were the symptoms most often mentioned by the participants (70% and 80%, respectively). Other important symptoms were anxiety, depression, and memory and sleep disorders. The consumption of opioids causes further unwanted symptoms such as drowsiness and dependence, which makes it difficult for patients to perform basic everyday activities. We believe it is vitally important to continue investigating this symptomatology in order to improve diagnosis and treatment for these patients.

The Role of Environmental Distractions in the Experience of Fibrofog in Real-World Settings

OBJECTIVE

Perceived cognitive dysfunction in people with fibromyalgia (FM), "fibrofog," is commonly reported and has been demonstrated in neurocognitive testing. Distractibility and inattention have been implicated as potential contributors to fibrofog, but the role of environmental distractions has not been explored. In this study, ambulatory assessment methods were used to examine whether FM is related to more environmental distractions and to examine the impact of distractions on subjective and objective cognitive functioning.

METHODS

Fifty people with FM and 50 age-, sex-, and education-matched controls without FM completed 8 consecutive days of ambulatory assessments. Five times per day, participants reported perceived cognitive functioning and environmental distractions and completed validated tests of processing speed and working memory.

RESULTS

The FM group reported distractions in a higher proportion of the ambulatory cognitive testing sessions (40.5%) compared with the group without FM (29.8%; P < 0.001) and more often reported multiple simultaneous distractions. For both groups, sound was the most common distraction. The group with FM reported more distractions caused by light, and the group without FM reported more social distractions. Group differences in subjective and objective cognitive functioning were not augmented during distraction relative to during periods of no distraction. There were no group differences in within-person changes in cognitive functioning as a function of distraction.

CONCLUSION

The group with FM reported more distractions than the group without FM; both groups reported poorer processing speed when distracted, and the effects of distraction on test performance did not differ significantly by group. Findings suggest that sensitivity to environmental distractions may play a role in the experience of cognitive dysfunction in FM.

Evaluation of Olfactory and Gustatory Functions in Patients With Fibromyalgia Syndrome: Its Relationship With Anxiety, Depression, and Alexithymia

Objectives

This study aims to evaluate smell and taste functions in patients with fibromyalgia syndrome (FMS) and the relationship between smell and taste functions, anxiety, depression, alexithymia, and quality of life (QoL).

Patients and methods

This cross-sectional study included 30 patients with FMS (3 males, 27 females; mean age 46.0±8.5 years; range, 18 to 70 years) and 20 age- and sex-matched healthy participants (2 males, 18 females; mean age 45.7±10.0 years; range, 18 to 70 years). Fibromyalgia Impact Questionnaire (FIQ) was applied to FMS patients. Hamilton Anxiety Scale, Depression Scale, Toronto Alexithymia Scale, and EuroQol Questionnaire Five-Dimensions (EQ-5D) were applied to all participants. Sniffin' Sticks test was used for olfactory function analysis while taste strips were used for gustatory function analysis.

Results

The FMS patients had higher anxiety, depression, and alexithymia while lower QoL scores. Olfactory and gustatory function test scores were lower in FMS patients. Total olfactory function scores were 25.96 and 36.40 for FMS and control groups, respectively. For taste function, they were 9.93 and 13.55, respectively. These scores were negatively correlated with anxiety, depression, and alexithymia scores whereas positively correlated with EQ-5D index score. There was no significant correlation with FIQ score.

Conclusion

Anxiety and depression are common symptoms of FMS. Patients with FMS had altered olfactory and gustatory functions and these impairments were correlated with their anxiety and depression. Further studies with larger sample sizes including functional magnetic resonance imaging evaluation should be performed.

Olfactory and cognitive functioning in patients with fibromyalgia

Fibromyalgia is a complex syndrome characterized by chronic musculoskeletal pain. Previous research has found impaired olfactory function and cognitive deficits in patients with fibromyalgia. In non-clinical population (middle-aged and elderly populations) an association has been found between olfactory function and cognitive impairment. Therefore, olfactory impairment identification could be considered as a reliable and early marker predicting the decline of cognitive function in mild cognitive impairment, Alzheimer's disease and Parkinson's disease. Nevertheless, the relationship between cognitive and olfactory functioning has not been studied in fibromyalgia patients. The aims of the study have been to analyze the cognitive and olfactory functioning and their association in a sample of women with fibromyalgia in comparison to women without a chronic pain disease. A transversal study was conducted with fibromyalgia patients (n = 146) and women without a chronic pain disease (n = 122). Data were collected using the WAIS-III (cognitive functioning) and the CCCRC test (olfactory functioning). Descriptive analysis, Student's t test and chi-square tests were conducted. There were significant differences in perceptive organization and processing speed, and in odour identification, odour threshold and total CCCRC score; the lower scores were for fibromyalgia patients. Among the fibromyalgia patients there were significant differences in the verbal scale, the manipulative scale, the total scale and processing speed between normosmic and hyposmic patients, the lowest scores were for hyposmic patients. Although previous literature has shown that self-reports by fibromyalgia patients inform about an enhanced olfactory acuity, the current study suggests that there are deficits in olfactory functioning in these patients. Also, the relationship between olfactory and cognitive functioning in fibromyalgia patients, due to the lack of previous studies, suggests a new line of research. Taken together, these results suggest that olfactory functioning could be included in a bio-psycho-social approach of fibromyalgia patients, because of the association with cognitive functioning.

Decreased olfactory bulb volumes in patients with fibromyalgia syndrome

Among the other symptoms, impaired olfactory function such as odor identification, threshold, and discrimination have been reported in patients with fibromyalgia syndrome (FMS). To investigate olfactory bulb (OB) volumes in FMS, by using magnetic resonance imaging (MRI), and to make reasonable suggestions are the goals of the present study. The study included 62 individuals as the FMS group (n = 30) and the control group (n = 32). MRI examinations were performed by a 1.5-T scanner and a standard head coil was used for the images. The coronal T2-weighted images were used for to measure OB volumes. Right, left, and total OB volumes were calculated with the aid of these images. The mean age of the FMS group was 44.2 ± 8.3 years and the control group was 41.7 ± 3.53 years. The mean volume of the right OB was 74.9 ± 12.4 mm³ in the FMS group and was 92.6 ± 12.9 mm³ in the control group. The mean value of the left OB volume was 74.3 ± 10.8 mm³ in the FMS group and 92.8 ± 12.6 mm³ in the control group. The mean of the total OB volume was 146.6 ± 20.81 mm³ in the FMS group and 186.5 ± 23.5 mm³ in the control group. Left, right, and total OB volumes were significantly lower in the FMS group than in the control group (all p < 0.05). Female patients with FMS are under the risk of the decreased olfactory bulb volumes. This situation should be kept in mind for proper and reasonable management of this tough syndrome.

A possible neural mechanism for photosensitivity in chronic pain

Patients with functional pain disorders often complain of generalized sensory hypersensitivity, finding sounds, smells, or even everyday light aversive. The neural basis for this aversion is unknown, but it cannot be attributed to a general increase in cortical sensory processing. Here, we quantified the threshold for aversion to light in patients with fibromyalgia, a pain disorder thought to reflect dysregulation of pain-modulating systems in the brain. These individuals expressed discomfort at light levels substantially lower than that of healthy control subjects. Complementary studies in lightly anesthetized rat demonstrated that a subset of identified pain-modulating neurons in the rostral ventromedial medulla unexpectedly responds to light. Approximately half of the pain-facilitating "ON-cells" and pain-inhibiting "OFF-cells" sampled exhibited a change in firing with light exposure, shifting the system to a pronociceptive state with the activation of ON-cells and suppression of OFF-cell firing. The change in neuronal firing did not require a trigeminal or posterior thalamic relay, but it was blocked by the inactivation of the olivary pretectal nucleus. Light exposure also resulted in a measurable but modest decrease in the threshold for heat-evoked paw withdrawal, as would be expected with engagement of this pain-modulating circuitry. These data demonstrate integration of information about light intensity with somatic input at the level of single pain-modulating neurons in the brain stem of the rat under basal conditions. Taken together, our findings in rodents and humans provide a novel mechanism for abnormal photosensitivity and suggest that light has the potential to engage pain-modulating systems such that normally innocuous inputs are perceived as aversive or even painful.

Olfactory impairment in patients with the fibromyalgia syndrome and systemic sclerosis

Patients with autoimmune diseases often present with olfactory impairment. The aim of the study was to assess the olfactory functions of female patients with fibromyalgia (FM) compared with patients with systemic sclerosis (SSc) and with healthy female controls. Olfactory functions were assessed in 24 patients with FM, 20 patients with SSc and 21 age-matched healthy controls. The sense of smell was evaluated using the Sniffin' Sticks test including the three stages of smell: threshold, discrimination, and identification (TDI) of the different odors. The severity of fibromyalgia was assessed using the fibromyalgia impact questionnaire (FIQ). The short form 36 (SF-36) questionnaire was also completed in order to seek a relationship between the patients perception of quality of life and the different aspects of the smell sense. Depression was evaluated in both FM and SSc patients utilizing the Beck depression inventory-II (BDI-II) questionnaire. Patients with FM had significantly lower TDI smell scores compared with both SSc patients and healthy controls (p < 0.005, One-Way ANOVA). Hyposmia (defined as TDI scores below 30) were observed in 14 of 24 (42 %) patients with FM compared to 3 of 20 (15 %) patients with SSc and 1 of the healthy controls (4.3 %) (p < 0.02). FM patients had significantly lower thresholds of smell compared to both healthy controls and patients with SSc (p < 0.001), whereas for patients with SSc only the ability to discriminate between odors was impaired (p < 0.006). We could not detect any statistical correlation between smell abilities and clinical manifestation of SSc or the FIQ and SF-36 scores among FM patients. However the correlation between depression, defined by the BDI-II score, and the sense of smell differed between patients with FM and patients with SSc. As only among SSc patients a lower sense of smell correlated with a higher BDI-II score (p = 0.02). Our findings suggest that there is a decrease in the sense of smell both in FM and SSc patients compared with healthy controls. However these impairments differ between patients group and might represent different mechanisms that affect the sense of smell.