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Colour perception in ADHD.
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Banaschewski T, Ruppert S, Tannock R, Albrecht B, Becker A, Uebel H, Sergeant JA, Rothenberger A
Attention-deficit/hyperactivity disorder (ADHD) is associated with unexplained impairments on speeded naming of coloured stimuli. These deficits may reflect hypofunctioning retinal dopaminergic mechanisms impairing particularly blue-yellow colour discrimination. Colour perception and rapid colour naming ability were investigated in 14 children with ADHD and 13 healthy peers matched for age, gender, and IQ, using the Farnsworth-Munsell 100 Hue Test (FMT) and the Stroop-Colour-Word test. Children with ADHD committed more errors on the FMT, particularly on discrimination of colours along the blue-yellow axis, and were slower on Stroop subtests involving colour naming. However, the latter deficit was accounted for similarly by blue-yellow and red-green discrimination abilities. Blue-yellow colour perception problems in ADHD contribute to but do not fully explain the observed slowed colour naming.
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Event rate and event-related potentials in ADHD.
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Wiersema R, van der Meere J, Roeyers H, Van Coster R, Baeyens D
Background: It has been repeatedly found that performance of children with attention deficit hyperactivity disorder (ADHD) is more impaired when a long inter-stimulus interval (ISI) is used than when a short ISI is used. According to the cognitive-energetic model, this may reflect difficulty in remaining in an optimal motor activation state because of insufficient effort allocation. Method: Event-related potentials (ERPs) were evaluated during a Go/No-Go task that incorporates a condition with a fast and a slow presentation rate. Results: ADHD, whether or not comorbid with oppositional defiant/conduct disorder (ODD/CD), was associated with a steeper increase in reaction time (RT) from the fast to the slow condition accompanied by a missing increment of the parietal P3. Speed of responding was found to be correlated with P3 amplitude. In the fast condition, children with ADHD made more errors of commission, accompanied by a smaller No-Go N2, a component thought to be related to inhibition; however, after controlling for ODD/CD these differences disappeared. Conclusions: The association between the steeper increase in RT and reduced parietal P3s may indicate that the children with ADHD did not allocate enough extra effort to adjust to a potentially under-activated state. However, the event rate effects could not account for all of the differences between groups and also early automatic information processing stages seem disturbed in this disorder as indexed by larger P2 amplitudes. Alternative explanations are discussed.
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Activation in Ventral Prefrontal Cortex is Sensitive to Genetic Vulnerability for Attention-Deficit Hyperactivity Disorder.
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Durston S, Mulder M, Casey BJ, Ziermans T, van Engeland H
BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) is a heritable neuropsychiatric disorder, associated with atypical patterns of brain activation in functional imaging studies. Neuroimaging measures may serve as an intermediate phenotype in genetic studies of ADHD, as they are putatively more closely linked to gene expression than a clinical diagnosis. METHODS: We used rapid, mixed-trial, event-related functional magnetic resonance imaging (fMRI) to investigate changes in brain activation during a go no-go task in boys with ADHD, their unaffected siblings, and matched control subjects. RESULTS: On the hardest inhibitory trials in our task, children and adolescents with ADHD had lower accuracy than control subjects, whereas their unaffected siblings did not. Control subjects activated a network of regions, including ventral prefrontal and inferior parietal cortex. Both children and adolescents with ADHD and their unaffected siblings showed decreased activation in these areas, as well as fewer correlations between performance and activation. CONCLUSIONS: These findings suggest that the magnitude of activation during successful inhibitions is sensitive to genetic vulnerability for ADHD in a number of regions, including ventral prefrontal cortex. If this can be replicated in future studies, this suggests that neuroimaging measures related to inhibitory control may be suitable as intermediate phenotypes in studies investigating gene effects in ADHD.
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Psychopathology in Females with Attention-Deficit/Hyperactivity Disorder: A Controlled, Five-Year Prospective Study.
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Biederman J, Monuteaux MC, Mick E, Spencer T, Wilens TE, Klein KL, Price JE, Faraone SV
BACKGROUND: Despite the importance of understanding the long-term outcome of children with attention-deficit/hyperactivity disorder (ADHD), the available literature is predominantly based on male samples. This study estimated the lifetime burden of comorbid psychopathology in a large sample of girls with and without ADHD followed up over five years. METHODS: We conducted a blind, five-year prospective longitudinal study of girls with (n=140) and without (n=122) ADHD, aged 6-18 years at baseline, consecutively ascertained from either community pediatricians or psychiatrists at an academic medical center. At the five-year follow-up, 123 (88%) and 112 (92%) of the ADHD and control children, respectively, were re-assessed at a mean age of 16.7 years. Psychiatric disorders were assessed using blinded structured diagnostic interviews. RESULTS: At follow-up, females with ADHD were at significantly higher risk than controls to manifest disruptive behavior, mood and anxiety disorders, and substance dependence. The magnitude of increased risk was greatest for major depression and oppositional-defiant disorder, followed by substance dependence and anxiety disorders. CONCLUSIONS: These prospective follow-up findings documenting high morbidity associated with ADHD extend to females previously reported findings in male samples and underscore the importance of early recognition and intervention efforts for youth with ADHD of both genders.
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No association of attention-deficit/hyperactivity disorder with genes of the serotonergic pathway in Han Chinese subjects.
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Li J, Wang Y, Zhou R, Wang B, Zhang H, Yang L, Faraone SV
Attention-deficit/hyperactivity disorder (ADHD) is a complex psychiatric syndrome with cardinal symptoms of inattention, hyperactivity and impulsivity, and is a significant risk factor for poor health outcomes in both adolescence and adulthood. Etiology is clearly multifactoral, with probable contributions from both genetic and environmental factors. The genetic contribution is prominent, with estimated heritability at about 0.80. Although effects in dopamine metabolism have long been implicated in the etiology of ADHD, the role for serotonin has gained more attention in recent years. The current study examined five variants in three serotonin genes [those that code for serotonin receptors 2A (HTR2A), 5A (HTR5A) and 6 (HTR6)] in a relatively large sample of ADHD nuclear families. The transmission disequilibrium test (TDT) and the extended transmission disequilibrium test (ETDT) were performed to test for evidence of distorted transmission of alleles or haplotypes. No significant biased transmission was observed. These results do not support a substantial role of these serotonin gene in ADHD, however, additional work may be warranted before this association is definitively discounted.
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Deficits in diagnosis, treatment and continuity of care in African-american children and adolescents with ADHD.
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Hervey-Jumper H, Douyon K, Franco KN
Despite the evidence that attention-deficit/hyperactivity disorder (ADHD) is not just a diagnosis of whites, it often goes undiagnosed and is underresearched in the African-American population. There are higher rates of delinquency, incarceration, teen pregnancy and sexually transmitted diseases associated with inadequate or delayed treatment of ADHD. Afrcan Americans generally respond well to treatments, but access to evaluation, medication and psychotherapy is limited or absent for many, The purpose of this research is to compare descriptive characteristics of African-American children with ADHD to age-matched Caucasian children with the same diagnosis. Age at diagnosis, treatment offered, perception of outcome, adherence, comorbid symptoms and frequency of follow-up were collected retrospectively from charts of children treated in the sections of child and adolescent psychiatry and pediatric neurology.
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Refining the attention deficit hyperactivity disorder phenotype for molecular genetic studies.
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Thapar A, Langley K, O'donovan M, Owen M
It is well established that attention deficit hyperactivity disorder (ADHD) is a familial and highly heritable disorder. Consequently, much effort is being directed towards searching for specific susceptibility genes. There is a growing trend, across the field of complex disease genetics, towards undertaking secondary analyses based on refined phenotypic definitions and in testing whether specific susceptibility genes modify the phenotypic presentation of the disorder in question. It is crucial that good, empirically derived arguments are made before undertaking multiple analyses on different phenotype refinements. In this review article, we consider the evidence from genetic epidemiological studies as well as key clinical studies that provide guidance on examining the ADHD phenotype for the purpose of molecular genetic studies. Specifically, findings on categorical versus dimensional conceptualisations of ADHD, reporter effects, comorbidity, ADHD subtypes and persistence are reviewed. Current evidence suggests that for the purpose of identifying susceptibility genes for ADHD, parent and teachers should be used as informants and that focusing on the clinical diagnosis of ADHD is useful. There is also good empirical support in favour of examining antisocial behaviour in ADHD. Genetic studies of dimensional ADHD are useful for other complementary purposes.Molecular Psychiatry advance online publication, 16 May 2006; doi:10.1038/sj.mp.4001831.
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Implementing ADHD guidelines in primary care: does one size fit all?
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Leslie LK, Stallone KA, Weckerly J, McDaniel AL, Monn A
To determine if the American Academy of Pediatrics Attention-Deficit/Hyperactivity Disorder (ADHD) guidelines require tailoring for different settings, the researchers used a mixed-method research design to review an ADHD quality improvement effort in community clinics and private offices in San Diego County. Clinically, no differences were noted in rates of ADHD in the two settings. Children in community clinics (58.3%) were more likely to report public insurance (p<.001), diverse ethnic backgrounds (p=.003), low household incomes (p<.001), single parent households (p=.009), and to screen positive for Oppositional Defiant Disorder/Conduct Disorder (p=.027). They were also more likely to have experienced socio-environmental stressors (p<.001) including foster care, homelessness, parental drug use, and domestic violence. No differences were noted by treatment received at 12 months post-evaluation by office type. Open-ended interviews with clinicians confirmed these findings and revealed a need for tailoring of implementation strategies to more closely fit the needs of children and families cared for in public sector settings.
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Methylphenidate fails to improve gait and muscle tone in patients with sporadic and hereditary spastic paraplegia.
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Klebe S, Deuschl G, Stolze H
Based on its action on multiple neurotransmitters, including dopamine, methylphenidate (MPH) is of growing interest as a possible treatment option for several movement disorders. Of special interest are diseases that share gait disturbance and cognitive decline. Based on a single case observation in a patient with hereditary spastic spinal paraplegia (HSP) in which gait was improved with MPH, we performed an open-label study with a longitudinal follow-up in 22 patients with HSP and its sporadic form (SSP). The patients were treated for 6 months with 60 mg of MPH per day. Computerized gait analysis and different scores were performed at baseline, after 6 weeks, and after 6 months of treatment. Although at 6 weeks, the gait velocity was somewhat improved, the drug failed to show any effect on other gait parameters and had no beneficial effect at all after 6 months. Although MPH is of interest for several movement disorders, our study did not show a beneficial effect. (c) 2006 Movement Disorder Society.
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Co-occurrence of developmental delays among preschool children with attention-deficit-hyperactivity disorder.
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Yochman A, Ornoy A, Parush S
The aim of this study was to provide a comprehensive profile of the sensory, motor, language, and intellectual functioning of a non-referred community sample of 49 preschool children with attention-deficit-hyperactivity disorder (ADHD; 39 males, 10 females; mean age 4y 7mo [SD 7mo]; range 3y 10mo-6y) and 48 typically developing children (38 males, 10 females; mean age 4y 8mo [SD 6mo]; range 3y 11mo-6y) matched by age, sex, and maternal education who underwent a broad battery of neurodevelopmental tests. The results showed that the scores of the ADHD group were significantly lower than the comparison group on all measures. In addition, 23 (47%) of the children with ADHD had clinically significant co-occurring deficits in two or more areas. Logistic regression indicated that the only significant predictors of group classification were scores of verbal intelligence and motor and sensory functioning, accounting for 44.1% of the variance. These findings suggest that preschool children with ADHD have multiple developmental deficits over and above the core symptoms of ADHD and emphasize the importance of evaluating the sensorimotor functioning of preschool children with ADHD symptoms.
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Symptoms of attention deficit hyperactivity disorder in severely obese women.
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Fleming JP, Levy LD, Levitan RD
OBJECTIVE: Past and current symptoms of Attention Deficit Hyperactivity Disorder (ADHD) were assessed in a clinical sample of severely obese females. METHOD: Core symptoms of ADHD were examined in 75 consecutive, severely obese (BMI > or = 35) women referred to a medical specialist for the non-surgical treatment of obesity. Subjects completed both a retrospective report of childhood symptoms of ADHD (Wender Utah Scale) and two standardized adult ADHD symptom scales. RESULTS: The frequency of clinically suggestive elevations in ADHD scores was substantially and significantly higher than the normative samples in 9 out of 11 symptom subscales. Inattentive symptoms, but not hyperactive symptoms of ADHD, were frequently reported. Overall, 26.7% of the sample reported significant symptoms of ADHD in both childhood and adulthood. CONCLUSIONS: This preliminary study suggests that severely obese women report significant symptomatology related to both childhood and adult ADHD.
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Executive function deficits in autism spectrum disorders and attention-deficit/hyperactivity disorder: Examining profiles across domains and ages.
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Happé F, Booth R, Charlton R, Hughes C
Deficits in 'executive function' (EF) are characteristic of several clinical disorders, most notably Autism Spectrum Disorders (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD). In this study, age- and IQ-matched groups with ASD, ADHD, or typical development (TD) were compared on a battery of EF tasks tapping three core domains: response selection/inhibition, flexibility, and planning/working memory. Relations between EF, age and everyday difficulties (rated by parents and teachers) were also examined. Both clinical groups showed significant EF impairments compared with TD peers. The ADHD group showed greater inhibitory problems on a Go-no-Go task, while the ASD group was significantly worse on response selection/monitoring in a cognitive estimates task. Age-related improvements were clearer in ASD and TD than in ADHD. At older (but not younger) ages, the ASD group outperformed the ADHD group, performing as well as the TD group on many EF measures. EF scores were related to specific aspects of communicative and social adaptation, and negatively correlated with hyperactivity in ASD and TD. Within the present groups, the overall findings suggested less severe and persistent EF deficits in ASD (including Asperger Syndrome) than in ADHD.
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Ethnic differences in parental detection of externalizing disorders.
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Zwirs BW, Burger H, Buitelaar JK, Schulpen TW
BACKGROUND: Previous research has reported lower treatment rates for externalizing disorders among non-Western children as compared to Western children. Ethnic differences in parental detection may be an explanation for this discrepancy. AIMS: In a cross-sectional study among the four largest ethnic groups in the Netherlands, namely Dutch, Moroccan, Turkish and Surinamese, we examined the influence of ethnicity on parental detection of behavioural disorders. METHOD: A total of 270 children (aged 6-10 years) and their parents were interviewed regarding psychiatric disorders and socio-demographic data. Sensitivity and specificity were calculated by using standard definitions, with adjustment for parental educational level. RESULTS: Sensitivity to detect any externalizing disorder and ADHD in particular was significantly lower among Moroccan and Surinamese parents when compared to Dutch parents. Sensitivity to detect ADHD tended to be lower among Turkish parents. Specificity to detect any externalizing disorder was higher among Moroccan and Turkish parents. Specificity to detect ADHD was higher among Moroccan parents and tended to be higher among Turkish parents. CONCLUSIONS: The detection rate of externalizing disorders is markedly lower among non-Dutch parents than among Dutch parents. This finding emphasizes the importance of taking parents' cultural context into account when appraising their report on possible externalizing disorders in their children.
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Social phobia, anxiety, oppositional behavior, social skills, and self-concept in children with specific selective mutism, generalized selective mutism, and community controls.
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Cunningham CE, McHolm AE, Boyle MH
We compared social phobia, anxiety, oppositional behavior, social skills, and self-concept in three groups: (1) 28 children with specific mutism (who did not speak to teachers but were more likely to speak to parents and peers at home and school); (2) 30 children with generalized mutism (whose speaking was restricted primarily to their homes); and (3) 52 community controls. Children with generalized mutism evidenced higher anxiety at school, and more separation anxiety, OCD, and depressive symptoms at home. Parents and teachers reported that the social phobia and anxiety scores of children in both the specific and generalized mutism subgroups were higher than controls. Children in both the specific and generalized mutism groups evidenced greater deficits in verbal and nonverbal social skills at home and school than controls. Teachers and parents did not report differences in nonverbal measures of social cooperation and conflict resolution and we found no evidence that selective mutism was linked to an increase in externalizing problems such as oppositional behavior or ADHD. Although children with specific mutism speak in a wider range of situations and appear less anxious to their teachers than children with generalized mutism, significant socially phobic behavior and social skills deficits are present in both groups.
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Measurement of methylphenidate-induced change in extrastriatal dopamine concentration using (11)CFLB 457 PET.
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Montgomery AJ, Asselin MC, Farde L, Grasby PM
[(11)C]FLB 457 is a very high-affinity radiotracer that allows the measurement of dopamine D(2/3) receptor availability in regions of the brain where densities are very low, such as the cerebral cortex. It is not known if [(11)C]FLB 457 binding is sensitive to the concentration of endogenous dopamine in humans in a manner analogous to [(11)C]raclopride and [(123)I]IBZM in the striatum. To test this possibility, extrastriatal [(11)C]FLB 457 binding was measured at baseline and after the oral administration of 40 to 60 mg of the psychostimulant methylphenidate (MP) in 12 healthy volunteers using positron emission tomography (PET) in a balanced-order, double-blind design. The dynamic PET data were quantified using a two-tissue compartment model with a metabolite-corrected arterial plasma input function. Two volunteers were excluded because of excessive head movement. In the remainder, MP caused significant reductions in the volume of distribution (VD) in temporal and frontal cortical regions and thalamus, suggesting that [(11)C]FLB 457 binding is sensitive to endogenous dopamine concentration. Moreover, the change in [(11)C]FLB 457 binding after MP correlated with the dose of MP (in mg/kg body weight) in all regions assessed. We conclude that MP in doses within the therapeutic range for the treatment of attention deficit hyperactivity disorder causes increases in dopamine concentrations in extrastriatal regions and that [(11)C]FLB 457 PET may be a useful tool for the assessment of change in dopamine concentration in these areas in humans.Journal of Cerebral Blood Flow & Metabolism advance online publication, 10 May 2006; doi:10.1038/sj.jcbfm.9600339.
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Methylphenidate enhances noradrenergic transmission and suppresses mid- and long-latency sensory responses in the primary somatosensory cortex of awake rats.
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Drouin C, Page ME, Waterhouse BD
Noradrenergic neurons send widespread projections to sensory networks throughout the brain and regulate sensory processing via norepinephrine (NE) release. As a catecholamine reuptake blocker, methylphenidate (MPH) is likely to interact with noradrenergic transmission and NE modulatory action on sensory systems. To characterize the neurochemical actions of MPH in the primary sensory cortex of freely behaving rats and their consequences on sensory processing, we measured extracellular NE levels in the primary somatosensory (SI) cortex by microdialysis and recorded basal and sensory-evoked discharge of infragranular SI cortical neurons, before and after intraperitoneal administrations of saline or MPH (1 and 5 mg/kg). Both doses of MPH significantly increased NE levels in the SI cortex (+64% and +101%, respectively). In most neurons, stimulation of the whisker-pad induced a triphasic response, consisting of a short-latency excitation (4.7+/-0.2 msec) followed by a post-excitatory inhibition (36+/-1.5 msec) and a long-latency excitation (105+/-2.6 msec). Under control conditions, the behavioral state of the animal was correlated with the magnitude of the short-latency excitation, but not with other aspects of the basal and sensory-evoked discharge of SI cortical neurons. At 5 mg/kg, MPH significantly increased locomotor activity and induced a significant suppression of the short-latency excitation, which probably resulted from the MPH-induced change in behavior. In addition, both doses of MPH suppressed the post-excitatory inhibition and the long-latency excitation evoked by the stimulation of the whisker-pad. These effects did not seem to result from the locomotor effect of MPH and probably involved MPH-induced enhancement of noradrenergic transmission.
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Autism Spectrum Disorders and Attention-Deficit/Hyperactivity Disorder in Boys with the Fragile X Premutation.
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Farzin F, Perry H, Hessl D, Loesch D, Cohen J, Bacalman S, Gane L, Tassone F, Hagerman P, Hagerman R
ABSTRACT.: Fragile X syndrome (FXS) is caused by a full mutation expansion (>200 CGG repeats) in the FMR1 gene that results in a deficiency of the fragile X mental retardation protein. Although most individuals with the premutation (55-200 CGG repeats) are considered unaffected by FXS, recent case studies have documented children with the premutation who have cognitive deficits, behavioral problems, and/or autism spectrum disorders. The objective of this study was to compare the prevalence of autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD) symptoms in boys with the premutation who presented as probands, in brothers with the premutation who did not present as probands, and in normal brothers of premutation and/or full mutation carriers. Participants included 43 male children: 14 probands who presented to clinic, 13 nonprobands who were identified through cascade testing (routine genetic testing of family members after identification of a proband) and confirmed to have the premutation, and a control group of 16 male siblings of individuals with the fragile X premutation or full mutation who were negative for the FMR1 mutation. Participants came from 1 of 2 collaborative sites: University of California, Davis and La Trobe University in Australia. Parents completed the Conners' Global Index-Parent Version for assessing symptoms of ADHD and the Social Communication Questionnaire (SCQ) for identifying symptoms of ASD. Children who were in the ASD range on the SCQ (n = 13) underwent further evaluation with either the Autism Diagnostic Observation Schedule-Generic (n = 10) or the Autism Diagnostic Interview-Revised (n = 3). A final diagnosis of ASD included clinical assessment utilizing DSM-IV-TR criteria in addition to the standardized assessments. There was a higher rate of ASD in boys with the premutation presenting as probands (p < 0.001) or nonprobands (p < .04) compared with sibling controls without the premutation. In addition, probands had a significant increase in ADHD symptoms compared with controls (p < .0001). Of the probands, 93% had symptoms of ADHD and 79% had ASD. In the nonproband premutation group, 38% had symptoms of ADHD and 8% had ASD. Thirteen percent of sibling controls had symptoms of ADHD and none had ASD. IQ scores were similar in all 3 groups (p = .13), but the use of psychotropic medications was significantly higher in probands with the premutation compared with that in controls (p < .0001). Developmental problems have been observed in premutation carriers, particularly those who present clinically with behavioral difficulties. Although this study is based on a small sample size, it suggests that premutation carriers, even those who do not present clinically, may be at increased risk for an ASD and/or symptoms of ADHD. If the premutation is identified through cascade testing, then further assessment should be carried out for symptoms of ADHD, social deficits, or learning disabilities.
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Behavior and orofacial characteristics of children with attention-deficit hyperactivity disorder during a dental visit.
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Atmetlla G, Burgos V, Carrillo A, Chaskel R
ADHD is a neuropsychological disorder, affecting attention, impulsiveness and activeness. The study included 36 children with ADHD, 47 without, and two silent observers. A dental form, SNAP-IV and ADHDT symptom checklists were used. Statistically significant differences were observed in hospitalization histories, oral habits, tongue characteristics, and facial biotype. Differences in orofacial characteristics and behavior between the groups were confirmed.
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The FG syndrome: Report of a large Italian series.
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Battaglia A, Chines C, Carey JC
Initially described as a rare MCA/MR syndrome occurring only in boys, due to a recessive mutation on the X chromosome [Opitz and Kaveggia, 1974], the FG syndrome (FGS) now emerges as a more common disorder also occurring in girls. Based on over 50 reported cases, FGS is associated with developmental delay (especially speech), hypotonia, postnatal onset relative macrocephaly, prominent forehead, frontal hair upsweep, telecanthus, or ocular hypertelorism, thin vermilion border of the upper lip, relatively short fingers with broad thumbs and halluces, persistent fetal fingertip pads, anal anomalies, and/or constipation. Major malformations are rare, and include pyloric stenosis, anal agenesis, cryptorchidism, hypospadias, and congenital heart defects. Abnormal EEGs and seizures have been reported in almost 70% of patients. Brain MRI shows corpus callosum abnormalities associated with dilatation of lateral ventricles and, less frequently, periventricular nodular heterotopias, mild cerebellar defects, and reduced periventricular white matter. Chiari 1 malformation seems to be frequent. The behavior phenotype appears to be characterized by ADHD, and relatively less developed language, fine motor and executive function skills; whereas visual-spatial abilities seem to be a relative strength. Five candidate loci are already known but no gene identified. We describe 25 patients referred to the Stella Maris Institute for evaluation of DD/MR, and diagnosed as FGS. They were between 2 and 15(1/2) years at the first observation. High resolution banding, FRAXA/FRAXE DNA analysis, and subtelomere FISH analysis were performed in all of them, and all had normal results. Thirteen patients were followed-up from 6 months to 9 years. Our report focuses on physical, neurological, developmental findings, and natural history of FGS. Experience with our series of patients suggests that the syndrome may be common, and should be routinely considered in the evaluation of children and adolescents with DD/MR. (c) 2006 Wiley-Liss, Inc.
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Discriminative analysis of brain function at resting-state for attention-deficit/hyperactivity disorder.
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Zhu CZ, Zang YF, Liang M, Tian LX, He Y, Li XB, Sui MQ, Wang YF, Jiang TZ
In this work, a discriminative model of attention deficit hyperactivity disorder (ADHD) is presented on the basis of multivariate pattern classification and functional magnetic resonance imaging (fMRI). This model consists of two parts, a classifier and an intuitive representation of discriminative pattern of brain function between patients and normal controls. Regional homogeneity (ReHo), a measure of brain function at resting-state, is used here as a feature of classification. Fisher discriminative analysis (FDA) is performed on the features of training samples and a linear classifier is generated. Our initial experimental results show a successful classification rate of 85%, using leave-one-out cross validation. The classifier is also compared with linear support vector machine (SVM) and Batch Perceptron. Our classifier outperforms the alternatives significantly. Fisher brain, the optimal projective-direction vector in FDA, is used to represent the discriminative pattern. Some abnormal brain regions identified by Fisher brain, like prefrontal cortex and anterior cingulate cortex, are well consistent with that reported in neuroimaging studies on ADHD. Moreover, some less reported but highly discriminative regions are also identified. We conclude that the discriminative model has potential ability to improve current diagnosis and treatment evaluation of ADHD.
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