[Show abstract][Hide abstract] ABSTRACT: Manganese is an essential element for human health and development. Previous studies have shown neurotoxic effects in children exposed to higher levels of manganese. Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder that impairs social interaction and communication. Several studies have hypothesized that ASD is caused through environmental exposures during crucial stages in brain development. We investigated the possible association between blood manganese concentrations (BMC) and ASD. We also identified factors associated with BMC in typically developing (TD) Jamaican children.
Environmental health : a global access science source. 08/2014; 13(1):69.
[Show abstract][Hide abstract] ABSTRACT: Background:
Clinicians, educators, and researchers have many alternative psychometric measures available to them tapping symptoms of ADHD. With the advent of DSM-5, a diagnosis of ADHD is no longer precluded in a child with ASD—and thus the need for assessment of ADHD in this population will likely rise. Although many commercially available instruments have excellent psychometric characteristics and provide information regarding comorbid conditions (e.g., anxiety), there are circumstances when these instruments are either unavailable (e.g., a parent seeking preliminary information) or when the cost of commercial instruments is prohibitive (e.g., in a rural school district with minimal psychological assessment funding). In these circumstances, a no-cost web-based screen for ADHD would be a helpful first step in determining which children with ASD might warrant a comprehensive follow-up evaluation. What is unknown is how strongly related internet-based and commercial measures of ADHD symptoms are in children with ASD.
The purpose of this study was to compare parent and teacher ratings of ADHD symptoms (e.g., inattention, hyperactivity) on the SNAP-IV [available at www.adhd.net] to parent and teacher ratings of ADHD symptoms on widely used commercial measures of ADHD symptoms.
Participants were 77 children (63 boys; mean age=9.3 yrs; mean IQ=86) who met DSM-IV criteria for autism on the ADI-R and the ADOS. Parent ratings on 12 subscales tapping ADHD symptoms on the Conners Parent Rating Scale-Revised (CPRS-R), Child Behavior Checklist (CBCL), Aberrant Behavior Checklist (ABC) and ADD-H Comprehensive Teacher's Rating Scale (ACTeRS) were compared to parent ratings on 2 subscales on the SNAP-IV tapping ADHD symptoms, using correlational methods. Similar comparisons were performed for corresponding teacher ratings.
Significant correlations (all p<.01, range: r=.30 to r=82; average r=.60) were obtained between the parent ratings of ADHD symptoms on the SNAP-IV with parent ratings of ADHD on the CPRS-R, CBCL, ABC, and ACTeRS. A similar pattern was seen for teacher ratings (all p<.01, range: r=.27 to r=.86; average r=.61).
These findings indicate that the parent and teacher ADHD ratings on this web-based measure of ADHD are highly correlated with commercial measures of ADHD in school-age children with ASD. Thus, the SNAP-IV, a web-based measure of ADHD symptomatology, would appear to have a helpful role in screening for a comprehensive assessment providing information regarding clinical severity of ADHD symptoms and its commonly comorbid concerns in school-age children with ASD.
2014 International Meeting for Autism Research; 05/2014
[Show abstract][Hide abstract] ABSTRACT: Some have suggested that parents of children with autism spectrum disorder (ASD) may present with less recognizable autistic-like phenotypic characteristics, leading them to highly systemizing occupations. Using secondary analysis of data from two previous studies of children with ASD, we tested associations between parental occupations and ASD diagnosis and the association of parental occupational characteristics on ASD severity. We found that fathers in healthcare (P < 0.01) and finance (P = 0.03) were more likely to have children with ASD. Additionally, joint effects of parental technical occupations were associated with communication (P < 0.01) and social impairment (P = 0.04). These results support that a “broader phenotype” and possible assortative mating in adults with autistic-like characteristics might contribute to intergenerational transmission and having offspring with greater ASD severity.
Research in Autism Spectrum Disorders 05/2014; 8(9):997–1007. · 2.96 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objectives Studies have suggested a link between diet and behavior in children with autism spectrum disorders (ASDs). Parental reports of behavioral changes upon exposure to gluten and/or casein are common in clinical practice. An association between diet type, intestinal permeability (IP) ('leaky gut'), and behavior has been long proposed but not substantiated. We explored this possible association in this trial. Methods This randomized double-blind, placebo-controlled study explored the effects of gluten and milk on IP and behavior in children with ASDs over a period of 4 weeks. IP assessed by lactulose:mannitol (L/M) sugar permeability test and behavior assessed by the Aberrant Behavior Checklist and Conners Parent Rating were measured. Gastrointestinal symptoms in both groups were also monitored. Results Neither the L/M ratio nor behavioral scores were different between groups exposed to gluten/dairy or placebo. The changes observed were noted to be small and not clinically significant. Discussion Our study although underpowered to show small differences does not support an association between dietary gluten/milk, IP, and behavioral changes in subjects with ASD.
[Show abstract][Hide abstract] ABSTRACT: Restricted interests and repetitive behaviors vary widely in type, frequency, and intensity among children and adolescents with autism spectrum disorder. They can be stigmatizing and interfere with more constructive activities. Accordingly, restricted interests and repetitive behaviors may be a target of intervention. Several standardized instruments have been developed to assess restricted interests and repetitive behaviors in the autism spectrum disorder population, but the rigor of psychometric assessment is variable. This article evaluated the readiness of available measures for use as outcome measures in clinical trials. The Autism Speaks Foundation assembled a panel of experts to examine available instruments used to measure restricted interests and repetitive behaviors in youth with autism spectrum disorder. The panel held monthly conference calls and two face-to-face meetings over 14 months to develop and apply evaluative criteria for available instruments. Twenty-four instruments were evaluated and five were considered "appropriate with conditions" for use as outcome measures in clinical trials. Ideally, primary outcome measures should be relevant to the clinical target, be reliable and valid, and cover the symptom domain without being burdensome to subjects. The goal of the report was to promote consensus across funding agencies, pharmaceutical companies, and clinical investigators about advantages and disadvantages of existing outcome measures.
[Show abstract][Hide abstract] ABSTRACT: Despite the high rate of anxiety in individuals with autism spectrum disorder (ASD), measuring anxiety in ASD is fraught with uncertainty. This is due, in part, to incomplete consensus on the manifestations of anxiety in this population. Autism Speaks assembled a panel of experts to conduct a systematic review of available measures for anxiety in youth with ASD. To complete the review, the panel held monthly conference calls and two face-to-face meetings over a fourteen-month period. Thirty eight published studies were reviewed and ten assessment measures were examined: four were deemed appropriate for use in clinical trials, although with conditions; three were judged to be potentially appropriate, while three were considered not useful for clinical trials assessing anxiety. Despite recent advances, additional relevant, reliable and valid outcome measures are needed to evaluate treatments for anxiety in ASD.
Journal of Autism and Developmental Disorders 10/2013; · 3.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract Objective: The purpose of this study was to examine the behavioral effects of four doses of psychostimulant medication, combining extended-release methylphenidate (MPH) in the morning with immediate-release MPH in the afternoon. Method: The sample comprised 24 children (19 boys; 5 girls) who met American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV-TR) criteria for an autism spectrum disorder (ASD) on the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS), and had significant symptoms of attention-deficit/hyperactivity disorder (ADHD). This sample consisted of elementary school-age, community-based children (mean chronological age=8.8 years, SD=1.7; mean intelligence quotient [IQ]=85; SD=16.8). Effects of four dose levels of MPH on parent and teacher behavioral ratings were investigated using a within-subject, crossover, placebo-controlled design. Results: MPH treatment was associated with significant declines in hyperactive and impulsive behavior at both home and school. Parents noted significant declines in inattentive and oppositional behavior, and improvements in social skills. No exacerbation of stereotypies was noted, and side effects were similar to those seen in typically developing children with ADHD. Dose response was primarily linear in the dose range studied. Conclusions: The results of this study suggest that MPH formulations are efficacious and well-tolerated for children with ASD and significant ADHD symptoms.
Journal of child and adolescent psychopharmacology 06/2013; 23(5):337-51. · 2.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Parent and teacher ratings of core attention-deficit/hyperactivity disorder (ADHD) symptoms, as well as behavioral and emotional problems commonly comorbid with ADHD, were compared in children with autism spectrum disorders (ASD).
Participants were 86 children (66 boys; mean: age=9.3 years, intelligence quotient [IQ]=84) who met American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) criteria for an ASD on the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS). Parent and teacher behavioral ratings were compared on the Conners' Parent and Teacher Rating Scales (CPRS-R; CTRS-R). The degree to which age, ASD subtype, severity of autistic symptomatology, and medication status mediated this relationship was also examined.
Significant positive correlations between parent and teacher ratings suggest that a child's core ADHD symptoms-as well as closely related externalizing symptoms-are perceived similarly by parents and teachers. With the exception of oppositional behavior, there was no significant effect of age, gender, ASD subtype, or autism severity on the relationship between parent and teacher ratings. In general, parents rated children as having more severe symptomatology than did teachers. Patterns of parent and teacher ratings were highly correlated, both for children who were receiving medication, and for children who were not.
Parents and teachers perceived core symptoms of ADHD and closely-related externalizing problems in a similar manner, but there is less agreement on ratings of internalizing problems (e.g., anxiety). The clinical implication of these findings is that both parents and teachers provide important behavioral information about children with ASD. However, when a clinician is unable to access teacher ratings (e.g., during school vacations), parent ratings can provide a reasonable estimate of the child's functioning in these domains in school. As such, parent ratings can be reliably used to make initial diagnostic and treatment decisions (e.g., medication treatment) regarding ADHD symptoms in children with ASDs.
Journal of child and adolescent psychopharmacology 07/2012; 22(4):284-91. · 2.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Arsenic is a toxic metal with harmful effects on human health, particularly on cognitive function. Autism Spectrum Disorders (ASDs) are lifelong neurodevelopmental and behavioral disorders manifesting in infancy or early childhood. We used data from 130 children between 2 and 8 years (65 pairs of ASD cases with age- and sex-matched control), to compare the mean total blood arsenic concentrations in children with and without ASDs in Kingston, Jamaica. Based on univariable analysis, we observed a significant difference between ASD cases and controls (4.03 μg/L for cases vs. 4.48 μg/L for controls, P<0.01). In the final multivariable General Linear Model (GLM), after controlling for car ownership, maternal age, parental education levels, source of drinking water, consumption of "yam, sweet potato, or dasheen", "carrot or pumpkin", "callaloo, broccoli, or pak choi", cabbage, avocado, and the frequency of seafood consumption per week, we did not find a significant association between blood arsenic concentrations and ASD status (4.36 μg/L for cases vs. 4.65 μg/L for controls, P=0.23). Likewise, in a separate final multivariable GLM, we found that source of drinking water, eating avocado, and eating "callaloo, broccoli, or pak choi" was significantly associated with higher blood arsenic concentrations (all three P<0.05). Based on our findings, we recommend assessment of arsenic levels in water, fruits, and vegetables, as well as increased awareness among the Jamaican population regarding potential risks for various exposures to arsenic.
Science of The Total Environment 07/2012; 433:362-70. · 3.16 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
Although many children with ASD are treated with psychostimulant medication (Aman et al., 2005), few controlled studies have explored the cognitive effects of stimulants in these children. While early small studies yielded inconsistent indications for MPH treatment in this group, the larger scale RUPP study of MPH treatment in children with PDDs found evidence of significant improvements in hyperactive and inattentive behaviors with methylphenidate (MPH) treatment (Posey et al., 2007; RUPP Autism Network, 2005). This study builds upon the RUPP findings [which used TID dosing of immediate release (IR) MPH] by using a treatment regimen that more closely mirrors current clinical practice: extended release (ER) MPH in the morning, and IR MPH in the afternoon.
The primary objectives of this study were to examine the effectiveness of extended release methylphenidate (MPH) on cognitive functioning in children with ASD and significant symptoms of ADHD, and to determine if higher doses of MPH were associated with progressive behavioral improvement—or if initial improvement was followed by lesser improvements (or even declines) at higher doses.
The cognitive effects of four doses of MPH were investigated using a within-subject, crossover, placebo-controlled design in 24 children (mean: CA=8.8 yrs, FSIQ=85) who met DSM-IV-TR criteria for ASD on the ADI-R and on the ADOS. Dosing strategy was based on the experience from the MTA Study,as well as the RUPP MPH trial. Cognitive measures (tapping sustained attention, selective attention, and inhibition/impulsivity) were obtained at each MPH dose.
Performance on cognitive tasks tapping sustained attention, selective attention, and inhibition/impulsivity improved significantly with MPH treatment. These improvements were generally linear in nature—i.e., higher doses of MPH were usually associated with improvements in task performance. There was only one dependent variable (SST Stop Signal Accuracy), for which the dose-response function had both significant linear and significant non-linear components of trend.
Psychostimulant treatment using ER MPH in children with ASD and significant symptoms of ADHD is associated with significant improvement in cognitive task performance—and higher MPH doses were associated with successive improvements in the dose range studied. These cognitive task data are consistent with the parent and teacher behavioral ratings obtained in the same trial (Pearson et al., 2010). However this does not necessarily mean that the same doses were optimal for both behavior and cognition, as we (Pearson et al., 2004) have previously shown that changes in behavior and cognition often occur rather independently in the same children. Combined with our previously reported findings, it appears that ER MPH treatment is associated, on average, with both cognitive and behavioral improvements in children with ASD and significant symptoms of ADHD.
2012 International Meeting for Autism Research; 05/2012
[Show abstract][Hide abstract] ABSTRACT: Mercury is a toxic metal shown to have harmful effects on human health. Several studies have reported high blood mercury concentrations as a risk factor for autism spectrum disorders (ASDs), while other studies have reported no such association. The goal of this study was to investigate the association between blood mercury concentrations in children and ASDs. Moreover, we investigated the role of seafood consumption in relation to blood mercury concentrations in Jamaican children. Based on data for 65 sex- and age-matched pairs (2-8 years), we used a General Linear Model to test whether there is an association between blood mercury concentrations and ASDs. After controlling for the child's frequency of seafood consumption, maternal age, and parental education, we did not find a significant difference (P = 0.61) between blood mercury concentrations and ASDs. However, in both cases and control groups, children who ate certain types of seafood (i.e., salt water fish, sardine, or mackerel fish) had significantly higher (all P < 0.05) geometric means blood mercury concentration which were about 3.5 times that of children living in the US or Canada. Our findings also indicate that Jamaican children with parents who both had education up to high school are at a higher risk of exposure to mercury compared to children with at least one parent who had education beyond high school. Based on our findings, we recommend additional education to Jamaican parents regarding potential hazards of elevated blood mercury concentrations, and its association with seafood consumption and type of seafood.
Neurotoxicity Research 04/2012; · 2.87 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Several studies have reported maternal and paternal age as risk factors for having a child with Autism Spectrum Disorder (ASD), yet the results remain inconsistent. We used data for 68 age- and sex-matched case-control pairs collected from Jamaica. Using Multivariate General Linear Models (MGLM) and controlling for parity, gestational age, and parental education, we found a significant (p < 0.0001) joint effect of parental ages on having children with ASD indicating an adjusted mean paternal age difference between cases and controls of [5.9 years; 95% CI (2.6, 9.1)] and a difference for maternal age of [6.5 years; 95% CI (4.0, 8.9)]. To avoid multicollinearity in logistic regression, we recommend joint modeling of parental ages as a vector of outcome variables using MGLM.
Journal of Autism and Developmental Disorders 01/2012; 42(9):1928-38. · 3.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
Putative structural and physiological differences in autistic versus typical brains must eventually manifest at the level of neural circuitry. Therefore, probing for differences in connectivity is a natural starting point for determining the neural phenotype. In this regard, proposals of local over-connectivity and long-range under-connectivity in the autistic brain are attractive candidates. Autism is a developmental disorder; therefore, abnormalities in the circuitry of autistic brains are likely to be pervasive and include regions involved in sensory processing. One such region is the somatosensory cortex. Afferents from adjacent fingers project via segregated neuronal clusters in the sub-cortical pathway and reach cortex, where the first neural interaction between them occurs. The cortical region to which the thalamic afferents corresponding to a given finger project is its hot spot, and the early part of its response to the stimulation of an adjacent finger assays the strength of local excitatory intracortical connectivity.
Local overconnectivity predicts that the tactile stimulation of a finger would yield a stronger response in the cortical hot spot corresponding to its adjacent finger in autism versus control. We tested this prediction with magnetoencephalography (MEG).
(i) We recorded neural responses to the passive tactile stimulation of the thumb (D1) and index finger (D2) of the dominant hand of young adult participants (13 high-functioning persons with autism spectrum disorder or ASDs and 17 typically developing persons or TDs, matched for gender and age) while they remained awake in an eyes-closed supine posture in a 248-sensor MEG scanner.
(ii) For each participant, we computed the evoked response in source space using a mathematical tool called singular value decomposition (SVD). This method creates a virtual sensor that approximates the response of the cortical hot spot corresponding to a particular finger. In this manner, two hot spots, one each for D1 and D2, were obtained.
(iii) Somatosensory evoked potentials (SEPs) in the hot spot to the tactile stimulations of D1 and D2 were computed. For M50 (short-latency SEP, mediated mainly by feedforward sub-cortical pathways) and M100 (mid-latency SEP, mediated by cortical feedback) SEP components separately, responses of the neighboring/primary hot spots were measured and optimal least-squares slopes computed. The slopes of the two groups were then compared.
M50: No between-group differences were found in the ratios of D2/D1 hot spot responses to D1 stimulation or D1/D2 hot spot responses to D2 stimulation.
M100: There were clear between-group differences. D1 stimulation: The slope of the D2 hot spot’s response to the D1 hot spot’s response to D1 stimulation was significantly smaller in the ASD group compared with the TD group (P=0.003). D2 hot spot: The results were similar. The slope of the D1 to the D2 hot spots’ responses to D2 stimulation was again, significantly smaller in the ASD group (P=0.015).
The findings indicate a weaker degree of local cortical interaction in the somatosensory cortex of the person with autism compared to the person without. Local underconnectivity in the autistic brain is consistent with our results.
International Meeting for Autism Research 2011; 05/2011