This study evaluated the impact of insomnia and chronic use of benzodiazepines on the cognitive and psychomotor performance of older adults. Three conditions, matched on age, gender, and education, ...were compared: 20 prolonged users of benzodiazepines for insomnia, 20 unmedicated insomniacs, and 20 good sleepers. The participants completed neuropsychological tests of memory, attention/concentration, psychomotor speed, and executive functions, as well as subjective evaluations of their actual performance. Individuals with insomnia, both medicated and unmedicated, performed worse than good sleepers on the attention/concentration factor. There was no other objective evidence of performance impairments. However, unmedicated insomniacs had lower performance expectancies and subjectively rated their performance more negatively relative to medicated insomniacs and good sleepers. Both insomnia conditions also rated their performance as lower compared with their perceived potential. It is suggested that the attention/concentration difficulties experienced by medicated and unmedicated older adults with insomnia may be linked to a state of hyperarousal. The discrepancies between subjective reports of daytime deficits and objective impairments may reflect a generalized faulty appraisal of sleep and daytime functioning among individuals with insomnia complaints. The implications of those findings for the assessment and treatment of late-life insomnia are discussed.
InAlN grown by plasma-assisted molecular beam epitaxy often contains a honeycomb microstructure. The honeycomb microstructure consists of 5–10nm diameter aluminum-rich regions which are surrounded by ...indium-rich regions. Layers without this microstructure were previously developed for nominally lattice-matched InAlN and have been developed here for higher indium content InAlN. In this study, InAlN was grown in a nitrogen-rich environment with high indium to aluminum flux ratios at low growth temperatures. Samples were characterized by high-resolution x-ray diffraction, atomic force microscopy, high-angle annular dark-field scanning transmission electron microscopy, and atom probe tomography. Atomic force microscopy showed InAlN layers grown at temperatures below 450°C under nitrogen-rich conditions were free of droplets. InAlN films with indium contents up to 81% were grown at temperatures between 410 and 440°C. High-angle annular dark-field scanning transmission electron microscopy and atom probe tomography showed no evidence of honeycomb microstructure for samples with indium contents of 34% and 62%. These layers are homogeneous and follow a random alloy distribution. A growth diagram for InAlN of all indium contents is reported.
•Demonstration of high indium content InAlN without honeycomb microstructure.•Development of growth diagram for high indium content InAlN.•Identification of regimes for nitrogen-rich growth of InAlN.
Abstract
Introduction:
Hyperarousal is linked to sleep misperception, which is especially present in paradoxical insomnia (PARA-I). ERP studies showed that hyperarousal can be expressed through ...enhanced information processing, which is different between PARA-I and psychophysiological insomnia (PSY-I). Our objective is to use ERPs to investigate the link between misperception and information processing. Specifically, N1 (vigilance) and P2 (inhibition) were chosen for information processing and sleep onset latency (SOL) and wake after sleep onset (WASO) were used for misperception. Our hypothesis is that the link between misperception and information processing will be stronger for PARA-I than for PSY-I and good sleepers (GS).
Methods:
50 GS (age 34.7 ± 9.0), 40 PSY-I (40.9 ± 9.1) and 29 PARA-I (39.41 ± 9.2) underwent four PSG nights. Subjective and objective sleep measures were obtained for SOL and WASO. ERPs were recorded all night on Night 4 (oddball paradigm). A linear mixed model including 3 within-subject factors (peak, N1 and P2; auditory stimuli, standard and deviant; recording time, S2E, S2L, SWS, REM), 3 between-subject independent factors (group, GS, PARA-I, PSY-I; SOL and WASO misperception, over, good, under) was computed on amplitude data at Cz. Misperception was calculated as the difference between subjective and objective measures.
Results:
Results revealed no differences between groups for information processing (p = 0.451). However, the interaction effect group x peak, (p=0.004), showed that P2 was higher in PARA-I. There was no moderator effect of group on the link between misperception and hyperarousal (p=0.769, p=0.440).
Conclusion:
A higher P2 in PARA-I would indicate that they need to deploy more energy to inhibit information processing, which would explain their greater misperception. Knowing that hyperarousal is a 24-hour problem, daytime ERPs should be investigated in connexion with sleep misperception. No group moderation effect means that the link between misperception and hyperarousal stays stable across sleep types. Consequently, mechanisms linking sleep misperception and hyperarousal appear similar for each group.
Support (If Any):
-
Sleep misperception is often observed in insomnia individuals (INS). The extent of misperception varies between different types of INS. The following paper comprised sections which will be aimed at ...studying the sleep EEG and compares it to subjective reports of sleep in individuals suffering from either psychophysiological insomnia or paradoxical insomnia and good sleeper controls. The EEG can be studied without any intervention (thus using the raw data) via either PSG or fine quantitative EEG analyses (power spectral analysis PSA), identifying EEG patterns as in the case of cyclic alternating patterns (CAPs) or by decorticating the EEG while scoring the different transient or phasic events (K-Complexes or sleep spindles). One can also act on the on-going EEG by delivering stimuli so to study their impact on cortical measures as in the case of event-related potential studies (ERPs). From the paucity of studies available using these different techniques, a general conclusion can be reached: sleep misperception is not an easy phenomenon to quantify and its clinical value is not well recognized. Still, while none of the techniques or EEG measures defined in the paper is available and/or recommended to diagnose insomnia, ERPs might be the most indicated technique to study hyperarousal and sleep quality in different types of INS. More research shall also be dedicated to EEG patterns and transient phasic events as these EEG scoring techniques can offer a unique insight of sleep misperception.
La mésestimation du sommeil est souvent observée chez les individus souffrant d’insomnie (INS). Cependant, l’ampleur de cette mésestimation varie entre les types d’INS. Cet article est composé de sections dédiées à l’étude de l’EEG et sa comparaison avec les rapports subjectifs de sommeil d’individus souffrant soit d’insomnie psychophysiologique ou paradoxale et bons dormeurs. L’EEG peut être étudié soit sans intervention (en utilisant les données brutes) comme dans le cas de la polysomnographie ou l’analyse spectrale, soit en identifiant des patrons d’activation comme pour les patrons cycliques alternants (cyclic alternating pattern) ou encore en décortiquant l’EEG en évènements phasiques ou transitoires (complexes-K et fuseaux de sommeil). On peut également agir sur l’EEG en délivrant des sons et en étudiant leur impact sur les ondes de l’EEG comme dans le cas des potentiels évoqués, et surtout ceux cognitifs. Du peu d’études disponibles utilisant ces différentes techniques/mesures, une conclusion générale peut tout de même être tirée : la mésestimation du sommeil n’est pas facilement quantifiable et sa valeur clinique n’est pas adéquatement reconnue. Alors qu’aucune des techniques/mesures définies ici n’est disponible ou recommandée afin de diagnostiquer l’insomnie, la technique utilisant les potentiels évoqués cognitifs semble la plus appropriée ou juste afin de mesurer l’hypervigilance corticale (hyperarousal) et la qualité du sommeil chez les différents types d’individus souffrant d’insomnie. Finalement, plus de recherches devraient être dédiées à l’étude des patrons EEG et des évènements phasiques du sommeil puisque ces techniques apportent une compréhension différemment unique de la mésestimation du sommeil.
Abstract
Introduction
Shift work is known to alter sleep quantity and quality. However, the way work schedule affects sleep in the presence of shift work disorder (SWD) is unclear. In addition, it is ...unknown if mood of shift workers differs according to work schedules.
Methods
79 shift workers of which 43 met SWD criteria were recruited. They worked 6 to 10 nights out of 14. Night shifts are either consecutive (CNS), or fragmented (FNS) (nights are intervened with free days). Participants completed sleep diaries for two weeks and self-reported questionnaires. Those without SWD and satisfied with their sleep were good sleepers (GS). Four groups were created: (1)CNS-SWD; (2)CNS-GS; (3)FNS-SWD; and (4)FNS-GS. Total Sleep Time (TST), Total Wake Time (TWT), and Sleep Onset Latency (SOL) were computed for the main sleep episode (longest sleep episode after night shift) and for the 24-hour sleep period (includes all sleep episodes occurring in that period).
Results
For main sleep episode, CNS-SWD have higher TWT and SOL and a lower TST than CNS-GS (ps< .001, .05, .02), while FNS-SWD have higher TWT (p< .04) than FNS-GS. For 24-hour sleep period, the same significant differences are observed for TWT and SOL. Depression and anxiety levels are higher for CNS-SWD compared to CNS-GS (ps< .008 and .01, respectively). There is no significant difference between FNS-SWD and FNS-GS for these variables.
Conclusion
Fragmented night shift reduces sleep time of shift workers with SWD and GS while continuous night shift reduces sleep only for those with SWD. Workers under consecutive or fragmented night shift present similar wake time. Anxiety and depression levels differ according to the work schedule and SWD. Depression symptoms are more important for continuous night shift workers with SWD. The two distinct work schedules differently impact sleep and mood: The fragmented one impact on sleep time while the continuous one impact on mood in presence of SWD.
Support (If Any)
Study supported by a CIHR funding 191771 awarded to A.V.
The present study examined the sleep microstructure in relation to insomnia and chronic use of benzodiazepines in older adults.
The participants were 46 older adults, aged 55 or older (mean age = ...62.9), who were divided into three groups: insomnia sufferers using BZ chronically (n = 15), drug-free insomnia sufferers (n = 15), and self-defined good sleepers (n = 16).
Participants completed 3 consecutive nights of polysomnography in the laboratory. Spectral analyses were carried on the second night of sleep recordings. Stages 2, 3, and 4 of the first 4 cycles of the second night were retained for the analysis.
Results showed no significant differences between drug-free insomnia sufferers and good sleepers. However, benzodiazepine users exhibited significantly less delta and theta activity over the night than did good sleepers. When compared to drug-free insomnia sufferers, benzodiazepine users had less delta and theta activity within cycle 2 only. Regarding high-frequency bands, benzodiazepine users had more beta 1 activity within cycle 3 than did good sleepers and more than both drug-free insomnia sufferers and good sleepers within cycle 4.
The findings show that spectral analysis is an efficient tool to detect and quantify the effects of benzodiazepine use on sleep structure, particularly with older adults, a group for whom macrostructure sleep alterations due to physiologic aging are hard to distinguish from sleep changes induced by insomnia and the use of hypnotic drugs. In addition, these results raise important questions about the effects and indications of prolonged use of benzodiazepine medications in older adults with insomnia complaints.
Familial incidence of insomnia Bastien, Célyne H.; Morin, Charles M.
Journal of sleep research,
March 2000, Letnik:
9, Številka:
1
Journal Article
Recenzirano
Odprti dostop
This study evaluated the familial incidence of sleep disturbances among individuals with insomnia complaints. The sample consisted of 285 patients evaluated for insomnia at a sleep disorders clinic. ...All patients completed a sleep survey and underwent a semistructured clinical interview as part of their initial evaluation of insomnia. Information on the presence and nature of sleep disturbances among their family members (first‐ and second‐degree relatives) was obtained from a sleep survey. The findings indicate that 35% of patients consulting for insomnia had a positive family history of sleep disturbances. Insomnia was the most common type of sleep disturbance identified (76%) and the mother was the most frequently afflicted family member. Reports of sleep disturbances among a family member were more prevalent when the onset of insomnia was before 40‐years‐old than when it was later in life. A positive family history was slightly higher when the insomnia complaint involved sleep‐onset difficulties relative to sleep‐maintenance or mixed insomnias. Although the present findings suggest that a positive family history of insomnia may be a potential risk factor for insomnia, it is unclear whether this reflects a genetic predisposition or a social learning phenomenon.
Abstract Objective A sleep spindle is an electroencephalographic feature that is unique to sleep. It has been suggested that this phasic event has a sleep-protective function. The objective of the ...present study was to document one aspect of sleep protection in chronic insomnia sufferers: the number and density of sleep spindles in Stage 2 sleep. Methods Sleep spindles were scored during Stage 2 sleep on the second and third nights of a protocol of polysomnographic recordings that lasted for four consecutive nights. The sample included 16 participants suffering from insomnia (INS group; mean age=43.4 years) and 14 good sleepers (GS group; mean age=38.1 years). Participants underwent sleep and psychological evaluations. The INS group participants met the diagnostic criteria for primary psychophysiological insomnia (mean duration of insomnia=9.6 years). Results The total number of sleep spindles in Stage 2 sleep and the density (sleep spindles per minute) according to the total time spent in Stage 2 sleep were compiled. Repeated-measures analyses of variance showed no significant difference in the number and in the density of sleep spindles between the INS group (68.46 and 0.60, respectively) and the GS group (56.28 and 0.46, respectively). Conclusion These results suggest no deficiency in the sleep-protection mechanism of psychophysiological insomnia sufferers in comparison with good sleeper controls, as measured by the number and density of sleep spindles.
Abstract Objective Spontaneous K-complexes are electroencephalographic features unique to non-rapid eye movement sleep. It has been suggested that this phasic event is a sleep-protective mechanism. ...Because insomnia sufferers report poor sleep quantity and quality, the objective of this study was to document the occurrence of spontaneous K-complexes in Stage 2 sleep of individuals with chronic insomnia. Specifically, the number and density of spontaneous K-complexes were studied in psychophysiological insomnia sufferers. Setting This study took place in a sleep and event-related potentials laboratory. Design Spontaneous K-complexes were scored during Stage 2 sleep on the second and third nights of a four-consecutive-nights protocol of polysomnographic recordings. Participants The sample included 14 participants suffering from psychophysiological insomnia (INS group; mean age=44.1 years) and 14 good sleepers (mean age=38.1 years). Participants underwent sleep and psychological evaluations. INS group participants met the diagnostic criteria for primary psychophysiological insomnia (mean duration of insomnia=9.6 years). Intervention Not applicable. Results The total number of spontaneous K-complexes and the density according to the total time spent in Stage 2 sleep (spontaneous K-complexes per minute) were compiled. Repeated-measures analyses of variance showed no significant difference in the number and density of spontaneous K-complexes between the INS group (313.98 and 2.66) and the GS group (361.10 and 2.88), respectively. Conclusion These results suggest no deficiency in the sleep-protective mechanism of psychophysiological insomnia sufferers in comparison with good sleepers, as measured by the spontaneous K-complexes' number and density.
Abstract
Introduction:
Dream incorporation in laboratory setting manifests itself by direct (ex: experimenter, electrodes, etc) or indirect (ex: participating in an experiment) presence of elements ...referencing to the experimental setting. The presence of increased cortical activation during sleep and wakefulness in insomnia sufferers (INS) is well documented and is often reflected through enhanced information processing. This latter could increase awareness of sleeping environments and lead to dream incorporation of the experimental settings. The objective of the present study is to compare INS and good sleepers (GS) regarding dream incorporation for laboratory settings.
Methods:
PSG was recorded in 12 INS and 12 GS (aged 30 to 45) for five consecutive nights (N1 to N5). On N3 and N5, participants were awoken during REM periods for dream collection. Dream incorporation of the laboratory setting was targeted with the following categories: environment (bed, electrodes, etc.) staff and experience (being awakened, report dreams, etc.). Dream elements referring to sleep but not related to laboratory settings were also quantified.
Results:
Independent sample T tests were used to assess between groups differences in regards to 1) Environment 2) Staff 3) Experience and 4) Sleep dream incorporation. Two participants were excluded due to extreme data. Results showed a significant difference between INS and GS for environmental dream incorporation (p=.001), INS reporting more environmental elements. No significant difference were found for Staff (p=.483), Experience (p=.289) and Sleep (p=.283).
Conclusion:
Because a greater number of elements from the laboratory environment is observed in INS’ dreams, it might suggest that INS are more hyperaroused at sleep onset and display enhanced information processing. Results also suggest that INS appeared more mindful of their surroundings since the immediate, concrete, external elements of the environment are more prone to be treated and so, incorporated in dreams.
Support (If Any):
CIHR (86571).
PDF
