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Cognitive and electroencephalographic disturbances in children with attention-deficit/hyperactivity disorder and sleep problems: New insights
Abstract
There is overlap between the behavioural symptoms and disturbances associated with Attention-Deficit/Hyperactivity Disorder (AD/HD) and sleep problems. The aim of this study was to examine the extent of overlap in cognitive and electrophysiological disturbances identified in children experiencing sleep problems and children with AD/HD or both. Four groups (aged 7-18) were compared: children with combined AD/HD and sleep problems (n=32), children with AD/HD (n=52) or sleep problems (n=36) only, and children with neither disorder (n=119). Electrophysiological and cognitive function measures included: absolute EEG power during eyes open and eyes closed, event-related potential (ERP) components indexing attention and working memory processes (P3), and a number of standard neuropsychological tests. Children with symptoms of both AD/HD and sleep problems had a different profile from those of children with either AD/HD or sleep problems only. These findings suggest it is unlikely that disturbances in brain and cognitive functioning associated with sleep problems also give rise to AD/HD symptomatology and consequent diagnosis. Furthermore, findings suggest that children with symptoms of both AD/HD and sleep problems may have a different underlying aetiology than children with AD/HD-only or sleep problems-only, perhaps requiring unique treatment interventions.
... Accumulating evidence indicates that inadequate sleep is associated with behavioral and emotional problems and impairments in cognitive functions in children (Beebe, 2011). Crosssectional studies in typically developing children have reported associations between sleep disturbances and internalizing problems (Alfano, Zakem, Costa, Taylor, & Weems, 2009), externalizing problems (Aronen, Paavonen, Fjallberg, Soininen, & Torronen, 2000), and impairments in neurocognitive functions such as working memory (Steenari et al., 2003) and attention (Sawyer et al., 2009). Longitudinal studies have demonstrated that sleep problems in preschool predict emotional and externalizing behavioral problems (Gregory & O'Connor, 2002), as well as impaired performance on neurocognitive tests (Gregory, Caspi, Moffitt, & Poulton, 2009) in adolescents. ...
... Studies examining the relation between sleep and performance on tests of attentional functioning in children with ADHD have yielded conflicting results. Subjectively reported sleep problems were associated with increased distractibility, but not inattention or impulsivity (Sawyer et al., 2009), and sleep restriction was associated with impaired sustained attention (Gruber et al., 2011) in children with ADHD. In contrast, actigraphically measured sleep quality was not associated with reduced performance in a range of neurocognitive tasks (including attention) in boys with ADHD (Gruber & Sadeh, 2004). ...
... Our finding of a lower alerting score associated with sleep problems in children with ADHD may be consistent with the results from a previous study that found an increased number of omission errors on a continuous performance test following 1 week of sleep restriction in children with ADHD (Gruber et al., 2011). However, another study reported increased distractibility, but not inattention, in children with ADHD and sleep problems (Sawyer et al., 2009). ...
This study examined associations between sleep problems and attentional and behavioral functioning in 137 children aged 7 to 13 years with anxiety disorders (n = 39), attention deficit hyperactivity disorder (ADHD; n = 38), combined anxiety disorder and ADHD (n = 25), and 35 controls. Diagnoses were made using the semistructured diagnostic interview Schedule for Affective Disorders and Schizophrenia for School-age Children-Present and Lifetime Version. Sleep problems were assessed using the Children's Sleep Habits Questionnaire, attention was measured by the Attention Network Test, and behavioral problems were measured by teacher ratings on the Achenbach System of Empirically Based Assessment, Teacher Report Form. Sleep problems were associated with reduced efficiency of the alerting attention system for all children and with increased internalizing problems in children with anxiety disorders.
... If ADHD symptoms are caused by dysregulation of arousal (Sergeant, 2005), then symptoms of both inattention and hyperactivity/impulsivity may be attributable to daytime sleepiness associated with heightened arousal at night (Andrillon et al., 2019). While sleep deprivation can lead to both daytime sleepiness and impulsivity in typically developing children (Sawyer et al., 2009), children with ADHD commonly exhibit sluggishness and hypo-vigilance, which correlates with more frequent sleep disturbances (Hvolby, 2015;Ludahl et al., 2015). These children have more severe ADHD symptoms and more functional impairments when compared to children with only ADHD or only sleep problems (Knight & Dimitriou, 2017;Sawyer et al., 2009). ...
... While sleep deprivation can lead to both daytime sleepiness and impulsivity in typically developing children (Sawyer et al., 2009), children with ADHD commonly exhibit sluggishness and hypo-vigilance, which correlates with more frequent sleep disturbances (Hvolby, 2015;Ludahl et al., 2015). These children have more severe ADHD symptoms and more functional impairments when compared to children with only ADHD or only sleep problems (Knight & Dimitriou, 2017;Sawyer et al., 2009). ...
Background: ADHD commonly occurs with sleep problems and secondary cognitive impairments such as inhibitory control. Sleep problems may explain attentional lapses and inhibition performance variability in children with ADHD. This study applied Bayesian analyses to examine the relationship between ADHD symptoms, sleep problems, and inhibition. Methods: Participants included 73 children with ADHD and 73 non-ADHD controls, aged 10.5 to 13.5 years. The Stop Signal Task measured inhibition. Sleep problems were measured with the Adolescent Sleep Wake Scale and parent-report. Results: ADHD symptoms are associated with sleep problems and reaction time variability, however, sleep problems accounted for more variance in inhibition performance than both hyperactive and inattentive symptoms. Conclusion: Sleep problems account for inhibition performance over and above ADHD symptom severity in children with and without ADHD diagnoses. This suggests clinical utility in assessing sleep in children with manifestations of ADHD, and interventions targeting sleep problems concurrently with behavioral symptoms. This further adds to the discussion on overdiagnosis of ADHD due to behavioral presentations of underlying sleep disorders. Treatment for phenotypes of ADHD could be enhanced by targeting sleep problems, in addition to inhibition deficits and attentional lapses.
... ADHD youth are also more likely to display sleep disorders (Herman, 2015), disrupted circadian rhythms (Imeraj et al., 2012), and daytime sleepiness (Cortese et al., 2009a(Cortese et al., , 2009bGolan, Shahar, Ravid, & Pillar, 2004;Lecendreux, Konofal, Bouvard, Falissard, & Mouren-Simeoni, 2000) than peers. Importantly, sleep difficulties may exacerbate ADHD symptom severity (Dahl, 1996) and neurocognitive deficits (Sawyer et al., 2009). ...
... Neurocognitive impairment associated with poor sleep in typical adolescents may be amplified in youth with ADHD. For example, children with ADHD and poor sleep display greater distractibility than youth with either disorder alone (Sawyer et al., 2009), and self-reported sleep problems among children with ADHD are related to working memory deficits (Sciberras, DePetro, Mensah, & Hiscock, 2015). Specific sleep deficits are also related to impaired neurocognition in youth with ADHD. ...
Objective:
Children with ADHD display higher rates of sleep problems, and both sleep disorders and ADHD have been shown to affect functioning in childhood. The current study examines the frequency and relationship between sleep problems and ADHD, and their impact on quality of life (QoL) and functional impairment.
Method:
Parents of 192 children with ADHD ( M = 10.23 years) completed measures regarding their child's ADHD symptoms (Swanson, Nolan and Pelham [SNAP]), sleep disorders (Pediatric Sleep Questionnaire [PSQ]), QoL (Child Health Illness Profile [CHIP-PE]), and functioning (Weiss Functional Impairment Rating Scale-Parent Report [WFIRS-P]).
Results:
Common sleep complaints in participants were insomnia, excessive daytime sleepiness (EDS), and variability in sleep schedule. Regression analysis indicated that sleep problems and ADHD symptoms independently predicted lower levels of QoL (Δ R(2) = .12, p < .001) and social functioning (Δ R(2) = .12, p < .001).
Conclusion:
The results suggest that ADHD may coexist with somnolence and that both conditions have a significant impact on a child's functioning and QoL.
... ADHD youth are also more likely to display sleep disorders (Herman, 2015), disrupted circadian rhythms (Imeraj et al., 2012), and daytime sleepiness Golan, Shahar, Ravid, & Pillar, 2004;Lecendreux, Konofal, Bouvard, Falissard, & Mouren-Simeoni, 2000) than peers. Importantly, sleep difficulties may exacerbate ADHD symptom severity (Dahl, 1996) and neurocognitive deficits (Sawyer et al., 2009). ...
... Neurocognitive impairment associated with poor sleep in typical adolescents may be amplified in youth with ADHD. For example, children with ADHD and poor sleep display greater distractibility than youth with either disorder alone (Sawyer et al., 2009), and selfreported sleep problems among children with ADHD are related to working memory deficits (Sciberras, DePetro, Mensah, & Hiscock, 2015). Specific sleep deficits are also related to impaired neurocognition in youth with ADHD. ...
Background:
Biological mechanisms underlying symptom and prognostic heterogeneity in Attention-Deficit/Hyperactivity Disorder (ADHD) are unclear. Sleep impacts neurocognition and daytime functioning and is disrupted in ADHD, yet little is known about sleep in ADHD during adolescence, a period characterized by alterations in sleep, brain structure, and environmental demands as well as diverging ADHD trajectories.
Methods:
A systematic review identified studies published prior to August 2016 assessing sleep in adolescents (aged 10-19years) with ADHD or participating in population-based studies measuring ADHD symptoms.
Results:
Twenty-five studies were identified (19 subjective report, 6 using actigraphy/polysomnography). Findings are mixed but overall suggest associations between sleep disturbances and 1) ADHD symptoms in the population and 2) poorer clinical, neurocognitive, and functional outcomes among adolescents with ADHD. Common limitations of studies included small or non-representative samples, non-standardized sleep measures, and cross-sectional methodology.
Conclusions:
Current data on sleep in adolescent ADHD are sparse and limited by methodological concerns. Future studies are critical for clarifying a potential role of sleep in contributing to heterogeneity of ADHD presentation and prognosis. Potential mechanisms by which sleep disturbances during adolescence may contribute to worsened symptom severity and persistence of ADHD into adulthood and an agenda to guide future research are discussed.
... Given that these areas are already impaired in many youth with ADHD (Shaw, Stringaris, Nigg, & Leibenluft, 2014;Willcutt, Doyle, Nigg, Faraone, & Pennington, 2005), it is likely that sleep problems will further exacerbate these impairments. For example, sleep problems in children with ADHD are related to working memory deficits (Sciberras, DePetro, Mensah, & Hiscock, 2015), and children with poor sleep and ADHD are more distractible than children with either disorder alone (Sawyer et al., 2009). However, studies to date that have investigated the relations between sleep and cognition in youth with ADHD have been cross-sectional, making directionality and causal contributions unknown. ...
... questions surrounding prevalence rates, mounting evidence substantiates the claim that sleep disturbances worsen ADHD symptomatology. For instance, poor sleep in ADHD has been associated with increased distractibility (Sawyer et al., 2009); increased prevalence of conduct problems, hyperactivity, and restlessness (Stephens, Chung, & Jovanovic et al., 2013); as well as deficits in the overnight consolidation of declarative and emotional memories (Prehn-Kristensen et al., 2011;Prehn-Kristensen et al., 2013). Probing the direction of this effect, Gruber et al. (2011) report that the experimental restriction of sleep in ADHD children serves to move subclinical levels of sustained attention into the clinical range. ...
Background: Sleep problems are commonly reported in attention deficit/hyperactivity disorder (ADHD), and are also a familiar characteristic of typical development (TD). We sought to elucidate the relationship between sleep, ADHD-trait behaviours and cognitive inattention, and how it manifests between ADHD and TD children.
Participants: 18 children diagnosed with ADHD and 20 age-matched TD controls aged 5–11 year-old participated in the study.
Methods: Sleep profiles were assessed using Children’s Sleep Habits Questionnaire and actigraphy measures. Behavioural functioning was examined using Conners’ Parent Report Scale and attention using the computerised Conners’ Continuous Performance Task.
Results: We found evidence of 1) poorer sleep quality in the ADHD group, despite no difference in actual sleep time; 2) poor sleep quality in TD children predicted increased ADHD-trait behaviours, despite no association with attention; 3) a consistent trend for poor sleep quality predicting reduced attentional control in ADHD children, despite no association with behaviour.
Conclusions: Poor sleep quality affects developmental sub-groups in different ways. For ADHD children poor sleep worsens their predisposed attentional deficit, whilst for TD children it mimics ADHD behaviours. These findings have important implications for the debate on over-diagnosis of childhood ADHD, and the use of sleep-based interventions. Above all, they highlight the importance of promoting good sleep hygiene in all children.
... Further support for taking a transdiagnostic approach when investigating sleep and working memory in children with neurological conditions comes from the finding that poor sleep quality is associated with reduced verbal working memory performance. These results are consistent with those of Zambrano-Sanchez et al. (2013) and Sawyer et al. (2009), who both found that problematic sleep is associated with working memory difficulties in children with ADHD. However, the present results extend their findings by demonstrating that the sleep and working memory relationship spans across many common childhood neurological conditions, rather than occurring in specific, individual diagnoses. ...
The objective of this study is to investigate whether sleep problems
might account for the increased working memory deficits
observed in school-aged children with neurological conditions. A
novel, transdiagnostic approach to the investigation was chosen,
and sleep is treated as a process that can potentially account for
working memory difficulties across a range of neurological conditions.
Prevalence estimates of sleep problems are also examined.
Archival data of 237 children aged 6 to 11 years were collected
from a Western Australian statewide neuropsychological service
for the period 26 July 2011 to 14 January 2014. Measures of
parent-reported sleep quality, snoring, and daytime sleepiness
were obtained, in addition to objective measures of verbal and
spatial working memory, storage capacity, and processing speed.
The results of the data analysis reveal that over one third of
participants reported having clinically-significant levels of sleep
problems and that poor sleep quality is significantly associated
with verbal working memory difficulties. This association remains
after partialling out the variance contributed to performance by
storage capacity and processing speed, suggesting that sleep is
impacting upon an executive component of working memory. No
other significant associations are observed. The results suggest
that poor sleep quality is associated with an executive component
of verbal (rather than spatial) working memory in children with
neurological conditions. This has implications for the biological
mechanisms thought to underlie the relationship between sleep
and cognition in children. The results also demonstrate the clinical
utility of a transdiagnostic approach when investigating sleep and
cognition in children with neurological conditions.
... Despite this, current evidence suggests that, in many cases of ADHD, sleep disturbance is secondary to the disorder itself. A study of electrophysiological and cognitive factors indicated that children with sleep difficulties and ADHD compose a separable group from those children with ADHD or sleep difficulties alone (Sawyer et al., 2009). Differences in periodic limb movements in sleep between children with ADHD from a community sample and those referred through a sleep clinic also point to a potentially different etiology in ADHD symptoms between those groups (O'Brian et al., 2003a). ...
... Par exemple, nous savons que certaines caractéristiques épileptiques telles que les pointes continues pendant le sommeil sont associées à un déclin cognitif (Tassinari, Meletti, Volpi & Michelucci, 2001.). Par ailleurs, il est bien documenté que les troubles du sommeil engendrent des difficultés cognitives diurnes, en particulier de l'attention et de la mémoire (Sawyer et al. 2009 ;Fallone et al. 2005). Ainsi, chez les enfants EPCT, les performances cognitives anormales pourraient être, en partie, dues à un manque de vigilance, secondaire à une fragmentation du sommeil (Kohrman et Carney, 2000 ;Stores, 2001). ...
L’epilepsie Rolandique est la forme la plus frequente des epilepsies idiopathiques de l’enfance, dont les premieres manifestations surviennent entre 3 et 13 ans. Le pronostic de ces patients est bon, en raison notamment de la remission spontanee de cette epilepsie a l’adolescence. Toutefois, des etudes recentes suggerent la presence de troubles specifiques, durant la phase active du syndrome, dans les spheres cognitive, affective et comportementale. Les particularites neuropsychologiques rapportees concernent les spheres langagieres et perceptuelles, les capacites mnesiques et attentionnelles. De plus, quelques auteurs suggerent la persistance de certaines specificites dans le traitement de l’information, chez ses patients, apres la remission complete de cette epilepsie. Cette revue de la litterature a pour but de recenser et de classer les divers troubles cognitifs et affectifs rapportes par les etudes recentes s’interessant aux consequences de cette epilepsie benigne. Des travaux investiguant la qualite de vie de ces enfants viennent completer cette recension.
Mots-cles : Epilepsie benigne a pointes centro-temporales ; epilepsie Rolandique ; cognition ; deficits neuropsychologiques
; comportement ; qualite de vie.
... Cognitive and electrophysiological disturbances were identified in children experiencing SD and in children with ADHD, or both, by Sawyer et al. 17 Four groups (age, 7-18 years) were compared: children with combined ADHD and SD, children with ADHD or SD alone, and children with neither disorder. Electrophysiological and cognitive function measurements included: absolute EEG power with eyes open and eyes closed, event-related potential (ERP) components indexing attention and working memory processes (P3 wave), in addition to a number of standard neuropsychological tests. ...
Objective:
To compare frequency of sleep disorders (SD) and executive dysfunction (ED) in children with attention deficit-hyperactivity disorder (ADHD) and a control group.
Method:
We studied 156 children with ADHD with a mean age of 8.5 years, and a control group with 111 children with a mean age of 8.3 years. We utilized the Pediatric Sleep Questionnaire (PSQ) to screen SD and the working memory measurement from the Wechsler intelligence scale for children (WISC-IV) to screen ED.
Results:
We did not observe an increased frequency of SD in children with ADHD compared with the controls. However, we did identify ED in children with ADHD; additionally a significant correlation was observed between the type of ADHD and SD and among ED, WISC-IV measurements, and type of SD in children with ADHD.
Conclusion:
An increase of SD frequency in children with ADHD was not observed, but we did identify ED in children with ADHD. Additionally, a correlation among ADHD types, SD, ED, and WISC-IV measurements was observed in children with ADHD.
Sleep problems can affect children and their families in multiple ways. They can worsen the child’s cognitive function (e.g., attention, executive control, processing speed, and working memory), social–emotional well-being, academic achievement, irritability, and classroom behavior. They can also impact adversely on parent mental health and broader functioning such as work attendance. This chapter will critically review the literature around the associations between sleep problems and other child and family outcomes, including the degree to which sleep problems versus attention deficit hyperactivity disorder symptoms account for these poorer outcomes, and the impact of sleep interventions on these other outcomes.
Study objectives:
The current study aimed to examine the association of insomnia symptoms with daytime behavior and cognitive functioning in children with attention deficit hyperactivity disorder (ADHD).
Methods:
Thirty-six children with ADHD and insomnia symptoms, 27 children with ADHD without insomnia symptoms and 21 age-matched healthy controls were recruited in this study (age range: 6-12 years, 70% male). They were assessed by parent-report questionnaires on insomnia symptoms (Children's Sleep Habit Questionnaire) and ADHD symptoms (Strengths and Weaknesses of ADHD Symptoms and Normal Behavior Scale, SWAN), and completed a battery of cognitive tests including Continuous Performance Test (CPT) for sustained attention, Letter-digit test for processing speed, Digit Span forward test and N-back task for working memory, Tower of London (TOL) test for planning skills and Bergs Card Sorting Test (BCST) for set-shifting ability.
Results:
Children with ADHD and insomnia symptoms had the highest scores on SWAN total, and inattention and hyperactivity subscales, followed by children with ADHD without insomnia and healthy controls (all ps < 0.05). After controlling for potential confounders, children with ADHD and insomnia symptoms showed poorer performance on CPT and Letter-digit test as compared to children with ADHD without insomnia and healthy controls (all ps < 0.05).
Conclusions:
Insomnia symptoms are associated with more severe ADHD symptoms and cognitive impairments in children with ADHD, especially deficits on sustained attention and processing speed. Future longitudinal studies are needed to explore the long-term impacts of insomnia symptoms and the effects of sleep-focused intervention on cognitive functioning in children with ADHD.
Objective
We meta-analyzed studies comparing perceptual timing abilities in the range of milliseconds to several seconds in individuals with ADHD and neurotypical participants, using the well-established time discrimination, time estimation, time production, and time reproduction paradigms.
Method
We searched Pubmed, OVID databases and WEB OF KNOWLEDGE through September 17, 2020. From 2,266 records, 55 studies were retained and meta-analyzed with random effects models. We conducted meta-regression analyses to explore moderating effects of task parameters and neuropsychological measures of working memory, attention, and inhibition on timing performance.
Results
Compared with those without ADHD, individuals with ADHD had significantly more severe difficulties in discriminating stimuli of very brief durations, especially in the sub-second range. They also had more variability in estimating the duration of stimuli lasting several seconds. Moreover, they showed deficits in time estimation and time production accuracy, indicative of an accelerated internal clock. Additional deficits in individual with ADHD were also found in the time reproduction paradigm, involving attentional (slower counting at short time intervals due to distraction) and motivational (faster counting at long time intervals due to increased delay aversion) functions.
Conclusion
There is meta-analytic evidence of a broad range of timing deficits in individuals with ADHD. Results have implications for advancing our knowledge in the field (e.g., for refinement of recent timing models in ADHD) and clinical practice (e.g., testing timing functions to characterize the clinical phenotype of the patient and implementation of interventions to improve timing abilities).
Objective. The article analyzes the clinical features of sleep in preschoolers aged 3-7 years in the city of Perm on the basis of a continuous questionnaire method. Materials and methods. The presence of complaints related to sleep at the time of the survey was substantiated in 45 % of children of the younger age group (from 3 to 5 years) and 41 % of children in the older age group (from 5 to 7 years). Results. Sexual dimorphism manifested itself in a significant dominance of intrasomnic disturbances with frequent awakenings and increased motor activity during sleep in older boys. Nocturnal pains and / or cramps in the leg muscles prevailed in girls of the older age group. In the structure of parasomnias in Perm preschool children, there predominated nightmares (16.5 %), night fears (13.3 %), bruxism (14.8 %), sleepwalking (12.8 %), enuresis (8.2 %). Every fifth child of preschool age had sleep with an open mouth, snoring or puffing, hyperhidrosis during sleep and chronic adenotonsillar pathology, which does not exclude the presence of obstructive sleep apnea / hypopnea syndrome in this category of children. Conclusions. Sleep disorders were noted in a quarter of children under one year of age, manifested by difficult falling asleep, restless sleep and sleep inversion, which can be a marker of both disorders of maturation of chronobiological mechanisms and a high percentage of childhood behavioral insomnia.
Background
Attention-Deficit/Hyperactivity Disorder (ADHD) often comorbid with sleep disturbances can produce profound disruption in daily life and impact negatively on quality of life of both the child and family. However, the temporal relationship between ADHD and sleep impairment is unclear, as are underlying common brain mechanisms.
Methods
This study used data from the Quebec Longitudinal Study of Child Development (n=1,601, 52% female) and the Adolescent Brain Cognitive Development Study (n=3,515, 48% female). Longitudinal relationships between symptoms were examined using cross-lagged panel models. Gray matter volume (GMV) neural correlates were identified using linear regression. The transcriptomic signature of the identified brain-ADHD-sleep relationship was characterized by gene enrichment analysis. Confounding factors, such as stimulant drugs for ADHD and social economic status, were controlled for.
Results
ADHD symptoms contributed to sleep disturbances at one or more subsequent time-points in both cohorts. Lower GMVs were associated with both ADHD symptoms and sleep disturbances in the middle frontal gyrus and inferior frontal gyrus, amygdala, striatum, and insula. ADHD symptoms significantly mediated the link between these structural brain abnormalities and sleep dysregulation, and genes differentially expressed in the implicated brain regions, included those involved in neurotransmission and circadian entrainment.
Conclusions
This study indicates that ADHD symptoms and sleep disturbances have common neural correlates, including structural changes of the ventral attention system and fronto-striatal circuitry. Leveraging data from large datasets, these results offer new mechanistic insights into this clinically important relationship between ADHD and sleep impairment, with potential implications for neurobiological models and future therapeutic directions.
Comorbid sleep disorders are at least twice as common in children with attention deficit hyperactivity disorder (ADHD) as compared with typically developing (TD) children. Subjective sleep-wake complaints most often reported by parents of children with ADHD are bedtime resistance, longer sleep latencies, more nighttime awakenings, and daytime sleepiness. Management of sleep problems in children with ADHD includes sleep hygiene and behavioral interventions which include establishing a consistent bedtime ritual, limit setting, a behavioral reward system, relaxation strategies, and setting times for returning to check on the child during the night. Parent-reported moderate-to-severe sleep problems found sleep hygiene and parenting were modifiable factors independently associated with sleep problems in children with ADHD. Poorer sleep hygiene was associated with increased bedtime resistance, sleep duration problems, and daytime sleepiness. More consistent parenting was associated with decreased bedtime resistance and sleep anxiety.
Benign Rolandic epilepsy is the most common form of idiopathic epilepsy in childhood. The onset is between 3 and 13 years old. These patients have a good prognosis, mainly because of a spontaneous remission in adolescence. However, recent studies indicate the presence of specific disabilities during the active phase of the syndrome on cognition, behavior and emotional control. Neuropsychological impairments affect language, perception, attention and memory. Moreover, a few studies show that some peculiarities in information processing persist in these patients after complete remission of the epilepsy. The aim of this literature review is to identify and classify the various cognitive and affective difficulties, which are associated with this epilepsy. Research investigating quality of life are also reported in order to complete this review.
Most of the disturbances of attention discussed earlier in the book occur primarily among adults secondary to neurological or medical diseases or injury that affect the brain. Major psychiatric disturbances, such as major depression and schizophrenia, likely reflect phenotypic variations in brain development and development but also typically occur as full-blown disorders when people reach adulthood. There are actually many cases of acquired attention disturbance among children suffering from congenital or chronic medical disease. For example, children with heart defects often experience attention disturbances for many of the same reasons that adults do [1–6]. Attention disturbances also occur in children as the result of certain cancers and their treatment with radiation and chemotherapy [7–17]. The functional impact of these childhood conditions is often substantial since they occur against the backdrop of the developing brain. While devastating for the children who experience these illnesses, they are relatively uncommon, as only a small percentage of children in the population experience these conditions, compared to the relatively high relevance of brain disturbances arising from stroke, cardiovascular disease, and other medical conditions in older adults. Yet, attention deficit disorder (ADD) is among the most commonly diagnosed childhood disorder, occurring in approximately 10 % of school-age children in this country [18]. The assessment and treatment of ADD has become a major focus of child psychiatry. There are now thousands of published studies on ADD and a number of excellent texts on the subject, including Russell Barkley’s “Attention Deficit Disorder: A handbook for diagnosis and treatment” [19] and the NICE guidelines [20], as well as several books that address the clinical neuroscience of ADD [21] and cognitive development [22]. In this chapter section, an overview of the normal development of attention and neuropsychological considerations regarding ADD will be provided.
Disorders like schizophrenia, bipolar disorder, major depression, and posttraumatic stress disorder have similar reticular activating system (RAS)-related dysfunction: (a) wake-sleep disturbances, reflex hyperactivity, and decreased P50 potential habituation and (b) decreased or interrupted gamma band activity. Comorbid symptoms and genetic factors overlap greatly. Treatment of these symptoms is available with some care. Disorders like attention deficit hyperactivity disorder and autism include very heterogeneous populations and/or manifest only partial RAS-related dysregulation.
It has been 15 years since the original publication of Neuropsychology of Attention. At the time of its publication, attention was a construct that had long been of theoretical interest in the field of psychology and was receiving increased research by cognitive scientists. Yet, attention was typically viewed as a nuisance variable; a factor that needed to be accounted for when assessing brain function, but of limited importance in its own right. There is a need for a new edition of this book within Neuropsychology to present an updated and integrated review of what is know about attention, the disorders that affect it, and approaches to its clinical assessment and treatment. Such a book will provide perspectives for experimental neuropsychological study of attention and also provide clinicians with insights on how to approach this neuropsychological domain. © Springer Science+Business Media New York 2014. All rights reserved.
Electroencephalography (EEG) has been used to examine the possibility of dysfunctional brain activity in externalizing behavior, but findings across studies have been inconsistent. Furthermore, studies of attention-deficit/hyperactivity disorder (ADHD) versus other externalizing behaviors, such as disruptive behavior disorders or antisocial behavior, have developed parallel literatures. The purpose of the present study was to reconcile these two literatures. A meta-analysis of 62 studies of EEG power at rest in relationship to externalizing behaviors was performed. Results of the meta-analyses showed significantly higher delta (Hedges's g = 0.25) and theta power (g = 0.40) and lower beta power (g = -0.22) in externalizing participants compared to controls. Alpha (g = -0.26) and gamma power (g = -0.26) were marginally lower in externalizing samples. Results were not moderated by type of externalizing behavior. Overall, the results of the meta-analyses were consistent with the hypoarousal theory of externalizing behavior.
Sleep problems are common in attention-deficit/hyperactivity disorder (ADHD) to the extent that they mimic or exacerbate daytime symptoms expression. In this review, we advocate the need for a better understanding of sleep alterations in youths with ADHD and their impact on neurobehavioral functions including learning, memory and emotional regulation. An in-depth exploration of existing data showed that although extensively studied, the actual nature of sleep problems in ADHD and their effects on daytime behavior are still less well understood. Important issues, among which developmental changes in sleep architecture and role of subtle sleep electroencephalogram signatures, are generally neglected. Future research of sleep effects on behavior in ADHD would benefit from considering developmental aspects and links between brain activation patterns during sleep and wake.
Sleep disturbances are common among children and adolescents with attention deficit hyperactivity disorder. This study sought to evaluate the effects of individualizing wear times of the methylphenidate transdermal system on sleep parameters. In this open-label, randomized trial, 26 children with attention deficit hyperactivity disorder and sleep disturbances were randomized (after dose optimization) to one of four groups with different sequences of patch wear times (i.e., 9, 10, 11, and 12 hours per day wear times each for week in different sequences). The primary endpoint comprised sleep latency. Secondary endpoints included total sleep time, sleep quality, and attention deficit hyperactivity disorder and related signs (assessed with Attention Deficit Hyperactivity Disorder Rating Scale-IV and Connor's Global Impression-Parent). A mixed-effects regression model evaluated the effects of patch wear time on sleep and symptom measures. Patch wear time exerted no significant effect on sleep latency or total sleep time, although a trend toward improved sleep quality was evident (P = 0.059) with longer patch wear times. Sleep parameters were not adversely affected by longer methylphenidate transdermal system patch wear times. Thus, if replicated in larger samples, the individualization of patch wear times should be considered according to the needs and responses of patients.
Prior research has shown that parenting stress levels can be quite high among families of children with attention deficit hyperactivity disorder (ADHD). This study investigated the degree to which such stress was related not only to the child's ADHD, but also to various other child, parent, and family-environment circumstances. Multimethod assessments were conducted on 104 clinic-referred children with ADHD. Data collected from these subjects were entered into hierarchical multiple-regression analyses, utilizing the Parenting Stress Index as the criterion. The results showed that the child and parent characteristics accounted for a substantial portion of the variance in overall parenting stress. The child's oppositional-defiant behavior and maternal psychopathology were especially potent predictors. The severity of the child's ADHD, the child's health status, and maternal health status also emerged as significant predictors. These findings are discussed in terms of their impact upon the clinical management of children with ADHD.
Questionnaire data from patients presenting at three sleep disorders centers were used to develop and assess a screening tool for sleep apnea based on the reporting of the frequency of various symptoms of sleep apnea and other sleep disorders plus age, body mass index (BMI) and gender. Patients were not specifically referred for suspicion of sleep apnea. Separate factor analyses of survey responses from 658, 193 and 77 respondents from the first, second and third sites, respectively, each yielded four orthogonal factors, one of which accounted for all the questions concerned with the frequency of disordered breathing during sleep. The survey was shown to be reliable in a subset of patients from one of the sites (test-retest correlation = 0.92). Survey data were then compared to a clinical measure of sleep apnea (respiratory disturbance index) obtained from polysomnography. A multivariable apnea risk index including survey responses, age, gender and BMI was estimated using multiple logistic regression in a total sample of 427 respondents from two of the sites. Predictive ability was assessed using receiver operating characteristic (ROC) curves. The area under the ROC curve was 0.79 (p < 0.0001). For BMI alone, it was 0.73, and for an index measuring the self-report of the frequency of apnea symptoms, it was 0.70. The multivariable apnea risk index has potential utility in clinical settings.
Daytime sleep tendency was assessed in 10 drug-free patients with narcolepsy-cataplexy and 10 normals matched for age and gender. Following nocturnal polysomnography, the alpha attenuation test (AAT) and the multiple sleep latency test (MSLT) were administered during five sessions occurring at 2-hour intervals beginning at 0900 and 1000 hours, respectively. For the AAT, participants were polysomnographically recorded for 8 minutes while seated in an illuminated room with their eyes alternately opened and closed. Power spectral analyses of electroencephalograph (EEG) activity at 02-A1 (10 second epochs) were calculated using fast Fourier transformations (FFT) within the alpha frequency range (8-12 Hz) to obtain ratios of mean eyes-closed to mean eyes-open alpha power (i.e. the alpha attenuation coefficient, AAC). The narcoleptics were sleepier than the normals as indicated by a significantly smaller mean AAC and a significantly shorter mean latency to stage 1 on the MSLT. These findings suggest that the AAT may provide a quick and practical objective assessment of the excessive daytime sleepiness (EDS) associated with narcolepsy.
This study examined how sleep loss affects neurophysiologic signals related to attention and working memory.
Subjective sleepiness, resting-state electroencephalogram, and behavior and electroencephalogram during performance of working-memory tasks were recorded in a within-subject, repeated-measures design.
Data collection occurred in a computerized laboratory setting. Participants: Sixteen healthy adults (mean age, 26 years; 8 female) Interventions: Data from alert daytime baseline tests were compared with data from tests during a late-night, extended-wakefulness session that spanned up to 21 hours of sleep deprivation.
Alertness measured both subjectively and electrophysiologically decreased monotonically with increasing sleep deprivation. A lack of alertness-related changes in electroencephalographic measures of the overall mental effort exerted during task execution indicated that participants attempted to maintain high levels of performance throughout the late-night tests. Despite such continued effort, responses became slower, more variable, and more error prone within 1 hour after participants' normal time of sleep onset. This behavior failure was accompanied by significant degradation of event-related brain potentials related to the transient focusing of attention.
Moderate sleep loss compromises the function of neural circuits critical to subsecond attention allocation during working-memory tasks, even when an effort is made to maintain wakefulness and performance. Multivariate analyses indicate that combinations of working-memory-related behavior and neurophysiologic measures can be sensitive enough to permit reliable detection of such effects of sleep loss in individuals. Similar methods might prove useful for assessment of functional alertness in patients with sleep disorders.
Cognitive measures are used frequently in the assessment and diagnosis of attention-deficit/hyperactivity disorder (ADHD). In this meta-analytic review, the authors sought to examine the magnitude of differences between ADHD and healthy participants on several commonly used intellectual and neuropsychological measures. Effect sizes for overall intellectual ability (Full Scale IQ; FSIQ) were significantly different between ADHD and healthy participants (weighted d =.61). Effect sizes for FSIQ were significantly smaller than those for spelling and arithmetic achievement tests and marginally significantly smaller than those for continuous performance tests but were comparable to effect sizes for all other measures. These findings indicate that overall cognitive ability is significantly lower among persons with ADHD and that FSIQ may show as large a difference between ADHD and control participants as most other measures.
Objective:
The aim of treatment for attention-deficit/hyperactivity disorder (ADHD) is to decrease symptoms, enhance functionality, and improve well-being for the child and his or her close contacts. However, the measurement of treatment response is often limited to measuring symptoms using behavior rating scales and checklists completed by teachers and parents. Because so much of the focus has been on symptom reduction, less is known about other possible health problems, which can be measured easily using health-related quality-of-life (HRQL) questionnaires, which are designed to gather information across a range of health domains. The aim of our study was to measure HRQL in a clinic-based sample of children who had a diagnosis of ADHD and consider the impact of 2 clinical factors, symptom severity and comorbidity, on HRQL. Our specific hypotheses were that parent-reported HRQL would be poorer in children with ADHD than in normative US and Australian pediatric samples, in children with increasing severity of ADHD symptoms, and in children who had diagnoses of comorbid psychiatric disorders.
Methods:
Cross-sectional survey was conducted in British Columbia, Canada. The sample included 165 respondents of 259 eligible children (63.7% response rate) who were referred to the ADHD Clinic in British Columbia between November 2001 and October 2002. Children who are seen in this clinic come from all parts of the province and are diverse in terms of socioeconomic status and case mix. ADHD was diagnosed in 131 children, 68.7% of whom had a comorbid psychiatric disorder. Some children had >1 comorbidity: 23 had 2, 5 had 3, and 1 had 4. Fifty-one children had a comorbid learning disorder (LD), 45 had oppositional defiant disorder or conduct disorder (ODD/CD), and 27 had some other comorbid diagnosis. The mean age of children was 10 years (standard deviation: 2.8). Boys composed 80.9% (N = 106) of the sample. We used the 50-item parent version of the Child Health Questionnaire to measure physical and psychosocial health. Physical domains include the following: physical functioning (PF), role/social limitations as a result of physical health (RP), bodily pain/discomfort (BP), and general health perception (GH). Psychosocial domains include the following: role/social limitations as a result of emotional-behavioral problems (REB), self-esteem (SE), mental health (MH), general behavior (BE), emotional impact on parent (PTE), and time impact on parents (PTT). A separate domain measures limitations in family activities (FA). There is also a single-item measure of family cohesion (FC). Individual scale scores and summary scores for physical (PhS) and psychosocial health (PsS) can be computed. Symptom severity data (parent and teacher) came from the Child/Adolescent Symptom Inventory 4. These checklists provide information on symptoms for the 3 ADHD subtypes (inattentive, hyperactive, and combined). Each child underwent a comprehensive psychiatric assessment by 1 of 4 child psychiatrists. Documentation included a full 5-axis Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis on the basis of a comprehensive assessment. Clinical information for each child was extracted from hospital notes.
Results:
Compared with both population samples, children with ADHD had comparable physical health but clinically important deficits in HRQL in all psychosocial domains, FA, FC, and PsS, with effect sizes as follows: FC = -0.66, SE = -0.90, MH = -0.97, PTT = -1.07, REB = -1.60, BE = -1.73, PTE = -1.87, FA = -1.95, and PsS = -1.98. Poorer HRQL for all domains of psychosocial health, FA, and PsS correlated significantly with more parent-reported inattentive, hyperactive, and combined symptoms of ADHD. Children with > or =2 comorbid disorders differed significantly from those with no comorbidity in most areas, including RP, GH, REB, BE, MH, SE, PTT, FA, and PsS, and from those with 1 comorbid disorder in 3 domains, including BE, MH, and FA and the PsS. The mean PsS score for children in the ODD/CD group (mean difference: -12.9; effect size = -1.11) and children in the other comorbidity group (-9.0; effect size = -.77) but not children in the LD group were significantly lower than children with no comorbid disorder. Predictors of physical health in a multiple regression model included child's gender (beta = .177) and number of comorbid conditions (beta = -.197). These 2 variables explained very little variation in the PhS. Predictors of psychosocial health included the number of comorbid conditions (beta = -.374) and parent-rated combined ADHD symptoms (beta = -.362). These 2 variables explained 31% of the variation in the PsS.
Conclusions:
Our study shows that ADHD has a significant impact on multiple domains of HRQL in children and adolescents. In support of our hypotheses, compared with normative data, children with ADHD had more parent-reported problems in terms of emotional-behavioral role function, behavior, mental health, and self-esteem. In addition, the problems of children with ADHD had a significant impact on the parents' emotional health and parents' time to meet their own needs, and they interfered with family activities and family cohesion. The differences that we found represent clinically important differences in HRQL. Our study adds new information about the HRQL of children with ADHD in relation to symptom severity and comorbidity. Children with more symptoms of ADHD had worse psychosocial HRQL. Children with multiple comorbid disorders had poorer psychosocial HRQL across a range of domains compared with children with none and 1 comorbid disorder. In addition, compared with children with no comorbidity, psychosocial HRQL was significantly lower in children with ODD/CD and children in the other comorbidity group but not in children with an LD. The demonstration of a differential impact of ADHD on health and well-being in relation to symptom severity and comorbidity has important implications for policies around eligibility for special educational and other supportive services. Because the impact of ADHD is not uniform, decisions about needed supports should incorporate a broader range of relevant indicators of outcome, including HRQL. Although many studies focus on measuring symptoms using rating scales and checklists, in our study, using a multidimensional questionnaire, we were able to show that many areas of health are affected in children with ADHD. We therefore argue that research studies of children with ADHD should include measurement of these broader domains of family impact and child health.
To review evidence on the association between restless legs syndrome (RLS) and attention-deficit/hyperactivity disorder (ADHD), to discuss the hypothetical mechanisms underlying this association, and to consider the potential interest for common pharmacologic treatments of RLS and ADHD when co-occurring.
A PubMed search.
In clinical samples, up to 44% of subjects with ADHD have been found to have RLS or RLS symptoms, and up to 26% of subjects with RLS have been found to have ADHD or ADHD symptoms. Several mechanisms may explain this association. Sleep disruption associated with RLS might lead to inattentiveness, moodiness, and paradoxical overactivity. Diurnal manifestations of RLS, such as restlessness and inattention, might mimic ADHD symptoms. Alternatively, RLS might be comorbid with idiopathic ADHD. Subjects with RLS and a subset of subjects with ADHD might share a common dopamine dysfunction. Limited evidence suggests that some dopaminergic agents, such as levodopa/carbidopa, pergolide, and ropinirole, may be effective in children with RLS associated with ADHD symptoms.
Although still limited, evidence from clinical studies demonstrates an association between RLS and ADHD or ADHD symptoms. Further clinical studies using standard criteria and procedures are needed to better estimate the degree of association. Epidemiologic studies are required to assess the relationship between ADHD and RLS symptoms in nonclinical samples. Further investigations should address the mechanisms underlying the relationship between RLS and ADHD. Several dopaminergic agents seem to be promising treatment for RLS associated with ADHD symptoms. To date, however, the absence of randomized and blinded controlled studies does not allow evidence-based recommendations.
The current study aimed to investigate whether children and adolescents diagnosed with Attention Deficit/Hyperactivity Disorder Predominantly Inattentive (AD/HD-in; Child n = 24, Adolescent n = 33) and Combined (AD/HD-com; Child n = 30, Adolescent n = 42) subtypes were more distractible than controls (Child n = 54; Adolescents n = 75), by assessing event-related potential (ERP), performance and peripheral arousal measures. All AD/HD groups displayed smaller amplitudes and/or shorter latencies of the P3a ERP component - thought to reflect involuntary attention switching - following task-deviant novel stimuli (checkerboard patterns) embedded in a Working Memory (WM) task. The P3a results suggested that both AD/HD-in and AD/HD-com subtypes ineffectively evaluate deviant stimuli and are hence more "distractible". These abnormalities were most pronounced over the central areas. AD/HD groups did not display any abnormalities in averaged heart rate over the WM task, a measure of peripheral arousal. They did display abnormalities in performance measures from the task, but these were unrelated to P3a abnormalities. AD/HD groups also displayed a number of deficits on Switching of Attention and Verbal Memory tasks, however, the pattern of abnormality mostly reflected general cognitive deficits rather than resulting from distraction.
Obstructive sleep apnea (OSA) is expected to impair vigilance and executive functioning, owing to the sensitivity of the prefrontal cortex to the effects of sleep fragmentation and intermittent hypoxia. Studies examining the pattern of cognitive dysfunction show variable results, with the heterogeneity in part due to small sample sizes in current studies and little consistency of the tests used. We examined a group of fifty subjects from the Brain Resource International Database (BRID), predicted to have OSA on the basis of the Multivariable Apnea Prediction Index, and compared them with 200 matched controls. On electrophysiological tests, the OSA group showed reduced eyes closed alpha power, increased auditory oddball N100 and P200 amplitude, but reduced N200 and P300 amplitude. The latency to P300 was not significantly different between groups, but latencies to N200 and P200 were prolonged in the OSA group. Performance testing of the executive function found that verbal interference and the switching of attention were impaired in the OSA group. We have demonstrated that a diagnostic algorithm based on apnea symptoms and demographic factors can be used to select a group with likely OSA manifesting deficits in information processing and executive function.
Objective: Databases bring together diverse information in neuroimaging and psychiatry. They usually aim for both size and diversity of measures. The present article outlines the potential insights from the first entirely standardized and centralized International Brain Database.
Method: The database consists of data from over 1000 normal subjects (age range 6-70 years) and a growing number of age-matched patients with a psychiatric illness, acquired from seven laboratories (New York, Rhode Island, London, Holland, Adelaide, Melbourne and Sydney). It is an ‘integrative’ neuroimaging (electroencephalography (EEG), event-related potentials (ERP), structural and functional magnetic resonance imaging (sMRI, fMRI)), psychometric, demographic and genomic database.
Results: The most notable relationships in normal controls thus far include (i) an association between grey matter volume and EEG alpha frequency in frontal regions; (ii) a systematic reduction with age in cortical arousal (EEG power), speed of processing (ERP components) and most aspects of cognitive function, particularly for >50 years; (iii) a greater cortical arousal in female versus male subjects, but slower speed of processing; and (iv) a dissociation between speed (greater in male subjects) and accuracy/verbal processing (greater in female subjects) for psychological tasks. There is potential to explore the specificity of findings in psychiatric disorders in this international standardized database.
Conclusions: The size of this database has allowed for statistical tests of greater power than normal. The combination of size and diversity of measure has broader significance in providing a normative framework for evidence-based psychiatric research. It enables control for widespread individual differences, enhancing investigations of the sensitivity and specificity of brain findings, and the efficacy of medication in psychiatric disorders.
Reviews the book, Psychophysiology: Human behavior and physiological response (4th ed.) by John L. Andreassi (see record 2000-07165-000). This is the fourth edition of a well-known and highly acclaimed book. Although the author modestly states, "The plan of this book is to provide students with elementary information...," the book is almost an encyclopaedic account of this extremely extensive field. Given this comprehensiveness, the book represents an excellent introduction and overview to the whole field of psychophysiology. There are two introductory chapters, the first of which provides a general introduction to the field of psychophysiology, starting very conventionally with definitions and followed by a short historical account. The following chapter provides information on the basic anatomy and physiology of the nervous system, as well as the principles behind the main techniques used. The remaining 17 chapters are grouped into three main conceptual areas: (1) measures of central nervous system activity, (2) measures of the activity of behaviourally relevant peripheral systems, and (3) applications and methodological issues including an appendix dealing with the extremely important issue of laboratory safety. Andreassi has written a comprehensive guide on research methods in psychophysiology, clearly written and very suitable for the group for whom the book is primarily intended: students of behavioural science. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The long-term effects of monotherapy with levodopa or the dopamine agonist pergolide on the motor/sensory, behavioral, and cognitive variables in seven children with restless legs syndrome/periodic limb movements in sleep (RLS/PLMS) and attention-deficit–hyperactivity disorder (ADHD) were investigated. Five of the seven children had previously been treated with stimulants that had either been determined to be ineffective or to have intolerable side effects. Dopaminergic therapy improved the symptoms of RLS and reduced the number of PLMS per hour of sleep (P = 0.018) and associated arousals (P = 0.042) for the entire group. After treatment, three children no longer met the criteria for ADHD, and three reverted to normal on the Test of Variable Attention. ADHD improved in all seven as measured by the Connors parent rating scale (P
This study investigated the functional significance of the N2 response to novel stimuli. In one condition, background, target, and deviant stimuli were simple geometric figures. In a second condition, all stimulus types were unfamiliar/unusual figures. In a third condition, background and target stimuli were unusual figures and deviant stimuli were simple shapes. Unusual figures, whether they were deviant, target, or background stimuli, evoked larger N2 responses than their simple, familiar counterparts. N2 elicited by an unusual background stimulus was larger than that evoked by simple, deviant stimuli, a pattern opposite that exhibited by the subsequent P3. Deviance from immediate context had limited influence over N2 amplitude. The results suggest that novelty N2 and novelty P3 reflect the processing of different aspects of “novel” visual stimuli. The novelty P3 is particularly sensitive to deviation from immediate context. In contrast, the novelty N2 is sensitive to deviation from long-term context that renders a stimulus unfamiliar and difficult to encode.
The present review focuses on the utility of the amplitude of P3 of as a measure of processing capacity and mental workload. The paper starts with a brief outline of the conceptual framework underlying the relationship between P3 amplitude and task demands, and the cognitive task manipulations that determine demands on capacity. P3 amplitude results are then discussed on the basis of an extensive review of the relevant literature. It is concluded that although it has often been assumed that P3 amplitude depends on the capacity for processing task relevant stimuli, the utility of P3 amplitude as a sensitive and diagnostic measure of processing capacity remains limited. The major factor that prompts this conclusion is that the two principal task variables that have been used to manipulate capacity allocation, namely task difficulty and task emphasis, have opposite effects on the amplitude of P3. I suggest that this is because, in many tasks, an increase in difficulty transforms the structure or actual content of the flow of information in the processing systems, thereby interfering with the very processes that underlie P3 generation. Finally, in an attempt to theoretically integrate the results of the reviewed studies, it is proposed that P3 amplitude reflects activation of elements in a event-categorization network that is controlled by the joint operation of attention and working memory.
Auditory event-related potentials (ERPs) were recorded from 14 subjects with obstructive sleep apnea (OSA) before and after treatment with nasal continuous positive airway pressure (nCPAP). After 2 nights of treatment, there was dramatic improvement in the sleep patterns of the OSA patients, improvements in measures of apnea severity and oxygenation, and decrease in daytime sleepiness. The results of neuropsychological tests of a broad range of cognitive functions failed to confirm the patients' subjective reports of improvement in psychological functioning after treatment. The latencies of the N2 and P3 components were significantly prolonged prior to treatment, and there was a trend towards smaller N2 and P3 amplitude in the apneic subjects. The latency of P3 (but not N2) changed with treatment, decreasing almost to normative values. The results suggest that ERPs may be useful in documenting neural dysfunction in patients with OSA, in evaluating treatment efficacy, and possibly in determining the causes of the daytime symptoms of OSA.
The present study examines whether monitoring and control behaviour are affected by sleep loss and fatigue. The effects of one night of sleep loss are investigated in a dual-task consisting of a monotonous tracking task that requires continuous control behaviour and a time estimation task that requires monitoring with an 'open-loop' character. In the tracking task subjects had to keep a square cursor in the centre of a U-shaped target. In the time estimation task subjects had to estimate consecutive time intervals and to respond when an interval had ended. There were three experimental conditions. In the first condition a clock was presented continuously on the screen; thus, subjects had a clear notion of the time course. In the second condition subjects could obtain time information by pressing a key. In the third condition subjects could not obtain time information, but the status of the time interval could be obtained by pressing a key; that is, information was given whether a time interval had ended or not. The present study confirms earlier findings that tracking performance is sensitive to sleep loss particularly towards the end of the half hour working session. In contrast, time estimation performance was not impaired, although subjects tended to make more observations when deprived of sleep. This result would not have been expected on the basis of a decreased level of activation due to sleep loss. It appears, however, that checking the time course with a motor response requires less effort than continuously updating an internal clock, which puts heavy demands on working memory. The observed difference between the tasks with respect to the vulnerability to sleep loss is explained in terms of their motivating properties.
Unlabelled:
Children on the adenotonsillectomy waiting list aged 6 years or more were screened by questionnaire and overnight sleep monitoring to identify 12 with a moderate sleep and breathing disorder (SBD) group. They were matched by age and sex with 11 children who had a similar history of snoring and sleep disturbance but without an obvious sleep and breathing problem when monitored (snorer group) and also with a group of ten children most of whom were refered for an unrelated surgical procedure (control group). All children were studied before and 3-6 months after surgery. Pre-operatively the SBD and snorer groups both had significantly more restless sleep than the control group. The SBD group also had significantly more (> 4%) dips in oxygen saturation than the other two groups. After surgery there were no longer any significant differences between the three groups. After adenotonsillectomy the SBD group showed a significant reduction in aggression, inattention and hyperactivity on the parent Conners scale, and an improvement in vigilance on the Continuous Performance Test. The snorer group also improved showing less hyperactive behaviour than pre-operatively and better vigilance. The control groups's behaviour and performance did not change significantly. There were no significant changes in the performance of the Matching Familiar Figures Test in any of the groups.
Conclusion:
Relief of mild to moderate sleep and breathing disorders in children is associated with improved behaviour and functioning. We confirm previous work which suggests that the relation between sleep disordered breathing and daytime problems in children is a causal one.
Auditory event-related potentials (ERPs) were recorded from 10 children diagnosed with attention deficit hyperactivity disorder (ADHD) and 10 age-, sex-, and IQ-matched control children. ERPs were recorded from 17 electrodes during an auditory two-tone discrimination ("oddball') paradigm. Subjects were instructed to press a hand-held response button to infrequently presented target tones. ERP components elicited to target and non-target stimuli were analyzed for between-group differences. Results indicated that for the children with ADHD relative to control children, an N2 component to non-target stimuli was larger in the posterior region and smaller in the frontal region. The P3b component to target stimuli was smaller in the posterior region and larger in the frontal region for the ADHD group compared with the control group. The between-group differences in P3b scalp distribution are indicative of a between-group difference in the neural generators of P3b. It is proposed that the ADHD group, relative to controls, utilizes an additional cognitive process when processing task-relevant stimuli. This process is more frontally distributed and may reflect an attentional compensation mechanism in the ADHD group.
Attention-deficit hyperactivity disorder (ADHD) children and normal controls (7-13 yrs old) performed an auditory and visual selective attention task. Subjects were instructed to respond to the infrequent (10%) stimuli in the relevant channel. Processing negativity (PN) and several other ERP peaks were scored at the midline electrodes. In the auditory task, controls had more correct detections (hits), less false alarms, larger P3b amplitudes to nontarget stimuli (but not to hits), a larger central PN and larger early frontal positivity (100-250 ms) to target stimuli than ADHD subjects. In the visual modality, controls had more correct detections, less false alarms, larger P3b amplitudes to nontarget stimuli (but not to hits), and larger frontal P3(1) amplitudes to infrequent than to frequent stimuli. It was hypothesized that in ADHD children in both the auditory and the visual task, there is a deficit in the activation of the P3b process. Incorrect triggering of the P3b process might be caused by disturbances in other aspects of the attention process, preceding the P3b.
Children with sleep disorders are often inattentive or hyperactive, and some carry a diagnosis of attention deficit/hyperactivity disorder (ADHD) until their sleep disorder is detected. However, the potential behavioral impact of undiagnosed sleep disorders is not known. We sought to determine whether children with higher levels of inattention and hyperactivity more frequently have symptoms of sleep-related breathing disorders (SRBDs) or periodic limb movement disorder (PLMD). We surveyed parents of 2-18-year-old patients at a child psychiatry clinic (n = 70) and a general pediatrics clinic (n = 73) to assess the children's behavior, snoring, complaints of restless legs at night, and daytime sleepiness. A validated pediatric sleep questionnaire provided the explanatory variables, and a scale for inattention and hyperactivity, derived from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), provided the dependent variable. Habitual snoring was more frequent (33%) among children who carried a diagnosis of ADHD than among the other children at the psychiatry or general pediatric clinics (11 and 9%, respectively, chi-square test, p = 0.01). Snoring scores, derived from six snoring- and SRBD-related question items, were associated with higher levels of inattention and hyperactivity. The complaint of restless legs and a composite score for daytime sleepiness showed some evidence, though less consistent, of an association with inattention and hyperactivity. The association of snoring with inattention and hyperactivity suggests that SRBDs and perhaps other sleep disorders could be a cause of inattention and hyperactivity in some children. If a causal effect is present, our data suggest that 81% of habitually snoring children who have ADHD--25% of all children with ADHD--could have their ADHD eliminated if their habitual snoring and any associated SRBD were effectively treated.
This study examined possible gender differences in children and adults with attention-deficit/hyperactivity disorder. Results indicated that adult self-ratings differed significantly by gender. Adult women reported fewer assets and more problems than did male counterparts, but there was no gender difference with respect to age at referral, intelligence quotient, indicators of neuropsychological performance, or parent or teacher ratings of behavior. Referral bias against girls is a possible reason for previously reported gender differences, so we interpreted our results in light of the participants' referral patterns. There was a nonsignificant trend for girls with relatively more severe ratings of hyperactivity, conduct disorder, or inattention to be referred earlier than were boys. Overall, our results suggest no evidence of cognitive or neuropsychological differences by gender in samples that are sensitive to behavioral deviance in girls (as evidenced by early referral), but adult women's self-perception is comparatively poorer than that of adult men.
Evidence is presented that EEG oscillations in the alpha and theta band reflect cognitive and memory performance in particular. Good performance is related to two types of EEG phenomena (i) a tonic increase in alpha but a decrease in theta power, and (ii) a large phasic (event-related) decrease in alpha but increase in theta, depending on the type of memory demands. Because alpha frequency shows large interindividual differences which are related to age and memory performance, this double dissociation between alpha vs. theta and tonic vs. phasic changes can be observed only if fixed frequency bands are abandoned. It is suggested to adjust the frequency windows of alpha and theta for each subject by using individual alpha frequency as an anchor point. Based on this procedure, a consistent interpretation of a variety of findings is made possible. As an example, in a similar way as brain volume does, upper alpha power increases (but theta power decreases) from early childhood to adulthood, whereas the opposite holds true for the late part of the lifespan. Alpha power is lowered and theta power enhanced in subjects with a variety of different neurological disorders. Furthermore, after sustained wakefulness and during the transition from waking to sleeping when the ability to respond to external stimuli ceases, upper alpha power decreases, whereas theta increases. Event-related changes indicate that the extent of upper alpha desynchronization is positively correlated with (semantic) long-term memory performance, whereas theta synchronization is positively correlated with the ability to encode new information. The reviewed findings are interpreted on the basis of brain oscillations. It is suggested that the encoding of new information is reflected by theta oscillations in hippocampo-cortical feedback loops, whereas search and retrieval processes in (semantic) long-term memory are reflected by upper alpha oscillations in thalamo-cortical feedback loops.
To determine the relationship of sleep problems to attention-deficit/hyperactivity disorder (ADHD), diagnostic subtype, comorbid disorders, and the effects of stimulant treatment.
On the basis of clinical diagnostic interviews, children aged 6 to 12 years were assigned to 4 groups: unmedicated ADHD (n = 79), medicated ADHD (n = 22), clinical comparison (n = 35), and healthy nonclinical comparison (n = 36). These groups were compared on 2 sleep questionnaires completed by the parents that assessed current sleep problems and factors associated with sleep difficulties (i.e., sleep routines, sleep practices, child and family sleep history).
Factor analysis revealed 3 sleep problem categories: dyssomnias, parasomnias, and sleep-related involuntary movements. Linear regression analyses showed that (1) dyssomnias were related to confounding factors (i.e., comorbid oppositional defiant disorder and stimulant medication) rather than ADHD; (2) parasomnias were similar in clinical and nonclinical children; and (3) the DSM-IV combined subtype of ADHD was associated with sleep-related involuntary movements. However, sleep-related involuntary movements were more highly associated with separation anxiety.
The results suggest that the relationship between sleep problems and ADHD is complex and depends on the type of sleep problem assessed as well as confounding factors such as comorbid clinical disorders and treatment with stimulant medication.
This study investigated the functional significance of the N2 response to novel stimuli. In one condition, background, target, and deviant stimuli were simple geometric figures. In a second condition, all stimulus types were unfamiliar/unusual figures. In a third condition, background and target stimuli were unusual figures and deviant stimuli were simple shapes. Unusual figures, whether they were deviant, target, or background stimuli, evoked larger N2 responses than their simple, familiar counterparts. N2 elicited by an unusual background stimulus was larger than that evoked by simple, deviant stimuli, a pattern opposite that exhibited by the subsequent P3. Deviance from immediate context had limited influence over N2 amplitude. The results suggest that novelty N2 and novelty P3 reflect the processing of different aspects of "novel" visual stimuli. The novelty P3 is particularly sensitive to deviation from immediate context. In contrast, the novelty N2 is sensitive to deviation from long-term context that renders a stimulus unfamiliar and difficult to encode.
Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed disorder in children today with estimated prevalence rates falling between 3 and 5% of children (American Psychiatric Association, 1994). From inception, research has focused on studying varying facets of this disorder with initial efforts primarily focusing on treatment outcome. However, prominent efforts have been made in recent research efforts to shed light on the etiology of this disorder. Such research has discovered the contribution of genetic inheritance, as well as environmental factors that lead to the development of this disorder. Furthermore, studies using neurological and neuropsychological assessment measures have implicated the involvement of various Parts of the brain. This article critically reviews this body of research in light of its impact on the current specific neuropsychologically based etiological theories, as well as the most beneficial directions for future research.
Barkley (1997a) proposed that the central deficit in Attention Deficit Hyperactivity Disorder (ADHD) is in behavioral inhibition, resulting in deficits both in working memory and sense of time. To test this theory, 21 children with ADHD and a matched sample (ages 6-13) completed a variety of tasks that measured behavioral inhibition, working memory, attention, and time reproduction. Children with ADHD performed significantly below controls on measures of inhibition, attention, and time reproduction. They did not differ significantly from controls, however, on tasks of working memory. In addition, performance on the working memory tasks was not correlated with the time reproduction task. We discuss the relevance of these results in the context of current theories of ADHD.
To identify the prevalence of three mental disorders (Depressive Disorder, Conduct Disorder and Attention-Deficit/Hyperactivity Disorder), the prevalence of mental health problems, the health-related quality of life of those with problems, and patterns of service utilisation of those with and without mental health problems, among 4-17-year-olds in Australia. To identify rates of health-risk behaviours among adolescents with mental health problems.
The mental disorders were assessed using the parent-version of the Diagnostic Interview Schedule for Children Version IV. Parents completed the Child Behaviour Checklist to identify mental health problems and standard questionnaires to assess health-related quality of life and service use. The Youth Risk Behaviour Questionnaire completed by adolescents was employed to identify health-risk behaviours.
Fourteen percent of children and adolescents were identified as having mental health problems. Many of those with mental health problems had problems in other areas of their lives and were at increased risk for suicidal behaviour. Only 25% of those with mental health problems had attended a professional service during the six months prior to the survey.
Child and adolescent mental health problems are an important public health problem in Australia. The appropriate balance between funding provided for clinical interventions focusing on individual children and families and funding for interventions that focus on populations, requires careful study. The latter are an essential component of any strategy to reduce mental health problems as the high prevalence of problems makes it unlikely that individual care will ever be available for all those needing help. Clinical and population health interventions must take into account the comorbid problems experienced by children with mental disorders.
To compare the health-related quality of life (HRQL) between children aged 6-17 years with one of three mental disorders (attention-deficit/hyperactivity disorder, major depressive disorder, or conduct disorder), a physical disorder, and those with none of these disorders.
Parent reports describing the HRQL, mental disorders, and physical disorders of a national sample of 3,597 children and adolescents in Australia, aged 6-17 years (response rate = 70%), were obtained by means of a structured diagnostic interview and questionnaires.
After controlling for age, gender, and family structure, children with mental disorders were reported to have a significantly worse HRQL in several domains than children with no disorder. In many areas they were reported to have a worse HRQL than children with physical disorders. Parents also reported that the problems of children with mental disorders interfered significantly with the daily lives of children, parents, and families.
The findings are consistent with previous studies which have reported that adults with mental disorders have substantial impairment in their HRQL. The findings suggest that children with a mental disorder require help in many areas of their lives. Achieving this will require an integrated approach to health care delivery rather than the current distinction between physical and mental health services.
This article reviews the electroencephalography (EEG) literature in relation to attention-deficit/hyperactivity disorder (AD/HD).
The review briefly outlines the history of the disorder, focusing on the changing diagnostic systems which both reflect and constrain research into AD/HD. Both qualitative and quantitative EEG studies are examined, and their results are discussed in relation to various models of AD/HD. Implications of these data for future research and development in AD/HD are considered.
In terms of resting EEG, elevated relative theta power, and reduced relative alpha and beta, together with elevated theta/alpha and theta/beta ratios, are most reliably associated with AD/HD. Theta/alpha and theta/beta ratios also discriminate diagnostic subgroups of AD/HD. Recent studies of EEG heterogeneity in this disorder indicate the existence of different profiles of cortical anomalies which may cut across diagnostic types.
The research to date has identified a substantial number of EEG correlates of AD/HD which hold promise for improving our understanding of the brain dysfunction(s) underlying the disorder. Further work in this field may benefit from a broader conceptual approach, integrating EEG and other measures of brain function.
To examine the effect of nasal bilevel positive airway pressure (BiPAP) treatment for concurrent sleep-related breathing disorders (SRBDs) and attention-deficit hyperactivity disorder (ADHD) on electrophysiological measures of spontaneous brain activity and auditory stimulus processing.
Nineteen children diagnosed with both SRBD and ADHD participated. Electroencephalogram (EEG) activity was recorded during a resting period and an auditory oddball task before beginning BiPAP treatment, after 6 months on treatment, and after a subsequent 1 week non-treatment period. Treatment effects on EEG and event-related potentials (ERPs) to target stimuli were examined via topographic analysis.
Thirteen of the initial 19 children completed 6 months of BiPAP therapy, with six lost mainly due to compliance problems. Children on BiPAP therapy showed a significant decrease in slow-wave (delta and theta) and an increase in fast wave (beta) EEG activity. The P3 component of the ERP showed treatment effects in amplitude and latency.
The electrophysiological data suggest that SRBDs may contribute to ADHD symptomatology. Treatment of SRBD with BiPAP therapy in children with concurrent ADHD can lead to significant changes, in the direction of normalization, of the typical electrophysiological features of ADHD.
Abnormal involuntary attention leading to enhanced distractibility may account for different behavioral and cognitive problems in children with attention deficit hyperactivity disorder (ADHD). This was investigated in the present experiment by recording event-related brain potentials (ERPs) to distracting novel sounds during performance of a visual discrimination task. The overall performance in the visual task was less accurate in the ADHD children than in the control children, and the ADHD children had a higher number of omitted responses following novel sounds. In both groups, the distracting novel sounds elicited a biphasic P3a ERP component and a subsequent frontal Late Negativity (LN). The early phase of P3a (180-240 ms) had significantly smaller amplitudes over the fronto-central left-hemisphere recording sites in the ADHD children than in the control group presumably due to an overlapping enhanced left-hemisphere dominant negative ERP component elicited in the ADHD group. Moreover, the late phase of P3a (300-350 ms) was significantly larger over the left parietal scalp areas in the ADHD children than in the controls. The LN had a smaller amplitude and shorter latency over the frontal scalp in the ADHD group than in the controls. In conclusion, the ERP and behavioral effects caused by the novel sounds reveal deficient control of involuntary attention in ADHD children that may underlie their abnormal distractibility.
To examine gender differences among children meeting symptom criteria for DSM-IV attention-deficit/hyperactivity disorder (ADHD) identified in a nationally representative sample of Australian children.
From 2,404 children aged 6 to 13 years, 225 boys and 99 girls with ADHD symptoms were identified using the parent version of the Diagnostic Interview Schedule for Children and compared on parent reports of children's behavioral problems and impairment.
When ADHD types were collapsed into a single group, boys and girls did not differ on core symptoms, comorbidity, and impairment with the exception that girls rated higher on somatic complaints and boys had poorer school functioning. However, gender patterns were found to vary across ADHD type on impairment measures of social problems, schoolwork difficulties, and self-esteem, with boys being generally rated as more impaired in the combined and hyperactive-impulsive groups but equally or less impaired in the inattentive group.
The findings suggest the possibility of gender-specific risks associated with high levels of inattentive and hyperactive-impulsive symptoms indicating that ADHD subtype membership should be considered when conducting ADHD gender comparisons.
Quantitative electroencephalography has contributed significantly to elucidating the neurobiologic mechanisms of attention-deficit hyperactivity disorder. The most consistent and robust electroencephalographic disturbance in attention-deficit hyperactivity disorder has been abnormally increased theta band during resting conditions. Separate research using attention-demanding tests has elucidated cognitive disturbances that differentiate attention-deficit hyperactivity disorder. This study attempts to integrate electroencephalographic and neuropsychological indices to determine whether cognitive performance is specifically related to increased theta. Theta activity was recorded during a resting condition for 46 children/adolescents with attention-deficit hyperactivity disorder and their sex- and age-matched control subjects. Accuracy and reaction time during an auditory oddball and a visual continuous performance test were then recorded. Compared with control subjects, the attention-deficit hyperactivity disorder group manifested significantly increased (primarily left) frontal theta. Furthermore, the attention-deficit hyperactivity disorder group scored significantly delayed reaction time and decreased accuracy in both tasks. Correlation analysis revealed a significant relationship between frontal (primarily left) theta and oddball accuracy for the attention-deficit hyperactivity disorder group compared with a significant relationship between posterior (primarily right) theta and reaction time in the continuous performance test for the control group. These results indicate that spatial neurophysiologic deficits in attention-deficit hyperactivity disorder may be related to disturbances in signal detection. This observation has important implications for the role of trait-like biologic deficits in attention-deficit hyperactivity disorder predicting performance in information processing.
This paper provides a summary of the current conceptualization of what AD/HD is, and its etiology, and then reviews some of the recent literature on the correlates and lifecourse outcomes for individuals diagnosed with Attention-Deficit/Hyperactivity Disorder (AD/HD). The intention is to synthesize that which is known, and to identify important gaps in the literature and knowledge base, which secondary analysis of prospective large-scale longitudinal cohorts, tracking individuals from birth to adulthood, could help to fill. This review highlights the fact that such datasets are rare and that their analysis offers important opportunities for advancing knowledge, particularly of the adult outcomes of childhood AD/HD.
We studied the relationship between sleep quality and quantity and subsequently recorded automatically evoked event-related potential (ERP) responses. In previous studies decrement of attentional processing has been associated with changes in sleep. Sleep is shown to associate also with ERPs elicited by unattended sound stream, however, there is no consensus on these effects. A recent study suggested that the early anterior P3a to novel stimuli in attended stream is attenuated and the late parietal P3a is strengthened by total sleep deprivation. We carried out 72-h consecutive actigraphy measurements in a naturalistic setting to collect information about variation in sleep duration, sleep onset latency, sleep efficiency, and percentage of sleep. MMN and P3a deflections to infrequent changes in sound duration and pitch in unattended sound stream were obtained in a separate recording session from the same subjects when they were awake. No significant correlations were found between sleep and MMN parameters, indicating that MMN is resistant to normal variation in sleep. However, P3a to both pitch and duration changes correlated positively with sleep onset latency, and P3a to duration changes correlated negatively with sleep efficiency and percentage of sleep. The correlation was higher in the posterior scalp areas. Our results suggest that the involuntary attention switching system, reflected by the P3a is sensitized as a function of decreased sleep quality.
The purpose of this study was to examine the preliminary validity of a newly developed battery of computerized cognitive measures, IntegNeuro. This standardized and semi-automated computerized battery assesses sensori-motor function, attention, new learning and memory, language fluency, executive function, and estimated intelligence. A total of 50 healthy individuals (aged 22-80 years) were included in the study. Correlational analyses revealed highly significant associations between the two cognitive batteries. These results support the use of IntegNeuro as a computerized cognitive system. Additional studies are needed to examine the clinical utility of the battery.
NeuroMarker combines EEG and ERP measures with neurocognitive tests in a fully computerized and standardized testing system. It is designed for use across the lifespan and has a large normative database of over 1,000 subjects. This study was a preliminary evaluation of "NeuroMarker" in subjects spanning four decades. Twenty-one healthy subjects (12-57 years) were tested at baseline and four weeks later. From the "Neuromarker" battery, the authors analyzed EEG data (eyes open and closed) and ERPs elicited during auditory oddball (N100, P200, N200, P300) and working memory (P150, P300) tasks. Concomitant neuropsychological data, acquired using a touch-screen system, comprised measures of sensori-motor, attention, verbal, executive, and memory function. Test-retest data were examined using analyses of variance and correlational procedures (corrected for multiple comparisons), with parallel analyses of age. EEG data did not differ across sessions, and showed high test-retest reliability (.71-.95), particularly for theta and delta (>.85). ERP components also showed sound reliability, particularly for sites where components are maximal: fronto-central N100 (.76-.77), centro-parietal P300 (.78-.81) to oddball targets, N100 and P200 (.74-.86) to oddball non-targets, and P150 amplitude and latency (.84-.93) to working memory stimuli. Neuropsychological tests showed a similarly sound level of consistency (on average, .70), with the most consistent tests tapping simple motor function, estimated intelligence, switching of attention (Part 2), verbal interference response time and memory intrusions (.71-.89). Age and sex did not have a differential impact on reliability for EEG, ERP, or neuropsychology measures. These findings provide preliminary evidence that the "NeuroMarker" battery is reliable for test-retest assessments. The results suggest that the standardized approach has utility for providing sensitive clinical and treatment evaluations across age groups.
To determine the effects of experimental restriction of sleep opportunity on teacher ratings of academic performance and behavior in healthy normal children.
Home-based, within-subjects design in which participants followed 3 week-long sleep schedules-Baseline (self-selected), Optimized, and Restricted-while attending school, with order of conditions counter-balanced (Optimized and Restricted).
Seventy-four children (39 boys; aged 6 to 12 years, mean = 10) screened for medical and psychological health.
Teachers masked to assigned hours of sleep completed paper-and-pencil questionnaires at the end of each study condition. Questionnaire items were selected from several published measures. Summary scores included Academic Problems, Hyperactive-Impulsive Behaviors, Internalizing, Oppositional-Aggressive, Sleepiness, Total Attention Problems, and Mean Severity of Attention Problems. Main effects of sleep condition were found forAcademic Problems, Sleepiness, Total Attention Problems, and Mean Severity of Attention Problems. Restricting sleep increased ratings of Academic Problems (medium effect) relative to both Baseline (P < .01, eta(p)2 = .11) and Optimized (P < .05, eta(p)2 = .10) conditions and increased the Mean Severity of Attention Problems (medium effect) relative to Baseline (P < .01, eta(p)2 = .12).
These findings provide experimental support for widely held beliefs about the importance of sufficient time-in-bed for academic functioning in children. Reducing sleep opportunity had a direct effect on academic performance, as rated by teachers, even among healthy students with no history of behavioral problems or academic difficulty. Findings also support insufficient sleep as a direct source of variability in the manifestation of attention problems but not hyperactivity.
The hypothesis that Attention-Deficit/Hyperactivity Disorder (ADHD) reflects a primary inhibitory executive function deficit has spurred a substantial literature. However, empirical findings and methodological issues challenge the etiologic primacy of inhibitory and executive deficits in ADHD. Based on accumulating evidence of increased intra-individual variability in ADHD, we reconsider executive dysfunction in light of distinctions between 'hot' and 'cool' executive function measures. We propose an integrative model that incorporates new neuroanatomical findings and emphasizes the interactions between parallel processing pathways as potential loci for dysfunction. Such a reconceptualization provides a means to transcend the limits of current models of executive dysfunction in ADHD and suggests a plan for future research on cognition grounded in neurophysiological and developmental considerations.
ADHD and sleep-disordered breathing are both prevalent in adulthood. Because both conditions may be responsible for similar symptoms of cognitive impairment, the authors investigate whether their presentation may overlap in adults diagnosed with ADHD.
Data are collected from six adults with sleep complaints who were diagnosed with ADHD using rigorous clinical criteria. All participants undergo overnight polysomnography and complete questionnaires about sleep quality, circadian sleep pattern, and daytime fatigue.
On standardized measures, all participants report poor sleep quality, two report daytime fatigue, and none report distinct deviation from normal sleep and wake cycle pattern. Polysomnography reveals evidence of sleep-disordered breathing and sleep fragmentation in all participants.
Objective evidence of breathing-related sleep disorders can be found in some adults with carefully diagnosed ADHD who report sleep complaints. This report highlights the importance of identifying treatable sleep disorder comorbidity in adults with ADHD.
Over the past 15 years, considerable progress has been made in understanding the etiology of childhood Attention Deficit Hyperactivity Disorder (ADHD), largely due to the publication of numerous twin studies which are consistent in suggesting substantial genetic influences (i.e., heritabilities ranging from 60% to 90%), non-shared environmental influences that are small-to-moderate in magnitude (i.e., ranging from 10% to 40%), and little-to-no shared environmental influences. Following from these quantitative genetic findings, numerous molecular genetic studies of association and linkage between ADHD and a variety of candidate genes have been conducted during the past 10 years. The majority of the candidate genes studied underlie various facets of the dopamine, norepinephrine, and serotonin neurotransmitter systems, although the etiological role of candidate genes outside of neurotransmitter systems (e.g., involved in various aspects of brain and nervous system development) have also been examined. In this paper, we review recent findings from candidate gene studies of childhood ADHD and highlight those candidate genes for which associations are most replicable and which thus appear most promising. We conclude with a consideration of some of the emerging themes that will be important in future studies of the genetics of ADHD.
This study is based on a comprehensive survey of the neuropsychological attention-deficit hyperactivity disorder (ADHD) literature and presents the first psychometric analyses of different parameters of intra-subject variability (ISV) in patients with ADHD compared to healthy controls, using the Continuous Performance Test, a Go-NoGo task, a Stop Signal Task, as well as N-back tasks.
Data of 57 patients with ADHD and 53 age- and gender-matched controls were available for statistical analysis. Different parameters were used to describe central tendency (arithmetic mean, median), dispersion (standard deviation, coefficient of variation, consecutive variance), and shape (skewness, excess) of reaction time distributions, as well as errors (commissions and omissions).
Group comparisons revealed by far the strongest effect sizes for measures of dispersion, followed by measures of central tendency, and by commission errors. Statistical control of ISV reduced group differences in the other measures substantially. One (patients) or two (controls) principal components explained up to 67% of the inter-individual differences in intra-individual variability.
Results suggest that, across a variety of neuropsychological tests, measures of ISV contribute best to group discrimination, with limited incremental validity of measures of central tendency and errors. Furthermore, increased ISV might be a unitary construct in ADHD.
We explored the possibility of diagnostic confusion between hypersomnias of central origin (narcolepsy and idiopathic hypersomnia, IH) and the adult form of attention-deficit/hyperactivity disorder (ADHD). We included 67 patients with narcolepsy, 7 with IH and 61 with ADHD. All patients completed the Epworth Sleepiness Scale and the ADHD Rating Scale. We found that 18.9% of the hypersomnia patients fulfilled the self-reported criteria for ADHD in adulthood, compared with 77% of the ADHD patients. A score > or =12 on the Epworth Sleepiness Scale (usually regarded to indicate excessive daytime sleepiness) was found in 37.7% of the ADHD patients compared 95.9% of the hypersomnia patients. In ADHD patients, inattention scores correlated with the excessive daytime sleepiness score. We conclude that one should be aware of possible diagnostic confusion between narcolepsy or IH and adult ADHD when using self-report questionnaires. The high percentage of symptom overlap found in our study raises questions about possible misdiagnosing of both conditions, comorbidity with sleep problems in adult ADHD, and the validation of the used scales. It remains unclear whether our findings indicate pathophysiological overlap.
The aim of the study was to characterize the sleep pattern in children with attention deficit/hyperactivity disorder (ADHD). By means of polysomnography (PSG), sleep patterns were studied in 17 unmedicated preadolescent boys rigorously diagnosed with ADHD and 17 control boys precisely matched for age and intelligence. Although ADHD children did not display a general sleep alteration, major PSG data showed a significant increase in the duration of the absolute rapid eye movement (REM) sleep and the number of sleep cycles in ADHD group when compared with controls. In addition, REM sleep latency tended to be shorter in ADHD children. These results suggest that in ADHD children, a forced REM sleep initiation may produce a higher incidence of sleep cycles and may also contribute to an increased duration of the absolute REM sleep. The overall pattern of the findings implies that a forced ultradian cycling appears characteristic for the sleep in ADHD children, which may be related to alterations of brain monoamines and cortical inhibitory control accompanying the ADHD psychopathology.