Maturation of sensory gating performance in children with and without sensory processing disorders

Disentangling the relationship between sensory processing, alexithymia and broad autism spectrum: A study in parents' of children with autism spectrum disorders and sensory processing disorders

BACKGROUND

Autistic features and sensory processing difficulties and their phenotypic co-expression with alexithymia share a transdiagnostic vulnerability. In this work, we explored whether the current concept of broad autism phenotype rather translates altered sensory processing (non-specific to autism), meaning that the characteristics of altered sensory processing should be overexpressed among individuals with heightened vulnerability to sensory processing atypicalities (parents of children with sensorial processing disorder, or SPD parents) and individuals with heightened vulnerability to autistic traits (parents of children with autism spectrum disorders, or ASD parents). In addition, the association between altered sensory processing and alexithymia was inspected.

METHOD

The Adolescent/Adult Sensory Profile, Autism Spectrum Quotient, and Toronto Alexithymia Scale were completed by 31 parents of children with ASD, 32 parents of children with SPD, and 52 parents of typically developed (TD) children.

RESULTS

Extreme sensory patterns were overexpressed both in parents of children with SPD and parents of children with ASD when compared to parents of TD children. In addition, extreme sensory patterns were significantly associated with alexithymia scores. Specifically, sensory avoidance, low registration, and sensory sensitivity were positively correlated with alexithymia. No significant differences were found regarding the proportion of autistic traits and alexithymia between ASD and SPD groups of parents.

CONCLUSIONS

These results challenge the specificity of broad autism phenotype and suggest a neurodevelopmental atypicity with roots in altered sensory and emotional processing.

The Functional-Cognitive and Sensory Treatment (F-CaST) to improve rehabilitation outcomes of individuals with substance use disorder: a study protocol for a mixed-method randomized controlled trial

BACKGROUND

Substance use disorder (SUD) is associated with executive function (EF) deficits and sensory modulation dysfunction (SMD). Yet, these deficits are not addressed therapeutically. This study aims to examine the effectiveness of the Functional-Cognitive and Sensory Treatment (F-CaST) compared to standard care to improve everyday performance and behavior and length of stay at the therapeutic community (TC) in individuals with SUD. In addition, to assess the improvement in EF, sensory modulation, participation, self-efficacy, life satisfaction, and use of strategies within and between groups. Satisfaction with F-CaST will also be assessed.

METHODS

Forty-eight participants from a community of men in a TC, aged 18-45 years will be randomly allocated to (i) F-CaST-(experimental group) providing sensory and EF strategies for improving daily function; (ii) standard care (control group) as provided in the TC. Assessments will be conducted by assessors blind to group allocation at 4 time points: T1- pre-intervention; T2- post-intervention; T3- 1-month follow-up; and T4- 3-month follow-up. Primary outcome measures will be everyday performance, assessed by the Canadian Occupational Performance Measure (COPM), behavior and length of stay in the TC; secondary outcome measures will assess EF, SMD. Semi-structured in-depth qualitative interviews will be conducted at T1, T2 and T4.

DISCUSSION

We hypothesize that F-CaST will lead to improved everyday performance and longer length of stay in the TC, compared to the control group. If F-CaST will prove to be effective, cognitive and sensory strategies may be incorporated as an adjunctive intervention in SUD rehabilitation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05647863 Registered on 13 December 2022, https://classic.

CLINICALTRIALS

gov/ct2/show/NCT05647863 .

The Effect of Attention on Auditory Processing in Adults on the Autism Spectrum

This study examined the effect of attention on auditory processing in autistic individuals. Electroencephalography data were recorded during two attention conditions (passive and active) from 24 autistic adults and 24 neurotypical controls, ages 17-30 years. The passive condition involved only listening to the clicks and the active condition involved a button press following single clicks in a modified paired-click paradigm. Participants completed the Adolescent/Adult Sensory Profile and the Social Responsiveness Scale 2. The autistic group showed delayed N1 latencies and reduced evoked and phase-locked gamma power compared to neurotypical peers across both clicks and conditions. Longer N1 latencies and reduced gamma synchronization predicted greater social and sensory symptoms. Directing attention to auditory stimuli may be associated with more typical neural auditory processing in autism.

Sensory sensitivity, intolerance of uncertainty and sex differences predicting anxiety in emerging adults

As multiple vulnerability factors have been defined for anxiety disorders, it is important to investigate the interactions among these factors to understand why and how some individuals develop anxiety. Sensory Sensitivity (SS) and Intolerance of Uncertainty (IU) are independent vulnerability factors of anxiety, but their unique relationship in predicting anxiety has rarely been studied in non-clinical populations. The objective of this investigation was to examine the combined effects of SS and IU on self-reported anxiety in a sample of university students. In addition, with the frequently reported sex bias in anxiety literature, we expected that the combined effects of vulnerability factors would be different for females and males. A convenience sample of 313 university students, ages 17-26 years was recruited. The participants completed the Intolerance of Uncertainty Scale (IUS-12), the Adult/Adolescent Sensory Profile (AASP), and the Beck Anxiety Inventory (BAI). Results of moderated mediation analyses demonstrated a strong partial mediation between SS and anxiety through IU, providing evidence that IU, a cognitive bias against the unknown, was one mechanism that explained how SS was related to anxiety. Further, the effect of IU on anxiety was approximately twice as strong in females. Our results highlight the importance of studying the unique relationships among multiple vulnerability factors to better understand anxiety susceptibility in emerging adults.

Sensory Processing and Autistic Traits: Mediation Effect of Frontal Alpha Asymmetry

A sensory processing approach can be used to intervene with behaviours in individuals with autistic symptoms. However, neural mechanisms linking sensory processing patterns and autistic features are less understood. The purpose of this study was to investigate whether frontal alpha asymmetry could mediate the relationship between atypical sensory processing and autistic traits. Seventy-three neurotypical young adults were included in this study. Resting-state brain activity was recorded using electroencephalography. After the recording, participants completed the Adolescent/Adult Sensory Profile and the Autism-Spectrum Quotient. Frontal alpha asymmetry was calculated by subtracting left frontal alpha power from right frontal alpha power. Correlation analysis was performed to find which sensory processing patterns were related to frontal alpha asymmetry and autistic traits. Mediation analysis was then conducted with sensory avoiding patterns as an independent variable, autistic traits as a dependent variable, and frontal alpha asymmetry as a mediator. Interrelations between higher sensation avoiding patterns, greater right-sided cortical activity, and increased autistic traits were found. The sensation avoiding patterns affected autistic traits directly and indirectly through right-sided cortical activity. Findings of the current study demonstrate a mediating role of frontal alpha asymmetry in the relationship between sensation avoiding patterns and autistic traits in neurotypical adults. This study suggests that sensation avoiding patterns and withdrawal-related emotions, which are associated with right-sided cortical activity, need to be considered to improve autism symptoms.

Sensory Inhibition and Speech Perception-in-Noise Performance in Children With Normal Hearing

PURPOSE

This study investigated whether sensory inhibition in children may be associated with speech perception-in-noise performance. Additionally, gating networks associated with sensory inhibition were identified via standardized low-resolution brain electromagnetic tomography (sLORETA), and the detectability of the cortical auditory evoked potential (CAEP) N1 response was enhanced using a 4- to 30-Hz bandpass filter.

METHOD

CAEP gating responses, reflective of inhibition, were evoked via click pairs and recorded using high-density electroencephalography in neurotypical 5- to 8-year-olds and 22- to 24-year-olds. Amplitude gating indices were calculated and correlated with speech perception in noise. Gating generators were estimated using sLORETA. A 4- to 30-Hz filter was applied to detect the N1 gating component.

RESULTS

Preliminary findings indicate children showed reduced gating, but there was a correlational trend between better speech perception and decreased N2 gating. Commensurate with decreased gating, children presented with incomplete compensatory gating networks. The 4- to 30-Hz filter identified the N1 response in a subset of children.

CONCLUSIONS

There was a tenuous relationship between children's speech perception and sensory inhibition. This may suggest that sensory inhibition is only implicated in atypically poor speech perception. Finally, the 4- to 30-Hz filter settings are critical in N1 detectability.

SIGNIFICANCE

Gating may help evaluate reduced sensory inhibition in children with clinically poor speech perception using the appropriate methodology. Cortical gating generators in typically developing children are also newly identified.

Habilitation Improves Mouse Gait Development Following Neonatal Brain Injury

OBJECTIVES

Neonatal brain injury during gait development disrupts neural circuits and causes permanent gait dysfunction. Rehabilitation as an intervention to improve impaired gait function has been used in adults as a treatment for stroke and spinal cord injury. However, although neonates have greater neuroplasticity and regenerative capacity than adults, normal gait development and the effects of habilitation on gait function following neonatal brain injury are largely unknown.

METHODS

In this study, we generated cryogenic injury in mice at postnatal day 2 and subsequently performed habilitative training to promote autonomous limb movement for 4 weeks. We also quantitatively analyzed the gait acquisition process in developing mice using the Catwalk XT system.

RESULTS

Using quantitative gait analyses, we showed that during normal gait development in mice, stance phase function matures later than swing phase function. We also demonstrated that habilitation in which active limb movements were enhanced by suspending mice with a rubber band with no floor grounding promotes motor learning, including gait function, in mice with impaired acquisition of gait function resulting from neonatal brain injury.

CONCLUSIONS

Our findings provide a basis for research on gait development in mice and suggest new habilitation strategies for patients with impaired gait development caused by perinatal brain diseases such as hypoxic-ischemic encephalopathy and periventricular leukomalacia.

A longitudinal exploratory study of changes in sensory processing in children with ASD from the ELENA cohort

Atypical sensory processing (SP) is a diagnostic criterion of autism spectrum disorder (ASD). However, little is known about its course during development. In this exploratory longitudinal study, we aimed to investigate the course of SP among children with ASD and identify clinical variables associated with changes. We used a subsample of 51 children with confirmed ASD, aged from 3 to 10 years, recruited from the ELENA cohort. SP was assessed using the Sensory Profile questionnaire at baseline and three years later. Our preliminary results highlight the heterogeneity of the evolution of SP during the children's development and the existence of three subgroups based on the course of SP (improvement, stable, and worsening). In addition, the children's adaptive skills and maladaptive behaviors were related to the course of SP. These results could be confirmed in future studies with a larger sample size using a longitudinal approach to capture individual variability in SP. In addition, our results highlight the importance of accounting for temporal changes in the sensory needs of individuals with ASD in clinical practice.

Prepulse Inhibition and P50 Suppression in Relation to Creativity and Attention: Dispersed Attention Beneficial to Quantitative but Not Qualitative Measures of Divergent Thinking

The current study investigated whether lower sensory and sensorimotor gating were related to higher levels of creativity and/or attentional difficulties in a natural population of primary school children (9- to 13-year-old). Gating abilities were measured with P50 suppression and prepulse inhibition of the startle reflex (PPI). The final sample included 65 participants in the P50 analyses and 37 participants in the PPI analyses. Our results showed that children with a high P50 amplitude to testing stimuli scored significantly higher on the divergent outcome measures of fluency and flexibility but not originality compared to children with a lower amplitude. No significant differences were found on any of the creativity measures when the sample was split on average PPI parameters. No significant differences in attention, as measured with a parent questionnaire, were found between children with low or high levels of sensory or sensorimotor gating. The data suggest that quantitative, but not qualitative measures of divergent thinking benefit from lower psychophysiological gating and that attentional difficulties stem from specific instead of general gating deficits. Future studies should take the effect of controlled attention into consideration.

Auditory Sensory Gating in Children With Cochlear Implants: A P50-N100-P200 Study

Background: While a cochlear implant (CI) can restore access to audibility in deaf children, implanted children may still have difficulty in concentrating. Previous studies have revealed a close relationship between sensory gating and attention. However, whether CI children have deficient auditory sensory gating remains unclear.

Methods: To address this issue, we measured the event-related potentials (ERPs), including P50, N100, and P200, evoked by paired tone bursts (S1 and S2) in CI children and normal-hearing (NH) controls. Suppressed amplitudes for S2 compared with S1 in these three ERPs reflected sensory gating during early and later phases, respectively. A Swanson, Nolan, and Pelham IV (SNAP-IV) scale was performed to assess the attentional performance.

Results: Significant amplitude differences between S1 and S2 in N100 and P200 were observed in both NH and CI children, indicating the presence of sensory gating in the two groups. However, the P50 suppression was only found in NH children and not in CI children. Furthermore, the duration of deafness was significantly positively correlated with the score of inattention in CI children.

Conclusion: Auditory sensory gating can develop but is deficient during the early phase in CI children. Long-term auditory deprivation has a negative effect on sensory gating and attentional performance.

Characteristics of Idiopathic Sensory Processing Disorder in Young Children

This study described the developmental and behavioral characteristics of children identified with idiopathic sensory processing disorder (SPD) as well as the relations among specific types of SPD as proposed by the nosology presented by Miller et al. (2007), adaptive behavior profiles, and behaviors associated with mental functioning. A retrospective, non-experimental design applying descriptive and correlational analyses was used. Data were obtained from clinic medical records of 78 children ages 2 to 7 years who were identified with sensory processing problems affecting daily life, but who did not meet criteria for any other neurodevelopmental or mental disorders following a comprehensive diagnostic evaluation. Results revealed that all SPD types as described by current typologies were well represented with the most common being the over-responsivity sensory modulation subtype. Within the sample, 53% of the children displayed more than one SPD type. Atypical externalizing and internalizing behavior scores associated with various mental disorders as measured by the child behavior checklist (CBCL) fell in the borderline dysfunctional range. Adaptive behavior for all developmental domains was below average, and the severity of SPD symptoms moderately and positively correlated with behaviors associated with mental disorders, and with lower adaptive behavior performance. It was concluded that symptoms characteristic of the various types of idiopathic SPD overlap substantially suggesting that current typologies may include more types/subtypes than are necessary or clinically useful. Children with SPD share similar, but often less severe pathological behaviors associated with other mental or related neurodevelopmental disorders. Psychometrically sound measures of SPD are needed, and further study of the neural mechanisms involved in sensory processing deficits is vital for validating idiopathic SPD as its own diagnostic entity.

Sensory Modulation Disorder and its Neural Circuitry in Adults with ADHD: A Pilot Study

Compared to healthy controls (HCs), individuals with attention-deficit/hyperactivity disorder (ADHD) exhibit more symptoms of sensory processing disorder (SPD), which is associated with difficulties in educational and social activities. Most studies examining comorbid SPD-ADHD have been conducted with children and have not explored relations to brain volumes. In this pilot study, we assessed a subtype of SPD, sensory modulation disorder (SMD), and its relation to select brain volumes in adults with ADHD. We administered part of the Sensory Processing 3-Dimensions Scale (SP3D) to assess subtypes of SMD and collected structural imaging scans from 25 adults with ADHD and 29 healthy controls (HCs). Relative to HCs, subjects with ADHD scored higher on sensory craving (SC) and sensory under-responsivity (SUR) subscales. Although sensory over-responsivity (SOR) was marginally higher, this was no longer true when accounting for co-occurring anxiety. In individuals with ADHD, both SC and SUR were positively associated with amygdalar volume, SUR was also positively associated with striatal volume, whereas SOR was negatively associated with posterior ventral diencephalon volume. These preliminary findings suggest that SC and SUR may be characteristic of ADHD while SOR may be driven by co-occurring anxiety. Because different modalities were associated with different brain volumes, our findings also suggest that the modalities may involve unique neural circuits, but with a partial overlap between SC and SUR. These pilot data provide support for conducting studies examining SMD in larger samples of adults with ADHD to determine reproducibility, applicability and implications of these findings.

Expanding our understanding of sensory gating in children with autism spectrum disorders

OBJECTIVE

This study examined sensory gating in children with autism spectrum disorders (ASD). Gating is usually examined at the P50 component and rarely at mid- and late-latency components.

METHODS

Electroencephalography data were recorded during a paired-click paradigm, from 18 children with ASD (5-12 years), and 18 typically-developing (TD) children. Gating was assessed at the P50, N1, P2, and N2 event-related potential components. Parents of all participants completed the Short Sensory Profile (SSP).

RESULTS

TD children showed gating at all components while children with ASD showed gating only at P2 and N2. Compared to TD children, the ASD group showed significantly reduced gating at P50, N1, and P2. No group differences were found at N2, suggesting typical N2 gating in the ASD group. Time-frequency analyses showed reduced orientation and neural synchronization of auditory stimuli. P50 and N1 gating significantly correlated with the SSP.

CONCLUSION

Although children with ASD have impaired early orientation and filtering of auditory stimuli, they exhibited gating at P2 and N2 components suggesting use of different gating mechanisms compared to TD children. Sensory deficits in ASD may relate to gating.

SIGNIFICANCE

The data provide novel evidence for impaired neural orientation, filtering, and synchronization in children with ASD.

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.

Self-Reported Sensory Gating and Stress-Related Hypertension

BACKGROUND

Increasing evidence views hypertension as a stress-induced disorder. Stressors must be "gated" by the brain before any inflammatory or immune processes that contribute to hypertension are initiated. No studies were found that examined sensory gating in relation to hypertension.

OBJECTIVES

The aim of the study was to determine if disturbances in self-reported sensory gating could differentiate normotensive from hypertensive young adults.

METHODS

A nonmatched, case-control design was used. We administered an online survey to 163 young adult participants. Participants were predominantly female, in their mid-20s, well educated, and approximately evenly distributed by race and hypertension status. The Sensory Gating Inventory (SGI) measured gating disturbances.

RESULTS

The mean SGI scores were significantly higher among persons diagnosed with hypertension, reflecting a moderate effect size of sensory gating. After adjusting for confounders, however, the normotensive and hypertensive groups were not significantly different on their SGI scores.

DISCUSSION

With an observed moderate effect size of 0.35, but low power, more research is warranted regarding the role of gating disturbances in the development of stress-induced hypertension. Clinically, the SGI may be important for screening patients who would benefit from ambulatory blood pressure monitoring to identify persons with masked hypertension.

The Influence of Background Auditory Noise on P50 and N100 Suppression Elicited by the Paired-Click Paradigm

Abstract. Auditory sensory gating is commonly assessed using the Paired-Click Paradigm (PCP), an electroencephalography (EEG) task in which two identical sounds are presented sequentially and the brain’s inhibitory response to the second sound is measured. Many clinical populations demonstrate reduced P50 and/or N100 suppression. Testing sensory gating in children may help to identify individuals at risk for neurodevelopmental disorders earlier, including autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), which could lead to more optimal outcomes. Minimal research has been done with children because of the difficulty of performing lengthy EEG experiments with young children, requiring them to sit still for long periods of time. We designed a modified, potentially child-friendly version of the PCP and evaluated it in typically developing adults. The PCP was administered twice, once in a traditional silent room (silent movie condition) and once with an audible movie playing (audible movie condition) to minimize boredom and enhance behavioral compliance. We tested whether P50 and N100 suppression were influenced by the presence of the auditory background noise from the movie. N100 suppression was observed in both hemispheres in the silent movie condition and in the left hemisphere only during the audible movie condition, though suppression was attenuated in the audible movie condition. P50 suppression was not observed in either condition. N100 sensory gating was successfully elicited with an audible movie playing during the PCP, supporting the use of the modified task for future research in both children and adults.

Sensory Processing and Attention Profiles Among Children With Sensory Processing Disorders and Autism Spectrum Disorders

This study explores the differences in the profile of relationships between sensory processing and attention abilities among children with sensory processing disorder (SPD), autism spectrum disorder (ASD), and typically developing (TD) children. The Test of Everyday Attention for Children (TEA-Ch), a performance-based measure of attention, was administered to 69 children (TD: n = 24; SPD: n = 21; ASD: n = 24), ages 6-10 years. All participants' parents completed the Short Sensory Profile (SSP), a standardized parent-report measure of sensory-related behaviors. Discriminant analyses using the TEA-Ch and the SSP domains revealed two classification functions; the first revealed that both clinical groups significantly differed from the TD group with greater sensory processing challenges in the categories of auditory filtering, under-responsive/seeks sensation, low energy/weak, and taste/smell sensitivity subscales of the SSP. The second function discriminated between the two clinical groups, indicating that children with ASD had significantly greater control and sustained attention deficits and less sensory issues than did children with SPD. Together, the two functions correctly classified 76.8% of the participants as to their group membership. The different profiles of sensory processing and attention abilities in children with SPD and ASD may provide guidance in identifying appropriate individualized therapeutic strategies for these children.

Prevalence and patterns of sensory processing behaviors in a large clinical sample of children with prenatal alcohol exposure

BACKGROUND

Atypical behavioral responses to sensation are reported in a large proportion of children affected by prenatal alcohol exposure (PAE). Systematic examination of symptoms across the fetal alcohol spectrum in a large clinical sample is needed to inform diagnosis and intervention.

AIMS

To describe the prevalence and patterns of atypical sensory processing symptoms in a clinical sample of children with PAE.

METHODS

Retrospective analysis of diagnostic clinical data from the University of Washington Fetal Alcohol Syndrome Diagnostic and Prevention Network (FASDPN). Participants were ages 3 through 11 years, had a diagnosis on the fetal alcohol spectrum, and Short Sensory Profile (SSP) assessment. The proportions of children categorized with definite differences on the SSP across selected clinical and demographic features were examined with chi-square analyses.

OUTCOMES

The sample consisted of 325 children; 73.2 % had SSP total scores in the definite difference range. Atypical sensory processing symptoms were significantly more prevalent among children with higher reported levels of PAE. The prevalence of atypical symptoms was comparably high across age, levels of diagnostic severity, and other prenatal/postnatal risks.

CONCLUSIONS

Results lend support for altered sensory processing as another domain of brain function affected by the teratogenic impact of PAE, guiding clinical work and research.

Sensory Habituation as a Shared Mechanism for Sensory Over-Responsivity and Obsessive-Compulsive Symptoms

Background

Some individuals who suffer from obsessive-compulsive (OC) disorder (OCD), report disturbing sensory preoccupations. The inability to stop obsessing over stimuli resonates with a difficulty in sensory habituation. Impaired sensory habituation, to a degree that clearly dysregulates response to sensory stimuli, and impairs participation in everyday activities, can be part of a disorder known as sensory over-responsivity (SOR). Although previous studies indicated a correlation between OCD and SOR, physiological experiments show that individuals with OCD are not more sensitive to sensory stimuli than controls. In the current study, we (1) validated a sensory habituation psycho-physiological protocol and (2) tested whether a "slow to habituate" mechanism can explain the occurrence of elevated SOR and OC symptoms.

Methods

We designed a protocol to test auditory sensory habituation through electrodermal activity (EDA) recording. The protocol included two randomly ordered aversive and neutral sound conditions; each set of six everyday life sounds was presented as a continuous stimulus. During the presentation of sounds, EDA was measured and participants could press a button to shorten the stimuli. Participants also completed sensory and OC symptom questionnaires. Participants included 100 typically developing adults that were divided into high versus low OC symptom groups. Mixed models analysis was used throughout to meet the need for capturing the temporal nature of habituation.

Results

Distinct physiological indices were computed to measure sensitivity versus habituation. Habituation was slower in the aversive versus neutral condition. Sensitivity was higher for the aversive stimuli. Self-report of sensory habituation and sensitivity partially correlated with the physiological habituation indices. A comparison of the physiological pattern between those with high versus low OC symptoms revealed significant differences in the habituation and sensitivity indices, across conditions.

Conclusion

The interplay between SOR and OC symptoms can be explained by a "slow to habituate" mechanism. Identifying behavioral and physiological markers of sensory problems in OCD is important for assessment, intervention and the discovery of underlying mechanisms.

Multisensory Audiovisual Processing in Children With a Sensory Processing Disorder (I): Behavioral and Electrophysiological Indices Under Speeded Response Conditions

Background

Maladaptive reactivity to sensory inputs is commonly observed in neurodevelopmental disorders (e.g., autism, ADHD). Little is known, however, about the underlying neural mechanisms. For some children, atypical sensory reactivity is the primary complaint, despite absence of another identifiable neurodevelopmental diagnosis. Studying Sensory Processing Disorder (SPD) may well provide a window into the neuropathology of these symptoms. It has been proposed that a deficit in sensory integration underlies the SPD phenotype, but objective quantification of sensory integration is lacking. Here we used neural and behavioral measures of multisensory integration (MSI), which would be affected by impaired sensory integration and for which there are well accepted objective measures, to test whether failure to integrate across the senses is associated with atypical sensory reactivity in SPD. An autism group served to determine if observed differences were unique to SPD.

Methods

We tested whether children aged 6–16 years with SPD (N = 14) integrate multisensory inputs differently from age-matched typically developing controls (TD: N = 54), or from children with an autism spectrum disorder (ASD: N = 44). Participants performed a simple reaction-time task to the occurrence of auditory, visual, and audiovisual stimuli presented in random order, while high-density recordings of electrical brain activity were made.

Results

Children with SPD showed large reductions in the extent to which they benefited from multisensory inputs compared to TDs. The ASD group showed similarly reduced response speeding to multisensory relative to unisensory inputs. Neural evidence for MSI was seen across all three groups, with the multisensory response differing from the sum of the unisensory responses. Post hoc tests suggested the possibility of enhanced MSI in SPD in timeframes consistent with cortical sensory registration (∼60 ms), followed by reduced MSI during a timeframe consistent with object formation (∼130 ms). The ASD group also showed reduced MSI in the later timeframe.

Conclusion

Children with SPD showed reduction in their ability to benefit from redundant audio-visual inputs, similar to children with ASD. Neurophysiological recordings, on the other hand, showed that major indices of MSI were largely intact, although post hoc testing pointed to periods of potential differential processing. While these exploratory electrophysiological observations point to potential sensory-perceptual differences in multisensory processing in SPD, it remains equally plausible at this stage that later attentional processing differences may yet prove responsible for the multisensory behavioral deficits uncovered here.

Attention modulates the gating of primary somatosensory oscillations

Sensory gating (SG) is a well-studied phenomenon in which neural responses are reduced to identical stimuli presented in succession, and is thought to represent the functional inhibition of primary sensory information that is redundant in nature. SG is traditionally considered pre-attentive, but little is known about the effects of attentional state on this process. In this study, we investigate the impact of directed attention on somatosensory SG using magnetoencephalography. Healthy young adults (n ​= ​26) performed a novel somato-visual paired-pulse oddball paradigm, in which attention was directed towards or away from paired-pulse stimulation of the left median nerve. We observed a robust evoked (i.e., phase-locked) somatosensory response in the time domain, and three stereotyped oscillatory responses in the time-frequency domain including an early theta response (4-8 ​Hz), and later alpha (8-14 ​Hz) and beta (20-26 ​Hz) responses across attentional states. The amplitudes of the evoked response and the theta and beta oscillations were gated for the second stimulus, however, only the gating of the oscillatory responses was altered by attention. Specifically, directing attention to the somatosensory domain enhanced SG of the early theta response, while reducing SG of the later alpha and beta responses. Further, prefrontal alpha-band coherence with the primary somatosensory cortex was greater when attention was directed towards the somatosensory domain, supporting a frontal modulatory effect on the alpha response in primary somatosensory regions. These findings highlight the dynamic effects of attentional modulation on somatosensory processing, and the importance of considering attentional state in studies of SG.

Multisensory Audiovisual Processing in Children With a Sensory Processing Disorder (II): Speech Integration Under Noisy Environmental Conditions

Background: There exists a cohort of children and adults who exhibit an inordinately high degree of discomfort when experiencing what would be considered moderate and manageable levels of sensory input. That is, they show over-responsivity in the face of entirely typical sound, light, touch, taste, or smell inputs, and this occurs to such an extent that it interferes with their daily functioning and reaches clinical levels of dysfunction. What marks these individuals apart is that this sensory processing disorder (SPD) is observed in the absence of other symptom clusters that would result in a diagnosis of Autism, ADHD, or other neurodevelopmental disorders more typically associated with sensory processing difficulties. One major theory forwarded to account for these SPDs posits a deficit in multisensory integration, such that the various sensory inputs are not appropriately integrated into the central nervous system, leading to an overwhelming sensory-perceptual environment, and in turn to the sensory-defensive phenotype observed in these individuals. Methods: We tested whether children (6-16 years) with an over-responsive SPD phenotype (N = 12) integrated multisensory speech differently from age-matched typically-developing controls (TD: N = 12). Participants identified monosyllabic words while background noise level and sensory modality (auditory-alone, visual-alone, audiovisual) were varied in pseudorandom order. Improved word identification when speech was both seen and heard compared to when it was simply heard served to index multisensory speech integration. Results: School-aged children with an SPD show a deficit in the ability to benefit from the combination of both seen and heard speech inputs under noisy environmental conditions, suggesting that these children do not benefit from multisensory integrative processing to the same extent as their typically developing peers. In contrast, auditory-alone performance did not differ between the groups, signifying that this multisensory deficit is not simply due to impaired processing of auditory speech. Conclusions: Children with an over-responsive SPD show a substantial reduction in their ability to benefit from complementary audiovisual speech, to enhance speech perception in a noisy environment. This has clear implications for performance in the classroom and other learning environments. Impaired multisensory integration may contribute to sensory over-reactivity that is the definitional of SPD.

Assessing the Impact of Music Therapy on Sensory Gating and Attention in Children With Autism: A Pilot and Feasibility Study

Children with autism spectrum disorder (ASD) frequently demonstrate atypical processing of sensory information and deficits in attentional abilities. These deficits may impact social and academic functioning. Although music therapy has been used to address sensory and attentional needs, there are no studies including physiologic indicators of sensory processing to determine the impact of music therapy. The objective of this study was to determine the feasibility of conducting study protocols, determine the adequacy of electroencephalography (EEG) and behavioral measures in identifying attentional differences in children with ASD compared with typically developing (TD) children, and to gather preliminary evidence of intervention effects on brain responses and attention outcomes. Seven children with high functioning ASD ages 5 -12 and seven age- and gender-matched TD completed procedures measuring brain responses (EEG) and behaviors (the Test of Everyday Attention for Children). Children with ASD then completed a 35-min individual music therapy attention protocol delivered by a board-certified music therapist ten times over 5 weeks. Children with ASD completed measures of brain responses and behavior post-intervention to determine pre- to post-test differences. Consent and completion rates were 100% for children who met the study criteria. Feasibility measures indicated that measures of brain responsivity could be used to determine attentional differences between children with ASD and typical children. Initial outcome data for brain responses and behavior indicated positive trends for the impact of music therapy on selective attention skills.

Sensory Gating Capacity and Attentional Function in Adults With ADHD: A Preliminary Neurophysiological and Neuropsychological Study

Objective: The inability to filter sensory input correctly may impair higher cognitive function in ADHD. However, this relationship remains largely elusive. The objectives of the present study is to investigate the relationship between sensory input processing and cognitive function in adult patients with ADHD. Method: This study investigated the relationship between deficit in sensory gating capacity (P50 amplitude changes in a double-click conditioning-testing paradigm and perceptual abnormalities related to sensory gating deficit with the Sensory Gating Inventory [SGI]) and attentional and executive function (P300 amplitude in an oddball paradigm and attentional and executive performances with a neuropsychological test) in 24 adult patients with ADHD. Results: The lower the sensory gating capacity of the brain and the higher the distractibility related to sensory gating inability that the patients reported, the lower the P300 amplitude. Conclusion: The capacity of the brain to gate the response to irrelevant incoming sensory input may be a fundamental protective mechanism that prevents the flooding of higher brain structures with irrelevant information in adult patients with ADHD.

Dunn's Model of Sensory Processing: An Investigation of the Axes of the Four-Quadrant Model in Healthy Adults

We examined the behavioral response (BR) and threshold (T) axes of Dunn's four-quadrant model of sensory processing (1997). We assessed whether they are ordinal ranges and if variation is associated with other similarly described characteristics: Introversion/Extraversion (I/E) of Eysenck's personality model (Sato, 2005), and somatosensory event related potentials (SERP) and their gating (Davies &amp; Gavin, 2007). From healthy adults (n = 139), we obtained: Adult/Adolescent Profile (A/ASP, Brown &amp; Dunn, 2002) and Eysenck's Personality Questionnaire, Brief Version (Sato, 2005) scores and peak amplitude and gating factor of SERP P50. We found that BR scores did not differ across normative categories of the A/ASP, but T scores significantly increased along the axis. I/E scores did not vary with BR scores. There were no differences or correlations in P50 amplitudes and gating with T scores. The findings suggest that the BR axis may not reflect a construct with ordinal range, but the T axis may. Dunn's concept of BR appears to be distinct from Eysenck's concept of I/E. SERP and its gating may not be directly reflective of sensory processing thresholds in healthy adults. Conclusions are limited by having few participants with passive behavior regulation or low threshold patterns of processing.

Exploring the pre-morbid contexts in which central sensitisation developed in individuals with non-specific chronic low back pain. A qualitative study

BACKGROUND

Central sensitisation pain is a predominant mechanism in a proportion of individuals with non-specific chronic low back pain and is associated with poor outcomes. It is proposed that the pre-morbid experiences and contexts may be related to the development of central sensitisation.

OBJECTIVES

The objective of this study was to explore the pre-morbid experiences and personal characteristics of participants with central sensitisation pain from a non-specific chronic low back pain population.

METHODS

This was a qualitative, exploratory study, using a concurrent nested design within a mixed methods protocol. n=9 participants were recruited purposively based on sensory profiles and trait anxiety-related personality types. Data were collected through semi structured interviews, managed using QSR NVivo 10 software and analysed using theoretical thematic analysis.

RESULTS

Four themes emerged: developmental learning experiences, personal characteristics, sensitivity and trauma. Reported was lack of confidence, low esteem and a need to please others, physical hyper-sensitivities (smell, light, sound) and emotional sensitivity (anxiety) as well as physical hypo-sensitivity. Participants had also suffered emotional and/or physical trauma. Learning difficulties, sensory sensitivities and trauma are associated with autonomic stress responses, which in turn have been linked to physiological changes seen in central sensitisation pain.

CONCLUSION

Central sensitisation pain developed in the context of sensory processing differences related to learning difficulties, sensitivities and trauma, and personal characteristics of low confidence and control, in a group of participants with non-specific chronic low back pain. The role of pre-existing sensory processing differences, as a component of altered central nervous system function, in relation to central sensitisation pain warrants further investigation.

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 Reduction on the General Milieu of a High-Acuity Inpatient Psychiatric Unit to Prevent Use of Physical Restraints: A Successful Open Quality Improvement Trial

BACKGROUND

Impaired sensory gating in patients with acute mental illness predisposes to overstimulation and behavioral dyscontrol.

OBJECTIVE

Explore use of sensory reduction interventions on a high-acuity inpatient milieu to reduce high assault/restraint rates.

DESIGN

A multidisciplinary team using failure mode and effect analysis to explore high restraint use between 4:00 p.m. and 7:00 p.m. observed patient/staff overstimulation contributed to behavioral escalations. The team implemented sensory reduction/integration improvements over a 5-month period to prevent excessive restraint use.

RESULTS

Restraint rates dropped immediately following light and sound reduction interventions and by 72% at 11 months postimplementation. Mann-Whitney statistics for unpaired 6-month comparisons, 1-year pre- and postintervention showed significant reductions: Assault rates (median pre = 1.37, post = 0.18, U = 4, p = .02); Restraint rates (median pre = 0.50, post = 0.06, U = 0, p = .002).

CONCLUSION

Sensory reduction during a high-stress time period on a high-acuity psychiatric unit was associated with a reduction in assaults and restraints.

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.

The State of the Science on Sensory Factors and Their Impact on Daily Life for Children: A Scoping Review

The objective of this study was to identify and synthesize research about how sensory factors affect daily life of children. We designed a conceptual model to guide a scoping review of research published from 2005 to October 2014 (10 years). We searched MEDLINE, CINAHL, and PsycINFO and included studies about sensory perception/processing; children, adolescents/young adults; and participation. We excluded studies about animals, adults, and review articles. Our process resulted in 261 articles meeting criteria. Research shows that children with conditions process sensory input differently than peers. Neuroscience evidence supports the relationship between sensory-related behaviors and brain activity. Studies suggest that sensory processing is linked to social participation, cognition, temperament, and participation. Intervention research illustrates the importance of contextually relevant practices. Future work can examine the developmental course of sensory processing aspects of behavior across the general population and focus on interventions that support children's sensory processing as they participate in their daily lives.

Multisensory temporal function and EEG complexity in patients with epilepsy and psychogenic nonepileptic events

Cognitive and perceptual comorbidities frequently accompany epilepsy and psychogenic nonepileptic events (PNEE). However, and despite the fact that perceptual function is built upon a multisensory foundation, little knowledge exists concerning multisensory function in these populations. Here, we characterized facets of multisensory processing abilities in patients with epilepsy and PNEE, and probed the relationship between individual resting-state EEG complexity and these psychophysical measures in each patient. We prospectively studied a cohort of patients with epilepsy (N=18) and PNEE (N=20) patients who were admitted to Vanderbilt's Epilepsy Monitoring Unit (EMU) and weaned off of anticonvulsant drugs. Unaffected age-matched persons staying with the patients in the EMU (N=15) were also recruited as controls. All participants performed two tests of multisensory function: an audio-visual simultaneity judgment and an audio-visual redundant target task. Further, in the cohort of patients with epilepsy and PNEE we quantified resting state EEG gamma power and complexity. Compared with both patients with epilepsy and control subjects, patients with PNEE exhibited significantly poorer acuity in audiovisual temporal function as evidenced in significantly larger temporal binding windows (i.e., they perceived larger stimulus asynchronies as being presented simultaneously). These differences appeared to be specific for temporal function, as there was no difference among the three groups in a non-temporally based measure of multisensory function - the redundant target task. Further, patients with PNEE exhibited more complex resting state EEG patterns as compared to their patients with epilepsy, and EEG complexity correlated with multisensory temporal performance on a subject-by-subject manner. Taken together, findings seem to indicate that patients with PNEE bind information from audition and vision over larger temporal intervals when compared with control subjects as well as patients with epilepsy. This difference in multisensory function appears to be specific to the temporal domain, and may be a contributing factor to the behavioral and perceptual alterations seen in this population.

Oscillatory dynamics and functional connectivity during gating of primary somatosensory responses

KEY POINTS

Sensory gating is important for preventing excessive environmental stimulation from overloading neural resources. Gating in the human somatosensory cortices is a critically understudied topic, particularly in the lower extremities. We utilize the unique capabilities of magnetoencephalographic neuroimaging to quantify the normative neural population responses and dynamic functional connectivity of somatosensory gating in the lower extremities of healthy human participants. We show that somatosensory processing is subserved by a robust gating effect in the oscillatory domain, as well as a dynamic effect on interhemispheric functional connectivity between primary sensory cortices. These results provide novel insight into the dynamic neural mechanisms that underlie the processing of somatosensory information in the human brain, and will be vital in better understanding the neural responses that are aberrant in gait-related neurological disorders (e.g. cerebral palsy).

ABSTRACT

Sensory gating (SG) is a phenomenon in which neuronal responses to subsequent similar stimuli are weaker, and is considered to be an important mechanism for preventing excessive environmental stimulation from overloading shared neural resources. Although gating has been demonstrated in multiple sensory systems, the neural dynamics and developmental trajectory underlying SG remain poorly understood. In the present study, we adopt a data-driven approach to map the spectrotemporal amplitude and functional connectivity (FC) dynamics that support gating in the somatosensory system (somato-SG) in healthy children and adolescents using magnetoencephalography (MEG). These data underwent time-frequency decomposition and the significant signal changes were imaged using a beamformer. Voxel time series were then extracted from the peak voxels and these signals were examined in the time and time-frequency domains, and then subjected to dynamic FC analysis. The results obtained indicate a significant decrease in the amplitude of the neural response following the second stimulation relative to the first in the primary somatosensory cortex (SI). A significant decrease in response latency was also found between stimulations, and each stimulation induced a sharp decrease in FC between somatosensory cortical areas. Furthermore, there were no significant correlations between somato-SG metrics and age. We conclude that somato-SG can be observed in SI in both the time and oscillatory domains, with rich dynamics and alterations in inter-hemispheric FC, and that this phenomenon has already matured by early childhood. A better understanding of these dynamics may provide insight to the numerous psychiatric and neurologic conditions that have been associated with aberrant SG across multiple modalities.

The neural dynamics of somatosensory processing and adaptation across childhood: a high-density electrical mapping study

Young children are often hyperreactive to somatosensory inputs hardly noticed by adults, as exemplified by irritation to seams or labels in clothing. The neurodevelopmental mechanisms underlying changes in sensory reactivity are not well understood. Based on the idea that neurodevelopmental changes in somatosensory processing and/or changes in sensory adaptation might underlie developmental differences in somatosensory reactivity, high-density electroencephalography was used to examine how the nervous system responds and adapts to repeated vibrotactile stimulation over childhood. Participants aged 6-18 yr old were presented with 50-ms vibrotactile stimuli to the right wrist over the median nerve at 5 blocked interstimulus intervals (ranging from ∼7 to ∼1 stimulus per second). Somatosensory evoked potentials (SEPs) revealed three major phases of activation within the first 200 ms, with scalp topographies suggestive of neural generators in contralateral somatosensory cortex. Although overall SEPs were highly similar for younger, middle, and older age groups (6.1-9.8, 10.0-12.9, and 13.0-17.8 yr old), there were significant age-related amplitude differences in initial and later phases of the SEP. In contrast, robust adaptation effects for fast vs. slow presentation rates were observed that did not differ as a function of age. A greater amplitude response in the later portion of the SEP was observed for the youngest group and may be related to developmental changes in responsivity to somatosensory stimuli. These data suggest the protracted development of the somatosensory system over childhood, whereas adaptation, as assayed in this study, is largely in place by ∼7 yr of age.

Perceptual abnormalities related to sensory gating deficit are core symptoms in adults with ADHD

This study investigated and compared perceptual abnormalities related to sensory gating deficit in adult patients with Attention Deficit Disorder with Hyperactivity (A-ADHD) and adult patients with schizophrenia. Subjects were evaluated with the Sensory Gating Inventory (SGI). We compared SGI scores between patients with A-ADHD, patients with schizophrenia and healthy subjects. We also assessed the relationship between SGI scores and clinical symptoms, and evaluated the ability of the SGI to detect perceptual abnormalities in A-ADHD. Seventy adult patients with ADHD reported higher SGI scores than the 70 healthy subjects and the 70 patients with schizophrenia. The inattention factor of the ASRS correlated significantly with the overall SGI score. The ROC AUC for the overall SGI score in the A-ADHD group (versus the healthy group) illustrated good performance. The findings suggest that i) perceptual abnormalities are core symptoms of adult patients with ADHD and ii) the attention of patients with A-ADHD may be involuntarily drowned by many irrelevant environmental stimuli leading to their impaired attention on relevant stimuli. They also confirm that the SGI could be a useful self-report instrument to diagnose the clinical features of A-ADHD.

Dopaminergic impact on local and global cortical circuit processing during learning

We have learned to detect, predict and behaviorally respond to important changes in our environment on short and longer time scales. Therefore, brains of humans and higher animals build upon a perceptual and semantic salience stored in their memories mainly generated by associative reinforcement learning. Functionally, the brain needs to extract and amplify a small number of features of sensory input with behavioral relevance to a particular situation in order to guide behavior. In this review, I argue that dopamine action, particularly in sensory cortex, orchestrates layer-dependent local and long-range cortical circuits integrating sensory associated bottom-up and semantically relevant top-down information, respectively. Available evidence reveals that dopamine thereby controls both the selection of perceptually or semantically salient signals as well as feedback processing from higher-order areas in the brain. Sensory cortical dopamine thereby governs the integration of selected sensory information within a behavioral context. This review proposes that dopamine enfolds this function by temporally distinct actions on particular layer-dependent local and global cortical circuits underlying the integration of sensory, and non-sensory cognitive and behavioral variables.

State of the Science: A Roadmap for Research in Sensory Integration

This article builds on the work of Case-Smith and colleagues and proposes a roadmap to guide future research in occupational therapy. To foster best practice in the application of principles and practices of sensory integration (SI), the pillars of practice, advocacy, and education are identified as elements that provide the foundation for research. Each pillar ensures that SI research is conducted in a rigorous and relevant manner. To this end, achievements to date are discussed, with proposed goals presented for each pillar. Finally, the roadmap builds on the pillars and outlines implications for occupational therapy with the overarching theme that a wide array of scientists, educators, therapists, and service recipients will be needed to ensure that those who may benefit most have access to intervention that is evidence based, theory driven, and provided within the highest standards of service delivery.

Sensory modulation disorders in childhood epilepsy

Background

Altered sensory sensitivity is generally linked to seizure-susceptibility in childhood epilepsy but may also be associated to the highly prevalent problems in behavioral adaptation. This association is further suggested by the frequent overlap of childhood epilepsy with autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), conditions in which altered behavioral responses to sensory stimuli have been firmly established. A continuum of sensory processing defects due to imbalanced neuronal inhibition and excitation across these disorders has been hypothesizedthat may lead to common symptoms of inadequate modulation of behavioral responses to sensory stimuli. Here, we investigated the prevalence of sensory modulation disorders among children with epilepsy and their relation with symptomatology of neurodevelopmental disorders.

Methods

We used the Sensory Profile questionnaire to assess behavioral responses to sensory stimuli and categorize sensory modulation disorders in children with active epilepsy (aged 4–17 years). We related these outcomes to epilepsy characteristics and tested their association with comorbid symptoms of ASD (Social Responsiveness Scale) and ADHD (Strengths and Difficulties Questionnaire).

Results

Sensory modulation disorders were reported in 49 % of the 158 children. Children with epilepsy reported increased behavioral responses associated with sensory “sensitivity,” “sensory avoidance,” and “poor registration” but not “sensory seeking.” Comorbidity of ASD and ADHD was associated with more severe sensory modulation problems, although 27 % of typically developing children with epilepsy also reported a sensory modulation disorder.

Conclusions

Sensory modulation disorders are an under-recognized problem in children with epilepsy. The extent of the modulation difficulties indicates a substantial burden on daily functioning and may explain an important part of the behavioral distress associated with childhood epilepsy.

Trajectories of Sensory Over-Responsivity from Early to Middle Childhood: Birth and Temperament Risk Factors

Sensory over-responsivity, a subtype of sensory modulation disorder, is characterized by extreme negative reactions to normative sensory experiences. These over-reactions can interfere with daily activities and cause stress to children and their families. The etiology and developmental course of sensory over-responsivity is still largely unknown. We measured tactile and auditory over-responsivity in a population-based, typically developing sample of twins (N=978) at age two years via a caregiver report temperament questionnaire and again at age seven years via a sensory over-responsivity symptom inventory. Participating twins were treated as singletons although all analyses controlled for clustering within families. Children were divided into four trajectory groups based on risk status at both ages: low symptom (N=768), remitted (N=75), late-onset (N=112), and chronic (N=24). A subset of children who screened positive for SOR in toddlerhood (N = 102) took part in a pilot study focused on sensory over-responsivity at four years of age. Children in the chronic group had more severe symptoms of sensory sensitivity at age four years, including more motion sensitivity, than the other trajectory groups. Children in the chronic group had a younger gestational age and were more likely to be low birth-weight than the low symptom group. Differences between remitted and late-onset groups and the low-symptoms group were inconsistent across measures. Sensory over-responsivity was modestly correlated across ages (r = .22 for tactile over-responsivity and r = .11 for auditory over-responsivity), but symptoms were more stable among children born prematurely or who had more fearful and less soothable temperaments. A clear implication is that assessment over development may be necessary for a valid sensory processing disorder diagnosis, and a speculative implication is that sensory over-responsivity symptoms may be etiologically heterogeneous, with different causes of transient and stable symptoms.

The Effect of Development in Respiratory Sensory Gating Measured by Electrocortical Activations

The perception of respiratory sensations can be of significant importance to individuals for survival and greatly impact quality of life. Respiratory sensory gating, similar to somatosensory gating with exteroceptive stimuli, is indicative of brain cortices filtering out repetitive respiratory stimuli and has been investigated in adults with and without diseases. Respiratory gating can be tested with the respiratory-related evoked potential (RREP) method in the electroencephalogram with a paired inspiratory occlusion paradigm. Here, the RREP N1 component elicited by the second stimulus (S2) shows reduced amplitudes compared to the RREP N1 component elicited by the first stimulus (S1). However, little is known regarding the effect of development on respiratory sensory gating. The present study examined respiratory sensory gating in 22 typically developed school-aged children and 22 healthy adults. Paired inspiratory occlusions of 150-ms each with an inter-stimulus-interval of 500-ms were delivered randomly every 2–4 breaths during recording. The main results showed a significantly larger RREP N1 S2/S1 ratio in the children group than in the adult group. In addition, children compared to adults demonstrated significantly smaller N1 peak amplitudes in response to S1. Our results suggest that school-aged children, compared to adults, display reduced respiratory sensory gating.

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.

An auditory-neuroscience perspective on the development of selective mutism

Selective mutism (SM) is a relatively rare psychiatric disorder of childhood characterized by consistent inability to speak in specific social situations despite the ability to speak normally in others. SM typically involves severe impairments in social and academic functioning. Common complications include school failure, social difficulties in the peer group, and aggravated intra-familial relationships. Although SM has been described in the medical and psychological literatures for many years, the potential underlying neural basis of the disorder has only recently been explored. Here we explore the potential role of specific auditory neural mechanisms in the psychopathology of SM and discuss possible implications for treatment.

Influence of emotional states on inhibitory gating: animals models to clinical neurophysiology

Integrating research efforts using a cross-domain approach could redefine traditional constructs used in behavioral and clinical neuroscience by demonstrating that behavior and mental processes arise not from functional isolation but from integration. Our research group has been examining the interface between cognitive and emotional processes by studying inhibitory gating. Inhibitory gating can be measured via changes in behavior or neural signal processing. Sensorimotor gating of the startle response is a well-used measure. To study how emotion and cognition interact during startle modulation in the animal model, we examined ultrasonic vocalization (USV) emissions during acoustic startle and prepulse inhibition. We found high rates of USV emission during the sensorimotor gating paradigm and revealed links between prepulse inhibition (PPI) and USV emission that could reflect emotional and cognitive influences. Measuring inhibitory gating as P50 event-related potential suppression has also revealed possible connections between emotional states and cognitive processes. We have examined the single unit responses during the traditional gating paradigm and found that acute and chronic stress can alter gating of neural signals in regions such as amygdala, striatum and medial prefrontal cortex. Our findings point to the need for more cross-domain research on how shifting states of emotion can impact basic mechanisms of information processing. Results could inform clinical work with the development of tools that depend upon cross-domain communication, and enable a better understanding and evaluation of psychological impairment.

Dopamine-modulated recurrent corticoefferent feedback in primary sensory cortex promotes detection of behaviorally relevant stimuli

Dopaminergic neurotransmission in primary auditory cortex (AI) has been shown to be involved in learning and memory functions. Moreover, dopaminergic projections and D1/D5 receptor distributions display a layer-dependent organization, suggesting specific functions in the cortical circuitry. However, the circuit effects of dopaminergic neurotransmission in sensory cortex and their possible roles in perception, learning, and memory are largely unknown. Here, we investigated layer-specific circuit effects of dopaminergic neuromodulation using current source density (CSD) analysis in AI of Mongolian gerbils. Pharmacological stimulation of D1/D5 receptors increased auditory-evoked synaptic currents in infragranular layers, prolonging local thalamocortical input via positive feedback between infragranular output and granular input. Subsequently, dopamine promoted sustained cortical activation by prolonged recruitment of long-range corticocortical networks. A detailed circuit analysis combining layer-specific intracortical microstimulation (ICMS), CSD analysis, and pharmacological cortical silencing revealed that cross-laminar feedback enhanced by dopamine relied on a positive, fast-acting recurrent corticoefferent loop, most likely relayed via local thalamic circuits. Behavioral signal detection analysis further showed that activation of corticoefferent output by infragranular ICMS, which mimicked auditory activation under dopaminergic influence, was most effective in eliciting a behaviorally detectable signal. Our results show that D1/D5-mediated dopaminergic modulation in sensory cortex regulates positive recurrent corticoefferent feedback, which enhances states of high, persistent activity in sensory cortex evoked by behaviorally relevant stimuli. In boosting horizontal network interactions, this potentially promotes the readout of task-related information from cortical synapses and improves behavioral stimulus detection.

Meclizine enhancement of sensorimotor gating in healthy male subjects with high startle responses and low prepulse inhibition

Histamine H1 receptor systems have been shown in animal studies to have important roles in the reversal of sensorimotor gating deficits, as measured by prepulse inhibition (PPI). H1-antagonist treatment attenuates the PPI impairments caused by either blockade of NMDA glutamate receptors or facilitation of dopamine transmission. The current experiment brought the investigation of H1 effects on sensorimotor gating to human studies. The effects of the histamine H1 antagonist meclizine on the startle response and PPI were investigated in healthy male subjects with high baseline startle responses and low PPI levels. Meclizine was administered to participants (n=24) using a within-subjects design with each participant receiving 0, 12.5, and 25 mg of meclizine in a counterbalanced order. Startle response, PPI, heart rate response, galvanic skin response, and changes in self-report ratings of alertness levels and affective states (arousal and valence) were assessed. When compared with the control (placebo) condition, the two doses of meclizine analyzed (12.5 and 25 mg) produced significant increases in PPI without affecting the magnitude of the startle response or other physiological variables. Meclizine also caused a significant increase in overall self-reported arousal levels, which was not correlated with the observed increase in PPI. These results are in agreement with previous reports in the animal literature and suggest that H1 antagonists may have beneficial effects in the treatment of subjects with compromised sensorimotor gating and enhanced motor responses to sensory stimuli.

Evoked potential correlates of post-traumatic stress disorder in refugees with history of exposure to torture

The presence and magnitude of information processing deviations associated with Post-Traumatic Stress Disorder (PTSD) are far from being well-characterized. In this study we assessed the auditory and visually evoked cerebral responses in a group of Iraqi refugees who were exposed to torture and developed PTSD (N = 20), Iraqi refugees who had been exposed to similar trauma but did not develop PTSD (N = 20), and non-traumatized controls matched for age, gender, and ethnicity (N = 20). We utilized two paired-stimulus paradigms in auditory and visual sensory modalities, respectively. We found significantly smaller amplitudes of both the auditory P50 and the visual N75 responses in PTSD patients compared to controls, reflecting decreased response to simple sensory input during a relatively early phase of information processing (interval 50-75 ms post stimulus). In addition, deficient suppression of the P50/N75 response to repeating stimuli at this early stage in both modalities is indicative of difficulty in filtering out irrelevant sensory input. Among associations between electrophysiological and clinical measures, a significant positive correlation was found between dissociation score and P50 S1 amplitudes (p = 0.024), as well as stronger auditory P50 gating correlated with higher quality-of-life index scores (p = 0.013). In addition, smaller amplitudes of N150 visual evoked response to S1 showed a significant association with higher avoidance scores (p = 0.015). The results of this study highlight the importance of early automatic auditory and visual evoked responses in probing the information processing and neural mechanisms underlying symptomatology in PTSD.