Future Perspectives on the Relevance of Auditory Markers in Prodromal Parkinson's Disease

Research on auditory processing in Parkinson's disease (PD) has recently made substantial progress. At present, evidence has been found for altered auditory processing in the clinical stage of PD. The auditory alterations in PD have been demonstrated with low-cost and non-invasive assessments that are already used in routine clinical practice. Since auditory alterations have been reported early in disease progression, it would be highly relevant to investigate whether auditory markers could be provided in the prodromal stage of PD. In addition, auditory alterations in early stage PD might be modulated by dopaminergic medication. Therefore, the aim of this review is (1) to summarize the literature on auditory processing in PD with a specific focus on the early disease stages, (2) to give future perspectives on which audiological and electrophysiological measurements could be useful in the prodromal stage of PD and (3) to assess the effect of dopaminergic medication on potential auditory markers in the prodromal stage of PD

Psychologie und Gehirn 2007

Die Fachtagung "Psychologie und Gehirn" ist eine traditionelle Tagung aus dem Bereich psychophysiologischer Grundlagenforschung. 2007 fand diese Veranstaltung, die 33. Jahrestagung der „Deutschen Gesellschaft für Psychophysiologie und ihre Anwendungen (DGPA)“, in Dortmund unter der Schirmherrschaft des Instituts für Arbeitsphysiologie (IfADo) statt. Neben der Grundlagenforschung ist auch die Umsetzung in die Anwendung erklärtes Ziel der DGPA und dieser Tradition folgend wurden Beiträge aus vielen Bereichen moderner Neurowissenschaft (Elektrophysiologie, bildgebende Verfahren, Peripherphysiologie, Neuroendokrinologie, Verhaltensgenetik, u.a.) präsentiert und liegen hier in Kurzform vor

An investigation of autonomic arousal and attentional mechanisms in children with ADHD and Autism

The present doctoral project was aimed at investigating the impact of Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) on measures of physiological arousal, alerting/vigilance, attention orienting and executive functions. 106 children between 7 and 15 years of age (31 typically developing; 24 ADHD-only; 18 ASD-only; 33 ADHD&ASD) performed a battery of eye-tracking and EEG experimental paradigms, while parent-reported measures were used to evaluate the severity of symptoms of ASD, ADHD and other psychiatric conditions. Children with clinical diagnoses of ADHD and ASD showed condition-specific signs of dysregulated physiological arousal and vigilance, with ADHD more likely to be associated with difficulties in up-regulating and maintaining an optimal level of vigilance to the environment, and ASD more associated with over-reactivity to sensory information and difficulties in down-regulating autonomic arousal in line with contextual demands. We also demonstrated that executive function and cognitive control mechanisms are likely to be less effective in children with comorbid ADHD+ASD, with negative effects on performance accuracy. In the discussion of this dissertation, some suggestions for clinical practice and future research studies, besides a description of the implications of the findings on the everyday life of people with ADHD and/or ASD, are provided

Attention-Mediated Neural and Behavioral Oscillation and Their Relationship to Dispositional Mindfulness

Over the past decades, there has been growing interest in mindfulness-based interventions (MBIs) and their association with attention. Preliminary research suggests that self-regulation of attention may mediate clinical benefits of MBIs. Although daily practice of mindfulness exercise and participation in MBI can produce noticeable intra-personal improvement in mindfulness skills over time, it is of greater theoretical significance to assess inter-individual differences in mindfulness and demonstrate the degree to which various levels of dispositional mindfulness relate to outcomes of interest. Furthermore, there are recent developments focusing on systematic temporal fluctuations in the brain waves and subsequent behavioral performance, which has been proposed as an underlying mechanism of attention. Thus, the current study aimed at evaluating the temporal pattern of behavioral performance and concurrent EEG data in visual cueing tasks via time-frequency techniques and investigating whether behavioral and neural parameters of selective attention in visual cueing tasks are associated with levels of dispositional mindfulness.To address these research questions, three experiments were conducted wherein participants completed an endogenous cueing task (n = 44, Experiment 1), an exogenous cueing task (n = 42, Experiment 2), or an endogenous cueing task with concurrent EEG recordings (n = 27). Additionally, participants from Experiment 1 and Experiment 2 completed self-report questionnaires including Mindfulness Attention Awareness Scale (MAAS), Five Facets Mindfulness Questionnaire (FFMQ), and Adult ADHD Self-Report Scale (ASRS). The results from the endogenous attention task suggest significant oscillatory activities at Delta, Theta, and Beta frequency bands for discrimination accuracy and at Delta, Alpha, and Beta frequency bands for reaction time. Likewise, behavioral data from the exogenous attention task indicates significant increases in evoked Theta and Alpha power in discrimination accuracy and reaction time, respectively. EEG data also support significant power spectral suppression in frontocentral electrodes in Delta and Theta bands when participants’ covert attention shifted either to the left or right target location compared with no-target condition. Moreover, we observed a positive correlation between FFMQ subscale scores and evoked power suggesting that levels of dispositional mindfulness are associated with spatial visual attention. Clinical implications and limitations of the current study will be further discussed

Dysfunctions in sensorimotor control and decision processing in schizophrenia

Στην παρούσα εργασία μελετήθηκε η βιβλιογραφία η σχετιζόμενη με την δυσλειτουργία του κινητικοαισθητικού ελέγχου και της επεξεργασίας λήψης αποφάσεων στην σχιζοφρένεια. Αρχικά, στην εισαγωγή γίνεται μια σύντομη περιγραφή των πιο χαρακτηριστικών συμπτωμάτων της διαταραχής. Ακολουθεί η ανατομική παρουσίαση των εγκεφαλικών δικτύων που μπορεί να παρουσιάζουν βλάβη στην σχιζοφρένεια. Κατόπιν εξετάζεται ο τρόπος επεξεργασίας της λήψης αποφάσεων σε υγιείς και σχιζοφρενείς. Το επόμενο κεφάλαιο παρουσιάζει την βιβλιογραφία σχετικά με τις κινητικοαισθητικές ανωμαλίες που απαντώνται στην σχιζοφρένεια. Έγινε προσπάθεια να συνδεθούν οι τύποι των κινητικοαισθητικών ανωμαλιών με τις ανατομικές τους βλάβες. Επίσης ελήφθησαν υπ’ όψη τα νευροφυσιολογικά δεδομένα και οι απεικονιστικές μελέτες. Κατόπιν παρουσιάζονται οι μελέτες που έγιναν με την χρήση χειρονακτικών και σακκαδικών χρόνων αντίδρασης που και οι δύο είναι γνωστό ότι επηρεάζονται στην σχιζοφρένεια. Επίσης παρουσιάζονται μελέτες που χρησιμοποίησαν ταυτόχρονα χειρονακτικούς και σακκαδικούς χρόνους αντίδρασης. Στο τέλος της μελέτης υπάρχει μια συζήτηση που αξιολογεί περιληπτικά τα ευρήματα της τεράστιας βιβλιογραφίας εν μέσω των ετών μαζί με υποδείξεις για περαιτέρω τρόπους διερεύνησης των δυσλειτουργιών του κινητικοαισθητικού ελέγχου και της λήψης αποφάσεων στην σχιζοφρένεια.In the present study, the literature on the dysfunctions of the sensorimotor control and the processes of decision making in schizophrenia (SZ) is reviewed. At the beginning, there is an introduction with a brief description of the most characteristic symptoms of the disorder. The anatomic presentation of the brain networks that may be lesioned in SZ follows. Afterwards, the way decision making is taking place in health and in SZ is presented. The next chapter presents a literature review on the sensorimotor abnormalities which are encountered in SZ. Effort was taken to combine the types of sensorimotor abnormalities with their anatomic lesions. Neurophysiological data and imaging studies were also taken into consideration. Next, are presented the studies which have been performed using manual and saccadic reaction times, which are both known to be affected in SZ. Studies that have used manual reaction time and saccadic reaction times simultaneously are also presented. At the end of the study there is a discussion summarizing the findings of the vast literature through the years together with suggestions for further ways of exploring the dysfunctions of the sensorimotor control and the decision making in SZ

Evaluating sleep and circadian rhythm disturbances and symptoms of impulsivity and inattention: Implications for adult attention-deficit/hyperactivity disorder

Reports of sleep disturbances and delayed sleep timing in attentiondeficit/ hyperactivity-disorder (ADHD) are common however the aetiology of such features is poorly understood. There is substantial evidence pointing to dysfunction of the circadian timing system in ADHD, and individual differences in human chronotype and diurnal preference have been linked with impulsivity and attention problems in adults. In the work presented here we examined associations between a later circadian phase of entrainment, impaired sleep quality, and circadian misalignment and how they relate to core symptoms of ADHD distributed among the general population. We report novel evidence which suggests that ‘social jetlag’ – an index of circadian misalignment arising from discordance between endogenous circadian timing and the timing of the social clock – is a consistent predictor of poorer ADHD-like symptom outcomes. Furthermore, objective assessment of the rest-activity rhythm and sleep intervals of subjects show that a failure to precisely entrain to the 24 h circadian period is associated with ADHD-like symptom severity which was in turn predicted by delayed circadian phase/sleep phase, sleep quality, and duration. Candidate gene approaches did not replicate previous findings linking symptoms of impulsivity, inattention, and later chronotype with elements of the core molecular clock. However, we did find differential susceptibility to the previously identified risk factors; poor sleep quality and social jetlag which were both modified by genotype. Preliminary data from an exploratory study examining the neurophysiological correlates of response inhibition and selective attention revealed interesting patters of ERP elicitation in individuals with high levels of social jetlag. The current findings highlight how examination of sleep and circadian rhythm disturbances associated with ADHD may inform our understanding of the disorder risk and might in the future be factored into interventions designed for better symptom management

An investigation of autonomic arousal and attentional mechanisms in children with ADHD and Autism

The present doctoral project was aimed at investigating the impact of Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) on measures of physiological arousal, alerting/vigilance, attention orienting and executive functions. 106 children between 7 and 15 years of age (31 typically developing; 24 ADHD-only; 18 ASD-only; 33 ADHD&ASD) performed a battery of eye-tracking and EEG experimental paradigms, while parent-reported measures were used to evaluate the severity of symptoms of ASD, ADHD and other psychiatric conditions. Children with clinical diagnoses of ADHD and ASD showed condition-specific signs of dysregulated physiological arousal and vigilance, with ADHD more likely to be associated with difficulties in up-regulating and maintaining an optimal level of vigilance to the environment, and ASD more associated with over-reactivity to sensory information and difficulties in down-regulating autonomic arousal in line with contextual demands. We also demonstrated that executive function and cognitive control mechanisms are likely to be less effective in children with comorbid ADHD+ASD, with negative effects on performance accuracy. In the discussion of this dissertation, some suggestions for clinical practice and future research studies, besides a description of the implications of the findings on the everyday life of people with ADHD and/or ASD, are provided

BRAIN CONNECTIVITY AND TREATMENT RESPONSE IN ADULT ADHD:understanding the relationship between individual differences in fronto-parietal and fronto-striatal brain networks and response to chronic treatment with methylphenidate

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder, characterised by disrupted anatomical and/or functional connectivity, mainly in the fronto-striatal and fronto-parietal networks. Stimulants, such as methylphenidate (MPH), represent a first-line treatment in ADHD, but one third of patients fail to respond, with severe consequences for the individual and the society at large. Hence, a comprehensive understanding of the relationship between individual differences in brain abnormalities and treatment response is needed.This thesis focused on two main brain networks: the fronto-striatal network, a central theme in ADHD research, and the fronto-parietal attentive network, formed by the three branches of the superior longitudinal fasciculus (SLF). The SLF branches have been only recently described in humans, and there is no detailed analysis of their distinct functional roles and involvement in disorders such as ADHD. Therefore, I first investigated the functional anatomy of the SLF branches by combining a meta-analytic approach with tractography, and revealed novel findings about the anatomical and functional segregation and integration of brain functions within fronto-parietal networks. Then, I showed, for the first time, that the three SLF branches are all significantly right-lateralised in ADHD patients but not in controls, and provided preliminary evidence that the pattern of lateralisation of the SLF I may be related to poor attentive performance in ADHD patients.Finally, I conducted functional and structural connectivity analysis to test whether a relationship exists between brain abnormalities and treatment response in adult ADHD. I employed a longitudinal crossover follow-up design. 60 non-medicated adult ADHD patients were recruited and underwent behavioural assessment (Qb test) and magnetic resonance imaging (MRI) scanning twice, once under placebo and once under a clinically effective dose of MPH. Clinical and behavioural response was measured after two months of treatment with MPH. I demonstrated for the first time that there is a relationship between ‘connectivity’ abnormalities within fronto-parietal networks and treatment response in adult ADHD, both at the anatomical and functional level.Ultimately, my investigation contributed towards the identification of potential biomarkers of treatment response, which in the future may help clinicians deliver more individualised treatments.<br/