Biomedical subjects

Jonathan D Blumenthal

Publications and source records attributed to Jonathan D Blumenthal.

6 recordsLinked to original sources

PubMed2007

A multivariate analysis of neuroanatomic relationships in a genetically informative pediatric sample.

An important component of brain mapping is an understanding of the relationships between neuroanatomic structures, as well as the nature of shared causal factors. Prior twin studies have demonstrated that much of individual differences in human anatomy are caused by genetic differences, but information is limited on whether different structures share common genetic factors. We performed a multivariate statistical genetic analysis on volumetric MRI measures (cerebrum, cerebellum, lateral ventricles, corpus callosum, thalamus, and basal ganglia) from a pediatric sample of 326 twins and 158 singletons. Our results suggest that the great majority of variability in cerebrum, cerebellum, thalamus and basal ganglia is determined by a single genetic factor. Though most (75%) of the variability in corpus callosum was explained by additive genetic effects these were largely independent of other structures. We also observed relatively small but significant environmental effects common to multiple neuroanatomic regions, particularly between thalamus, basal ganglia, and lateral ventricles. These findings are concordant with prior volumetric twin studies and support radial models of brain evolution.

Adolescent↗

PubMed2007

XXY (Klinefelter syndrome): a pediatric quantitative brain magnetic resonance imaging case-control study.

OBJECTIVE: An extra X chromosome in males (XXY), known as Klinefelter syndrome, is associated with characteristic physical, cognitive, and behavioral features of variable severity. The objective of this study was to examine possible neuroanatomical substrates of these cognitive and behavioral features during childhood and adolescence. METHODS: MRI brain scans were acquired for 42 XXY and 87 healthy XY age-matched control males. We compared these 2 groups on regional brain volumes and cortical thickness. RESULTS: Total cerebral volume and all lobar volumes except parietal white matter were significantly smaller in the XXY group, whereas lateral-ventricle volume was larger. Consistent with the cognitive profile, the cortex was significantly thinner in the XXY group in left inferior frontal, temporal, and superior motor regions. CONCLUSION: The brain-imaging findings of preferentially affected frontal, temporal, and motor regions and relative sparing of parietal regions are consistent with observed cognitive and behavioral strengths and weaknesses in XXY subjects.

Adolescent↗

PubMed2006

Puberty-related influences on brain development.

Puberty is a time of striking changes in cognition and behavior. To indirectly assess the effects of puberty-related influences on the underlying neuroanatomy of these behavioral changes we will review and synthesize neuroimaging data from typically developing children and adolescents and from those with anomalous hormone or sex chromosome profiles. The trajectories (size by age) of brain morphometry differ between boys and girls, with girls generally reaching peak gray matter thickness 1-2 years earlier than boys. Both boys and girls with congenital adrenal hyperplasia (characterized by high levels of intrauterine testosterone), have smaller amygdala volume but the brain morphometry of girls with CAH did not otherwise significantly differ from controls. Subjects with XXY have gray matter reductions in the insula, temporal gyri, amygdala, hippocampus, and cingulate-areas consistent with the language-based learning difficulties common in this group.

Adolescent↗

PubMed2004

Depression and anxiety in parents of children with ADHD and varying levels of oppositional defiant behaviors: modeling relationships with family functioning.

This study investigated the relation between parental anxiety and family functioning. Parental anxiety and depression, child attention deficit hyperactivity disorder (ADHD), and oppositional defiant disorder (ODD) symptoms were all included as predictors of 3 measures of family functioning to examine the independent contributions of each. Using a self-report battery completed by 45 mother-father pairs, 3 family functioning factors were derived: Parental Warmth and Positive Involvement, Intrusiveness and Negative Discipline, and Social Distress. Multilevel modeling simultaneously estimated the unique contributions of parental and child symptoms on family functioning. Results indicated that parental anxiety was negatively associated with Parental Warmth and Positive Involvement, Intrusiveness and Negative Discipline, and Social Distress; parental depression was only negatively associated with Social Distress. Child ODD symptoms had independent associations with all outcomes; no relations were found with ADHD. Sex moderated the effects of parental anxiety on Parental Warmth and Positive Involvement such that only for mothers did greater anxiety lead to less Parental Warmth and Positive Involvement.

Adult↗

PubMed2002

Developmental trajectories of brain volume abnormalities in children and adolescents with attention-deficit/hyperactivity disorder.

CONTEXT: Various anatomic brain abnormalities have been reported for attention-deficit/hyperactivity disorder (ADHD), with varying methods, small samples, cross-sectional designs, and without accounting for stimulant drug exposure. OBJECTIVE: To compare regional brain volumes at initial scan and their change over time in medicated and previously unmedicated male and female patients with ADHD and healthy controls. DESIGN, SETTING, AND PARTICIPANTS: Case-control study conducted from 1991-2001 at the National Institute of Mental Health, Bethesda, Md, of 152 children and adolescents with ADHD (age range, 5-18 years) and 139 age- and sex-matched controls (age range, 4.5-19 years) recruited from the local community, who contributed 544 anatomic magnetic resonance images. MAIN OUTCOME MEASURES: Using completely automated methods, initial volumes and prospective age-related changes of total cerebrum, cerebellum, gray and white matter for the 4 major lobes, and caudate nucleus of the brain were compared in patients and controls. RESULTS: On initial scan, patients with ADHD had significantly smaller brain volumes in all regions, even after adjustment for significant covariates. This global difference was reflected in smaller total cerebral volumes (-3.2%, adjusted F(1,280) = 8.30, P =.004) and in significantly smaller cerebellar volumes (-3.5%, adjusted F(1,280) = 12.29, P =.001). Compared with controls, previously unmedicated children with ADHD demonstrated significantly smaller total cerebral volumes (overall F(2,288) = 6.65; all pairwise comparisons Bonferroni corrected, -5.8%; P =.002) and cerebellar volumes (-6.2%, F( 2,288) = 8.97, P<.001). Unmedicated children with ADHD also exhibited strikingly smaller total white matter volumes (F(2,288) = 11.65) compared with controls (-10.7%, P<.001) and with medicated children with ADHD (-8.9%, P<.001). Volumetric abnormalities persisted with age in total and regional cerebral measures (P =.002) and in the cerebellum (P =.003). Caudate nucleus volumes were initially abnormal for patients with ADHD (P =.05), but diagnostic differences disappeared as caudate volumes decreased for patients and controls during adolescence. Results were comparable for male and female patients on all measures. Frontal and temporal gray matter, caudate, and cerebellar volumes correlated significantly with parent- and clinician-rated severity measures within the ADHD sample (Pearson coefficients between -0.16 and -0.26; all P values were <.05). CONCLUSIONS: Developmental trajectories for all structures, except caudate, remain roughly parallel for patients and controls during childhood and adolescence, suggesting that genetic and/or early environmental influences on brain development in ADHD are fixed, nonprogressive, and unrelated to stimulant treatment.

Adolescent↗

PubMed2002

Motion artifact in magnetic resonance imaging: implications for automated analysis.

Automated measures of cerebral magnetic resonance images (MRI) often provide greater speed and reliability compared to manual techniques but can be particularly sensitive to motion artifact. This study employed an automatic MRI analysis program that quantified regional gray matter volume and created images for verification and quality control. Motion artifact was assessed on each image and assigned a rating of none, mild, moderate, or severe. Greater motion artifact was associated with smaller gray matter volumes. Severity of motion artifact is an important, but often overlooked, consideration in the interpretation of automated MRI measures.

Adolescent↗