Atypical central pain processing in sensory modulation disorder: absence of temporal summation and higher after-sensation

Breastfeeding-related Pain, Sensory Over-responsiveness, and Exclusive Breastfeeding at 6 Months: A Prospective Cohort Study

BACKGROUND

Exclusive breastfeeding (EBF) is recommended for the first 6 months of life, yet EBF rates at 6 months (T3) in most developed countries are low. Painful and nonpainful sensory stimuli processing is linked, and while pain has been suggested to restrict breastfeeding, its coupling with sensory over-responsiveness (SOR) in relation to breastfeeding has not yet been reported.

OBJECTIVE

We aimed to explore whether breastfeeding-related pain, SOR, and general pain sensitivity predict nonexclusive breastfeeding (NEBF) at T3.

STUDY DESIGN

In this prospective study, participants were recruited at 2 days postpartum (enrollment). For the assessment of breastfeeding-related pain, participants completed the visual analogue scale and the Short-Form McGill Pain Questionnaire at enrollment, and at 6 weeks after birth. At T3, they completed the Pain Sensitivity Questionnaire and the Sensory Responsiveness Questionnaire-Intensity Scale and then provided information about their breastfeeding status. Participants were divided into two groups accordingly: EBF and NEBF.

RESULTS

A total of 164 participants were reached at T3: EBF (n = 105) and NEBF (n = 59). The incidence of SOR was significantly higher among NEBF compared with EBF participants (25.4% vs. 11.4%; p = .020). Between enrollment and 6 weeks after birth, 72.3% of the EBF participants had reported a ≥30% pain reduction, compared with 44.8% of the NEBF participants (p = .001). Logistic regression modeling revealed that both breastfeeding-related pain reduction and SOR predicted NEBF at T3 (p < .001), indicating a 3.2 times (p = .001) and 2.5 times (p = .041) odds ratio for NEBF, respectively.

CONCLUSIONS

SOR and sustained breastfeeding-related pain predict NEBF at T3 and may emerge as substantial breastfeeding barriers.

Indifference or hypersensitivity? Solving the riddle of the pain profile in individuals with autism

ABSTRACT

Excitatory-inhibitory (E/I) imbalance is a mechanism that underlies autism spectrum disorder, but it is not systematically tested for pain processing. We hypothesized that the pain modulation profile (PMP) in autistic individuals is characterized by less efficient inhibitory processes together with a facilitative state, indicative of a pronociceptive PMP. Fifty-two adults diagnosed with autism and 52 healthy subjects, age matched and sex matched, underwent quantitative sensory testing to assess the function of the (1) pain facilitatory responses to phasic, repetitive, and tonic heat pain stimuli and (2) pain inhibitory processes of habituation and conditioned pain modulation. Anxiety, pain catastrophizing, sensory, and pain sensitivity were self-reported. The autistic group reported significantly higher pain ratings of suprathreshold single ( P = 0.001), repetitive (46°C- P = 0.018; 49°C- P = 0.003; 52°C- P < 0.001), and tonic ( P = 0.013) heat stimuli that were cross correlated ( r = 0.48-0.83; P < 0.001) and associated with sensitivity to daily life pain situations ( r = 0.39-0.45; P < 0.005) but not with psychological distress levels. Hypersensitivity to experimental pain was attributed to greater autism severity and sensory hypersensitivity to daily stimuli. Subjects with autism efficiently inhibited phasic but not tonic heat stimuli during conditioned pain modulation. In conclusion, in line with the E/I imbalance mechanism, autism is associated with a pronociceptive PMP expressed by hypersensitivity to daily stimuli and experimental pain and less-efficient inhibition of tonic pain. The latter is an experimental pain model resembling clinical pain. These results challenge the widely held belief that individuals with autism are indifferent to pain and should raise caregivers' awareness of pain sensitivity in autism.

Multisensory sensitivity differentiates between multiple chronic pain conditions and pain-free individuals

ABSTRACT

Multisensory sensitivity (MSS) to nonpainful stimuli has been identified as a risk factor for the presence of coexisting chronic pain conditions. However, it remains unclear whether MSS can differentiate pain phenotypes involving different levels of central sensitivity. Both pain-free and those with chronic pain, particularly fibromyalgia (FM), migraine, or low back pain (LBP) were recruited, with pain comorbidities assessed. MSS was highest in FM, followed by migraine, then LBP, and lowest in pain-free individuals (adjusted between condition Cohen d = 0.32-1.2, P ≤ 0.0007). However, when secondly grouping patients by the total number of pain comorbidities reported, those with a single pain condition (but not FM) did not have significantly elevated MSS vs pain-free individuals (adj d= 0.17, P = 0.18). Elevated MSS scores produced increased odds of having 2 or more pain comorbidities; OR [95% CI] =2.0 [1.15, 3.42], without, and 5.6 [2.74, 11.28], with FM ( P ≤ 0.0001). Furthermore, those with low MSS levels were 55% to 87% less likely to have ≥ 2 pain comorbidities with or without FM (OR 0.45 [0.22, 0.88]-0.13 [0.05, 0.39]; P ≤ 0.0001). Our findings support that MSS can differentiate between pain phenotypes with different degrees of expected central mechanism involvement and also serve as a risk and resilience marker for total coexisting chronic pain conditions. This supports the use of MSS as a marker of heightened central nervous system processing and thus may serve as a clinically feasible assessment to better profile pain phenotypes with the goal of improving personalized treatment.

Opening a window into the riddle of misophonia, sensory over-responsiveness, and pain

Introduction

Misophonia and sensory over-responsiveness (SOR) share physiological and psychological symptoms. While individuals with SOR demonstrate pain perception alterations, these were not explored in misophonia.

Methods

This exploratory study comprised thirty healthy adults with (n = 15; based on the Misophonia Questionnaire) and without misophonia. The Sensory Responsiveness Questionnaire (SRQ) was used for evaluating sensory responsiveness. In addition, psychophysical tests were applied for quantification of: (i) stimulus-response function of painful stimuli, (ii) the individual perceived pain intensity, (iii) pain modulation efficiency, (iv) auditory intensity discrimination capability, and (v) painful and unpleasantness responses to six ecological daily sounds using the Battery of Aversiveness to Sounds (BAS).

Results

Individuals with misophonia reported higher scores in the SRQ-Aversive (p = 0.022) and SRQ-Hedonic (p = 0.029) scales as well as in auditory (p = 0.042) and smell (p = 0.006) sub-scales, indicating higher sensory responsiveness. Yet they were not identified with the SOR type of sensory modulation dysfunction. Groups did not differ in the pain psychophysical tests, and in auditory discrimination test scores (p > 0.05). However, in the misophonia group the BAS evoked higher pain intensity (p = 0.046) and unpleasantness (p <0.001) ratings in the apple biting sound, and higher unpleasantness rating in the scraping a dish sound (p = 0.007), compared to the comparison group.

Conclusion

Findings indicate increased sensory responsiveness in individuals with misophonia, yet not defined as SOR. Thus, this suggests that misophonia and SOR are two distinct conditions, differing in their behavioral responses to painful and non-painful stimuli.

"When I'm in Pain, Everything Is Overwhelming": Implications of Pain in Adults With Autism on Their Daily Living and Participation

Pain sensation in autism spectrum disorder (ASD) has been a growing research field in the last two decades. Existing pain research has focused on pain sensitivity, suggesting either hyposensitivity or hypersensitivity to pain in individuals with ASD. However, research about other aspects of pain experience is scarce. Moreover, most pain-related research in ASD focused on quantitative measures, such as neuroimaging or parental reports. Instead, this paper aimed to illuminate the various aspects of pain experience as perceived by adults with ASD. Its descriptive qualitative research design incorporated semi-structured interviews and deductive thematic analysis. This phenomenological approach captured the subjective pain experience through the lens of people with ASD. Four primary themes emerged from the data: (a) physical pain experience, including the sequence of pain sensitivity, pain awareness, pain-related emotional aspects, and pain communication; (b) direct and indirect coping strategies; (c) function and participation outcomes; and (d) suggestions for Healthcare Providers. The findings echo the crucial role of pain awareness and communication in the pain experience of people with ASD. These two factors have been reported as profoundly influencing coping strategies, function, and participation. The results emphasize the need to expand the exploration of pain in this population, calling for greater understanding, and listening to this population's unique pain profiles and experiences to promote better-suited evaluation, diagnosis, and intervention in pain conditions.

Neurofeedback Therapy for Sensory Over-Responsiveness-A Feasibility Study

Background: Difficulty in modulating multisensory input, specifically the sensory over-responsive (SOR) type, is linked to pain hypersensitivity and anxiety, impacting daily function and quality of life in children and adults. Reduced cortical activity recorded under resting state has been reported, suggestive of neuromodulation as a potential therapeutic modality. This feasibility study aimed to explore neurofeedback intervention in SOR. Methods: Healthy women with SOR (n = 10) underwent an experimental feasibility study comprising four measurement time points (T1—baseline; T2—preintervention; T3—postintervention; T4—follow-up). Outcome measures included resting-state EEG recording, in addition to behavioral assessments of life satisfaction, attaining functional goals, pain sensitivity, and anxiety. Intervention targeted the upregulation of alpha oscillatory power over ten sessions. Results: No changes were detected in all measures between T1 and T2. Exploring the changes in brain activity between T2 and T4 revealed power enhancement in delta, theta, beta, and gamma oscillatory bands, detected in the frontal region (p = 0.03−<0.001; Cohen’s d = 0.637−1.126) but not in alpha oscillations. Furthermore, a large effect was found in enhancing life satisfaction and goal attainment (Cohen’s d = 1.18; 1.04, respectively), and reduced pain sensitivity and anxiety trait (Cohen’s d = 0.70). Conclusion: This is the first study demonstrating the feasibility of neurofeedback intervention in SOR.

High Sensory Responsiveness in Older Adults is Associated with Walking Outside but Not Inside: Proof of Concept Study

Background and Purpose

Reduced mobility and a higher risk of falls among older adults are related to aging-associated sensory alteration. Sensory responsiveness (SR) has been found to be strongly correlated with postural control in studies on young adults in stimulating environments; however, SR has not been studied in the context of mobility among older adults, despite its potential to enhance fall risks. The aim of the current study is to characterize the associations between SR and gait under single and dual-task (ST, DT) conditions inside and outside the laboratory.

Methods

Twenty-six community-dwelling older adults (age 70.3 ± 4.6 years, 65.4% women) participated in this cross-sectional study. Gait variables were measured using the APDM system under single and dual task conditions, in a quiet corridor inside and in an ecological (outside) environment. SR was evaluated using the SR questionnaire and cognition was assessed with the Trail-Making Test and the Montreal Cognitive Assessment.

Results

SR was negatively associated with gait speed during ST (r_s = −0.491, p < 0.05) and DT (r_s = −0.528, p < 0.01) outside and with ST gait speed inside (r_s = −0.528, p < 0.01). SR was positively associated with gait variability under DT (r_s = 0.41, p < 0.05) and with DT cost (r_s = 0.44, p < 0.05) only outside.

Conclusion

SR may play an important role in understanding mobility deterioration throughout the aging process, especially outside, illuminating the importance of SR evaluation among older adults during mobility assessment. Therefore, accounting for SR in gait research may contribute to a better understanding of mobility decline throughout the aging process.

An Exploratory Study Testing Autonomic Reactivity to Pain in Women with Sensory Over-Responsiveness

BACKGROUND

Difficulty modulating sensory input related to multi-sensory integration dysfunction, specifically the sensory over-responsive (SOR) type, is associated with psychological distress and hyperalgesia in children and adults. Scares reports suggest atypical autonomic nervous system (ANS) reactivity to innocuous sensory stimuli in children with SOR. Thus, the ANS may contribute to sensory stimuli responses and psychological distress. This exploratory study aimed to characterize the ANS reactivity to single and dual pain stimulation, and in relation to psychological distress in adults with SOR.

METHODS

Healthy women with SOR (n = 9) vs. without SOR (n = 9) underwent two runs of single pain stimulation and a third run comprised of dual pain stimulation. Pain was self-rated, while heart rate variability was measured and analyzed in the time and frequency domains. In addition, questionnaires assessing anxiety and somatization were utilized.

RESULTS

While controls demonstrated a vagal tone withdrawal (root mean square of successive differences in R-R-intervals; (RMSSD)) p = 0.029 from base-line to the third run, this was absent in the SOR group. However, no group differences were found in pain ratings. Furthermore, groups differed in the correlations between R-R mean and the level of both anxiety (p = 0.006) and somatization (p < 0.001); while in the SOR group, higher levels of anxiety and somatization correlated with shorter R-R intervals, the opposite was found in the control group.

CONCLUSIONS

This is the first study to demonstrate in women with SOR atypical vagal tone reactivity to challenging pain load. Vagal tone reactivity is related to both pain ratings and psychological distress.

Multisensory Sensitivity is Related to Deep-Tissue but Not Cutaneous Pain Sensitivity in Healthy Individuals

PURPOSE

Some individuals with chronic pain find daily life sensations (eg, noise, light, or touch) aversive. This amplification of multisensory sensations has been associated with centrally mediated plasticity; for example, greater multisensory sensitivity (MSS) occurs in patients with fibromyalgia than rheumatoid arthritis. However, whether MSS preferentially relates to pain measures which reflect central influences (eg, dynamic quantitative sensory testing (QST) or referred pain), or whether the MSS-pain relationship requires priming from chronic pain, is unknown. Thus, this cross-sectional study investigated the relationships between MSS assessed in a pain-free state and evoked pain sensitivity.

METHODS

Experimental intramuscular infusion pain and multiple static and dynamic QST were assessed in 465 healthy, pain-free adults: pain thresholds using pressure (PPTs) and heat (HPTs), temporal summation of pain (TSP) using pressure, heat or punctate stimuli, and conditioned pain modulation (CPM) using pressure or heat test stimuli. MSS was assessed using 7 items from Barsky's Somatosensory Amplification Scale. Differences in pain and QST between sex-specific MSS quartiles were assessed, adjusting for multiple comparisons. All participants completed at least one intramuscular infusion condition, but not all were asked to complete each QST (n=166-465).

RESULTS

Both static and dynamic QST differed between highest and lowest MSS quartiles using pressure stimuli: lower PPTs (adjusted-p<0.01); increased pressure TSP (adjusted-p=0.02); lower pressure CPM (adjusted-p=0.01). However, none of the heat or punctate QST measures (HPTs, TSP, or CPM) differed between MSS quartiles (adjusted-p>0.05). Odds of experiencing TSP or referred pain was not greater, whereas CPM was 8-fold less likely, in those with highest MSS.

CONCLUSION

Normal variation in non-noxious MSS is related to both static and dynamic pain sensitivity, without sensitization associated with chronic pain, but is dependent on the QST stimulus. Thus, common influences on MSS and pain sensitivity may involve central mechanisms but are likely more complex than previously recognized.

Perceived Sensitivity to Pain and Responsiveness to Non-noxious Sensation in Substance Use Disorder

OBJECTIVE

This comparative cross-sectional study aimed to characterize individuals with substance use disorder (SUD) in self-perception of pain sensitivity, experimental auditory aversiveness, and non-noxious sensory responsiveness, as well as examine the associations with SUD.

METHODS

Therapeutic community (TC) individuals with SUD (N = 63, male 88.9%) and healthy controls (N = 60, male 86.7%) completed the Pain Sensitivity Questionnaire (PSQ) and the Sensory Responsiveness Questionnaire-Intensity Scale (SRQ-IS), followed by a psychophysical auditory battery, the Battery of Averseness to Sounds (BAS)-Revised.

RESULTS

The SUD group scored higher on the PSQ (P < 0.0001), BAS-R aversiveness (P < 0.0001), BAS-R-unpleasantness (P < 0.0001), and on the aftersensation of auditory aversiveness (P < 0.0001) and unpleasantness (P < 0.000). Fifty-four percent of the SUD group vs 11.7% of the control group were identified as having sensory modulation dysfunction (SMD; P < 0.0001). Logistic regression modeling revealed that the SRQ-IS-Aversive score had a stronger relationship, indicating a 12.6-times odds ratio for SUD (P = 0.0002). Finally, a risk score calculated from a linear combination of the logistic regression model parameters is presented based on the PSQ and SRQ.

CONCLUSIONS

This is the first study to explore sensory and aversive domains using experimental and self-reporting in situ, revealing pain perception alteration that co-occurs with high prevalence of SMD, specifically of the over-responsive type. Findings may be significant in clinical practice for treating pain, and for expanding therapeutic modalities as part of broader rehabilitation in TC and beyond, to better meet personalized therapy.

Investigation of the relationship between kinesiophobia and sensory processing in fibromyalgia patients

Purpose/aim: The aims of this study are to investigate the relationship between kinesiophobia and sensory processing in fibromyalgia (FM) patients and obtain new information about kinesiophobia in light of these results.Materials and methods: This study has been conducted with 82 literate subjects aged 18-65 years and diagnosed with FM based on ACR 2010 diagnostic criteria. Fibromyalgia Impact Questionnaire was used for measuring functional status in FM patients, The Tampa Scale of Kinesiophobia was used for determine the levels of kinesiophobia and Adolescent/Adult Sensory Profile was used for determine the characteristics of sensory process patterns of the individuals.Results: Among the participants, sensory sensitivity scores of 65.85% and sensation avoiding scores of 40.24% were higher than that in the general population. Sensation seeking scores of 48.78% the subjects were lower compared to the general population. A significant and weak positive correlation was found between the kinesiophobia scores and responses of sensory sensitivity and sensation avoiding (r = 0.23, p = 0.04; z = 0.29, p = 0.01)Conclusion: This is the first study conducted to investigate the relationship between kinesiophobia and sensory processing in fibromyalgia patients. However, different studies investigating this subject are warranted in order to be able to generalize the findings and increase the value of evidence.

Pediatric Persistent Pain: Associations Among Sensory Modulation, Attachment, Functional Disability, and Quality of Life

IMPORTANCE

Although attachment is associated with sensory modulation among children and adolescents and insecure attachment is associated with pain severity among adolescents, relationships among sensory modulation, attachment, and function have not previously been demonstrated in a clinical sample of children and adolescents with complex persistent pain.

OBJECTIVE

To investigate relationships among sensory modulation, attachment, function, and quality of life (QOL) in a pediatric population with persistent pain.

DESIGN

Cross-sectional quantitative design. From October 2015 to July 2017, all children, adolescents, and parents attending a clinic for assessment completed questionnaires and were provided information and consent forms. Those who consented completed sensory modulation and attachment questionnaires.

SETTING

Tertiary pain management clinic.

PARTICIPANTS

Children (ages 8-12 yr) and adolescents (ages 13-18 yr) with persistent pain (pain of >3 mo duration or a specific pain disorder) and the capacity to answer questionnaires independently.

MEASURES

Standardized sensory modulation, attachment, pain intensity, functional disability, and QOL questionnaires. Hypotheses were generated before data collection.

RESULTS

Of 152 children and adolescents, 114 children (30 girls, 9 boys) and adolescents (68 girls, 7 boys) met study criteria and consented to participate. Hierarchical multiple regression analyses revealed that sensory sensitivity predicted disability for children and adolescents, and attachment anxiety mediated the relationship between low registration and poorer school-related QOL.

CONCLUSION AND RELEVANCE

Behaviors related to insecure attachment patterns provide a mediating pathway from sensory modulation to functional disability; addressing such behaviors clinically may facilitate engagement in daily activities for children and adolescents with persistent pain.

WHAT THIS ARTICLE ADDS

Results support the need to consider the interactions between sensory modulation and attachment when addressing functional abilities with occupational therapy treatment.

Sensory Modulation in Children Exposed to Continuous Traumatic Stress

Preliminary evidence supports a possible association between post-traumatic stress disorder (PTSD) and sensory modulation disorder (SMD). Nevertheless, the research focusing on this relationship in children is notably limited. This study examined children with and without PTS symptoms, by comparing their mothers' perceptions of their responses to sensory events in daily life. Mothers of 134 non-referred children aged 5-11, exposed to continuous traumatic stress due to political violence, completed the UCLA-RI and the Short Sensory Profile questionnaires. Significant differences emerged between children with different levels of PTS symptoms in various sensory modalities. Furthermore, half of the symptomatic children had suspected clinically significant deficits in sensory processing. In addition, PTSD symptoms were significantly associated with most of the sensory processing scores. Logistic regression indicated that the overall sensory processing score was a significant predictor of group classification. The results indicate that children with PTS symptoms may be at increased risk for sensory processing deficits. Evaluation of sensory processing should be incorporated into the routine evaluation of this population in order to determine whether this is an additional factor contributing to a child's difficulties in participating in daily activities. Subsequent intervention programs should then address the multiple needs of these children.

Multi-sensory Responsiveness and Personality Traits Predict Daily Pain Sensitivity

Background: A continuous effort has been devoted to identifying factors that contribute to individual differences in pain perception. Amongst the personality traits, Neuroticism is assumed to be the most significant moderator of experimental and clinical pain. Multi-sensory responsiveness to daily sensations has been shown to be associated with pain perception. Yet, neither the relationship between personality traits and multi-sensory responsiveness nor the impact of both these factors to pain perception have been examined. Thus, this study aims to explore the contribution of both multi-sensory responsiveness and personality traits to pain perception in a daily context.

Methods: A community-based sample of 204 adults completed the Sensory Responsiveness Questionnaire-Intensity Scale (SRQ-IS); the Big Five Inventory (BFI); and the Pain Sensitivity Questionnaire (PSQ).

Results: The partial eta-square demonstrated that the SRQ-IS Aversive sub-scale score had the strongest relationship with the PSQ-Total score, accounting for 9% of the variation. The regression coefficient relating PSQ-Total score with SRQ-IS Aversive, and BFI sub-scales of Extraversion, Neuroticism and Openness-to-Experience scores was found to be r = 0.39 (p < 0.0001), accounting for 16% of the variance, and yielding a large effect size.

Discussion: To the best of our knowledge this is the first study to report on the interplay between aversive responsiveness to daily sensations and personality traits of Neuroticism, Openness-to-Experience, and Extraversion as contributing factors to daily pain sensitivity, amongst which aversive responsiveness was found as the major contributing factor. This study may broaden the understanding of the pain experience variability, both in practice and in experimental research.

Sensory processing of women diagnosed with genito-pelvic pain/penetration disorder: a research proposal

Objectives

The study objectives are to describe the sensory processing patterns of women diagnosed with genito-pelvic pain/penetration disorder (GPPPD), to explore the level of anxiety when both GPPPD and sensory processing disorder (SPD) are present and to investigate participants’ experience of participating in a sensory-based home programme.

Methods

A descriptive two-phased study design will be used. Phase one is a quantitative, cross sectional non-experimental descriptive study, using the Adolescent/Adult Sensory History (ASH) and Hospital Anxiety and Depression Scales (HADS) to obtain data from purposive sampling. Phase two is an exploratory qualitative study involving participants who were identified with SPD in phase one. They will participate in a sensory-based home programme and their experience thereof will be established during semi-structured interviews.

Outcomes

Descriptive studies are known to be useful in planning health services and to develop hypotheses for future testing. This study could improve practitioners’ understanding of GPPPD and SPD and make alternative, non-invasive, non-pharmacological treatment options available to better assist these patients. The study could further clarify the role of the occupational therapist in sexuality. Exploring participants’ anxiety has important implications for treatment protocols in occupational therapy and assisting in describing the signs and symptoms of GPPPD.

An exploration of sensory processing patterns and their association with demographic factors in healthy adults

Purpose

Previous research has provided limited evidence on whether and how demographic factors associate with sensory processing patterns (SPP) in adults. This paper aims to examine relationships between SPPs and sociodemographic factors of age, sex, education and ethnicity in healthy adults.

Design/methodology/approach

A cross-sectional study design was used. A total of 71 adult participants was recruited from the community, using convenience sampling. Each participant completed the Adolescent/Adult Sensory Profile (AASP) and the Depression Anxiety Stress Scales – short version (DASS-21). Demographic information on age, sex, education and ethnicity was collected. Results were analysed using descriptive statistics and multivariate analyses of covariance (MANCOVA).

Findings

SPPs, as measured by the AASP, were significantly correlated to demographic factors of age and education after controlling for emotional distress using the DASS-21. A statistically significant multivariate effect was found across the four dependent variables (low registration, seeking, sensitivity and avoiding) for the age category, F = 6.922, p = 0.009, ηp2 = 0.145, in the presence of a covariate DASS. The education category showed significance only in the seeking domain (p = 0.008, ηp2 = 0.10) after controlling for DASS. There was no significant correlation between SPPs and gender or ethnicity. Results also indicated that mean scores of participants in this study were “similar to most people” as standardised in the AASP.

Research limitations/implications

This was a cross-sectional study with limitations including that the study used a relatively small sample and was based on self-reported healthy participants.

Practical implications

SPPs may correlate with healthy adults’ age and to a lesser extent education. This suggests that it might be helpful to consider such demographic factors when interpreting SPPs in clinical populations, although further research in larger samples is needed to reach firmer conclusions about possible implications of demographic variables.

Originality/value

The findings in this paper add to the growing evidence that suggest that SPPs vary with sociodemographic factors.

Sensory Modulation Disorder (SMD) and Pain: A New Perspective

Sensory modulation disorder (SMD) affects sensory processing across single or multiple sensory systems. The sensory over-responsivity (SOR) subtype of SMD is manifested clinically as a condition in which non-painful stimuli are perceived as abnormally irritating, unpleasant, or even painful. Moreover, SOR interferes with participation in daily routines and activities (Dunn, 2007; Bar-Shalita et al., 2008; Chien et al., 2016), co-occurs with daily pain hyper-sensitivity, and reduces quality of life due to bodily pain. Laboratory behavioral studies have confirmed abnormal pain perception, as demonstrated by hyperalgesia and an enhanced lingering painful sensation, in children and adults with SMD. Advanced quantitative sensory testing (QST) has revealed the mechanisms of altered pain processing in SOR whereby despite the existence of normal peripheral sensory processing, there is enhanced facilitation of pain-transmitting pathways along with preserved but delayed inhibitory pain modulation. These findings point to central nervous system (CNS) involvement as the underlying mechanism of pain hypersensitivity in SOR. Based on the mutual central processing of both non-painful and painful sensory stimuli, we suggest shared mechanisms such as cortical hyper-excitation, an excitatory-inhibitory neuronal imbalance, and sensory modulation alterations. This is supported by novel findings indicating that SOR is a risk factor and comorbidity of chronic non-neuropathic pain disorders. This is the first review to summarize current empirical knowledge investigating SMD and pain, a sensory modality not yet part of the official SMD realm. We propose a neurophysiological mechanism-based model for the interrelation between pain and SMD. Embracing the pain domain could significantly contribute to the understanding of this condition’s pathogenesis and how it manifests in daily life, as well as suggesting the basis for future potential mechanism-based therapies.

Resting-State Electroencephalography in Participants With Sensory Overresponsiveness: An Exploratory Study

OBJECTIVE

People with sensory overresponsiveness (SOR) perceive nonpainful stimuli as noxious and demonstrate hyperalgesia and lingering sensation to laboratory pain stimuli. Electroencephalography (EEG) of cortical activity at rest is widely used to explore endophenotypes but has not yet been tested in people with SOR. Therefore, we investigated the characteristics of resting-state EEG in participants with SOR.

METHOD

Resting-state EEG (5-min, eyes-closed recording) was compared in participants with (n = 9) and without (n = 12) SOR.

RESULTS

Participants with SOR demonstrated a global reduction of the EEG activity, including significantly lower θ and α1 activity as well as faster peak α frequency. Higher sensory-responsiveness scores were associated with high peak α power in participants without SOR.

CONCLUSION

Reduced α activity is commonly interpreted as an electrophysiological indicator of arousal and sensitivity to pain. The EEG pattern of response may partly explain the reported ongoing daily alertness to environmental stimuli in participants with SOR.

Sustained attention in sensory modulation disorder and attention deficit/hyperactivity disorder

BACKGROUND

There are high comorbidity rates between sensory modulation disorder (SMD) and attention deficit hyperactivity disorder (ADHD). Knowledge regarding the objective neuropsychological differentiation between them is scarce.

AIM

This study examines the effects of SMD and ADHD on a sustained attention task with and without aversive auditory conditions.

METHOD

Sixty six young adult females were tested on the Conjunctive - Continuous Performance Task-Visual (CCPT-V) measuring sustained attention, under two conditions: 1) aversive condition (with the three most aversive sounds chosen by the participant), and 2) non-aversive condition (without sounds).

RESULTS

Both the SMD and ADHD factors exhibited performance deficits in the sustained attention task. All study participants performed worse on both sustained attention and speed of processing when aversive sounds were present.

CONCLUSION

We conclude that impaired sustained attention cannot differentiate between SMD and ADHD. Hence, these results should be taken under consideration in the assessment process of ADHD vs. SMD.

Sensory modulation dysfunction is associated with Complex Regional Pain Syndrome

OBJECTIVE

Complex Regional Pain Syndrome (CRPS), a chronic pain condition, develops mainly after limb trauma and severely inhibits function. While early diagnosis is essential, factors for CRPS onset are elusive. Therefore, identifying those at risk is crucial. Sensory modulation dysfunction (SMD), affects the capacity to regulate responses to sensory input in a graded and adaptive manner and was found associated with hyperalgesia in otherwise healthy individuals, suggestive of altered pain processing.

AIM

To test SMD as a potential risk factor for CRPS.

METHODS

In this cross-sectional study, forty-four individuals with CRPS (29.9±11 years, 27 men) and 204 healthy controls (27.4±3.7 years, 105 men) completed the Sensory Responsiveness Questionnaire-Intensity Scale (SRQ-IS). A physician conducted the CRPS Severity Score (CSS), testing individuals with CRPS.

RESULTS

Thirty-four percent of the individuals with CRPS and twelve percent of the healthy individuals were identified to have SMD (χ2 (1) = 11.95; p<0.001). Logistic regression modeling revealed that the risk of CRPS is 2.68 and 8.21 times higher in individuals with sensory over- and sensory under-responsiveness, respectively, compared to non-SMD individuals (p = 0.03 and p = 0.01, respectively).

CONCLUSIONS

SMD, particularly sensory under-responsiveness, might serve as a potential risk factor for CRPS and therefore screening for SMD is recommended. This study provides the risk index probability clinical tool a simple evaluation to be applied by clinicians in order to identify those at risk for CRPS immediately after injury. Further research is needed.

Assessment of Responsiveness to Everyday Non-Noxious Stimuli in Pain-Free Migraineurs With Versus Without Aura

Migraineurs with aura (MWA) express higher interictal response to non-noxious and noxious experimental sensory stimuli compared with migraineurs without aura (MWoA), but whether these differences also prevail in response to everyday non-noxious stimuli is not yet explored. This is a cross-sectional study testing 53 female migraineurs (30 MWA; 23 MWoA) who underwent a wide battery of noxious psychophysical testing at a pain-free phase, and completed a Sensory Responsiveness Questionnaire and pain-related psychological questionnaires. The MWA group showed higher questionnaire-based sensory over-responsiveness (P = .030), higher magnitude of pain temporal summation (P = .031) as well as higher monthly attack frequency (P = .027) compared with the MWoA group. Overall, 45% of migraineurs described abnormal sensory (hyper- or hypo-) responsiveness; its incidence was higher among MWA (19 of 30, 63%) versus MWoA (6 of 23, 27%, P = .012), with an odds ratio of 3.58 for MWA. Sensory responsiveness scores were positively correlated with attack frequency (r = .361, P = .008) and temporal summation magnitude (r = .390, P = .004), both regardless of migraine type. MWA express higher everyday sensory responsiveness than MWoA, in line with higher response to experimental noxious stimuli. Abnormal scores of sensory responsiveness characterize people with sensory modulation dysfunction, suggesting possible underlying mechanisms overlap, and possibly high incidence of both clinical entities.

PERSPECTIVE

This article presents findings distinguishing MWA, showing enhanced pain amplification, monthly attack frequency, and over-responsiveness to everyday sensations, compared with MWoA. Further, migraine is characterized by a high incidence of abnormal responsiveness to everyday sensation, specifically sensory over-responsiveness, that was also found related to pain.

Sensory Over-Responsiveness among Healthy Subjects is Associated with a Pronociceptive State

OBJECTIVE

Chronic pain patients show hypersensitivity to sensory nonpainful stimuli. Sensory over-responsiveness (SOR) to innocuous daily stimuli, experienced as painful, is prevalent in 10% of the healthy population. This altered sensory processing may be an expression of overfacilitation, or a less efficient pain-inhibitory process in the pain pathways. We therefore aimed to investigate specifically the pain-inhibitory system of subjects with SOR who are otherwise healthy, not studied as of yet.

METHODS

Thirty healthy subjects, divided into an SOR group (n = 14) and a non-SOR group (n = 16) based on responses to the Sensory Responsiveness Questionnaire, were psychophysically tested in order to evaluate (1) hyperalgesic responses; (2) adaptation/sensitization to 14 phasic heat stimuli; (3) habituation; (4) 6-minute after-sensations; and (5) conditioned pain modulation (CPM) (ie, phasic heat stimuli applied with and without hand immersion in a hot water bath).

RESULTS

The SOR group differed from the non-SOR group in (1) a steeper escalation in NPS ratings to temperature increase (P = 0.003), indicating hyperalgesia; (2) increased sensitization (P < 0.001); (3) habituation responses (P < 0.001); (4) enhanced pain ratings during the after-sensation (P = 0.006); and (5) no group difference was found in CPM.

CONCLUSIONS

SOR is associated with a pronociceptive state, expressed by amplification of experimental pain, yet with sufficient inhibitory processes. Our results support previous findings of enhanced facilitation of pain-transmitting pathways but also reveal preserved inhibitory mechanisms, although they were slower to react.

Atypical Sensory Modulation and Psychological Distress in the General Population

OBJECTIVE

Atypical sensory modulation (ASM) is characterized by over- or underresponsiveness to sensory stimuli in one or more sensory systems. Faulty sensory information processing could result in anxiety. Because the relation between ASM and psychological distress has not been examined, we explored psychological distress and ASM in the general population.

METHOD

A community-based sample of 204 adults (105 men; mean age = 27.4 yr, standard deviation = 3.71) completed the Sensory Responsiveness Questionnaire--Intensity Scale (SRQ-IS; Bar-Shalita, Seltzer, Vatine, Yochman, & Parush, 2009); the Brief Symptom Inventory (BSI; Derogatis & Coons, 1993); and the Short Form--36 Health Survey, Version 2 (SF-36; Ware, Kosinski, & Gandek, 2005).

RESULTS

The ASM group displayed considerably more distress symptoms than the comparison group. Multivariate linear regression showed SRQ-IS and SF-36 scores as significant predictors of BSI score (r = .64).

CONCLUSION

ASM may be a risk factor for developing other mental health concerns.

Ecological aspects of pain in sensory modulation disorder

BACKGROUND

Sensory Modulation Disorder (SMD) interferes with the daily life participation of otherwise healthy individuals and is characterized by over-, under- or seeking responsiveness to naturally occurring sensory stimuli. Previous laboratory findings indicate pain hyper-sensitivity in SMD individuals suggesting CNS alteration in pain processing and modulation. However, laboratory studies lack ecological validity, and warrant clinical completion in order to elicit a sound understanding of the phenomenon studied. Thus, this study explored the association between sensory modulation and pain in a daily life context in a general population sample.

METHODS

Daily life context of pain and sensations were measured in 250 adults (aged 23-40 years; 49.6% males) using 4 self-report questionnaires: Pain Sensitivity Questionnaire (PSQ) and Pain Catastrophizing Scale (PCS) to evaluate the sensory and cognitive aspects of pain; the Sensory Responsiveness Questionnaire (SRQ) to appraise SMD; and the Short Form - 36 Health Survey, version 2 (SF36) to assess health related Quality of Life (QoL).

RESULTS

Thirty two individuals (12.8%) were found with over-responsiveness type of SMD, forming the SOR-SMD group. While no group differences (SOR-SMD vs. Non-SMD) were found, low-to-moderate total sample correlations were demonstrated between the SRQ-Aversive sub-scale and i) PSQ total (r=0.31, p<0.01) and sub-scales scores (r=0.27-0.28, p<0.01), as well as ii) PCS total and the sub-scales of Rumination and Helplessness scores (r=0.15, p<0.05). PSQ total and sub-scale scores were more highly correlated with SRQ-Aversive in the SOR-SMD group (r=0.57-0.68, p=0.03-<0.01) compared to Non-SMD group. The Physical Health - Total score (but not the Mental Health - Total) of the SF36 was lower for the SOR-SMD group (p=0.03), mainly due to the difference in the Body pain sub-scale (p=0.04).

CONCLUSIONS

Results suggest that SOR-SMD is strongly associated with the sensory aspect of pain but weakly associated with the cognitive aspect. This indicates that SMD co-occurs with daily pain sensitivity, thus reducing QoL, but less with the cognitive-catastrophizing manifestation of pain perception.

Sensory Sensitivity and Strategies for Coping With Pain

OBJECTIVE. Our goal was to investigate the relationship between sensory processing styles and use of pain coping strategies in an experimental setting to understand individual differences in pain coping.

METHOD. A cross-sectional design was used with a convenience sample of 116 healthy adults. Measures of sensory processing style and mood state were collected before participation in a cold pressor pain-inducement task, and measures of coping strategies were collected afterward. Multiple regression models were constructed to examine relationships between sensory processing and coping strategies.

RESULTS. Sensory sensitivity and sensation avoiding were significantly associated with higher levels of catastrophizing. Sensation seeking was linked with active coping strategies, such as coping self-statements. Low registration was not significantly associated with any particular coping strategy after controlling for salient variables.

CONCLUSION. This study highlights associations between sensory processing and pain coping strategies, which may inform more tailored approaches to clinical practice for people in pain.

Sensory modulation and daily-life participation in people with schizophrenia

Schizophrenia is considered to be an extreme mental health disturbance that affects a person's well-being and participation in everyday activities. Participation in meaningful everyday occupations is an important component of recovery from mental illness, the ultimate goal of mental health services. The participation restrictions of people with schizophrenia have been widely investigated through different factors, such as illness symptoms and course, cognition, and demographic data; however, the resulting explanations were incomplete. The purpose of the study was to explore the contribution of sensory modulation (SM), in addition to cognition and schizophrenia symptoms, to participation in daily life activities of people with schizophrenia. Forty nine in-patients with schizophrenia (study group) and 32 adults without mental illness (control group) comprised the study. They were assessed for their participation patterns, sensory modulation processes, cognitive functioning and symptoms severity. Results indicate significant differences between the study groups in most measurements addressed: participation (diversity and satisfaction), sensory modulation scores (intensity of the response and frequency of response), and cognitive measurements. The most contributive parameters for the prediction of participation dimensions among people with schizophrenia were negative symptoms severity and general cognitive status. In conclusion, people with schizophrenia experience SM disorder with an under responsive tendency. However the complex condition of schizophrenia dominates its influence on participation dimensions.

Comparing the executive attention of adult females with ADHD to that of females with sensory modulation disorder (SMD) under aversive and non-aversive auditory conditions

Certain behavioral expressions of sensory modulation disorder (SMD) such as distractibility, hyperactivity, and impulsivity are often similar to those of attention deficit/hyperactivity disorder (ADHD) in pediatric and adult populations. There is also a high comorbidity rate between these two diagnoses and absence of research regarding the objective neuropsychological differentiation between them. In the present study we employed a factorial design which enabled us to: (a) systematically examine the effects of SMD and ADHD on executive attention in a sample of adult females using a Stroop-like task, and (b) measure the effect of aversive conditions (sounds) on executive attention. The experimental measures used were the Stroop-like Location-Direction Task (SLDT) to assess executive attention and the battery of aversiveness to sounds (BAS), a standardized measure of aversive sounds that was developed for this study and enabled individual customization of aversive auditory sounds. Results revealed, as expected, a specific core deficit in executive attention for the ADHD factor. In addition to that, the present study provides an important, pioneering finding of SMD impairment in a unique combination of a cognitively demanding task with aversive sounds, providing preliminary objective evidence differentiating SMD from ADHD.