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Project log

Gerry Leisman
added a research item
We provide evidence to support the contention that many aspects of Autistic Spectrum Disorder (ASD) are related to interregional brain functional disconnectivity associated with maturational delays in the development of brain networks. We think a delay in brain maturation in some networks may result in an increase in cortical maturation and development in other networks, leading to developmental asynchrony and unevenness of functional skills and symptoms. The paper supports the close relationship between retained primitive reflexes and cognitive and motor function in general and in ASD in particular provided to indicate that the inhibition of RPRs can effect positive change in ASD.
Gerry Leisman
added a research item
A study was performed on 2,175 individuals between the ages of 3.2 and 22.04 years diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) and drawn from 89 separate locations across the United States in satellite clinics with common practices and common staff training and equipment. The objective was to determine the efficacy of a hemispheric-based training program to reduce extant retained primitive reflexes (RPRs) and examine the relationship to motor function by metronome-based motor, DL, and cognitive tasks measured by subtests of the Wechsler Wide Range Achievement Test. After a 12-week program, RPR’s were significantly reduced, as well as performance on all motor and cognitive measures significantly increased. Listening comprehension demonstrated significant increases between pre- and post-testing of 7% (W = 1213000; df = 2094; p < 0.0001) and mathematical problem solving revealed a significant increase of 5% (W = 1331500; df = 2091; p < 0.0001) associated with a significant reduction in primitive reflexes. The study concluded that the incorporation of relatively simple hemispheric-based programming within the educational system worldwide could relatively inexpensively increase academic, cognitive, and motor performance.
Gerry Leisman
added a research item
We outline the basis of how functional disconnection with reduced activity and coherence in the right hemisphere would explain all of the symptoms of autistic spectrum disorder as well as the observed increases in sympathetic activation. If the problem of autistic spectrum disorder is primarily one of desynchronization and ineffective interhemispheric communication, then the best way to address the symptoms is to improve coordination between areas of the brain. To do that the best approach would include multimodal therapeusis that would include a combination of somatosensory, cognitive, behavioral, and biochemical interventions all directed at improving overall health, reducing inflammation and increasing right hemisphere activity to the level that it becomes temporally coherent with the left hemisphere. We hypothesize that the unilateral increased hemispheric stimulation has the effect of increasing the temporal oscillations within the thalamocortical pathways bringing it closer to the oscillation rate of the adequately functioning hemisphere. We propose that increasing the baseline oscillation speed of one entire hemisphere will enhance the coordination and coherence between the two hemispheres allowing for enhanced motor and cognitive binding.
Calixto Machado
added a research item
ADHD is the most common and most studied neurodevelopmental problem. Recent statistics from the CDC state that 11% approximately 1 out of every 9 children in the US and 1 in 5 high school boys are diagnosed with ADHD. Lacking from treatment is an interdisciplinary knowledge-based strategy to intervention with child public health concerns addressed the educational system. This study is based on previous findings that ADHD children possess underactivity between sub-cortical and cortical regions. An imbalance of activity or arousal in one area can result in functional disconnections similar to that seen in split-brain patients. As ADD/ADHD children exhibit deficient performance on tests measuring perceptual laterality, evidence of weak laterality or failure to develop laterality has been found across various modalities (auditory, visual, tactile) resulting in abnormal cerebral organization and associated dysfunctional specialization needed for lateralized processing of language and non-language function. This pilot study examines groups of ADD/ADHD and control elementary school children all of whom were administered all the subtests of the Wechsler Individual Achievement Tests, the Brown Parent Questionnaire, and given objective performance measures on tests of motor and sensory coordinative abilities. Results measured after a 12-week remediation program aimed at increasing the activity of the hypothesized underactive right hemisphere function, yielded significant improvement of greater than two years in grade level in all domains except in mathematical reasoning. The treated group also displayed a significant improvement in behavior with a reduction in Brown scale behavioral scores. Non-treated control participants did not exhibit significant differences during the same 12-week period in academic measurements, but did so when compared to the treated group. Results are discussed in the context of the concept of functional disconnectivity in ADD/ADHD children.
Calixto Machado
added 2 research items
Antecedentes: El trastorno del espectro autista (TEA) es complejo trastorno del neurodesarrollo que se caracteriza clínicamente por dificultades de la interacción social, alteraciones del lenguaje, variados estereotipos de comportamiento, y déficits cognitivos. Hoy en día muchos autores consideran a TEA como una “epidemia” a nivel mundial. Muchos autores defienden que el TEA es un modelo para el estudio de la conectividad cerebral, y que los trastornos de la conectividad anatómica (CA) y funcional (CF), constituyen las bases neurales de este síndrome. Objetivo: Evaluar la CA y la CF en niños autistas mediante técnica de imágenes de resonancia magnética, así como mediante estudios de coherencia del EEG. Resultados: En esta ocasión se presentan 2 artículos científicos y un capítulo de un libro que fueron publicados en el año 2015, pero que en realidad no son más que la continuidad de distintos protocolos de investigación del Autor y sus Coautores para el estudio de los TEA. En el primer artículo, “QEEG Spectral and Coherence Assessment of Autistic Children in Three Different Experimental”, se demuestran cambios de la CF, medidos por la coherencia y del espectro del EEG, comparados con sujetos controles, que indican un trastorno de la interacción visuo-auditiva, lateralizada al hemisferio derecho. En el segundo artículo “Anatomic and functional connectivity relationship in autistic children during three different experimental conditions”, se determina la relación entre la conectividad anatómica CA vs. CF, en el que se demuestran diferentes relaciones de las mismas, en la diferentes condiciones experimentales, que se basan en cambios de las redes neurales, tanto anatómicas como funcionales en el TEA. En el capítulo de un libro, “Neuroimages in Autism”, se hace una revisión de las diferentes técnicas deneuroimágenes que nuestro grupo viene empleando en los distintos protocolos para el estudio de los trastornos del espectro autista, así como los trastornos de la conciencia. En el mismo se muestran resultados originales que hemos encontrado en los cerebros de los niños autistas, que constituyen marcadores biológicos para el diagnóstico y para seguir la evolución de estos pacientes. Conclusiones: Se encontraron resultados originales a nivel mundial que indican cambios en la CA y CF de las redes neurales en los cerebros de los niños autistas, que aportan nuevos conocimientos acerca de los mecanismos anatómicos y fisiopatológicos de este síndrome
Calixto Machado
added a research item
The study examined the efficacy of low-level laser therapy, a form of photobiomodulation, for the treatment of irritability associated with autistic spectrum disorder in children and adolescents aged 5–17 years. Twenty-one of the 40 participants received eight 5-min procedures administered to the base of the skull and temporal areas across a 4-week period (test, i.e., active treatment participants). All the participants were evaluated with the Aberrant Behavior Checklist (ABC), with the global scale and five subscales (irritability/agitation, lethargy/social withdrawal, stereotypic behavior, hyperactivity/noncompliance, and inappropriate speech), and the Clinical Global Impressions (CGI) Scale including a severity-of-illness scale (CGI-S) and a global improvement/change scale (CGI-C). The evaluation took place at baseline, week 2 (interim), week 4 (endpoint), and week 8 (post-procedure) of the study. The adjusted mean difference in the baseline to study endpoint change in the ABC irritability subscale score between test and placebo participants was −15.17 in favor of the test procedure group. ANCOVA analysis found this difference to be statistically significant (F = 99.34, p < 0.0001) compared to the baseline ABC irritability subscale score. The study found that low-level laser therapy could be an effective tool for reducing irritability and other symptoms and behaviors associated with the autistic spectrum disorder in children and adolescents, with positive changes maintained and augmented over time.
Gerry Leisman
added a research item
Diffusion tensor imaging is an ideal technique with which to study it in order to detect the degree of integrity of white matter. WE attempted to establish a method to explore the microstructural integrity of white matter in children autism using diffusion tensor imaging and fiber tractography algorithms. In this study we propose a method for a DTI analysis in autism child, considering theses particulars brain. This method should improve our understanding of ASD exploring the basic neural defects that are implicated in autism. Using diffusivity indices: fractional anisotropy and mean diffusivity, is possible establish a connectivity pattern, and the different ROIs obtained from the atlasing process allows us study both hemispheric independently.
Gerry Leisman
added a research item
Diffusion tensor imaging (DTI), offers various diffusivity indices that relate to the micro-structural organization of brain white matter. The most common indices are mean diffusivity (MD), reflecting the amplitude of water diffusion, and fractional anisotropy (FA), reflecting the directionality of water diffusion. Recently, researchers have applied DTI to obtain information about the white matter connectivity in individuals with autism spectrum disorders (ASD), a heterogeneous syndrome with complex neuropathology.These findings revealed abnormal white matter microstructure in various regions relevant to the core impairments of autism, suggesting that alterations of local connectivity might contribute to the pathology of autism. The present study aimed to use diffusion tensor imaging and fiber tractography algorithms to explore themicrostructural integrity of the two pairs ofassociation fibers, namely the cingulum (Cg) and the corpus callosum (CC).Eleven children with ASD wereincluded in this analysis. The trajectories of the brain network system were reconstructed using regions of interest (ROIs) approach based on Individual Brain Atlas Statistical Parametric Mapping (IBASPM) software packages. Mean values of MD and FA, were calculated for each fiber. Tensor calculation and tractography were performed using DSI Studio software and DTI reconstruction method, which is able to characterize the major diffusion direction of the fiber in human brains. The tracking method introduced a random process that determined the deviation of the moving directions.We offer an analysis of a structural connectivity defined as the probability suggesting the existence of a fiber tract between two regions. We described measures that quantify the white matter connectivity. Our results illustrate how the DTI analysis has emerged as an important tool for characterization of anatomical brain connectivity, allowing researchers to start exploring the basic neural defects that are implicated in ASD. Keywords: DTI, tractography, autism, anatomical connectivity
Calixto Machado
added a research item
fMRI does not offer sufficient temporal resolution to describe functional and effective connectivity; EEG/MEG methodology does. Integrated transient activity in diverse brain regions is essential for information processing. EEG measures sensitive to changes in dynamic connectivity is a function of quadratic coherence examining synchronous co-activation of different brain areas. Our previous work suggested a temporal binding deficit in autism. We examined the effects of Low Level Laser Therapy (LLLT) on neural connectivities and cognitive function. Quantum interference effects in amplitudes of optical transitions lead to modifications of optical properties and electromagnetically induced transparency (EIT), allowing for transcranial stimulation. Four autistic children were examined. fMRI images were acquired using a Siemens 3T and digital EEG system (Medicid-05, Neuronic, S.A.). A previously developed graph framework was employed that represented the cerebral volume as a non-directed weighted graph G, in which nodes correspond to atlas-defined regions and arcs to the connections joining them. Anatomical Connection Density measured anatomic connectivity between a pair of nodes. We studied autistic children with video/audio stimuli. Autistics showed lower coherence in right hemispheres, suggesting impairment of visual and auditory sensory integration. We have previously reported that the association of Anatomic (AC) and Functional (FC) connectivities differs when comparing resting-state with other experimental tasks, with hemispheric lateralization in autistics. This study observed differences before and after application of LLLT in autistic children to determine the relationship between AC versus FC. The effects of LLLT were associated with changes for autistics in both AC and FC but not with non-autistics.
Gerry Leisman
added 2 research items
Objective: To determine the relationship between the anatomic (AC) vs. functional (FC) connectivity, considering short-range and long-range brain networks. Background: In a recent published paper (Machado et al., 2013), we showed that in autistics studied with video without audio tasks vs. video without audio tasks, tended to show lower coherence values in the right hemispheres, suggesting an impairment of visual and auditory sensory integration in autistics. Design/Methods: Aanatomic connectivity was assessed by the DW-MRI technique and functional connectivity by EEG coherence calculation, in three experimental conditions: basal, watching a popular cartoon with audio (V-A), and with muted audio track (VwA). Results: For short-range connections, basal records, statistical significant correlations for all EEG bands in the left hemisphere were found, meanwhile in the right hemispheres no significant correlation for fast EEG frequency bands were noticed. For the V-A condition, significant correlations mainly diminished for the left hemisphere; for the right hemisphere again no significant correlations for the fast EEG frequency bands were found. For the VwA condition, significant correlations for the rapid EEG frequencies mainly disappeared for the right hemisphere. For long-range connections, basal records, similar correlations were found for both hemispheres. For the right hemisphere significant correlations incremented to all EEG bands for the V-A condition, but these significant correlations disappeared for the fast EEG frequencies in the VwA condition. Conclusions: It appears that in a resting-state condition, AC is better associated with functional connectivity for short-range connections in the left hemisphere. V-A experimental condition enriches AC and FC association for long-range connections in the right hemisphere. This might be related to an effective connectivity improvement due to visual and auditory stimulation. An impaired audiovisual interaction in the right hemisphere Study Supported by: NA
Background: The neuropathology underlying Attention Deficit/Hyperactivity and Neurobehavioral disorders in general most consistently points to dysfunction in cortical-striatal pathways leading to inactivation, or insufficient engagement, of frontal and prefrontal lobes. By implication, there may exist functional disconnections between the anterior and posterior higher cortical regions, instead of a fixed dysfunction in either one. Given this premise, reconnection of these systems through cognitive and motor-based interventions constitutes a logical remedial approach in the treatment of ADHD and Neurobehavioral disorders. A fundamental understanding of the nature of functional connectivities and disconnection syndromes informs a more comprehensive understanding of consciousness, awareness, attention, awake and sleep states and their dysfunction. Objectives was to outline the nature of functional disconnectivities in explaining cognitive neurologically compromised states. Methodology: Coherence analysis of steady-state and event-related EEG activity was compared in individuals, persistent vegetative, minimally conscious, Autistic Spectrum Disorders, ADHD, relaxed wakeful, and those in attentive states. Results: All subjects clin ical particiapnts demonstrated functional disconnectivities but ADHD and Autistic Spectrum participants revealed underactive right and overactive left hemisphere activity in specific leads measured by Power Spectral Density and coherence measures for specific freqency bands. The findings were confirmed by MRI tractography. Conclusions: An individual’s state of consciousness may be effectively studied by indicting the degree of coherent function or shared electrophysiological activity. The lack of integrated activity is an example of less optimized and less developmentally efficiently functioning system nervous system whose sate can be modified by external means.
Gerry Leisman
added 2 research items
We studied autistics by quantitative EEG spectral and coherence analysis during three experimental conditions: basal, watching a cartoon with audio (V-A), and with muted audio band (VwA). Significant reductions were found for the absolute power spectral density (PSD) in the central region for delta and theta, and in the posterior region for sigma and beta bands, lateralized to the right hemisphere. When comparing VwA versus the V-A in the midline regions, we found significant decrements of absolute PSD for delta, theta and alpha, and increments for the beta and gamma bands. In autistics, VwA versus V-A tended to show lower coherence values in the right hemisphere. An impairment of visual and auditory sensory integration in autistics might explain our results.
We studied autistics by quantitative EEG spectral and coherence analysis during three experimental conditions: basal, watching a cartoon with audio (V–A), and with muted audio band (VwA). Significant reductions were found for the absolute power spectral density (PSD) in the central region for delta and theta, and in the posterior region for sigma and beta bands, lateralized to the right hemisphere. When comparing VwA versus the V–A in the midline regions, we found significant decrements of absolute PSD for delta, theta and alpha, and increments for the beta and gamma bands. In autistics, VwA versus V–A tended to show lower coherence values in the right hemisphere. An impairment of visual and auditory sensory integration in autistics might explain our results.
Gerry Leisman
added 2 research items
Con la presente le adjuntamos el artículo científico: “EEG Spectral and Coherence Assessment of Autistic Children in Three Different Experimental Conditions”, del Dr. Calixto Machado Curbelo, y coautores, que ha sido evaluado por nuestro Consejo Científico, y lo considera un aporte original en el estudio de los trastornos de la conciencia, y lo proponemos para optar por el Premio Anual de la Salud 201 4. En este trabajo se estudiaron 11 niños autistas, así como 14 sujetos controles. No se encontraron diferencias significativas en cuanto a la edad entre ambos grupos. Se estudiaron ambos grupos mediante el análisis espectral y de coherencia del EEG cuantitativo (QEEG) en tres condiciones experimentales: basal, con la presentación de un video popular para niños con audio (V-A), y presentándole el mismo video sin audio (VwA). Se encontraron reducciones significativas del poder espectral en la región central y posterior para las bandas sigma y beta, lateralizadas al hemisferio derecho en los enfermos. Cuando se compararon las condiciones experimentales VwA contra V-A en las regiones de la línea media, se encontraron reducciones significativas en los autistas, para los valores absolutos de las bandas delta, theta, alfa, e incrementos en las bandas beta y gamma. Con relación al cálculo de la coherencia, que es una medición de la conectividad funcional, al comparar las condiciones experimentales VwA contra V-A, se encontraron valores reducidos en el hemisferio derecho. Se concluyó que estos resultados indican un trastorno de la interacción visuo-auditiva, lateralizada al hemisferio derecho. Page 4 Este artículo fue publicado en la revista “Autism and Develpmental Disorders”, considerada la publicación más importante del mundo en el área del trastorno del espectro autista. Esta revista tiene un factor de impacto de 3.723. Este trabajo fue presentado recientemente en el IV Congreso Internacional de la Asociación de Neurología Funcional y Rehabilitación (IAFNR), 2013, Phoenix, EE.UU., y recibió el Premio al Mejor Trabajo del Año de dicha Asociación. Este artículo formó parte de una colección de artículos del Dr. Calixto Machado, que recibió el Premio Anual de la Academia de Ciencias de Cuba, 2013.
Con la presente le adjuntamos el artículo científico: “Machado-Ferrer Y, et al. Heart rate variability for assessing comatose patients with different Glasgow Coma Scale scores”, de la Dra. Yazmina Machado Ferrer y coautores, quien realizó esta investigación bajo la tutoría del Prof. Calixto Machado Curbelo, y coautores, que ha sido evaluado por nuestro Consejo Científico, y lo considera un aporte original en el estudio de los trastornos de la conciencia, y lo proponemos para optar por el Premio Anual de la Salud 2014. En este artículo recientemente publicado en Clinical Neurophysiology, se evaluó el sistema nervioso autónomo (SNA) mediante la variabilidad de la frecuencia cardíaca (VFC) en 16 pacientes comatosos, comparados con 22 sujetos controles. Los pacientes se clasificaron en 2 subgrupos de acuerdo con los valores de la Escala de Glasgow (EG) para la evalución del coma: pacientes con EG = 3, y el otro subgrupo con EG de 4 a 8. Se calcularon variables en el dominio del tiempo y la frecuencia para la VFC. En general se encontró un notable reducción de la VFC para los pacientes en comparación con los sujetos controles. Se encontró un decremento significativo para los poderes absolutos de las bandas de muy baja frecuencia (VLF), y de baja frecuencia (LF) en el subgrupo con pacientes con EG = 3. También el índice LF/HF, y el índice de la entropía de Shannon resultaron significativamente reducidos en dicho subgrupo, comparado con el subgrupo con EG de 4 a 8. Se discute la importancia de la medición de la VFC en el curso evolutivo del coma, con el énfasis de que es una técnica sencilla, no invasiva, que sólo requiere el registro de una derivación de electrocardiografía. Page 4 Este estudio había sido precedido por un estudio similar pero sólo con la medición de índices en el dominio del tiempo, por lo que se ha considerado un aporte original en el estudio del coma, y en la evolución de este estado hacia la muerte encefálica. La revista Clinical Neurophysiology es la publicación oficial de la “Federación Internacional de Neurofisiología Clínica (IFCN), y tiene un factor de impacto de 3.707. Este artículo formó parte de una colección de artículos para el estudio de los trastornos de la conciencia, que recibió el Premio Anual de la Academia de Ciencias de Cuba, 201 3. (3) (PDF) Premio Anual de Salud 2014. Available from: https://www.researchgate.net/publication/289673655_Premio_Anual_de_Salud_2014 [accessed Sep 30 2021].
Rafael Rodriguez-Rojas
added a research item
Objective Subthalamotomy is an effective alternative for the treatment of Parkinson’s disease (PD). However, uncertainty about the optimal target location and the possibility of inducing haemichorea-ballism have limited its application. We assessed the correlation between the topography of radiofrequency-based lesions of the subthalamic nucleus (STN) with motor improvement and the emergence of haemichorea-ballism. Methods Sixty-four patients with PD treated with subthalamotomy were evaluated preoperatively and postoperatively using the Unified Parkinson’s Disease Rating Scale motor score (UPDRSm), MRI and tractography. Patients were classified according to the degree of clinical motor improvement and dyskinesia scale. Lesions were segmented on MRI and averaged in a standard space. We examined the relationship between the extent of lesion-induced disruption of fibres surrounding the STN and the development of haemichorea-ballism. Results Maximum antiparkinsonian effect was obtained with lesions located within the dorsolateral motor region of the STN as compared with those centre-placed in the dorsal border of the STN and the zona incerta (71.3%, 53.5% and 20.8% UPDRSm reduction, respectively). However, lesions that extended dorsally beyond the STN showed lower probability of causing haemichorea-ballism than those placed entirely within the nucleus. Tractography findings indicate that interruption of pallidothalamic fibres probably determines a low probability of haemichorea-ballism postoperatively. Conclusions The topography of the lesion is a major factor in the antiparkinsonian effect of subthalamotomy in patients with PD. Lesions involving the motor STN and pallidothalamic fibres induced significant motor improvement and were associated with a low incidence of haemichorea-ballism.
Gerry Leisman
added a research item
Raw Data of an FDA approved clinical trial of the effects of Low Level Light Therapy (LLLT), a form of photobiomodulation, in Autistic Spectrum Disorder
Gerry Leisman
added 2 research items
Introduction: Autistic spectrum disorder (ASD) can be better understood by examining its nature by analyzing brain connectivity. Objective: To better understand the nature of brain connectivities in autistics electrophysiologically. Methods: Brain connectivity can be subdivided into structural or anatomical connectivity (AC) and functional connectivity (FC). A group of 21 autistics, 13 male and 8 female, aged 3 to 9 years were studied. A control group, matched for age and sex with the patient group were also examined. Results: Increased connectivity between closely related structures was observed, indicating local over-connectivity in ASD as well as a lower power spectral density value, probability, and strength of connection (sub-connectivity) for networks of medium and long distances. The “grand average” fractional anisotropy (FA) measured at the longitudinal superior fasciculus, the longitudinal inferior fasciculus, and at the arcuate fasciculus, showed that there is a significantly higher (FA) in the right cerebral hemisphere compared with the left. A significantly lower concentration of normalized N-acetyl aspartate (NAA/Cr) was found in the left hemisphere, and calculating the correlation between the FA and the concentration of NAA/Cr, a significant positive correlation for the left hemisphere was shown, while the right hemisphere correlation was significantly negative. ASD individuals showed lower values of coherence in the right hemisphere in the video without audio condition. Conclusions: It is concluded that in the pathophysiology of ASD is associated with an excess of local connectivity, with a deficit of connectivity in medium and long distances, perhaps as a result of alterations in the elimination or synapse formation.
Calixto Machado
added a research item
lntroduction: Autistic spectrum disorder (ASD) can be better understood by examiningits nature by analyzing brainconnectivity. Objective:To better understand the nature of brainconnectivities inautistics electrophysiologically. .Methods:Brain connectivity can be subdivided into structural or anatomical connectivity (AC) and functional connectivity (FC). A group of 21autistics,13 male and 8 female, aged 3 to 9 years were studied.A control group,matched for age and sex with the patient group were also examined. Results:lncreased connectivity between closely related structures was observed, indicating local over-connectivity in ASD as well as a lower power spectral density value, probability, and strength of connection (sub-connectivity) for networks of medium and long distances. The "grand average" fractional anisotropy {FA) measured at the longitudinal superior fasciculus, the longitudinal inferior fasciculus, and at the arcuate fasciculus, showed that there is a significantly higher {FA) in the right cerebral hemisphere compared with the left. A significantly lower concentration of normalized N-acetyl aspartate (NAA/Cr) was found in the left hemisphere, and calculating the correlation between the FA and the concentration of NAA/Cr,a significant positive correlation for the left hemisphere was shown, while the right hemisphere correlation was significantly negative.ASD individuals showed lower values of coherence in the right hemiisphere iinthe video without audio condition.
Calixto Machado
added a research item
Graf et al. published an interesting review on autism spectrum disorder (ASD), emphasizing the term "autism epidemic," [1] supported by an editorial. [2] Among other factors, increasing ASD diagnoses can be attributed to broader diagnostic criteria and the recognition of ASD existence differentiated from other neurodevelopmental diseases. [2-4] One important issue, defended by the authors, is an early screening and diagnosis with emphasis on the evolving practice of genetic testing for ASD. [1] Brain connectivity assessment, both anatomical (AC) and functional (FC), is fundamental to diagnose and follow-up with intervention in ASD. [3-5] Many studies assess either AC or FC, but literature regarding the correlation between both types of connectivity in autism is lacking. We studied children with autism, determining the relationship between AC and FC, with consideration of short-range and long-range brain networks. [4] AC was assessed by the DW-MRI technique and FC by EEG coherence calculation. We found correlations among AC and FC measurements, and concluded that an impaired audiovisual interaction in the right-brain hemisphere might be the cause. [4] The study of brain connectivity should be a tool to assess ASD in present and future research. [3,4] 1. Graf WD, Miller G, Epstein LG, Rapin I. The autism "epidemic": Ethical, legal, and social issues in a developmental spectrum disorder. Neurology 2017;88:1371-1380. 2. Jeste SS, Schor NF. Autism today: Have we put the cart before the horse? Neurology 2017;88:1303-1304. 3. Machado C, Estevez M, Leisman G, et a. QEEG spectral and coherence assessment of autistic children in three different experimental conditions. J Autism Dev Disord 2015;45:406-424. 4. Machado C, Rodriguez R, Estevez M, et al. Anatomic and Functional Connectivity Relationship in Autistic Children During Three Different Experimental Conditions. Brain Connect 2015;5:487-496. 5. Chen S, Xing Y, Kang J. Latent and Abnormal Functional Connectivity Circuits in Autism Spectrum Disorder Front Neurosci 2017;11:125.
Gerry Leisman
added a research item
Background: Theoretical conceptions of autistic spectrum disorder (ASD) suggest abnormalities in connections among distributed neural systems. EEG coherence studies had a twofold objective: to scrutinize the theory of cortical optimization in autism and detect coherence between cortical areas in specific frequency bands in autistics and controls. Methods: Functional connectivity was assessed with coherence between electrode pairs in narrow frequency bands among 18 adult ASDs and 18 controls in an eyes closed resting state. Results: Explorative analysis in six frequency bands (0.5–31.5 Hz) indicated locally elevated coherence in autistics compared to a more distributed coherence. Autistics demonstrated elevated local coherence, especially in the left hemisphere, frontal, and temporal regions in the 3–6 Hz frequency range. In the 8–10 Hz, globally reduced coherence was evident for ASDs within frontal regions and between frontal and all other scalp regions. Coherence brain maps revealed more pronounced and widespread increases in coherences in the 8–10 Hz band in the low optimized ASD individuals than in the more highly optimized controls and corroborated for both groups by multivariate permutation tests. These tests revealed additional differences between the low- and the high-proficiency group also for coherences within the 13–18 Hz and the 18.5–31.5 Hz bands. ASDs exhibited significantly greater relative power between 3 and 6 Hz. Conclusions: Robust patterns of over- and under-connectivity were apparent at distinct spatial and temporal scales in ASDs in the eyes-closed resting state. Autistics demonstrate underactivity of right hemisphere and overactivity of left relative to controls.
Calixto Machado
added 2 research items
We studied autistics by quantitative EEG spectral and coherence analysis during three experimental conditions: basal, watching a cartoon with audio (V-A), and with muted audio band (VwA). Significant reductions were found for the absolute power spectral density (PSD) in the central region for delta and theta, and in the posterior region for sigma and beta bands, lateralized to the right hemisphere. When comparing VwA versus the V- A in the midline regions, we found significant decrements of absolute PSD for delta, theta and alpha, and increments for the beta and gamma bands. In autistics, VwA versus V-A tended to show lower coherence values in the right hemisphere. An impairment of visual and auditory sensory integration in autistics might explain our resells.
Abstract The EEG has not been comprehensively used to study the brain function in Autistic Spectrum Disorder (ASD) patients. Therefore, the researchers recently developed a specifically designed software (EEGConn) to explore brain function based on advanced algorithms to explore EEG activity. They studied a group of 14 righthanded autistic patients with age 70.3±29.32 and 14 healthy subjects with IQs over 85. All recordings were performed with the subjects lying in a recumbent position, in eye opened condition; EEG ...
Calixto Machado
added a research item
A group of 21 autistic children were studied for determining the relationship between the anatomic (AC) versus functional (FC) connectivity, considering short-range and long-range brain networks. AC was assessed by the DW-MRI technique and FC by EEG coherence calculation, in three experimental conditions: basal, watching a popular cartoon with audio (V-A), and with muted audio track (VwA). For short-range connections, basal records, statistical significant correlations were found for all EEG bands in the left hemisphere, but no significant correlations were found for fast EEG frequencies in the right hemisphere. For the V-A condition, significant correlations were mainly diminished for the left hemisphere; for the right hemisphere, no significant correlations were found for the fast EEG frequency bands. For the VwA condition, significant correlations for the rapid EEG frequencies mainly disappeared for the right hemisphere. For long-range connections, basal records showed similar correlations for both hemispheres. For the right hemisphere, significant correlations incremented to all EEG bands for the V-A condition, but these significant correlations disappeared for the fast EEG frequencies in the VwA condition. It appears that in a resting-state condition, AC is better associated with functional connectivity for short-range connections in the left hemisphere. The V-A experimental condition enriches the AC and FC association for long-range connections in the right hemisphere. This might be related to an effective connectivity improvement due to full video stimulation (visual and auditory). An impaired audiovisual interaction in the right hemisphere might explain why significant correlations disappeared for the fast EEG frequencies in the VwA experimental condition.