Event-Related Potential Brain Correlates of Episodic and Semantic Memory in Adults with Autism Spectrum Disorder

The aim of this thesis was to refine current models of memory in Autism Spectrum Disorder (ASD) and elucidate similarities and differences between memory in ASD and that of Typically Developing (TD) individuals. This thesis built upon recently established behavioural patterns of preserved semantic and diminished episodic memory in ASD, by linking these with established patterns of electrophysiological activity in different cortical regions of the brain in TD individuals. Event-Related Potential (ERP) Old-New effects (enhanced positivity in the brain for correctly recognised Old stimuli compared to correctly rejected New stimuli) were recorded for episodic and semantic memory judgments (the parietal Old-New effect 400-800 ms, and the mid-frontal Old-New effect 300-500 ms respectively) in ASD, and were compared to TD individuals in terms of (1) temporal and (2) topographical similarities and differences. A series of five experimental studies were conducted using nameable line drawings, non-nameable kaleidoscope images and words as stimuli. A combination of two experimental paradigms were used; the Remember/Know paradigm and the Inclusion/Exclusion paradigm. The current thesis demonstrates that recognition memory Old-New effects are attenuated in ASD for word stimuli and nameable line drawings, but that the topography remains comparable between groups. The current findings suggest that although episodic memory is quantitatively diminished in ASD during behavioural tests, residual episodic memory judgements are phenomenologically similar to TD individuals. Despite demonstrating quantitatively preserved semantic memory, different patterns of neurophysiology are observed for these judgements in ASD, suggesting that different processes are engaged in this group. Finally, although individuals with ASD demonstrated diminished Old-New effects for nameable line drawing and word stimuli compared to TD individuals, enhanced Old-New effects were observed for non-nameable and novel kaleidoscope images in ASD. These findings have important implications for our understanding of verbal mediation and its relation to thought in ASD. The findings are interpreted within a theoretical account of diminished episodic memory and verbal processing difficulties in ASD

Event-related potential brain correlates of episodic and semantic memory in adults with autism spectrum disorder

The aim of this thesis was to refine current models of memory in Autism Spectrum Disorder (ASD) and elucidate similarities and differences between memory in ASD and that of Typically Developing (TD) individuals. This thesis built upon recently established behavioural patterns of preserved semantic and diminished episodic memory in ASD, by linking these with established patterns of electrophysiological activity in different cortical regions of the brain in TD individuals. Event-Related Potential (ERP) Old-New effects (enhanced positivity in the brain for correctly recognised Old stimuli compared to correctly rejected New stimuli) were recorded for episodic and semantic memory judgments (the parietal Old-New effect 400-800 ms, and the mid-frontal Old-New effect 300-500 ms respectively) in ASD, and were compared to TD individuals in terms of (1) temporal and (2) topographical similarities and differences. A series of five experimental studies were conducted using nameable line drawings, non-nameable kaleidoscope images and words as stimuli. A combination of two experimental paradigms were used; the Remember/Know paradigm and the Inclusion/Exclusion paradigm. The current thesis demonstrates that recognition memory Old-New effects are attenuated in ASD for word stimuli and nameable line drawings, but that the topography remains comparable between groups. The current findings suggest that although episodic memory is quantitatively diminished in ASD during behavioural tests, residual episodic memory judgements are phenomenologically similar to TD individuals. Despite demonstrating quantitatively preserved semantic memory, different patterns of neurophysiology are observed for these judgements in ASD, suggesting that different processes are engaged in this group. Finally, although individuals with ASD demonstrated diminished Old-New effects for nameable line drawing and word stimuli compared to TD individuals, enhanced Old-New effects were observed for non-nameable and novel kaleidoscope images in ASD. These findings have important implications for our understanding of verbal mediation and its relation to thought in ASD. The findings are interpreted within a theoretical account of diminished episodic memory and verbal processing difficulties in ASD.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

ERP Correlates of Recognition Memory in Autism Spectrum Disorder

Recognition memory in autism spectrum disorder (ASD) tends to be undiminished compared to that of typically developing (TD) individuals (Bowler et al. 2007), but it is still unknown whether memory in ASD relies on qualitatively similar or different neurophysiology. We sought to explore the neural activity underlying recognition by employing the old/new word repetition event-related potential effect. Behavioural recognition performance was comparable across both groups, and demonstrated superior recognition for low frequency over high frequency words. However, the ASD group showed a parietal rather than anterior onset (300–500 ms), and diminished right frontal old/new effects (800–1500 ms) relative to TD individuals. This study shows that undiminished recognition performance results from a pattern of differing functional neurophysiology in ASD

Meta-analysis and systematic review of skin graft donor-site dressings with future guidelines.

Background: Many types of split-thickness skin graft (STSG) donor-site dressings are available with little consensus from the literature on the optimal dressing type. The purpose of this systematic review was to analyze the most recent outcomes regarding moist and nonmoist dressings for STSG donor sites. Methods: A comprehensive systematic review was conducted across PubMed/MEDLINE, EMBASE, and Cochrane Library databases to search for comparative studies evaluating different STSG donor-site dressings in adult subjects published between 2008 and 2017. The quality of randomized controlled trials was assessed using the Jadad scale. Data were collected on donor-site pain, rate of epithelialization, infection rate, cosmetic appearance, and cost. Meta-analysis was performed for reported pain scores. Results: A total of 41 articles were included comparing 44 dressings. Selected studies included analysis of donor-site pain (36 of 41 articles), rate of epithelialization (38 of 41), infection rate (25 of 41), cosmetic appearance (20 of 41), and cost (10 of 41). Meta-analysis revealed moist dressings result in lower pain (pooled effect size = 1.44). A majority of articles (73%) reported better reepithelialization rates with moist dressings. Conclusion: The literature on STSG donor-site dressings has not yet identified an ideal dressing. Although moist dressings provide superior outcomes with regard to pain control and wound healing, there continues to be a lack of standardization. The increasing commercial availability and marketing of novel dressings necessitates the development of standardized research protocols to design better comparison studies and assess true efficacy.R01 EB021308 - NIBIB NIH HHSPublished versio

Role of Acorus calamus in preventing depression, anxiety, and oxidative stress in long-term socially isolated rats

Background and Aim: Social isolation stress (SIS) and individual housing have been shown to cause abnormal cognitive insufficiencies, altered anxiety levels, and signs of psychiatric diseases. Acorus calamus (AC), commonly known as Sweet Flag, has been widely used in India to treat neurological, metabolic, and respiratory disorders, indicating its potential therapeutic value. This study aimed to determine the antidepressant and antioxidative effects of AC on rats subjected to long-term, social-isolation-induced stress. Materials and Methods: This study involved 2-month-old male rats (24) weighing approximately 180200 g bred in-house. The rats were divided into four groups (n = 6): Group-1 received saline, Group-2 received SIS, Group-3 received only 50mg/kg AC, and Group-4 received 50mg/kg AC and SIS for 6 weeks. After this, behavioral, biochemical, and neuronal assay was conducted. Results: Behavioral experiments showed significantly higher activity levels (p < 0.001) in AC-treated rats than in the SIS group. In addition, rats subjected to SIS with AC treatment exhibited enhanced total antioxidants, superoxide dismutase, and neuronal assays compared to rats subjected to SIS alone. Conclusion: Acorus calamus treatment improved the antidepressant and antioxidant potential against SIS in rat brain tissue. Moreover, we proved that AC can effectively reverse the neurotoxicity induced by SIS in animal models. As we battle against the coronavirus disease 2019 pandemic and social isolation, AC could be considered a supplementary treatment to alleviate depressive-like symptoms in oBackground and Aim: Social isolation stress (SIS) and individual housing have been shown to cause abnormal cognitive insufficiencies, altered anxiety levels, and signs of psychiatric diseases. Acorus calamus (AC), commonly known as Sweet Flag, has been widely used in India to treat neurological, metabolic, and respiratory disorders, indicating its potential therapeutic value. This study aimed to determine the antidepressant and antioxidative effects of AC on rats subjected to long-term, social-isolation-induced stress. Materials and Methods: This study involved 2-month-old male rats (24) weighing approximately 180200 g bred in-house. The rats were divided into four groups (n = 6): Group-1 received saline, Group-2 received SIS, Group-3 received only 50mg/kg AC, and Group-4 received 50mg/kg AC and SIS for 6 weeks. After this, behavioral, biochemical, and neuronal assay was conducted. Results: Behavioral experiments showed significantly higher activity levels (p < 0.001) in AC-treated rats than in the SIS group. In addition, rats subjected to SIS with AC treatment exhibited enhanced total antioxidants, superoxide dismutase, and neuronal assays compared to rats subjected to SIS alone. Conclusion: Acorus calamus treatment improved the antidepressant and antioxidant potential against SIS in rat brain tissue. Moreover, we proved that AC can effectively reverse the neurotoxicity induced by SIS in animal models. As we battle against the coronavirus disease 2019 pandemic and social isolation, AC could be considered a supplementary treatment to alleviate depressive-like symptoms in our present-day lifestyle

Health comorbidities and cognitive abilities across the lifespan in Down syndrome.

BACKGROUND: Down syndrome (DS) is associated with variable intellectual disability and multiple health and psychiatric comorbidities. The impact of such comorbidities on cognitive outcomes is unknown. We aimed to describe patterns of physical health and psychiatric comorbidity prevalence, and receptive language ability, in DS across the lifespan, and determine relationships with cognitive outcomes. METHODS: Detailed medical histories were collected and cognitive abilities measured using standardised tests for 602 individuals with DS from England and Wales (age range 3 months to 73 years). Differences in prevalence rates between age groups and between males and females were determined using chi-squared or Fisher's exact tests. In adults, rates for psychiatric comorbidities were compared to expected population rates using standardised morbidity ratios (SMRs). Adapted ANCOVA functions were constructed to explore age and sex associations with receptive language ability across the lifespan, and regression analyses were performed to determine whether the presence of health comorbidities or physical phenotypes predicted cognitive abilities. RESULTS: Multiple comorbidities showed prevalence differences across the lifespan, though there were few sex differences. In adults, SMRs were increased in males and decreased in females with DS for schizophrenia, bipolar disorder, and anxiety. Further, SMRs were increased in both males and females with DS for dementia, autism, ADHD, and depression, with differences more pronounced in females for dementia and autism, and in males for depression. Across the lifespan, receptive language abilities increasingly deviated from age-typical levels, and males scored poorer than females. Only autism and epilepsy were associated with poorer cognitive ability in those aged 16-35 years, with no relationships for physical health comorbidities, including congenital heart defects. CONCLUSIONS: Our results indicate the prevalence of multiple comorbidities varies across the lifespan in DS, and in adults, rates for psychiatric comorbidities show different patterns for males and females relative to expected population rates. Further, most health comorbidities are not associated with poorer cognitive outcomes in DS, apart from autism and epilepsy. It is essential for clinicians to consider such differences to provide appropriate care and treatment for those with DS and to provide prognostic information relating to cognitive outcomes in those with comorbidities

Spontaneous spinal subarachnoid hemorrhage associated with subdural hematoma at different spinal levels

We describe the clinical features and MR-imaging findings of spontaneous spinal subarachnoid hemorrhage located in the lumbar spine associated with subdural hematoma at a higher, thoracic level in a 66-year-old man without neurological deficit. The sequential MR-imaging changes of hemorrhage at various stages in its evolution are portrayed. The possible pathogenetic mechanism for these very unusual, combined hemorrhages in both spinal compartments is discussed

The influence of task demands, verbal ability and executive functions on item and source memory in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is generally associated with difficulties in contextual source memory but not single item memory. There are surprising inconsistencies in the literature, however, that the current study seeks to address by examining item and source memory in age and ability matched groups of 22 ASD and 21 comparison adults. Results show that group differences in source memory are moderated by task demands but not by individual differences in verbal ability, executive function or item memory. By contrast, unexpected group differences in item memory could largely be explained by individual differences in source memory. These observations shed light on the factors underlying inconsistent findings in the memory literature in ASD, which has important implications for theory and practice