Atypical Postural Control Variability and Coordination Persist Into Middle and Older Adulthood in Autism Spectrum Disorder / Jingying WANG ; Desirae J. SHIRLEY ; Hanna M. GEMMELL ; Danielle CHRISTENSEN ; Ann-Marie ORLANDO ; Regilda A. ROMERO ; Brandon A. ZIELINSKI ; Zheng WANG in Autism Research, 18-4 (April 2025)  

Public ISBD [article]  inAutism Research > 18-4 (April 2025) . - p.752-764 Titre : Atypical Postural Control Variability and Coordination Persist Into Middle and Older Adulthood in Autism Spectrum Disorder Type de document : texte imprimé Auteurs : Jingying WANG, Auteur ; Desirae J. SHIRLEY, Auteur ; Hanna M. GEMMELL, Auteur ; Danielle CHRISTENSEN, Auteur ; Ann-Marie ORLANDO, Auteur ; Regilda A. ROMERO, Auteur ; Brandon A. ZIELINSKI, Auteur ; Zheng WANG, Auteur Article en page(s) : p.752-764 Langues : Anglais (eng) Mots-clés : aging  autism spectrum disorder  dynamic postural sway  middle aged and older  postural control  static stance Index. décimale : PER Périodiques Résumé : ABSTRACT Postural control deviations remain largely unexplored in middle aged and older autistic adults. With the increased prevalence of neurodegenerative conditions and heightened fall risk, precise quantification of postural variability and coordination may provide valuable insights into aging associated neuromotor deviations in autistic adults. Forty-seven autistic and 48 non-autistic individuals completed static stance, anterior?posterior (AP), and mediolateral (ML) postural sway on a force platform. Center of pressure (COP) metrics were derived and interpreted using ANCOVAs for between-group comparisons and multilinear regressions for group? ? ?age interaction. Correlations between clinical measures and COP variables that differentiated groups were explored. Compared to non-autistic individuals, autistic adults exhibited greater COP standard deviation (COPSD) and COP trajectory length during static stance and demonstrated significant COPSD-AP reductions in older age. Autistic adults also exhibited decreased COP range of motion (ROM) but increased ROM variability in the target direction during dynamic stance. Autistic adults' postural sway was jerkier during dynamic stance, and increased ROM variability during dynamic AP sway was moderately associated with lower verbal IQ in autistic adults. Our findings highlight persistent postural control deviations in middle aged and older autistic adults. Static and dynamic stance are differentially associated with unique profiles of postural control in ASD. Specifically, autistic adults demonstrated pronounced increases in postural sway variability during static stance, while reducing coordination during dynamic conditions. The extent to which postural control deviations found in autistic adults are predictive to the onset of neurodegenerative conditions and the severity of falls warrants future longitudinal research. En ligne : https://doi.org/10.1002/aur.70024 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=554 [article] Atypical Postural Control Variability and Coordination Persist Into Middle and Older Adulthood in Autism Spectrum Disorder [texte imprimé] / Jingying WANG, Auteur ; Desirae J. SHIRLEY, Auteur ; Hanna M. GEMMELL, Auteur ; Danielle CHRISTENSEN, Auteur ; Ann-Marie ORLANDO, Auteur ; Regilda A. ROMERO, Auteur ; Brandon A. ZIELINSKI, Auteur ; Zheng WANG, Auteur . - p.752-764. Langues : Anglais (eng) in Autism Research > 18-4 (April 2025) . - p.752-764 Mots-clés : aging  autism spectrum disorder  dynamic postural sway  middle aged and older  postural control  static stance Index. décimale : PER Périodiques Résumé : ABSTRACT Postural control deviations remain largely unexplored in middle aged and older autistic adults. With the increased prevalence of neurodegenerative conditions and heightened fall risk, precise quantification of postural variability and coordination may provide valuable insights into aging associated neuromotor deviations in autistic adults. Forty-seven autistic and 48 non-autistic individuals completed static stance, anterior?posterior (AP), and mediolateral (ML) postural sway on a force platform. Center of pressure (COP) metrics were derived and interpreted using ANCOVAs for between-group comparisons and multilinear regressions for group? ? ?age interaction. Correlations between clinical measures and COP variables that differentiated groups were explored. Compared to non-autistic individuals, autistic adults exhibited greater COP standard deviation (COPSD) and COP trajectory length during static stance and demonstrated significant COPSD-AP reductions in older age. Autistic adults also exhibited decreased COP range of motion (ROM) but increased ROM variability in the target direction during dynamic stance. Autistic adults' postural sway was jerkier during dynamic stance, and increased ROM variability during dynamic AP sway was moderately associated with lower verbal IQ in autistic adults. Our findings highlight persistent postural control deviations in middle aged and older autistic adults. Static and dynamic stance are differentially associated with unique profiles of postural control in ASD. Specifically, autistic adults demonstrated pronounced increases in postural sway variability during static stance, while reducing coordination during dynamic conditions. The extent to which postural control deviations found in autistic adults are predictive to the onset of neurodegenerative conditions and the severity of falls warrants future longitudinal research. En ligne : https://doi.org/10.1002/aur.70024 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=554

Atypical Visually Guided Precision Grip Control in Middle-Aged and Older Autistic Adults / Zheng WANG in Autism Research, 19-2 (February 2026)  

Public ISBD [article]  inAutism Research > 19-2 (February 2026) . - e70154 Titre : Atypical Visually Guided Precision Grip Control in Middle-Aged and Older Autistic Adults Type de document : texte imprimé Auteurs : Zheng WANG, Auteur ; Hang QU, Auteur ; Danielle CHRISTENSEN, Auteur ; Hanna M. GEMMELL, Auteur ; Ellen M. PARKS, Auteur ; Kyla E. WETHERINGTON, Auteur ; Ann-Marie ORLANDO, Auteur ; Regilda A. ROMERO, Auteur ; Bikram KARMAKAR, Auteur ; David E. VAILLANCOURT, Auteur Article en page(s) : e70154 Langues : Anglais (eng) Mots-clés : aging  autism spectrum disorder  fine motor control  middle-aged and older adults  precision grip Index. décimale : PER Périodiques Résumé : ABSTRACT Sensorimotor impairments are well documented in autism spectrum disorder (ASD). However, little is known about how these difficulties present in middle-aged and older autistic adults or how they relate to demographic factors and autistic traits. In this study, 52 autistic and 56 age- and sex-matched non-autistic adults (aged 30?73?years) completed a visually guided precision grip task designed to assess temporal (reaction time, duration), spatial (force accuracy, variability), and dynamic (rate of force change) features of grip control under two conditions: varying motor output demands (target force test) and visual feedback (visual gain test). Autistic adults showed prolonged duration, delayed reaction time, and greater target overshooting at lower force levels during the rise phase. During the sustained phase, they exhibited increased grip force variability across both tasks. In contrast, autistic adults demonstrated shorter reaction times during the relaxation phase. Subgroup analyses revealed that the middle-aged autistic subgroup displayed elevated grip force variability, whereas the older autistic subgroup showed broader impairments affecting both spatial and temporal aspects of precision gripping. Within the autistic group, temporal grip force variables under the low target force condition were significantly associated with age and repetitive behaviors. These findings demonstrate that manual motor impairments persist into adulthood in ASD, and suggest shared neurobiological networks that underlie both motor dysfunction and core autistic traits. En ligne : https://doi.org/10.1002/aur.70154 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=582 [article] Atypical Visually Guided Precision Grip Control in Middle-Aged and Older Autistic Adults [texte imprimé] / Zheng WANG, Auteur ; Hang QU, Auteur ; Danielle CHRISTENSEN, Auteur ; Hanna M. GEMMELL, Auteur ; Ellen M. PARKS, Auteur ; Kyla E. WETHERINGTON, Auteur ; Ann-Marie ORLANDO, Auteur ; Regilda A. ROMERO, Auteur ; Bikram KARMAKAR, Auteur ; David E. VAILLANCOURT, Auteur . - e70154. Langues : Anglais (eng) in Autism Research > 19-2 (February 2026) . - e70154 Mots-clés : aging  autism spectrum disorder  fine motor control  middle-aged and older adults  precision grip Index. décimale : PER Périodiques Résumé : ABSTRACT Sensorimotor impairments are well documented in autism spectrum disorder (ASD). However, little is known about how these difficulties present in middle-aged and older autistic adults or how they relate to demographic factors and autistic traits. In this study, 52 autistic and 56 age- and sex-matched non-autistic adults (aged 30?73?years) completed a visually guided precision grip task designed to assess temporal (reaction time, duration), spatial (force accuracy, variability), and dynamic (rate of force change) features of grip control under two conditions: varying motor output demands (target force test) and visual feedback (visual gain test). Autistic adults showed prolonged duration, delayed reaction time, and greater target overshooting at lower force levels during the rise phase. During the sustained phase, they exhibited increased grip force variability across both tasks. In contrast, autistic adults demonstrated shorter reaction times during the relaxation phase. Subgroup analyses revealed that the middle-aged autistic subgroup displayed elevated grip force variability, whereas the older autistic subgroup showed broader impairments affecting both spatial and temporal aspects of precision gripping. Within the autistic group, temporal grip force variables under the low target force condition were significantly associated with age and repetitive behaviors. These findings demonstrate that manual motor impairments persist into adulthood in ASD, and suggest shared neurobiological networks that underlie both motor dysfunction and core autistic traits. En ligne : https://doi.org/10.1002/aur.70154 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=582

Subcortical brain volume variations in autistic individuals across the lifespan / Danielle CHRISTENSEN in Molecular Autism, 16 (2025)  

Public ISBD [article]  inMolecular Autism > 16 (2025) . - 46 Titre : Subcortical brain volume variations in autistic individuals across the lifespan Type de document : texte imprimé Auteurs : Danielle CHRISTENSEN, Auteur ; Young Seon SHIN, Auteur ; Jingying WANG, Auteur ; Carolina R. CUOMO, Auteur ; Tyler DENTRY, Auteur ; Hanna M. GEMMELL, Auteur ; Stormi L. PULVER, Auteur ; Ann-Marie ORLANDO, Auteur ; Walker S. MCKINNEY, Auteur ; Cassie J. STEVENS, Auteur ; Kathryn E. UNRUH, Auteur ; Bikram KARMAKAR, Auteur ; Stephen A. COOMBES, Auteur ; Matthew W. MOSCONI, Auteur ; Zheng WANG, Auteur ; Danielle CHRISTENSEN, Auteur ; Young Seon SHIN, Auteur ; Jingying WANG, Auteur ; Carolina R. CUOMO, Auteur ; Tyler DENTRY, Auteur ; Hanna M. GEMMELL, Auteur ; Stormi L. PULVER, Auteur ; Ann-Marie ORLANDO, Auteur ; Walker S. MCKINNEY, Auteur ; Cassie J. STEVENS, Auteur ; Kathryn E. UNRUH, Auteur ; Bikram KARMAKAR, Auteur ; Stephen A. COOMBES, Auteur ; Matthew W. MOSCONI, Auteur ; Zheng WANG, Auteur Article en page(s) : 46 Langues : Anglais (eng) Mots-clés : Humans  Adult  Male  Female  Child  Middle Aged  Adolescent  Magnetic Resonance Imaging  Aged  Young Adult  Cross-Sectional Studies  Brain/pathology/diagnostic imaging  Autistic Disorder/pathology/diagnostic imaging  Organ Size  Amygdala/pathology/diagnostic imaging  Longevity  Autism Spectrum Disorder/pathology/diagnostic imaging  Hippocampus/pathology/diagnostic imaging  Basal Ganglia/pathology/diagnostic imaging  Aging  Amygdala  Autism spectrum disorder  Basal ganglia  Brain atrophy  Cerebral ventricles  Hippocampus  Lifespan  MRI  Institutional Review Boards (IRB) at UTSW and Children’s Hospital of Dallas  (STU052013-4  approval date: August 30, 2011), KU Medical Center (STUDY00140269  approval date: March 17, 2017), and UF (IRB201801378  approval date: July 26,  2022). Consent for publication: All participants provided their informed consent  regarding data handling procedures. Competing interests: The authors declare no  competing interests. Index. décimale : PER Périodiques Résumé : BACKGROUND: Structural alterations in subcortical brain regions-including the amygdala, hippocampus, basal ganglia, and cerebral ventricles-have been linked to various clinical features of autism spectrum disorder (ASD). However, volumetric features among these regions in autistic individuals across the lifespan remain poorly understood. This cross-sectional study aimed to investigate age-associated volumetric deviations in these clinically implicated subcortical regions of autistic individuals and neurotypical controls, and to examine the structural interrelationships within each group. METHODS: We examined multi-site T1-weighted MRI data from 119 autistic and 122 neurotypical participants aged 7-73 years. Volumetric data for the amygdala, hippocampus, basal ganglia, and cerebral ventricles were harmonized across sites using the ComBat algorithm. Following this, volumetric composite indices (principal component scores) were extracted for each region using principal component analysis. These scores represent dominant volumetric patterns of each subcortical region, with higher values reflecting greater volume. These composite scores were then compared between groups and with increasing age. RESULTS: Autistic participants exhibited greater amygdala volume in early life, followed by more pronounced age-associated reductions in adulthood compared to neurotypical controls. A similar trend was observed for the hippocampus, with early volumetric enlargement giving way to steeper declines in later years. In contrast, the autistic group consistently trended towards larger basal ganglia across the lifespan. Additionally, autistic participants showed accelerated enlargement in the cerebral ventricles with increasing age. Both groups exhibited patterns of inverse volumetric associations between the cerebral ventricles and surrounding subcortical regions in later adulthood; however, these relationships were more pronounced and widely distributed in the autistic group. LIMITATIONS: The cross-sectional design of this study limited us from capturing intra-individual differences at baseline and quantifying the lifespan trajectories of each participant. Site-related sampling differences may have introduced cohort bias in the results. CONCLUSIONS: Autistic participants and neurotypical controls exhibit distinct, age-related volumetric patterns across key subcortical brain regions. Enlargement of the cerebral ventricles and their inverse structural relationships with neighboring structures in later life may indicate atrophic processes beginning in middle adulthood in ASD. These findings highlight the need to further investigate mechanisms of atypical brain aging in ASD and consider these subcortical brain regions as potential biomarkers of neurodegeneration and intervention targets across the adult lifespan. En ligne : https://dx.doi.org/10.1186/s13229-025-00673-1 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=569 [article] Subcortical brain volume variations in autistic individuals across the lifespan [texte imprimé] / Danielle CHRISTENSEN, Auteur ; Young Seon SHIN, Auteur ; Jingying WANG, Auteur ; Carolina R. CUOMO, Auteur ; Tyler DENTRY, Auteur ; Hanna M. GEMMELL, Auteur ; Stormi L. PULVER, Auteur ; Ann-Marie ORLANDO, Auteur ; Walker S. MCKINNEY, Auteur ; Cassie J. STEVENS, Auteur ; Kathryn E. UNRUH, Auteur ; Bikram KARMAKAR, Auteur ; Stephen A. COOMBES, Auteur ; Matthew W. MOSCONI, Auteur ; Zheng WANG, Auteur ; Danielle CHRISTENSEN, Auteur ; Young Seon SHIN, Auteur ; Jingying WANG, Auteur ; Carolina R. CUOMO, Auteur ; Tyler DENTRY, Auteur ; Hanna M. GEMMELL, Auteur ; Stormi L. PULVER, Auteur ; Ann-Marie ORLANDO, Auteur ; Walker S. MCKINNEY, Auteur ; Cassie J. STEVENS, Auteur ; Kathryn E. UNRUH, Auteur ; Bikram KARMAKAR, Auteur ; Stephen A. COOMBES, Auteur ; Matthew W. MOSCONI, Auteur ; Zheng WANG, Auteur . - 46. Langues : Anglais (eng) in Molecular Autism > 16 (2025) . - 46 Mots-clés : Humans  Adult  Male  Female  Child  Middle Aged  Adolescent  Magnetic Resonance Imaging  Aged  Young Adult  Cross-Sectional Studies  Brain/pathology/diagnostic imaging  Autistic Disorder/pathology/diagnostic imaging  Organ Size  Amygdala/pathology/diagnostic imaging  Longevity  Autism Spectrum Disorder/pathology/diagnostic imaging  Hippocampus/pathology/diagnostic imaging  Basal Ganglia/pathology/diagnostic imaging  Aging  Amygdala  Autism spectrum disorder  Basal ganglia  Brain atrophy  Cerebral ventricles  Hippocampus  Lifespan  MRI  Institutional Review Boards (IRB) at UTSW and Children’s Hospital of Dallas  (STU052013-4  approval date: August 30, 2011), KU Medical Center (STUDY00140269  approval date: March 17, 2017), and UF (IRB201801378  approval date: July 26,  2022). Consent for publication: All participants provided their informed consent  regarding data handling procedures. Competing interests: The authors declare no  competing interests. Index. décimale : PER Périodiques Résumé : BACKGROUND: Structural alterations in subcortical brain regions-including the amygdala, hippocampus, basal ganglia, and cerebral ventricles-have been linked to various clinical features of autism spectrum disorder (ASD). However, volumetric features among these regions in autistic individuals across the lifespan remain poorly understood. This cross-sectional study aimed to investigate age-associated volumetric deviations in these clinically implicated subcortical regions of autistic individuals and neurotypical controls, and to examine the structural interrelationships within each group. METHODS: We examined multi-site T1-weighted MRI data from 119 autistic and 122 neurotypical participants aged 7-73 years. Volumetric data for the amygdala, hippocampus, basal ganglia, and cerebral ventricles were harmonized across sites using the ComBat algorithm. Following this, volumetric composite indices (principal component scores) were extracted for each region using principal component analysis. These scores represent dominant volumetric patterns of each subcortical region, with higher values reflecting greater volume. These composite scores were then compared between groups and with increasing age. RESULTS: Autistic participants exhibited greater amygdala volume in early life, followed by more pronounced age-associated reductions in adulthood compared to neurotypical controls. A similar trend was observed for the hippocampus, with early volumetric enlargement giving way to steeper declines in later years. In contrast, the autistic group consistently trended towards larger basal ganglia across the lifespan. Additionally, autistic participants showed accelerated enlargement in the cerebral ventricles with increasing age. Both groups exhibited patterns of inverse volumetric associations between the cerebral ventricles and surrounding subcortical regions in later adulthood; however, these relationships were more pronounced and widely distributed in the autistic group. LIMITATIONS: The cross-sectional design of this study limited us from capturing intra-individual differences at baseline and quantifying the lifespan trajectories of each participant. Site-related sampling differences may have introduced cohort bias in the results. CONCLUSIONS: Autistic participants and neurotypical controls exhibit distinct, age-related volumetric patterns across key subcortical brain regions. Enlargement of the cerebral ventricles and their inverse structural relationships with neighboring structures in later life may indicate atrophic processes beginning in middle adulthood in ASD. These findings highlight the need to further investigate mechanisms of atypical brain aging in ASD and consider these subcortical brain regions as potential biomarkers of neurodegeneration and intervention targets across the adult lifespan. En ligne : https://dx.doi.org/10.1186/s13229-025-00673-1 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=569

Transcallosal white matter and cortical gray matter variations in autistic adults aged 30-73 years / Danielle CHRISTENSEN ; Jingying WANG ; Desirae J. SHIRLEY ; Ann-Marie ORLANDO ; Regilda A. ROMERO ; David E. VAILLANCOURT ; Bradley J. WILKES ; Stephen A. COOMBES ; Zheng WANG in Molecular Autism, 16 (2025)  

Public ISBD [article]  inMolecular Autism > 16 (2025) . - 16 Titre : Transcallosal white matter and cortical gray matter variations in autistic adults aged 30-73 years Type de document : texte imprimé Auteurs : Danielle CHRISTENSEN, Auteur ; Jingying WANG, Auteur ; Desirae J. SHIRLEY, Auteur ; Ann-Marie ORLANDO, Auteur ; Regilda A. ROMERO, Auteur ; David E. VAILLANCOURT, Auteur ; Bradley J. WILKES, Auteur ; Stephen A. COOMBES, Auteur ; Zheng WANG, Auteur Article en page(s) : 16 Langues : Anglais (eng) Mots-clés : Humans  Male  Gray Matter/diagnostic imaging/pathology  White Matter/diagnostic imaging/pathology  Female  Adult  Middle Aged  Aged  Case-Control Studies  Autistic Disorder/diagnostic imaging/pathology  Corpus Callosum/diagnostic imaging/pathology  Autism Spectrum Disorder/diagnostic imaging/pathology  Anisotropy  Diffusion Magnetic Resonance Imaging  Aging  Autism spectrum disorder  Autistic adults  Diffusion MRI  Free water  Free water corrected fractional anisotropy  Free water corrected mean diffusivity  Gray matter  Transcallosal tracts  White matter  in this study were approved by the Institutional Review Board (IRB) at the  University of Florida following the Declaration of Helsinki. The IRB number is  202100659, with an approval date of July 26, 2022. Consent for publication: All  authors have read and approved the submission. Competing interests: The authors  declare no competing interests. Index. décimale : PER Périodiques Résumé : BACKGROUND: Autism spectrum disorder (ASD) is a lifelong condition that profoundly impacts health, independence, and quality of life. However, research on brain aging in autistic adults is limited, and microstructural variations in white and gray matter remain poorly understood. To address this critical gap, we assessed novel diffusion MRI (dMRI) biomarkers, free water, and free water corrected fractional anisotropy (fwcFA), and mean diffusivity (fwcMD) across 32 transcallosal tracts and their corresponding homotopic grey matter origin/endpoint regions of interest (ROIs) in middle and old aged autistic adults. METHODS: Forty-three autistic adults aged 30-73 and 43 age-, sex-, and IQ-matched neurotypical controls underwent dMRI scans. We examined free water, fwcFA, fwcMD differences between the two groups and age-related pattern of each dMRI metric across the whole brain for each group. The relationships between clinical measures of ASD and free water in regions that significantly differentiated autistic adults from neurotypical controls were also explored. In supplementary analyses, we also assessed free water uncorrected FA and MD using conventional single tensor modeling. RESULTS: Autistic adults exhibited significantly elevated free water in seven frontal transcallosal tracts compared to controls. In controls, age-related increases in free water and decreases in fwcFA were observed across most transcallosal tracts. However, these age-associated patterns were entirely absent in autistic adults. In gray matter, autistic adults showed elevated free water in the calcarine cortices and lower fwcMD in the dorsal premotor cortices compared to controls. Lastly, age-related increases in free water were found across all white matter and gray matter ROIs in neurotypical controls, whereas no age-related associations were detected in any dMRI metrics for autistic adults. LIMITATIONS: We only recruited cognitively capable autistic adults, which limits the generalizability of our findings across the full autism spectrum. The cross-sectional design precludes inferences about microstructural changes over time in middle and old aged autistic adults. CONCLUSIONS: Our findings revealed increased free water load in frontal white matter in autistic adults and identified distinct age-associated microstructural variations between the two groups. These findings highlight more heterogeneous brain aging profiles in autistic adults. Our study also demonstrated the importance of quantifying free water in dMRI studies of ASD. En ligne : https://dx.doi.org/10.1186/s13229-025-00652-6 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=555 [article] Transcallosal white matter and cortical gray matter variations in autistic adults aged 30-73 years [texte imprimé] / Danielle CHRISTENSEN, Auteur ; Jingying WANG, Auteur ; Desirae J. SHIRLEY, Auteur ; Ann-Marie ORLANDO, Auteur ; Regilda A. ROMERO, Auteur ; David E. VAILLANCOURT, Auteur ; Bradley J. WILKES, Auteur ; Stephen A. COOMBES, Auteur ; Zheng WANG, Auteur . - 16. Langues : Anglais (eng) in Molecular Autism > 16 (2025) . - 16 Mots-clés : Humans  Male  Gray Matter/diagnostic imaging/pathology  White Matter/diagnostic imaging/pathology  Female  Adult  Middle Aged  Aged  Case-Control Studies  Autistic Disorder/diagnostic imaging/pathology  Corpus Callosum/diagnostic imaging/pathology  Autism Spectrum Disorder/diagnostic imaging/pathology  Anisotropy  Diffusion Magnetic Resonance Imaging  Aging  Autism spectrum disorder  Autistic adults  Diffusion MRI  Free water  Free water corrected fractional anisotropy  Free water corrected mean diffusivity  Gray matter  Transcallosal tracts  White matter  in this study were approved by the Institutional Review Board (IRB) at the  University of Florida following the Declaration of Helsinki. The IRB number is  202100659, with an approval date of July 26, 2022. Consent for publication: All  authors have read and approved the submission. Competing interests: The authors  declare no competing interests. Index. décimale : PER Périodiques Résumé : BACKGROUND: Autism spectrum disorder (ASD) is a lifelong condition that profoundly impacts health, independence, and quality of life. However, research on brain aging in autistic adults is limited, and microstructural variations in white and gray matter remain poorly understood. To address this critical gap, we assessed novel diffusion MRI (dMRI) biomarkers, free water, and free water corrected fractional anisotropy (fwcFA), and mean diffusivity (fwcMD) across 32 transcallosal tracts and their corresponding homotopic grey matter origin/endpoint regions of interest (ROIs) in middle and old aged autistic adults. METHODS: Forty-three autistic adults aged 30-73 and 43 age-, sex-, and IQ-matched neurotypical controls underwent dMRI scans. We examined free water, fwcFA, fwcMD differences between the two groups and age-related pattern of each dMRI metric across the whole brain for each group. The relationships between clinical measures of ASD and free water in regions that significantly differentiated autistic adults from neurotypical controls were also explored. In supplementary analyses, we also assessed free water uncorrected FA and MD using conventional single tensor modeling. RESULTS: Autistic adults exhibited significantly elevated free water in seven frontal transcallosal tracts compared to controls. In controls, age-related increases in free water and decreases in fwcFA were observed across most transcallosal tracts. However, these age-associated patterns were entirely absent in autistic adults. In gray matter, autistic adults showed elevated free water in the calcarine cortices and lower fwcMD in the dorsal premotor cortices compared to controls. Lastly, age-related increases in free water were found across all white matter and gray matter ROIs in neurotypical controls, whereas no age-related associations were detected in any dMRI metrics for autistic adults. LIMITATIONS: We only recruited cognitively capable autistic adults, which limits the generalizability of our findings across the full autism spectrum. The cross-sectional design precludes inferences about microstructural changes over time in middle and old aged autistic adults. CONCLUSIONS: Our findings revealed increased free water load in frontal white matter in autistic adults and identified distinct age-associated microstructural variations between the two groups. These findings highlight more heterogeneous brain aging profiles in autistic adults. Our study also demonstrated the importance of quantifying free water in dMRI studies of ASD. En ligne : https://dx.doi.org/10.1186/s13229-025-00652-6 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=555

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