EEG and electrodermal activity in girls with Attention-Deficit/Hyperactivity Disorder.

OBJECTIVE: This study investigated the Hypoarousal Model of Attention-Deficit/Hyperactivity Disorder (AD/HD) in girls. METHODS: 40 girls with AD/HD and 40 girl controls (aged 7-12 years) had an eyes-closed resting EEG recorded from 19 electrodes and Fourier transformed. Estimates for total power, absolute and relative power in the delta, theta, alpha, beta and gamma frequency bands, and theta/beta ratio were analysed in nine cortical regions. Skin conductance level (SCL) was simultaneously recorded. Regression analyses explored relationships between symptoms and physiology. RESULTS: Compared with controls, girls with AD/HD had globally elevated relative delta, globally reduced absolute beta, and globally reduced absolute and relative gamma activity. Girls with AD/HD also had lower mean SCL. Inattentive symptoms were predicted by elevated frontal relative delta, reduced SCL, and reduced temporal relative gamma activity, while elevated hyperactive-impulsive symptoms correlated with elevated frontal relative delta activity in both the patient and control groups. CONCLUSIONS: These EEG results are comparable with the limited female AD/HD literature. Girls with AD/HD are hypoaroused, indicated by reduced SCL, and appear to have an anomalous arousal mechanism. Absolute and relative gamma results are similar to previous findings in AD/HD children. Symptom correlations with physiology offer intriguing insights for future research. SIGNIFICANCE: This is the first study to examine CNS arousal exclusively in girls with AD/HD.

Hyperkinetic disorder in the ICD-10: EEG evidence for a definitional widening?

This study investigated EEG differences between children with Hyperkinetic Disorder (HKD), HKD sub-threshold attention deficit (HKDsub), and control children, in order to determine from an EEG perspective whether children with HKDsub represent a valid clinical disorder. Twenty-four boys were included in each of the three age-matched groups. The HKD group had greater total power and absolute delta and theta, more relative theta, and less relative alpha and beta than the control group. The HKDsub group had EEG profiles which were different from both control children and children with HKD, with the HKDsub group having EEG results generally between the HKD and control group. Additionally, a number of topographic differences were found in the frontal regions which suggest that the two HKD groups have independent EEG components. These results support the inclusion of a diagnostic category of attention deficit in future editions of the ICD.

EEG-defined subtypes of children with attention-deficit/hyperactivity disorder.

OBJECTIVES: This study investigated the presence of EEG clusters within a sample of children with the combined type of attention-deficit/hyperactivity disorder (ADHD). METHODS: Subjects consisted of 184 boys with ADHD and 40 age-matched controls. EEG was recorded from 21 sites during an eyes-closed resting condition and Fourier transformed to provide estimates for total power, and relative power in the delta, theta, alpha and beta bands, and for the theta/beta ratio. Factor analysis was used to group sites into 3 regions, covering frontal, central and posterior regions. These data were subjected to cluster analysis. RESULTS: Three distinct EEG clusters of children with ADHD were found. These were characterized by (a) increased slow wave activity and deficiencies of fast wave, (b) increased high amplitude theta with deficiencies of beta activity, and (c) an excess beta group. CONCLUSIONS: These results indicate that children with ADHD do not constitute a homogenous group in EEG profile terms. This has important implications for studies of the utility of EEG in the diagnosis of ADHD. Efforts aimed at using EEG as a tool to discriminate ADHD children from normals must recognize the variability within the ADHD population if such a tool is to be valid and reliable in clinical practice.

Excess beta activity in children with attention-deficit/hyperactivity disorder: an atypical electrophysiological group.

Studies of children with attention deficit/hyperactivity disorder (ADHD) have typically found elevated levels of slow wave activity in their EEGs, but in two of our previous studies, a small subset of ADHD children with excess beta activity in the EEG was identified. The aim of this study was to determine whether children with excess beta activity represent a distinct electrophysiological subtype of ADHD, to quantify the differences in their EEGs, and to determine if this group of children with ADHD have behavioural profiles different from other children with ADHD. Results indicated that children with excess beta represent a small independent subset of children diagnosed with ADHD, which primarily consists of children with a diagnosis of ADHD combined type. Behaviourally, this group was similar to other children with ADHD, although the excess-beta group were more prone to temper tantrums and to be moody. The excess in beta activity was found primarily in the frontal regions and may be associated with frontal lobe self-regulation and inhibition control.

Electroencephalogram differences in two subtypes of attention-deficit/hyperactivity disorder.

This study investigated EEG differences between children with two subtypes of Attention-Deficit/Hyperactivity Disorder (ADHD) and normal control subjects. EEG was recorded during an eyes-closed resting condition and Fourier transformed to provide absolute and relative power estimates for the delta, theta, alpha, and beta bands, and the mean frequency for each band was calculated. Ratio coefficients were also calculated between frequency bands. Mean group differences were found in the theta, alpha, and beta bands between all three groups. Similarly, differences were found between all three groups for the theta/alpha and theta/beta ratios and for the mean frequency of the total EEG. These results support a model of ADHD resulting from a developmental deviation rather than a maturational lag in the central nervous system. Differences between the clinical groups in frontal activity suggest that different neuroanatomical systems are involved in the different subtypes of ADHD.

Age and sex effects in the EEG: development of the normal child.

OBJECTIVES: This study investigated age-related changes and sex differences in the EEGs of normal children. METHODS: Forty boys and 40 girls, between the ages of 8 and 12 years, participated in this study. The EEG was recorded during an eyes-closed resting condition and Fourier transformed to provide estimates for total power, absolute and relative power in the delta, theta, alpha and beta bands, and for theta/alpha and theta/beta ratios. RESULTS: Absolute delta activity decreased with age. Relative delta and theta decreased and alpha and beta increased with increasing age. The theta/alpha and theta/beta ratios decreased with increasing age. All of these indicated a developmental reduction in slow wave activity. Maturational differences were found in the rates of change between the midline and the two hemispheres. In the absolute delta and the theta/beta ratio, the midline and the two hemispheres became more equipotential with age. In the beta band, power increased at a greater rate than in the two hemispheres. Sex differences were found, with males having less theta and more alpha than females. CONCLUSIONS: These results indicated that maturation occurs earlier at the midline than in the two hemispheres. Females were also found to have a developmental lag in the EEG compared with males.

Age and sex effects in the EEG: differences in two subtypes of attention-deficit/hyperactivity disorder.

OBJECTIVES: This study investigated age-related changes and sex differences in the EEGs of two groups of children with attention-deficit/hyperactivity disorder (ADHD) combined type and ADHD predominantly inattentive type, in comparison with a control group of normal children. METHODS: Forty boys and forty girls were included in each group. The EEG was recorded during an eyes-closed resting condition and Fourier transformed to provide estimates for total power, absolute and relative power in the delta, theta, alpha and beta bands, and for theta/alpha and theta/beta ratios. RESULTS: Total power, relative alpha, and the theta/alpha and theta/beta ratios were differentiated between all 3 groups. Sex differences between the ADHD subjects and the control group were greater in males than females and matured faster in males. With increasing age, the EEG of the ADHD inattentive group was found to change at a similar rate to the changes found in the normal group, with the differences in power levels remaining constant. In the ADHD combined group, the power was found to change at a greater rate than in the ADHD inattentive group, with power levels of the two ADHD groups becoming similar with age. CONCLUSIONS: These results are supportive of a two-component model of ADHD, with the hyperactive/impulsive component maturing with age and the inattentive component remaining more stable.

EEG analysis in Attention-Deficit/Hyperactivity Disorder: a comparative study of two subtypes.

This study investigated differences in the EEG between children with Attention-Deficit/Hyperactivity Disorder of the Combined Type, Attention-Deficit/Hyperactivity Disorder of the Predominantly Inattentive Type and control subjects. All subjects were between the ages of 8 and 12 years, and groups were matched on age and gender. The EEG was recorded during an eyes-closed resting condition from 21 monopolar derivations and these were clustered into nine regions prior to analysis. One minute of trace was analysed using Fourier transformation to obtain both absolute and relative power estimates in the delta, theta, alpha and beta frequency bands. The patient groups were found to have greater levels of theta and deficiencies of alpha and beta in comparison to the control group. Children with Attention-Deficit/Hyperactivity Disorder of the Predominantly Inattentive type were found to be significantly different from those of the Combined type in the same measures, appearing to be closer to the normal profiles. The general results support a maturational lag model of the central nervous system in Attention Deficit/Hyperactivity Disorder. The differences between the subtypes suggest a difference in the severity of the disorder rather than a different neurological dysfunction.

Chromosome testing in children with developmental delay in whom the aetiology is not evident clinically.

A review was carried out to establish the value of chromosome testing in children with significant developmental delay, where the aetiology was not evident clinically. During 1990, 315 children had been assessed at a child development clinic and found to be significantly delayed in one or more areas of development; in 256, the aetiology was not evident clinically. Chromosome testing of these children revealed an abnormality in 10 (3.9%). Thirty children had dysmorphic features; six (20%) of these had an abnormal karyotype. Four (2%) of the 226 who had no dysmorphic features had a chromosome abnormality. One hundred and fifty-five children had intellectual disability; eight (5%) of these had an abnormal karyotype. Two (2%) of 101 who had a specific delay in their development had a chromosome abnormality. The advantages of chromosome testing in children with developmental delay in whom the aetiology is not evident clinically are discussed.

Short-term efficacy of tympanostomy tubes for secretory otitis media in children with Down syndrome.

Twenty-four children with Down syndrome, aged six to 14 years, were tested with audiometry six to nine weeks after insertion of tympanostomy tubes for bilateral secretory otitis media (SOM). There was no improvement in hearing in 40 per cent of ears, compared with only 9 per cent of ears in 21 age-matched controls with bilateral SOM. Tympanostomy tubes for SOM in children with Down syndrome have a high short-term failure rate, which should be explained to the parents before insertion, and the children should have audiometry tests shortly after the operation. Persistent hearing-loss may require the fitting of hearing aids. Management should involve ensuring that the children are in a situation in which they can hear as well as possible, and making allowances for the hearing impairment.

A five-year longitudinal study of thyroid function in children with Down syndrome.

The thyroid function and health status of 101 children with Down syndrome were assessed annually for five years. One child had congenital hypothyroidism at entry to the study. During the study period, eight more developed compensated hypothyroidism. Five of 10 children with compensated hypothyroidism still had the condition at the end of the study, it resolved spontaneously in four and one child developed uncompensated hypothyroidism. There were no significant differences in growth and development between those with compensated hypothyroidism and those with normal thyroid function. Two children developed transient rises in thyroxine, associated with elevations in thyroid-stimulating hormone (TSH). A large proportion of thyroid dysfunction in children with Down syndrome is transient and may be related to inappropriate secretion of TSH or thyroid insensitivity to TSH, rather than to auto-immune thyroiditis.

Health problems and health checks in school-aged children with Down syndrome.

A survey by parent questionnaire and interview was carried out to determine the frequency of health problems in 204 children with Down syndrome. Seventy-two children (35.3%) had a congenital heart defect. Refraction had been performed on 196 and 68 (34.6%) of these had a refractive error. A diagnosis of 'glue ear' had been made in 112 (54.9%) and in 12 (11%) of these permanent hearing loss was present. Significant ill-health over the previous 12 months consisted of cardiac failure (two children), more than three upper respiratory tract infections (24 children), bronchitis (eight children), pneumonia (two children) and asthma (seven children). A neck X-ray had been performed in 172 (84.3%) and had demonstrated the presence of atlanto-axial instability in 12 (7%) of these. One hundred and thirty-two (64.7%) of the children had been tested for hypothyroidism in the previous 18 months and this had been found in four (3%) of these children. The implications of these and other findings are discussed in relation to parental counselling and planning of routine health checks.

Fenfluramine in Prader-Willi syndrome: a double blind, placebo controlled trial.

A double blind trial was conducted to determine the effect of fenfluramine on the weight and behaviour of patients with the Prader-Willi syndrome. Fifteen subjects, aged 5.5 to 27 years, received the placebo and the active drug, each for a period of six weeks. The dose of fenfluramine varied according to the age of the patient. Treatment with fenfluramine was associated with significant weight loss, improvement in food related behaviour, and a decrease in aggressive behaviour directed towards others. Skin picking and other self mutilation were unaffected by the drug. None of the subjects suffered from any side effects while taking the drug. These findings suggest that short term treatment with fenfluramine may have a role in the management of some patients with Prader-Willi syndrome. It could be used during periods when exposure to large amounts of food cannot be avoided and aggressive behaviour is particularly difficult to contain. It may also be useful in those whose lives are threatened by the complications of obesity.

A survey of 22 individuals with Prader-Willi syndrome in New South Wales.

Twenty-two individuals with Prader-Willi Syndrome in New South Wales were surveyed. The results show that males were diagnosed at a significantly earlier age than females and suggest a recent trend towards earlier diagnosis. The advantages of early diagnosis are discussed. In those in whom cytogenetic studies had been performed, 47% were found to have a deletion involving chromosome 15q11-13. Profound neonatal hypotonia had been present in all cases. Obesity became apparent between 1.5 and 10 years (mean = 3.8 years). Facial dysmorphism was reported in 83% and acromicria in 100%. Sixty-two per cent of subjects were regarded as less pigmented than first degree relatives. Cognitive assessments were performed on nine subjects. Two (22%) were functioning in the normal range of intelligence. Behaviour problems, both food-related and non-food-related, were present in the majority and placed considerable stress on the family caring for the individual with Prader-Willi Syndrome.

Deletion 15q21.1----q22.1 resulting from a paternal insertion into chromosome 5.

A 15 month old boy with an interstitial deletion 15q derived from a paternal insertion (5;15)(q31.3;q21.1q22.1) is described and compared with one other reported case. A beak like nose with hypoplastic nasal alae, a thin upper lip, failure to thrive in infancy with later onset of obesity, and severe mental retardation are features common to both.

Heterozygous expression of X-linked mental retardation and X-chromosome marker fra(X)(q27).

Males affected by one form of X-linked retardation possess the X-chromosomal marker fra(X)(q27) and are physically normal except for macro-orchidism. To relate possession of the marker X to phenotypic expression in female heterozygotes, we investigated 128 mildly retarded (IQ, 55 to 75) school-girls in Sydney, New South Wales, Australia. Seventy-two girls had no physical abnormalities and of these, five (7 per cent) carried the marker X. Investigation of relatives revealed retarded males in four of the five families. Pedigree and chromosomal analysis identified a further 18 heterozygotes; six were regarded as intellectually or educationally retarded. We conclude that expression of the X-linked mutation in female carriers contributes to mild mental retardation of girls, that those who are physically normal should be screened for the marker X, and that their relatives should be investigated in order to identify additional females with a high risk of conceiving affected males.