1. Berman JI, Liu S, Bloy L, Blaskey L, Roberts TP, Edgar JC. {{Alpha-to-Gamma Phase-Amplitude Coupling Methods and Application to Autism Spectrum Disorder}}. {Brain Connect};2014 (Sep 22)
Abstract Adult studies have shown that a basic property of resting-state (RS) brain activity is the coupling of posterior alpha oscillations (alpha phase) to posterior gamma oscillations (gamma amplitude). The present study examined whether this basic RS process is present in children. Given reports of abnormal parietal-occipital RS alpha in children with autism spectrum disorder (ASD), the present study examined whether RS alpha-to-gamma phase-amplitude coupling (PAC) is disrupted in ASD. Simulations presented in this study showed limitations with traditional PAC analyses. In particular, to avoid false-positive PAC findings, simulations showed the need to use a unilateral passband to filter the upper frequency band as well as the need for longer epochs of data. For the human study, eyes-closed RS magnetoencephalography data were analyzed from 25 children with ASD and 18 typically developing (TD) children with at least 60 sec of artifact-free data. Source modeling provided continuous time course data at a midline parietal-occipital source for PAC analyses. Greater alpha-to-gamma PAC was observed in ASD than TD (p<0.005). Although children with ASD had higher PAC values, in both groups gamma activity increased at the peak of the alpha oscillation. In addition, an association between alpha power and alpha-to-gamma PAC was observed in both groups, although this relationship was stronger in ASD than TD (p<0.05). Present results demonstrated that although alpha-to-gamma PAC is present in children, this basic RS process is abnormal in children with ASD. Finally, simulations and the human data highlighted the need to consider the interplay between alpha power, epoch length, and choice of signal processing methods on PAC estimates.
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2. DePape AM, Lindsay S. {{Parents’ Experiences of Caring for a Child With Autism Spectrum Disorder}}. {Qual Health Res};2014 (Sep 22)
Autism spectrum disorder (ASD) is a developmental disorder involving abnormal communication, repetitive and restrictive interests, and impaired social functioning. ASD can have a profound impact on family life, including the roles and responsibilities that parents assume. In this metasynthesis, we explore the experiences of parents who care for a child with ASD. We undertook a thematic synthesis to integrate qualitative evidence, searching 10 electronic databases and reviewing 4,148 abstracts. We selected 31 articles for inclusion (involving 160 fathers and 425 mothers) and examined the articles using a constant comparative approach. We identified six themes: prediagnosis, diagnosis, family life adjustment, navigating the system, parental empowerment, and moving forward. Our findings can inform the development of programs and services for families, provide insight for health care workers who advocate on behalf of parents, and provide valuable information to parents, particularly those of children newly diagnosed with ASD.
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3. Schmidt RJ, Tancredi DJ, Krakowiak P, Hansen RL, Ozonoff S. {{Maternal Intake of Supplemental Iron and Risk of Autism Spectrum Disorder}}. {Am J Epidemiol};2014 (Sep 22)
Iron deficiency affects 40%-50% of pregnancies. Iron is critical for early neurodevelopmental processes that are dysregulated in autism spectrum disorder (ASD). We examined maternal iron intake in relation to ASD risk in California-born children enrolled in a population-based case-control study (the Childhood Autism Risks from Genetics and the Environment (CHARGE) Study) from 2003 to 2009 with a diagnosis of ASD (n = 520) or typical development (n = 346) that was clinically confirmed using standardized assessments. Mean maternal daily iron intake was quantified on the basis of frequency, dose, and brands of supplements and cereals consumed each month from 3 months before pregnancy through the end of pregnancy and during breastfeeding (the index period), as reported in parental interviews. Mothers of cases were less likely to report taking iron-specific supplements during the index period (adjusted odds ratio = 0.63, 95% confidence interval: 0.44, 0.91), and they had a lower mean daily iron intake (51.7 (standard deviation, 34.0) mg/day) than mothers of controls (57.1 (standard deviation, 36.6) mg/day; P = 0.03). The highest quintile of iron intake during the index period was associated with reduced ASD risk compared with the lowest (adjusted odds ratio = 0.49, 95% confidence interval: 0.29, 0.82), especially during breastfeeding. Low iron intake significantly interacted with advanced maternal age and metabolic conditions; combined exposures were associated with a 5-fold increased ASD risk. Further studies of this link between maternal supplemental iron and ASD are needed to inform ASD prevention strategies.
