Age and gender effects in EEG coherence: III. Girls with attention-deficit/hyperactivity disorder.

OBJECTIVE: This study investigated intrahemispheric and interhemispheric EEG coherences as a function of age in girls with different DSM-IV subtypes of Attention-Deficit/Hyperactivity Disorder (AD/HD). It completes a series of 3 studies aimed at clarifying developmental and gender impacts on the coupling between brain regions in this disorder. METHODS: Three groups of 40 children (AD/HD combined type, AD/HD inattentive type, and normal controls) participated. Each group contained 8 females in each of 5, 1-year age bands from 8 to 12 years. EEG was recorded from 21 sites during an eyes-closed resting condition. Wave-shape coherence was calculated for 8 intrahemispheric electrode pairs (4 in each hemisphere), and 8 interhemispheric electrode pairs, within each of the delta, theta, alpha and beta bands. RESULTS: Developmental effects in intrahemispheric coherences at shorter and longer inter-electrode distances were not as predicted by Thatcher's two-compartment model, contrary to previous findings in boys. Females with AD/HD showed evidence of developmental delay and widespread anomalous elevations in coherence. Girls with AD/HD of the combined type showed similar but greater anomalies than girls with AD/HD of the inattentive type. CONCLUSIONS: Girls with AD/HD show coherence anomalies relative to age- and gender-matched controls, which differ substantially from those shown by boys with AD/HD. These coherence anomalies did not differ in nature between girls with different DSM-IV subtypes of AD/HD, suggesting that subtype differences in girls reflect only symptom severity. SIGNIFICANCE: The data reported here indicate qualitative differences in EEG coherences in girls with AD/HD compared with controls, and quantitative differences between girls with different subtypes of AD/HD. Both sets of effects differ in nature from those previously found in boys with AD/HD, showing the need to carefully consider gender in future studies of AD/HD.     

Effects of stimulant medications on the EEG of children with Attention-Deficit/Hyperactivity Disorder Predominantly Inattentive type.

Stimulant medications are the most commonly-used treatments for Attention-Deficit/Hyperactivity Disorder (ADHD) in North America and Australia, although it is still not entirely known how these medications work. This study investigated the effects of stimulant medications on the EEG of children with the Inattentive type of ADHD. An initial 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. Theta/alpha and theta/beta ratios were also calculated. Subjects were placed on a 6-month trial of a stimulant and a second EEG was recorded at the end of the trial. Subjects were included in this study only if they showed a good clinical response during the trial. The unmedicated ADHD group had significantly greater absolute and relative theta, less relative alpha, and higher theta/alpha and theta/beta ratios than the control group. The stimulant medications resulted in a normalisation of the EEG, with changes in the theta, alpha and beta bands being most evident. These results suggest that stimulants act to increase cortical arousal in children with ADHD, normalising their EEG.     

Mule spinner's disease

Mule spinner's disease represents the occurrence of scrotal cancer in cotton textile workers exposed to mineral oils on a long-term basis while working on a machine called "the mule." We describe a 66-year-old cotton textile worker who had frequent scrotal contact with mineral oils and later had multiple squamous cell carcinomas of the scrotum develop. He also had a variety of other keratotic lesions develop on the scrotum that histopathologically demonstrated features of verruca, lichenoid keratoses, and squamous cell carcinomas in situ. We have termed these lesions mule spinner's keratoses.     

Effects of stimulant medications on the EEG of children with attention-deficit/hyperactivity disorder

Abstract Rationale. Stimulant medications are the most commonly used treatments for attention deficit/hyperactivity disorder (ADHD) in North America and Australia, although it is still not entirely known how these medications work. Objectives. This study aimed to investigate the effects of stimulant medications on the EEG of children with the Combined subtype of ADHD. Method. An initial 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. Theta/alpha and theta/beta ratios were also calculated. Subjects were placed on a 6-month trial of a stimulant and a second EEG was recorded at the end of the trial. Results. The ADHD group had significantly greater absolute delta and theta, less posterior absolute beta, more relative theta, and less relative alpha than the control group, which is typical of EEG studies of children with ADHD. The use of stimulant medications resulted in normalisation of the EEG, primarily evident in changes in the theta and beta bands. Conclusions. These results suggest that stimulants act to increase cortical arousal in children with ADHD, normalising their brain activity. Electronic Publication     

Prevalence of dental caries in a group of adult Vietnamese refugees in Norway

About 3500 Vietnamese refugees have settled in Norway since 1975. The purpose of this survey was to investigate the dental health of 200 Vietnamese refugees, 142 males and 58 females above the age of 12 years. The clinical examinations were done 3 weeks after arrival in Norway and included decayed, extracted and filled surfaces and teeth (DMFS and DMFT). The sample was divided into four age groups, 12-19, 20-29, 30-39 and 40+. Only 9% of the sample was cariesfree. Mean DMFT ranged from 8.7 in the youngest age group to 11.5 in the oldest. DMFS scores consisted primarily of decayed surfaces and mean DS did not vary much in the different age groups. The examinations revealed a higher prevalence of caries in the permanent second molars than in the permanent first molars in all age groups. The present study seems to support previous reports on the caries situation of the Vietnamese which have indicated a dramatic rise in the caries prevalence. In this study the average DMFT was similar to other Asian populations, but less than Norwegians of comparable age. The results suggest a high treatment need in the Vietnamese refugees.     

Methylphenidate effects in attention deficit/hyperactivity disorder: electrodermal and ERP measures during a continuous performance task

Rationale Previous research investigating the effects of stimulants, such as methylphenidate (MPH), on children with attention deficit/hyperactivity disorder (AD/HD) has rarely included autonomic measures of arousal.Objective Our aim was to clarify the effects of MPH on central and autonomic measures in AD/HD children during a continuous performance task (CPT) using a naturalistic open-label study.Method Thirty-six boys (18 AD/HD and 18 control) participated in a CPT over two trial periods, allowing a more valid estimate of the effects of medication, rather than assuming that retesting per se has no substantial impact. MPH was administered to the AD/HD group 1 h prior to the second trial. Errors and reaction time (RT) were recorded as measures of performance, electrodermal activity as an autonomic nervous system measure and event-related potentials (ERPs) as an index of central nervous system activity.Results AD/HD children made more errors than controls in the first session, but no group differences were found after medication. No significant differences were observed for RT. Skin conductance level was found to be lower in AD/HD children than controls, but this difference was also ameliorated after medication. Conversely, mean skin conductance response to target stimuli was found not to differ between groups during the initial test phase but became significantly different in phase 2. ERP data showed topographic differences between groups in N1, P2, N2 and P3 at the initial test phase, which were reduced at the second test.Conclusion Stimulant medication ameliorated some of the dysfunctions in AD/HD children, which are reflected in behavioural and ERP measures. These results, in combination with general differences in electrodermal activity, support a hypoarousal model of AD/HD, which can explain the action of MPH in these children.     

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.     

The relationship between periodontal conditions and perceptions of periodontal health among Pakistani immigrants in Norway

The purpose of the present study was to assess the periodontal status of Pakistani immigrants in Norway, a Third World population in an industrialized country. The findings were related to treatment needs, socio-demographic variables and cultural beliefs about periodontal health. The mean number of remaining teeth ranged from 27.7 in the 20-24-year-old age group to 25.1 in the group of 35-year-olds and older. Very few of the study population had no plaque or no subgingival calculus. Only 7.5% of the participants exhibited no bleeding at any index teeth. Age and residence in Pakistan were the strongest predictors of subgingival calculus and pocket depth. Those from the rural areas of Pakistan had deeper pockets than those from the cities. The data showed a population with high prevalences of teeth with plaque, subgingival calculus and frequent gingival bleeding, but few sites with deep pockets. A periodontal treatment need index would indicate a substantial amount of treatment time. The present study suggests that also the perceived periodontal conditions, should be taken into account when periodontal services and health education strategies are planned. The concept of periodontal illness is introduced, defined as a person's perceptions and interpretations of periodontal symptoms.     

EEG evidence for a new conceptualisation of attention deficit hyperactivity disorder.

OBJECTIVES: This study investigated the presence of electroencephalographic (EEG) clusters within a sample of children with the inattentive type of attention-deficit/hyperactivity disorder (ADHD).METHODS: Subjects consisted of 100 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. Factor analysis was used to group sites into 3 regions; frontal, central and posterior. These data were subjected to cluster analysis.RESULTS: Two distinct EEG clusters of children with the inattentive type of ADHD were found. These were characterised by (a) increased high-amplitude theta with deficiencies of delta and beta activities, and (b) increased slow wave and deficiencies of fast wave activity.CONCLUSIONS: These two subtypes are independent of current diagnostic categories, and consist of a cortically hypoaroused group and a group typified by a maturational lag in central nervous system (CNS) development. These results support a re-conceptualisation of ADHD based on the CNS abnormality underlying the disorder rather than the behavioural profile of the child. This has the potential to add a level of predictive validity, which is currently lacking in the present diagnostic systems.     

Effects of stimulant medications on the EEG of girls with Attention-Deficit/Hyperactivity Disorder

OBJECTIVE: Stimulant medications are the most commonly used treatments for Attention-Deficit/Hyperactivity Disorder (AD/HD) in North America and Australia, although it is still not entirely known how these medications work. This study investigated the effects of stimulant medications on the EEG of girls with AD/HD. METHODS: An initial EEG was recorded during an eyes-closed resting condition. Data from 19 electrode sites were Fourier transformed to provide absolute and relative power estimates for the delta, theta, alpha and beta bands. The data were then averaged into 9 regions and an analysis of both global and regional differences was performed. Subjects were placed on a six-month trial of a stimulant and a second EEG was recorded at the end of the trial. RESULTS: The unmedicated girls had significantly greater total power, absolute delta and theta, more relative theta especially in the frontal regions, and reduced frontal relative delta and beta activity compared with controls. Medication resulted in normalisation of theta power, but after medication, increased relative beta was also apparent in the AD/HD group. CONCLUSIONS: These results indicate that stimulant medications result in a normalisation of slow wave activity in the EEG. In line with published research on the effects of arousal on the EEG, these results suggest that stimulant medications may have their therapeutic effect by improving the EEG substrate of processing deficits in these children. However, this requires further testing during active processing tasks. SIGNIFICANCE: This is the first study to investigate the effect of stimulant medications on the EEG of girls with AD/HD.