PubMed · 9610161
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A Meymandi. Brain and behavior.. https://pubmed.ncbi.nlm.nih.gov/9610161/
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This review revisits the thesis that a dysregulation of the central noradrenergic networks may underlie the pathophysiology of ADHD. We review the pertinent neurobiological and pharmacological literature on ADHD. The noradrenergic system has been intimately associated with the modulation of higher cortical functions including attention, alertness, vigilance and executive function. Noradrenergic activation is known to profoundly affect the performance of attention, especially the maintenance of arousal, a cognitive function known to be deficient in ADHD. Data from family, adoption, twin, and segregation analysis strongly support a genetic hypothesis for this disorder. Although molecular genetic studies of ADHD are relatively new and far from definitive, several replicated reports have found associations between ADHD with DAT and D4 receptor genes. Brain imaging studies fit well with the idea that dysfunction in fronto-subcortical pathways occurs in ADHD with its underlying dysregulation of noradrenergic function. A wealth of pharmacological data (within and without the stimulant literature) provides strong evidence for selective clinical activity in ADHD for drugs with noradrenergic and dopaminergic pharmacological profiles. Available research provides compelling theoretic, basic biologic and clinical support for the notion that ADHD is a brain disorder of likely genetic etiology with etiologic and pathophysiologic heterogeneity. Neurobiological and pharmacological data provide compelling support for a noradrenergic hypothesis of ADHD and suggest that drugs with noradrenergic activity may play an important role in the therapeutics of this disorder.
STUDY OBJECTIVES: Measurement of arousals from sleep is clinically important, however, their definition is not well standardized, and little data exist on reliability. The purpose of this study is to determine factors that affect arousal scoring reliability and night-to-night arousal variability. DESIGN: The night-to-night arousal variability and interscorer reliability was assessed in 20 subjects with and without obstructive sleep apnea undergoing attended polysomnography during two consecutive nights. Five definitions of arousal were studied, assessing duration of electroencephalographic (EEG) frequency changes, increases in electromyographic (EMG) activity and leg movement, association with respiratory events, as well as the American Sleep Disorders Association (ASDA) definition of arousals. SETTING: NA. PATIENTS: NA. INTERVENTIONS: NA. RESULTS: Interscorer reliability varied with the definition of arousal and ranged from an Intraclass correlation (ICC) of 0.19 to 0.92. Arousals that included increases in EMG activity or leg movement had the greatest reliability, especially when associated with respiratory events (ICC 0.76 to 0.92). The ASDA arousal definition had high interscorer reliability (ICC 0.84). Reliability was lowest for arousals consisting of EEG changes lasting <3 seconds (ICC 0.19 to 0.37). The within subjects night-to-night arousal variability was low for all arousal definitions CONCLUSION: In a heterogeneous population, interscorer arousal reliability is enhanced by increases in EMG activity, leg movements, and respiratory events and decreased by short duration EEG arousals. The arousal index night-to-night variability was low for all definitions.