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EEG and Clinical Neuroscience Society (ECNS) 2019. An elevated theta/beta ratio in the EEG has long been observed among individuals with Attention Deficit Hyperactivity Disorder (ADHD). The theta/beta ratio was previously hypothesised to be an index of arousal, but a number of studies failed to find any association between the ratio and indices of arousal, instead proposing that the theta/beta ratio may actually be indicative of cognitive processing. This hypothesis was tested by Clarke et al using a sample of healthy adults, with results indicating that the theta/beta ratio correlated with a marker of cognitive processing (P300 latency in an auditory oddball task), while P300 amplitude correlated with an arousal marker (alpha power). The aim of this study was to test whether similar results could be found in a sample of 41 adults with the combined type of ADHD. EEGs were recorded during an eyes-closed resting condition and an auditory oddball task. Results demonstrated that the theta/beta ratio correlated significantly with P300 latency. Absolute alpha power did not correlate significantly with P300 amplitude or P300 latency. These results support the hypotheses that the theta/beta ratio is a marker of cognitive processing capacity in both the general population and in participants with ADHD, and that the alpha/arousal linkage is anomalous in ADHD.

Objective: Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common psychiatric disorders found in children. While an extensive literature has documented the EEG in this clinical population, few studies have investigated EEG throughout the lifespan in ADHD. This study aimed to investigate EEG maturational changes, in subjects with ADHD combined type, that spanned from childhood into adulthood. Method: Twenty five male adults with ADHD were assessed between the ages of 8-12 years and again as adults. At both ages, an EEG was recorded during an eyes-closed resting period, and power estimates were calculated for relative delta, theta, alpha and beta. Results: At the childhood assessment, the ADHD subjects had elevated posterior delta. Relative theta was elevated, with diminished alpha activity across all sites. Significant maturational changes were observed, with reductions in the delta and theta bands, and increases in the alpha and beta bands across all electrodes. In adulthood, relative to controls, diminished frontal delta and elevated global theta activity were apparent. Conclusions: Substantial developmental changes occurred in the EEG of these subjects. These results identify important issues when using EEG as part of the diagnosis for ADHD. Significance: This study is the first to explore EEG changes from childhood to adulthood over an 11 year period in the same subjects with ADHD.

Objective: Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common psychiatric disorders found in children. While an extensive literature has documented the EEG in this clinical population, few studies have investigated EEG throughout the lifespan in ADHD. This study aimed to investigate EEG maturational changes, in subjects with ADHD combined type, that spanned from childhood into adulthood. Method: Twenty five male adults with ADHD were assessed between the ages of 8-12 years and again as adults. At both ages, an EEG was recorded during an eyes-closed resting period, and power estimates were calculated for relative delta, theta, alpha and beta. Results: At the childhood assessment, the ADHD subjects had elevated posterior delta. Relative theta was elevated, with diminished alpha activity across all sites. Significant maturational changes were observed, with reductions in the delta and theta bands, and increases in the alpha and beta bands across all electrodes. In adulthood, relative to controls, diminished frontal delta and elevated global theta activity were apparent. Conclusions: Substantial developmental changes occurred in the EEG of these subjects. These results identify important issues when using EEG as part of the diagnosis for ADHD. Significance: This study is the first to explore EEG changes from childhood to adulthood over an 11 year period in the same subjects with ADHD.

Stimulant medications are the most commonly prescribed treatment for Attention-Deficit/Hyperactivity Disorder (AD/HD). These medications result in a normalization of the EEG. However, past research has found that complete normalization of the EEG is not always achieved. One reason for this may be that studies have used different medications interchangeably, or groups of subjects on different stimulants. This study investigated whether methylphenidate and dexamphetamine produce different levels of normalization of the EEG in children with AD/HD. Three groups of 20 boys participated in this study. There were 2 groups with a diagnosis of AD/HD; one group, good responders to methylphenidate, and the second, good responders to dexamphetamine. The third group was a normal control group. Baseline EEGs were recorded using an eyes-closed resting condition, and analyzed for total power and relative delta, theta, alpha, and beta. Subjects were placed on a 6-month trial of methylphenidate or dexamphetamine, after which a second EEG was recorded. At baseline, the children with AD/HD had elevated relative theta, less relative alpha and beta compared with controls. Baseline differences were found between the two medication groups, with the dexamphetamine group having greater EEG abnormalities than the methylphenidate group. The results indicate that good responders to methylphenidate and dexamphetamine have different EEG profiles when assessed before medication, and these differences may represent different underlying central nervous system deficits. The 2 medications were found to result in substantial normalization of the EEG, with no significant differences in EEG changes occurring between the 2 medications. This indicates that the degree of pretreatment EEG abnormality was the major factor contributing to the degree of normalization of the EEG. As good responders to the 2 medications appear to have different central nervous system abnormalities, it is recommended that stimulan

Objective This study investigated differences in the EEG power and coherence of children with Asperger’s Syndrome. Method Twenty boys with Asperger’s Syndrome, aged 7–12 years, and an age and sex matched control group, participated in this study. The EEG was recorded during an eyes-closed resting condition from 19 electrode sites, which were clustered into nine regions prior to analysis. One minute of trace was analysed using Fourier transformations to obtain both absolute and relative power estimates in the delta, theta, alpha and beta frequency bands. Wave-shape coherence was calculated for 8 intrahemispheric and 8 interhemispheric electrode pairs. Results The Asperger’s group had a global increase in absolute delta and an anterior increase in relative delta. Both absolute and relative theta were globally increased and relative alpha was globally decreased. Subjects with Asperger’s Syndrome exhibited a broad pattern of reduced hemispheric asymmetry in intrahemispheric coherence. Reduced anterior interhemispheric coherence in the alpha and beta bands was also found in the Asperger’s Syndrome group. Conclusions These results suggest the existence of frontal lobe abnormalities in children with Asperger’s Syndrome, and possible abnormalities in normal CNS maturational processes. Significance This is the first major study to investigate EEG power and coherence anomalies in children with Asperger’s Syndrome.

Objective: This study investigated differences in EEG coherence measures between two groups of children with Attention-Deficit/Hyperactivity Disorder (AD/HD) - one with the more common EEG profile (increased theta), and a group with excess alpha activity as the dominant EEG abnormality. Methods: 26 children (aged 9-13 years) with AD/HD were included in each of the excess-theta and excess-alpha groups, and were age- and sex-matched with 26 control subjects. EEG was recorded from 19 electrode sites during an eyes-closed resting condition. Wave-shape coherence was calculated for eight intrahemispheric and eight interhemispheric electrode pairs, for the delta, theta, alpha and beta bands. Results: In comparison with the controls, the excess-theta AD/HD group had increased theta intrahemispheric coherences at short-medium inter-electrode distances. Frontally, the excess-theta AD/HD group had increased interhemispheric theta and reduced beta coherences. The excess-alpha group primarily showed increased slow wave (delta and theta) intrahemispheric coherence at short-medium inter-electrode distances, and reduced alpha coherence at longer inter-electrode distances, compared with controls. An increase in frontal interhemispheric theta coherence was also found. Conclusions: These results suggest that AD/HD children with excess alpha power have an underlying connectivity dysfunction in the frontal lobes, which is found in common with other subjects with the excess-theta EEG profile. However, a number of qualitative differences exist that could be associated with other aspects of the AD/HD diagnosis. The excess-alpha group appeared to have fewer frontal-lobe abnormalities than the excess-theta AD/HD group. Significance: This is the first study to investigate coherence in AD/HD children who have the atypical profile of increased alpha power in their EEG.

Objective This study investigated differences in the EEG power and coherence of children with Asperger’s Syndrome. Method Twenty boys with Asperger’s Syndrome, aged 7–12 years, and an age and sex matched control group, participated in this study. The EEG was recorded during an eyes-closed resting condition from 19 electrode sites, which were clustered into nine regions prior to analysis. One minute of trace was analysed using Fourier transformations to obtain both absolute and relative power estimates in the delta, theta, alpha and beta frequency bands. Wave-shape coherence was calculated for 8 intrahemispheric and 8 interhemispheric electrode pairs. Results The Asperger’s group had a global increase in absolute delta and an anterior increase in relative delta. Both absolute and relative theta were globally increased and relative alpha was globally decreased. Subjects with Asperger’s Syndrome exhibited a broad pattern of reduced hemispheric asymmetry in intrahemispheric coherence. Reduced anterior interhemispheric coherence in the alpha and beta bands was also found in the Asperger’s Syndrome group. Conclusions These results suggest the existence of frontal lobe abnormalities in children with Asperger’s Syndrome, and possible abnormalities in normal CNS maturational processes. Significance This is the first major study to investigate EEG power and coherence anomalies in children with Asperger’s Syndrome.

Objective: This study investigated differences in EEG coherence measures between two groups of children with Attention-Deficit/Hyperactivity Disorder (AD/HD) - one with the more common EEG profile (increased theta), and a group with excess alpha activity as the dominant EEG abnormality. Methods: 26 children (aged 9-13 years) with AD/HD were included in each of the excess-theta and excess-alpha groups, and were age- and sex-matched with 26 control subjects. EEG was recorded from 19 electrode sites during an eyes-closed resting condition. Wave-shape coherence was calculated for eight intrahemispheric and eight interhemispheric electrode pairs, for the delta, theta, alpha and beta bands. Results: In comparison with the controls, the excess-theta AD/HD group had increased theta intrahemispheric coherences at short-medium inter-electrode distances. Frontally, the excess-theta AD/HD group had increased interhemispheric theta and reduced beta coherences. The excess-alpha group primarily showed increased slow wave (delta and theta) intrahemispheric coherence at short-medium inter-electrode distances, and reduced alpha coherence at longer inter-electrode distances, compared with controls. An increase in frontal interhemispheric theta coherence was also found. Conclusions: These results suggest that AD/HD children with excess alpha power have an underlying connectivity dysfunction in the frontal lobes, which is found in common with other subjects with the excess-theta EEG profile. However, a number of qualitative differences exist that could be associated with other aspects of the AD/HD diagnosis. The excess-alpha group appeared to have fewer frontal-lobe abnormalities than the excess-theta AD/HD group. Significance: This is the first study to investigate coherence in AD/HD children who have the atypical profile of increased alpha power in their EEG.

This study further investigated electroencephalogram (EEG) differences between girls with the Combined and Inattentive types of attention-deficit/hyperactivity disorder (AD/HD). We selected subjects with widely separated scores on hyperactivity-impulsivity symptoms to behaviorally exaggerate diagnostic group differences. Twenty girls with AD/HD Combined type, 20 girls with AD/HD Inattentive type, and 20 controls (aged 7-12 years) had an eyes-closed resting EEG recorded from 19 electrodes. The EEG was fast Fourier transformed, and estimates for total power, absolute and relative power in the delta, theta, alpha, and beta frequency bands, and the theta/beta ratio were calculated and analyzed in 9 scalp regions. Girls of the Combined type, compared with girls of the Inattentive type, had elevated midline total power, elevated temporal absolute alpha activity, elevated posterior absolute beta activity, reduced right hemisphere relative delta and reduced left hemisphere relative alpha activity, and reduced theta/beta ratio in the left hemisphere. Although topographic differences were again found between the AD/HD types, significant global differences remain elusive in the EEGs of girls with the Combined and Inattentive types. Despite creating behaviorally exaggerated AD/HD type groups, girls' EEG activity failed to replicate differences found previously in mixed-sex groups. The EEG profiles of AD/HD types in girls are markedly different from those found in boys. This reinforces the notion that it is no longer appropriate to apply the male-based literature to all AD/HD groups; rather, the use of single-sex subject groups is necessary in EEG research of AD/HD.

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.

Past research has reported that a small proportion of children with attention-deficit/hyperactivity disorder (AD/HD) have excess beta activity in their EEG, rather than the excess theta typical of the syndrome. This atypical group has been tentatively labeled as hyperaroused. The aim of this study was to determine whether these children have a hyperaroused central nervous system. Participants included 104 boys aged 8 to 13 years old, with a diagnosis of either the Combined or Inattentive type of AD/HD (67 combined type), and 67 age-matched male controls. Ten and a half minutes of EEG and skin conductance (SCL) were simultaneously recorded during an eyes-closed resting condition. The EEG was Fourier transformed and estimates of total power, and relative power in the delta, theta, alpha, and beta bands, and the theta/beta ratio, were calculated. AD/HD patients were divided into an excess beta group and a typical excess theta group. Relative to controls, the typical excess theta group had significantly increased frontal total power, theta and theta/beta ratio, with reduced alpha and beta across the scalp. The excess beta group had significantly reduced posterior total power, increased centro-posterior delta, globally reduced alpha, globally increased beta activity, and globally reduced theta/beta ratio. Both AD/HD groups had significantly reduced SCL compared to the control group, but the two groups did not differ from each other on SCL. These results indicate that AD/HD children with excess beta activity are not hyperaroused, and confirm that the theta/beta ratio is not associated with arousal. This is the first study of arousal measures in AD/HD children with excess beta activity, and has implications for existing models of AD/HD.

Past research has reported that a small proportion of children with attention-deficit/hyperactivity disorder (AD/HD) have excess beta activity in their EEG, rather than the excess theta typical of the syndrome. This atypical group has been tentatively labeled as hyperaroused. The aim of this study was to determine whether these children have a hyperaroused central nervous system. Participants included 104 boys aged 8 to 13 years old, with a diagnosis of either the Combined or Inattentive type of AD/HD (67 combined type), and 67 age-matched male controls. Ten and a half minutes of EEG and skin conductance (SCL) were simultaneously recorded during an eyes-closed resting condition. The EEG was Fourier transformed and estimates of total power, and relative power in the delta, theta, alpha, and beta bands, and the theta/beta ratio, were calculated. AD/HD patients were divided into an excess beta group and a typical excess theta group. Relative to controls, the typical excess theta group had significantly increased frontal total power, theta and theta/beta ratio, with reduced alpha and beta across the scalp. The excess beta group had significantly reduced posterior total power, increased centro-posterior delta, globally reduced alpha, globally increased beta activity, and globally reduced theta/beta ratio. Both AD/HD groups had significantly reduced SCL compared to the control group, but the two groups did not differ from each other on SCL. These results indicate that AD/HD children with excess beta activity are not hyperaroused, and confirm that the theta/beta ratio is not associated with arousal. This is the first study of arousal measures in AD/HD children with excess beta activity, and has implications for existing models of AD/HD.

presented at the 23rd Australasian Society for Psychophysiology Conference, 20-22 Nov 2013, Wollongong, Australia

presented at the 23rd Australasian Society for Psychophysiology Conference, 20-22 Nov 2013, Wollongong, Australia

This study investigated sex differences between the EEGs of Combined and Inattentive types of attention-deficit/hyperactivity disorder (AD/HD) within boys and girls aged 8-12 years. Subject groups included 80 AD/HD Combined type (40 boys and 40 girls), 80 AD/HD Inattentive type (40 boys and 40 girls) and 80 controls (40 boys and 40 girls). An eyes-closed resting EEG was recorded and Fourier transformed to provide estimates for absolute and relative power in the delta, theta, alpha and beta frequency bands, as well as total power and the theta/beta ratio. The boy AD/HD groups, compared with boy controls, had greater absolute and relative theta, greater theta/beta ratio, reduced absolute and relative alpha, and reduced absolute and relative beta. The girl AD/HD groups, compared with girl controls, had greater absolute delta, greater absolute and relative theta, greater theta/beta ratio, greater total power, and reduced relative delta and relative beta. Between AD/HD types, Combined type boys had globally greater absolute and relative theta, greater theta/beta ratio, and less relative alpha than Inattentive type boys. While topographical differences emerged, there were no significant global differences between AD/HD types in girls. That is, EEG differences between AD/HD types are dissimilar in boys and girls. Different EEG maturational patterns between boys and girls also obscure AD/HD-related EEG abnormalities. These results have important implications for our understanding of AD/HD in girls. Ignoring such sex differences may have compromised the value of previous AD/HD investigations, and these sex differences should be recognised in future research.

Both Attention-Deficit/Hyperactivity Disorder (AD/HD) and divorce are very prevalent in western societies, and they may occur together. AD/HD is generally viewed as a neurobiological disorder, which has led to a commonly held belief that social-environmental factors play little role in the symptom profile of children diagnosed with the disorder. This study investigated the association between parental divorce, remarriage, multiple transitions, the quality of relationships with family members and the psychological well-being of children and adolescents with AD/HD. First, differences in children's AD/HD symptom profiles in relation to parents' divorce status (single/multiple divorce) and family composition (single parent/stepfamily) were examined. Second, the association between the quality of children's relationships with each family member and parents' marital status (divorced/non-divorced) and family composition was investigated. In addition, age, gender and AD/HD subtype differences were assessed. Third, the association between the quality of children's interactions with family members and children's AD/HD symptom profile was explored. No significant differences in children's behavioural profiles were found in terms of parents' divorce status. Living in stepfamilies was associated with greater AD/HD severity and social malfunctioning. Disruptive parent-child and sibling relationships were found to be related to children's age, gender, AD/HD subtype and parents' marital status. Further, poor interactions with family members correlated with children's AD/HD severity and psychological well-being. In summary, divorce, remarriage and the quality of relationships with family members are important correlates of the symptom profile of children with AD/HD, and this emphasises the need for special treatment modules for these families.

The effect of a single oral dose of caffeine was examined in a randomised double-blind placebo-controlled repeated-measures cross-over study. Eighteen children with AD/HD, aged between 8 and 13 years, were individually age- and gender-matched with a control group. All children participated in two sessions, one week apart. Skin conductance level (SCL) from a 3 min eyes-closed epoch, commencing 30 min after ingestion of caffeine or placebo, was examined. Across conditions, mean SCL was lower in the AD/HD group than controls, confirming hypoarousal in AD/HD. Caffeine produced an increase in SCL, and this increase did not differ between the groups. However, arousal increases were dose-dependent in controls, but not in AD/HD. Rather, caffeine-induced arousal increases in the AD/HD group were positively related to their hyperactivity/impulsivity levels. This suggests an anomalous arousal mechanism in AD/HD functionally related to impairment in one symptom dimension.

The effect of a single oral dose of caffeine was examined in a randomised double-blind placebo-controlled repeated-measures cross-over study. Eighteen children with AD/HD, aged between 8 and 13 years, were individually age- and gender-matched with a control group. All children participated in two sessions, one week apart. Skin conductance level (SCL) from a 3 min eyes-closed epoch, commencing 30 min after ingestion of caffeine or placebo, was examined. Across conditions, mean SCL was lower in the AD/HD group than controls, confirming hypoarousal in AD/HD. Caffeine produced an increase in SCL, and this increase did not differ between the groups. However, arousal increases were dose-dependent in controls, but not in AD/HD. Rather, caffeine-induced arousal increases in the AD/HD group were positively related to their hyperactivity/impulsivity levels. This suggests an anomalous arousal mechanism in AD/HD functionally related to impairment in one symptom dimension.

The effect of a single oral dose of caffeine was examined in a randomised double-blind placebo-controlled repeated-measures cross-over study. Eighteen children with AD/HD, aged between 8 and 13 years, were individually age- and gender-matched with a control group. All children participated in two sessions, one week apart. Skin conductance level (SCL) from a 3 min eyes-closed epoch, commencing 30 min after ingestion of caffeine or placebo, was examined. Across conditions, mean SCL was lower in the AD/HD group than controls, confirming hypoarousal in AD/HD. Caffeine produced an increase in SCL, and this increase did not differ between the groups. However, arousal increases were dose-dependent in controls, but not in AD/HD. Rather, caffeine-induced arousal increases in the AD/HD group were positively related to their hyperactivity/impulsivity levels. This suggests an anomalous arousal mechanism in AD/HD functionally related to impairment in one symptom dimension.

The effect of a single oral dose of caffeine was examined in a randomised double-blind placebo-controlled repeated-measures cross-over study. Eighteen children with AD/HD, aged between 8 and 13 years, were individually age- and gender-matched with a control group. All children participated in two sessions, one week apart. Skin conductance level (SCL) from a 3 min eyes-closed epoch, commencing 30 min after ingestion of caffeine or placebo, was examined. Across conditions, mean SCL was lower in the AD/HD group than controls, confirming hypoarousal in AD/HD. Caffeine produced an increase in SCL, and this increase did not differ between the groups. However, arousal increases were dose-dependent in controls, but not in AD/HD. Rather, caffeine-induced arousal increases in the AD/HD group were positively related to their hyperactivity/impulsivity levels. This suggests an anomalous arousal mechanism in AD/HD functionally related to impairment in one symptom dimension.

The effect of a single oral dose of caffeine was examined in a randomised double-blind placebo-controlled repeated-measures cross-over study. Eighteen children with AD/HD, aged between 8 and 13 years, were individually age- and gender-matched with a control group. All children participated in two sessions, one week apart. Skin conductance level (SCL) from a 3 min eyes-closed epoch, commencing 30 min after ingestion of caffeine or placebo, was examined. Across conditions, mean SCL was lower in the AD/HD group than controls, confirming hypoarousal in AD/HD. Caffeine produced an increase in SCL, and this increase did not differ between the groups. However, arousal increases were dose-dependent in controls, but not in AD/HD. Rather, caffeine-induced arousal increases in the AD/HD group were positively related to their hyperactivity/impulsivity levels. This suggests an anomalous arousal mechanism in AD/HD functionally related to impairment in one symptom dimension.

Objective: We compared EEG coherence in children with and without AD/HD, and sought to relateobserved anomalies to AD/HD symptoms.Methods: Forty children with AD/HD and 40 age- and sex-matched controls had eyes-closed resting EEGcoherence calculated for eight interhemispheric electrode pairs and eight intrahemispheric pairs (fourwithin each hemisphere) in the delta, theta, alpha, beta and ``40 Hz¿¿ gamma bands.Results: At short-medium inter-electrode distances, the AD/HD group had increased intrahemisphericcoherence in delta and theta, and reduced (L > R) laterality in delta, alpha, beta and gamma. Over longerinter-electrode distances, the AD/HD group had reduced intrahemispheric coherence in alpha. In interhemisphericcomparisons, the AD/HD group had reduced frontal coherence in delta, alpha and gamma,increased temporal theta and reduced temporal alpha coherences, and increased central/parietal/occipitalcoherence in theta. Smaller left-lateralized coherences in AD/HD correlated negatively with DSM Inattentiveand DSM Total scores, and smaller frontal interhemispheric coherence in alpha correlatednegatively with DSM Hyperactive/Impulsive score.Conclusions: The negative correlations between AD/HD coherence anomalies and symptoms suggest thatseveral anomalies reflect compensatory brain function.Significance: Coherence differences in AD/HD may reflect anomalous frontal right-hemisphere linkagesthat help compensate functional brain anomalies in the left frontal regions in this disorder. 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd.

Objective: We compared EEG coherence in children with and without AD/HD, and sought to relateobserved anomalies to AD/HD symptoms.Methods: Forty children with AD/HD and 40 age- and sex-matched controls had eyes-closed resting EEGcoherence calculated for eight interhemispheric electrode pairs and eight intrahemispheric pairs (fourwithin each hemisphere) in the delta, theta, alpha, beta and ``40 Hz¿¿ gamma bands.Results: At short-medium inter-electrode distances, the AD/HD group had increased intrahemisphericcoherence in delta and theta, and reduced (L > R) laterality in delta, alpha, beta and gamma. Over longerinter-electrode distances, the AD/HD group had reduced intrahemispheric coherence in alpha. In interhemisphericcomparisons, the AD/HD group had reduced frontal coherence in delta, alpha and gamma,increased temporal theta and reduced temporal alpha coherences, and increased central/parietal/occipitalcoherence in theta. Smaller left-lateralized coherences in AD/HD correlated negatively with DSM Inattentiveand DSM Total scores, and smaller frontal interhemispheric coherence in alpha correlatednegatively with DSM Hyperactive/Impulsive score.Conclusions: The negative correlations between AD/HD coherence anomalies and symptoms suggest thatseveral anomalies reflect compensatory brain function.Significance: Coherence differences in AD/HD may reflect anomalous frontal right-hemisphere linkagesthat help compensate functional brain anomalies in the left frontal regions in this disorder. 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd.

Objective: We compared EEG coherence in children with and without AD/HD, and sought to relateobserved anomalies to AD/HD symptoms.Methods: Forty children with AD/HD and 40 age- and sex-matched controls had eyes-closed resting EEGcoherence calculated for eight interhemispheric electrode pairs and eight intrahemispheric pairs (fourwithin each hemisphere) in the delta, theta, alpha, beta and ``40 Hz¿¿ gamma bands.Results: At short-medium inter-electrode distances, the AD/HD group had increased intrahemisphericcoherence in delta and theta, and reduced (L > R) laterality in delta, alpha, beta and gamma. Over longerinter-electrode distances, the AD/HD group had reduced intrahemispheric coherence in alpha. In interhemisphericcomparisons, the AD/HD group had reduced frontal coherence in delta, alpha and gamma,increased temporal theta and reduced temporal alpha coherences, and increased central/parietal/occipitalcoherence in theta. Smaller left-lateralized coherences in AD/HD correlated negatively with DSM Inattentiveand DSM Total scores, and smaller frontal interhemispheric coherence in alpha correlatednegatively with DSM Hyperactive/Impulsive score.Conclusions: The negative correlations between AD/HD coherence anomalies and symptoms suggest thatseveral anomalies reflect compensatory brain function.Significance: Coherence differences in AD/HD may reflect anomalous frontal right-hemisphere linkagesthat help compensate functional brain anomalies in the left frontal regions in this disorder. 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd.

Objective: This study investigated the presence and nature of EEG clusters within a clinically-referredsample of children with Attention-Deficit/Hyperactivity Disorder (AD/HD), and whether behavioural differencesexist between clusters.Method: Participants were 155 boys with AD/HD and 109 age- and gender-matched controls. EEG wasrecorded during an eyes-closed resting condition and Fourier transformed to provide estimates for totalpower, and relative delta, theta, alpha, and beta. EEG data were grouped into 3 regions, and subjected toCluster Analysis. Behavioural data for each cluster were compared against the remaining AD/HD subjects.Results: Four EEG clusters were found. These were characterised by (a) elevated beta activity, (b) elevatedtheta with deficiencies of alpha and beta, (c) elevated slow wave with less fast wave activity, and (d) elevatedalpha. An exploratory analysis of behavioural correlates with these EEG subtypes indicated thepresence of interesting trends that need further investigation.Conclusions: This study found that the AD/HD EEG profiles reported in past studies are robust and notsubstantially affected by the inclusion of children with other comorbid conditions. The observed groupdifferences in behavioural profiles indicated that different patterns of EEG activity have importance indetermining behaviour.Significance: This is the first study to link behavioural profiles of children with AD/HD to specific EEGabnormalities.

Objective: We compared EEG coherence in children with and without AD/HD, and sought to relateobserved anomalies to AD/HD symptoms.Methods: Forty children with AD/HD and 40 age- and sex-matched controls had eyes-closed resting EEGcoherence calculated for eight interhemispheric electrode pairs and eight intrahemispheric pairs (fourwithin each hemisphere) in the delta, theta, alpha, beta and ``40 Hz¿¿ gamma bands.Results: At short-medium inter-electrode distances, the AD/HD group had increased intrahemisphericcoherence in delta and theta, and reduced (L > R) laterality in delta, alpha, beta and gamma. Over longerinter-electrode distances, the AD/HD group had reduced intrahemispheric coherence in alpha. In interhemisphericcomparisons, the AD/HD group had reduced frontal coherence in delta, alpha and gamma,increased temporal theta and reduced temporal alpha coherences, and increased central/parietal/occipitalcoherence in theta. Smaller left-lateralized coherences in AD/HD correlated negatively with DSM Inattentiveand DSM Total scores, and smaller frontal interhemispheric coherence in alpha correlatednegatively with DSM Hyperactive/Impulsive score.Conclusions: The negative correlations between AD/HD coherence anomalies and symptoms suggest thatseveral anomalies reflect compensatory brain function.Significance: Coherence differences in AD/HD may reflect anomalous frontal right-hemisphere linkagesthat help compensate functional brain anomalies in the left frontal regions in this disorder. 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd.

Objective: This study investigated the presence and nature of EEG clusters within a clinically-referredsample of children with Attention-Deficit/Hyperactivity Disorder (AD/HD), and whether behavioural differencesexist between clusters.Method: Participants were 155 boys with AD/HD and 109 age- and gender-matched controls. EEG wasrecorded during an eyes-closed resting condition and Fourier transformed to provide estimates for totalpower, and relative delta, theta, alpha, and beta. EEG data were grouped into 3 regions, and subjected toCluster Analysis. Behavioural data for each cluster were compared against the remaining AD/HD subjects.Results: Four EEG clusters were found. These were characterised by (a) elevated beta activity, (b) elevatedtheta with deficiencies of alpha and beta, (c) elevated slow wave with less fast wave activity, and (d) elevatedalpha. An exploratory analysis of behavioural correlates with these EEG subtypes indicated thepresence of interesting trends that need further investigation.Conclusions: This study found that the AD/HD EEG profiles reported in past studies are robust and notsubstantially affected by the inclusion of children with other comorbid conditions. The observed groupdifferences in behavioural profiles indicated that different patterns of EEG activity have importance indetermining behaviour.Significance: This is the first study to link behavioural profiles of children with AD/HD to specific EEGabnormalities.

Objective: We compared EEG coherence in children with and without AD/HD, and sought to relateobserved anomalies to AD/HD symptoms.Methods: Forty children with AD/HD and 40 age- and sex-matched controls had eyes-closed resting EEGcoherence calculated for eight interhemispheric electrode pairs and eight intrahemispheric pairs (fourwithin each hemisphere) in the delta, theta, alpha, beta and ``40 Hz¿¿ gamma bands.Results: At short-medium inter-electrode distances, the AD/HD group had increased intrahemisphericcoherence in delta and theta, and reduced (L > R) laterality in delta, alpha, beta and gamma. Over longerinter-electrode distances, the AD/HD group had reduced intrahemispheric coherence in alpha. In interhemisphericcomparisons, the AD/HD group had reduced frontal coherence in delta, alpha and gamma,increased temporal theta and reduced temporal alpha coherences, and increased central/parietal/occipitalcoherence in theta. Smaller left-lateralized coherences in AD/HD correlated negatively with DSM Inattentiveand DSM Total scores, and smaller frontal interhemispheric coherence in alpha correlatednegatively with DSM Hyperactive/Impulsive score.Conclusions: The negative correlations between AD/HD coherence anomalies and symptoms suggest thatseveral anomalies reflect compensatory brain function.Significance: Coherence differences in AD/HD may reflect anomalous frontal right-hemisphere linkagesthat help compensate functional brain anomalies in the left frontal regions in this disorder. 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd.

Objective: This study investigated the presence and nature of EEG clusters within a clinically-referredsample of children with Attention-Deficit/Hyperactivity Disorder (AD/HD), and whether behavioural differencesexist between clusters.Method: Participants were 155 boys with AD/HD and 109 age- and gender-matched controls. EEG wasrecorded during an eyes-closed resting condition and Fourier transformed to provide estimates for totalpower, and relative delta, theta, alpha, and beta. EEG data were grouped into 3 regions, and subjected toCluster Analysis. Behavioural data for each cluster were compared against the remaining AD/HD subjects.Results: Four EEG clusters were found. These were characterised by (a) elevated beta activity, (b) elevatedtheta with deficiencies of alpha and beta, (c) elevated slow wave with less fast wave activity, and (d) elevatedalpha. An exploratory analysis of behavioural correlates with these EEG subtypes indicated thepresence of interesting trends that need further investigation.Conclusions: This study found that the AD/HD EEG profiles reported in past studies are robust and notsubstantially affected by the inclusion of children with other comorbid conditions. The observed groupdifferences in behavioural profiles indicated that different patterns of EEG activity have importance indetermining behaviour.Significance: This is the first study to link behavioural profiles of children with AD/HD to specific EEGabnormalities.