Habituation is a filter that optimizes the processing of information by our brain in all sensory modalities. It results in an unconscious reduced responsiveness to continuous or repetitive stimulation. In olfaction, the main question is whether habituation works the same way for any odorant or whether we habituate differently to each odorant? In particular, whether chemical, physical or perceptual cues can limit or increase habituation. To test this, the odour intensity of 32 odorants differing in physicochemical characteristics was rated by 58 participants continuously during 120s. Each odorant was delivered at a constant concentration. Results showed odorants differed significantly in habituation, highlighting the multifactoriality of habituation. Additionally habituation was predicted from 15 physico-chemical and perceptual characteristics of the odorants. The analysis highlighted the importance of trigeminality which is highly correlated to intensity and pleasantness. The vapour pressure, the molecular weight, the Odor Activity Value (OAV) and the number of double bonds mostly contributed to the modulation of habituation. Moreover, length of the carbon chain, number of conformers and hydrophobicity contributed to a lesser extent to the modulation of habituation. These results highlight new principles involved in the fundamental process of habituation, notably trigeminality and the physicochemical characteristics associated.

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<p>Touch plays a key role in facilitating social communication and is often presented in conjunction with auditory stimuli such as speech. Individuals with autism spectrum disorder (ASD) frequently show atypical behavioral responsivity to both tactile and auditory stimuli, which is associated with increased ASD symptomatology. However, as discussed throughout Chapter 1, the neural mechanisms associated with responsivity to tactile and auditory stimuli in ASD are not fully understood. For example, some have argued that differences in responding to tactile and auditory stimuli may be attributed to sensory and perceptual factors, whereas others suggest that these differences could be related to atypicalities in allocation of attention to incoming stimuli. In Chapter 2, I address these competing hypotheses by examining early and late ERP components (indicative of perceptual and attentional processing respectively) in response to tactile and auditory stimuli. Next, despite the evidence suggesting that touch plays a role in modulating attention in typical development (TD), it is unclear whether touch cues affect the response of the phasic alerting network – a subcomponent of attention – in ASD and TD, and whether the alerting response may be atypical in children with ASD. In Chapter 3, I address this gap in the literature by examining whether tactile cues presented at different intervals before auditory targets facilitate reaction times differently in children with ASD and TD. Lastly, because prior research has shown associations between sensory and attentional processes and ASD symptomatology, in Chapters 2 and 3, I examine the associations of neural and behavioral indices of tactile and auditory processing with ASD symptomatology and language skills in children with ASD and TD. </p><p>In Chapter 2, I show that children in both the ASD and TD groups do not exhibit differences in both early and later neurological responses to tactile and auditory stimuli, suggesting that under certain experimentally-controlled conditions, behavioral differences to tactile and auditory stimuli may not be attributable to atypicalities in perceiving or attending to the incoming sensory input. However, neural responsivity to tactile and auditory stimuli is linked with sensory responsivity and social skills in all children. Specifically, reduced early contralateral activation to tactile stimuli is related to increased tactile symptoms, and reduced early amplitudes to auditory oddball stimuli are associated with impairments in reciprocal social communication in children with ASD as well as when examined across all children, and greater tendency of overall sensory hyper-reactivity. Additionally, in the TD group, greater later amplitudes to touch and auditory oddball stimuli are related to differences in reciprocal social communication and sensory reactivity respectively, indicating that patterns of allocation of attention may be related to ASD-like traits in typical development. Lastly, there is an association between greater sensitivity to changes to a stream of auditory stimuli and expressive language skills in all children. These results suggest that, although there are no group differences between neurological responses to tactile and auditory stimuli in ASD and TD, individual neural differences may be related to sensory and socio-communicative skills in all children. </p><p>In Chapter 3, I show that although children with ASD responded more slowly than children with TD, both groups displayed faster reaction times as a result of tactile cues before auditory targets, suggesting equivalent phasic alerting in response to tactile stimuli. Longer intervals between cues and targets benefitted children in both groups resulting in faster reaction times. Contrary to my hypotheses, touch-related behavioral facilitation was not associated with ASD symptomatology and language skills. </p>Taken together, the results of these studies suggest that, at least in certain contexts and with certain cues, children with ASD may show typical neurological processing in response to tactile and auditory stimuli, and that touch may facilitate the response of the alerting network similarly in ASD and TD. Therefore, everyday behavioral differences in response to tactile and auditory stimuli may be related to the specific nature of the stimuli as well as social contexts in which such stimuli are more likely to be encountered. Differences between processing rich and dynamic sensory stimuli experienced in the outside world vs experimentally-controlled sensory stimuli presented in the laboratory settings are discussed in Chapter 4. Additionally, I argue that individual responses expected in social vs non-social experimental settings may affect neural and behavioral responses in individuals with ASD. Finally, future research directions are discussed.

Syfte: Undersöka och beskriva aktivitetsbalans hos individer med högkänsligt personlighetsdrag. Metod: En kvantitativ enkätstudie genomfördes. Webbenkäten utformades efter Occupational Balance Questionnaire 11 [OBQ11]. Fyra bakgrundsvariabler lades till. Vid analys av data tillämpades en kvantitativ bearbetning. I studien deltog 203 högkänsliga individer. Resultat: De högkänsliga individerna skattade i genomsnitt låg aktivitetsbalans. Resultatet visade att det fanns en signifikant skillnad i skattad aktivitetsbalans mellan de individer som har barn mot de individer utan barn samt mellan de som bor ensam eller är sammanboende. Vissa delar av OBQ11 utmärkte sig mer då de visade lägre skattad aktivitetsbalans än andra. Inget samband mellan ålder och skattad aktivitetsbalans kunde urskiljas. Slutsats: Deltagarna i studien har en genomgående låg aktivitetsbalans. Mer forskning behövs för att undersöka kopplingen mellan arbetsterapi och högkänslighet. Däremot skulle arbetserapeuters kunskap om hur miljön påverkar en individ kunna vara till nytta för högkänsliga individer. / Aim: Examine and describe occupational balance in individuals with highly sensitive personality traits. Method: A quantitative questionnaire study was conducted. The web survey was designed according to Occupational Balance Questionnaire 11 [OBQ11]. Four background variables were added. In the analysis of data, a quantitative processing was applied. The study involved 203 highly sensitive individuals. Result: The highly sensitive individuals estimated an average low occupational balance. The results showed that there was a significant difference in the estimated occupational balance between the individuals who have children against the individuals without children and between those who live alone or live together. Some parts of OBQ11 excelled more as they showed lower estimated occupational balance than others. No relationship between age and estimated occupational balance could be discerned. Conclusion: The participants in the study have a consistently low occupational balance. More research is needed to investigate the link between occupational therapy and highly sensitive personality traits. On the other hand, occupational therapists' knowledge of how the environment affects an individual could be useful for highly sensitive individuals.

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No description available.

La neurofibromatose de type 1 (NF1) est une condition génétique entraînant des répercussions dans différents systèmes, y compris le système nerveux. Les enfants atteints de la NF1 sont à risque de rencontrer différents défis sur le plan cognitif et comportemental. Un chevauchement avec les symptômes associés à d’autres troubles neurodéveloppementaux, notamment le trouble déficitaire de l’attention avec ou sans hyperactivité (TDAH) et le trouble du spectre de l’autisme (TSA), est d’ailleurs présent dans cette condition génétique. Les études réalisées avec des modèles animaux de NF1 ont permis d’identifier des déséquilibres dans la neurotransmission qui pourraient sous-tendre les déficits cognitifs. Comment ces déséquilibres se traduisent sur le plan de l’activité cérébrale chez l’humain ayant la NF1 demeure peu compris à ce jour. L’objectif général de cette thèse est donc d’étudier, à l’aide de l’électroencéphalographie (EEG), les réponses neuronales lors du traitement sensoriel chez les enfants ayant la NF1 ainsi que les associations avec le fonctionnement cognitif et comportemental. Dans le premier article, nous avons étudié l’intégrité de la réponse de synchronisation neuronale lors de stimulations visuelles rythmiques à différentes fréquences. Considérant l’importance des déficits visuo-perceptifs ainsi que les indices de perturbations de la transmission GABAergique au niveau du cortex occipital dans la NF1, nous avons émis l’hypothèse d’une réduction de la synchronisation neuronale dans le groupe NF1 par rapport au groupe d’enfants neurotypiques. Une puissance réduite de la synchronisation neuronale a effectivement été trouvée dans la NF1, particulièrement en réponse à la plus haute fréquence de stimulation. Cette réponse neuronale affaiblie a été corrélée à une plus grande sévérité des symptômes comportementaux du TDAH. Cela soulève la possibilité d’une modulation de la réponse sensorielle par les réseaux attentionnels et soulève également des questions en lien avec l’impact du diagnostic de TDAH en comorbidité avec la NF1. L’impact de la médication psychostimulante, testé avec un sous-groupe de l’échantillon NF1, s’est d’ailleurs révélé par une amélioration de la réponse de synchronisation neuronale à la plus faible fréquence de stimulation. La réponse de synchronisation neuronale apparait donc comme un marqueur à investiguer davantage pour comprendre les mécanismes qui sous-tendent les déficits cognitifs dans la NF1 et pour évaluer l’impact de traitements. Dans le deuxième article, nous avons étudié les oscillations cérébrales dans la réponse de suppression neuronale et de détection du changement, toujours en comparant un groupe d’enfants ayant la NF1 à un groupe d’enfants neurotypiques. Une modulation atypique des oscillations cérébrales était attendue dans la NF1 en réponse à la répétition et au changement dans la séquence de stimuli audio-visuels. Les résultats ont démontré une réponse de suppression neuronale préservée dans le groupe NF1, mais une puissance accrue des oscillation thêta dans la condition de détection du changement. Les symptômes comportementaux du TDAH ont été associés à une réduction de la puissance des oscillations dans la réponse de détection du changement et ne contribueraient donc pas à la réponse accrue identifiée dans le groupe NF1. En somme, les résultats de la thèse ont permis d’identifier des particularités dans les réponses électrophysiologiques du traitement sensoriel chez les enfants ayant la NF1 et de mettre de l’avant des mesures dont le potentiel translationnel pourrait faciliter le transfert des connaissances accumulées dans les modèles animaux de NF1. Les résultats soulignent la complexité d’établir les bases neuronales des déficits cognitifs dans la NF1 compte tenu de l’hétérogénéité du profil cognitif. Cela dit, les associations établies entre les réponses neuronales et les symptômes comportementaux du TDAH suggèrent la possibilité de considérer le profil électrophysiologique pour guider le développement de traitements et interventions visant à améliorer le fonctionnement cognitif chez les enfants ayant la NF1. / Neurofibromatosis type 1 (NF1) is a genetic condition that has implications across different systems, including the nervous system. Children with NF1 are at risk of facing various cognitive and behavioral challenges. An overlap with symptoms associated with other neurodevelopmental disorders, including attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), is also present in this genetic condition. Studies conducted using animal models of NF1 have identified imbalances in neurotransmission that may underlie cognitive deficits. However, how these imbalances translate into human brain activity in individuals with NF1 remains poorly understood to date. The overall objective of this thesis is to investigate, using electroencephalography (EEG), neural responses during sensory processing in children with NF1 and their associations with cognitive and behavioral functioning. In the first article, we studied the integrity of the neural synchronization response during rhythmic visual stimulation at different frequencies. Given the significance of visuo-perceptual deficits as well as indications of disrupted GABAergic transmission in the occipital cortex of individuals with NF1, we hypothesized a reduction in neural synchronization in the NF1 group compared to neurotypical children. Reduced power of neural synchronization was indeed found in NF1, particularly in response to the highest stimulation frequency. This weakened neural response was correlated with greater severity of ADHD behavioral symptoms. These results suggest a possible modulation of this sensory response by attentional networks and raise questions regarding the impact of comorbid ADHD diagnosis on neural activity in NF1. The intake of psychostimulant medication, in a subgroup of the NF1 sample, resulted in an increased neural synchronization at the lowest stimulation frequency. Neural synchronization should be further investigated as a potential biomarker in NF1 and could help understand the underlying mechanisms of cognitive deficits and assess the impact of treatments. In the second article, we studied brain oscillations in the repetition suppression and change detection response, again comparing a group of children with NF1 to a group of neurotypical children. Atypical modulation of brain oscillations was expected in NF1 in response to repetition and change in the audio-visual stimuli sequence. Results showed preserved repetition suppression response in the NF1 group, but increased power of theta oscillations in the change detection condition. Behavioral symptoms of ADHD were associated with reduced oscillatory power in the change detection response, which suggest that the ADHD comorbidity did not contribute to the increased response identified in the NF1 group. In summary, results of this thesis have demonstrated distinct electrophysiological responses during sensory processing in children with NF1 and have highlighted measures with translational potential that could facilitate the transfer of knowledge gained from animal models of NF1. The results emphasize the complexity of establishing the neural basis of cognitive deficits in NF1, given the heterogeneity of the cognitive profile. However, the associations established between neural responses and ADHD behavioral symptoms suggest the possibility of considering the electrophysiological profile to guide the development of treatments and interventions aimed at improving cognitive functioning in children with NF1.

In dieser Studie untersuchten wir den Mechanismus und die neuronalen Strukturen, die an der auditorischen Filterung bedeutungsvoller Reize während des Schlafs beteiligt sind. Zunächst entwickelten wir ein Verhaltensparadigma, bei dem Geräusche in einer bedeutungsabhängigen Weise Veränderungen in schlafassoziierten Oszillationen hervorrufen. Interessanterweise traten diese Störungen bereits bei niedrigen Schallintensitäten während des NREM- und REM-Schlafs auf, was die starke Einflussnahme bedeutungsvoller Reize auf die Schlafdynamik betont. Darüber hinaus unterstrich unsere Analyse von Verallgemeinerungsseffekten unter Verwendung verschiedener neutraler Klangreize die breite Wirkung bedeutungsvoller Klänge auf das EEG, unabhängig von der Unterscheidbarkeit der Geräusche. Wir erweiterten unserer Verhaltensparadigma auf kopffixierte Tiere und konnten NREM- und REM-Schlafphasen nach einer längeren Habituation nachweisen. Bemerkenswerterweise waren unsere Befunde für kopffixierte im Vergleich zu sich frei bewegenden Tieren sehr ähnlich, da das konditionierte Geräusch im Vergleich zu neutralen Reizen einen erhöhten Einfluss auf schlafassoziierte Oszillationen hatte. Schließlich untersuchten wir den neuronalen Zusammenhang der auditiven Verarbeitung während des Wachzustands und des Schlafs, wobei wir uns auf den Colliculus Inferior (CI) konzentrierten. Unsere Analysen enthüllten unterschiedliche neuronale Reaktionen auf bedeutungsvolle und neutrale Reize, wobei der bedeutungsvolle Reiz während des Wachzustands, aber nicht während des NREM-Schlafs, höhere Feuerraten auslöste, was auf eine zustandsabhängige neuronale Verarbeitung hinweist. Darüber hinaus zeigten unsere Untersuchungen eine verstärkte zeitliche Musterbildung als Reaktion auf den bedeutungsvollen Reiz während des NREM-Schlafs, was auf eine Rolle des CI bei der Kodierung bedeutungsvoller auditorischer Reize während des Schlafs hindeutet. Insgesamt liefert unsere Studie überzeugende Belege dafür, dass die Bedeutung eines Geräuschs signifikanten Einfluss auf schlafassoziierte Oszillationen sowie zeitliche Muster der neuronalen Aktivität im IC hat. / In this study, we delved into the mechanism and neural structures involved in the auditory gating of meaningful stimuli during sleep. First, we developed a behavioural paradigm in which sounds elicit changes in sleep-associated oscillations in a meaning-dependent manner. Interestingly, these disruptions occurred even at relatively low sound intensities during NREM and REM sleep, highlighting the potent influence of meaningful stimuli on sleep dynamics. Additionally, our exploration of generalization effects using various neutral sound stimuli underlined the broad influence of meaningful sounds on NREM EEG patterns, independent of sound discriminability. We extended our investigation to head-fixed animals, confirming their ability to achieve NREM and REM sleep phases following a prolonged habituation period. Notably, our findings were very similar for head-fixed compared to freely moving animals since the conditioned sound had increased influence on sleep-associated oscillations, compared to neutral stimuli. Finally, we studied the neural correlates of auditory processing during wakefulness and sleep, focusing on the inferior colliculus (IC). Our analyses revealed differential neuronal responses to meaningful and neutral stimuli, with the conditioned sound eliciting higher firing rates during wakefulness but not during NREM sleep, indicating state-dependent neural processing. Furthermore, our investigations unveiled enhanced temporal patterning in response to the conditioned sound during NREM sleep, suggesting a role of the IC in encoding meaningful auditory stimuli during sleep. Overall, our study provides compelling evidence that the meaning of a sound significantly influences sleep-associated oscillations as well as temporal patterning of neural activity in the IC.

M.Sc.(Occupational Therapy), Faculty of Health Sciences, University of the Witwatersrand, 2009 / Title: The agreement found between the sensory profiles of children 3-10 years and their parents Author: Elsje Geyser Promoter: Denise Franszen School: Therapeutic Sciences Faculty: Health Sciences Degree: MSc.OT Key Concepts: Sensory modulation dysfunction, sensory processing disorder, high threshold, low threshold, sensory profile, low registration behaviour, sensory seeking behaviour, sensory sensitive behaviour, sensation avoiding behaviour. In order to treat a child with sensory modulation disorder (SMD), the impact of SMD on the child’s occupational sphere should be taken into account. This includes the effect of SMD in the parent on the child’s development and behaviour. This study determined the probability of agreement between the parent and child’s sensory profiles. A quantitative, cross sectional study design established the sensory profiles of 81 children and their parents. Results indicated a moderate probability that a child with SMD may have a parent with SMD. A moderate to high probability existed for a parent with SMD to have a child with SMD. This supports the supposition that there is a hereditary component to SMD, with learned sedentary behavioural patterns. The treatment implications include considering the parent’s reaction to their own sensory thresholds and the influence this has on the child’s treatment and learnt behaviour.

A mensuração do desenvolvimento sensorial tem se tornado um componente necessário na avaliação clínica e no planejamento terapêutico ocupacional para intervenções com bebês e crianças pequenas. Estudos sobre traduções, adaptações culturais e validação de instrumentos para obtenção de medidas válidas e confiáveis tem sido incorporado mais frequentemente em pesquisas no campo da terapia ocupacional. Este estudo metodológico, transversal, de abordagem quantitativa, teve como objetivo descrever o processo de tradução, adaptação cultural e validação das propriedades psicométricas dos instrumentos Infant Sensory Profile 2 (ISP 2) e Toddler Sensory Profile 2 (TSP 2) para crianças brasileiras. A pequisa foi conduzida em ambulatório pediátrico e em laboratórios de pesquisas vinculados à Universidade de São Paulo e Universidade Federal do Triângulo Mineiro. A amostra total incluiu 303 pais/cuidadores de crianças de 0 a 35 meses com desenvolvimento típico e atípico. Métodos: O desenvolvimento das versões para o português do Brasil constou de duas etapas, a primeira consistiu do processo de tradução, retrotradução, estudo de validade de conteúdo e de fase pré-teste em estudo piloto; na segunda etapa, foram realizados estudos psicométricos por meio da consistência interna, fidedignidade teste-reteste, análise fatorial confirmatória, e análise de pontos de corte de escores. Para a primeira etapa, os resultados mostraram que, a partir da validade de face, houve adequação semântica e compreensibilidade de ambos os instrumentos por parte dos respondentes. Para a etapa dois, o software STATA auxiliou nas análises, e o ISP 2 apresentou consistência interna total > 0.70, mas quando analisado por áreas sensoriais a consistência foi < que 0.70. Com relação ao TSP 2, apresentou consistência interna total > 0.80, mas quando analisado por áreas sensoriais a consistência foi < que 0.70 com exceção das áreas auditiva e visual, e em relação aos quadrantes, todos os valores de alfa foram < que 0.70. Sobre o teste-reteste, para ambos os instrumentos, houve alta concordância com valor de Kappa ponderado na categoria quase perfeita. Entretanto, a análise fatorial confirmatória não confirma a estrutura atual dos instrumentos. A rotação da matriz mostrou que itens poderiam ser alocados em domínios diferentes aos que pertencem originalmente, demonstrando correlações distintas entre os itens e dimensões. Os pontos de corte dos escores brasileiros foram diferentes dos americanos. Destaca-se, como considerações finais, a importância em analisar e testar a estrutura fatorial exploratória e confirmatória de ambos os instrumentos uma vez que houve diferenças significantes ente as versões brasileiras do ISP 2 e TSP 2 para a população brasileira de crianças de 0 a 3 meses de idade, verificar as equivalências das cargas fatoriais, as quantidades de itens por domínios, as covariâncias entre os fatores dos instrumentos e os erros de medida. Ainda seria importante verificar a invariância das medidas, seja através da análise fatorial ou da teoria de resposta ao item / Sensory development measurement has become a necessary component in clinical assessment and occupational therapy planning for interventions with infants and young children. Studies related to translations, cultural adaptations and validation of instruments to obtain valid and reliable measures have been incorporated more frequently in researches in the occupational therapy field. This cross-sectional methodological study, with a quantitative approach, aimed to describe the process of translation, cultural adaptation and validation of the psychometric properties of the Infant Sensory Profile 2 (ISP 2) and Toddler Sensory Profile 2 (TSP 2) to brazilian children. The research was conducted in a pediatric outpatient clinic and in research laboratories linked to the University São Paulo and the Federal University of the Triângulo Mineiro. The total sample included 303 parents/caregivers of children aged 0-35 months with typical and atypical development. The development of the Brazilian Portuguese versions was done in two steps, the first one consisted of the translation process, back translation, content validity study and pre-test phase in a pilot study; in the second stage, psychometric studies were performed through internal consistency, test-retest reliability, confirmatory factor analysis, and analysis of cut-off scores. For the first step, the results showed that, from the face validity, there was semantic adequacy and comprehensibility of both instruments by the respondents. For step two, the STATA software assisted in the analyzes, and the ISP 2 presented total internal consistency > 0.70, but when analyzed by sensory areas the consistency was < 0.70. Regarding TSP 2, it presented total internal consistency > 0.80, but when analyzed by sensory areas the consistency was < 0.70, except for auditory and visual areas, and in relation to the quadrants, all alpha values were lower than 0.70. On test-retest analysis, for both instruments, there was high agreement with weighted Kappa value in the almost perfect category. However, the confirmatory factor analysis does not confirm the current structure of this instrument. The rotation of the matrix showed that items could be allocated in domains other than those that originally belonged, showing distinct correlations between items and dimensions. The cut-off points of the Brazilian scores were different from the American ones. As final considerations, it is important to analyze and test the exploratory and confirmatory factorial structure of both instruments since there were significant differences between the Brazilian versions of ISP 2 and TSP 2 for the Brazilian population of children aged 0 to 3 months age; to verify the equivalence of factorial loads; the quantity of items by domains; the covariance between the factors of the instrument and the measurement errors. It is still important to verify the invariance of the measurements, either through factor analysis or item response theory