Behavioral, event-related potential (ERP), and EEG measures were obtained to describe more fully the relationship between brain activity and arousal level during the process of falling asleep. In addition to standard polysomnographic measures, tones were presented at random intervals throughout two nights to each of nine subjects. Subjects were instructed to respond to the tones whenever they heard them. Initial sleep onset was disrupted five times following zero through four successive response failures. Sampling of EEG was initiated 5 s prior to tone onset (EEG analyses) and continued for 5 s following tone onset (ERP data). With EEG ordered as a function of response rate, significant increases in power were found across all standard frequency bands for the pretone data at sleep onset. Significant changes in amplitude were related to decreasing responsivity for all late ERP components except P2. Inasmuch as virtually all EEG frequencies and ERP components were strongly influenced by momentary changes in arousal, arousal must be considered a (possibly the) primary determinant of the characteristics of the overall electrical output of the brain. Response cessation coupled with sharp increases in EEG synchronization mark the point of sleep onset.

AHSTK/UT Can the fundamental differences in sleep structure known to differentiate good from insomniac sleepers (e.g., sleep length, sleep onset latency f SOLI, number of sleep disruptions, etc.) be identified using a behavioural slccp/wakc (S/W) monitor in the home? Sixteen women (8 good and 8 insomniac sleepers) enrolled in an introductory psychology course participated in a study of S/W patterns. They used a portable version of the Ogilvic and Wilkinson (1988) behavioural response (BR) system in their homes for 4 consecutive nights. Insomniacs had greater SOLs, less efficient sleep, and tended to have a greater number of arousals as compared with good sleepers. The data indicate that the behavioural system could be used as a diagnostic tool for in-home evaluations of disorders of initiating and maintaining slccp.RESUMK Est-il possible, a partir des differences fondamcntales dans la structure du sommeil, dcdistinguer les bonsdormeursdes insomniaques (e.g., durcedu sommeil, la latencc d'induction du sommeil | SOL], le nombrc dc perturbations du sommeil, etc...) a l'aide d'un monitcur behavioral sommeil-cvcil installc dans la maison? Seize femmes (8 bonnes dormcuscs et 8 insomniaques) inscrites a un cours d'introduction a la psychologie ont participe a I'etude de patrons S/W. Klles etaient dotccs d'une version porative du systcme de reponse behavioralc (BR) d'Ogilvie et dans leur maison pour une periode de 4 nuits consecutive*. Les insomniaques avaient des SOL plus grands, un sommeil moins cfficacc, et claienl plus scnsiblcs aux periodes d'eveil par rapport aux bons dormeurs. Les rcsultats indiquent quc lc systeme behavioral pourrait ctre utilise commc un outil diagnostique pour revaluation a domicile des troubles de ("induction ct du maintien du sommeil.A relatively inexpensive and efficient method of assessing insomnia is long overdue. Research into all aspects of insomnia is crucial due to the high prevalence of the disorder. Several studies examining the occurrence of sleep disorders including insomnia have found a high frequency of sleep-related problems in the general population ranging from 15% to 42.