Gail R. Marsh

Insomnia And The Eye Of The Beholder: Are There Clinical Markers Of Objective Sleep Disturbances Among Adults With And Without Insomnia Complaints?

Previous findings suggest that some who report insomnia sleep well, whereas some noncomplaining individuals sleep rather poorly. This study was conducted to determine if mood, anxiety, and sleep-related beliefs might relate to perceived sleep disturbance. Thirty-two women and 32 men (aged 40-79 years) with primary insomnia and an aged-matched sample of 61 normal sleepers (31 women, 30 men) completed 6 nocturnal sleep recordings, as well as the Beck Depression Inventory (BDI), the Trait portion of the State-Trait Anxiety Inventory (STAI-2), and the Dysfunctional Beliefs and Attitudes About Sleep Questionnaire. Sleep and interview data were used to subdivide the majority of the sample (n = 108) into objective normal sleepers and subjective insomnia sufferers who seemingly slept well and subjective normal sleepers and objective insomnia sufferers who slept poorly. The 2 subjective subgroups showed the most marked differences on most of the psychometric measures. The findings suggest that the psychological factors scrutinized in this study may mediate sleep satisfaction and/or predict objective sleep difficulties.

Binaural Auditory Beats Affect Vigilance Performance and Mood

When two tones of slightly different frequency are presented separately to the left and right ears the listener perceives a single tone that varies in amplitude at a frequency equal to the frequency difference between the two tones, a perceptual phenomenon known as the binaural auditory beat. Anecdotal reports suggest that binaural auditory beats within the electroencephalograph frequency range can entrain EEG activity and may affect states of consciousness, although few scientific studies have been published. This study compared the effects of binaural auditory beats in the EEG beta and EEG theta/delta frequency ranges on mood and on performance of a vigilance task to investigate their effects on subjective and objective measures of arousal. Participants (n = 29) performed a 30-min visual vigilance task on three different days while listening to pink noise containing simple tones or binaural beats either in the beta range (16 and 24 Hz) or the theta/delta range (1.5 and 4 Hz). However, participants were kept blind to the presence of binaural beats to control expectation effects. Presentation of beta-frequency binaural beats yielded more correct target detections and fewer false alarms than presentation of theta/delta frequency binaural beats. In addition, the beta-frequency beats were associated with less negative mood. Results suggest that the presentation of binaural auditory beats can affect psychomotor performance and mood. This technology may have applications for the control of attention and arousal and the enhancement of human performance.

Sleep in peri-menopausal and post-menopausal women

Despite the fact that a large number of women report sleep disturbances associated with peri-menopausal and post-menopausal periods, there is a surprising lack of literature related to this issue. In fact, there has not been enough work in this area to even definitively establish whether there is a sleep disorder that is specifically related to these life-stage changes. Herein we review the available literature which suggests that insomnia may be directly linked to the changes that occur during the peri/post-menopausal periods. This insomnia appears to be due to night sweats caused by the hormonal changes which occur and which lead to an increase in arousals. Persistence of insomnia symptoms after adequate hormone replacement therapy may indicate that behavioral conditioning of the insomnia initially triggered by the night sweats may have occurred. Alternatively, such an insomnia in a peri/post-menopausal woman could be due to unresolved grief related to going through menopause or could reflect an independent sleep disorder, such as periodic movements of sleep, sleep apnea, depression, anxiety, etc. Whereas menopausal changes do not directly lead to an increase in sleep apnea they seemingly contribute to an increased risk for this disorder. In view of these considerations, we provide guidelines for the proper diagnosis and treatment of peri/post-menopausal women with sleep complaints.

Age differences in evoked potential correlates of a memory scanning process

Elderly subjects when compared to young, mature subjects in a memory-scanning task were shown to have longer response times (RT). A late positive component (LPC) of the average evoked potential did not reflect this difference between groups. However, in both groups, the LPC was seen to occur with longer latency at RT increased. LPC amplitudes also declined with increasing RT. There were greater differences between left- and right-hemisphere LPC amplitude and between LPC recorded along the midline scalp in the younger group than in the older subjects.

Slow-wave sleep and waking cognitive performance II: Findings among middle-aged adults with and without insomnia complaints

Previous studies showing a relationship between nocturnal slow-wave sleep (SWS) and subsequent diurnal performance among young normal sleepers and older insomnia sufferers have provided limited support for the notion that this sleep stage serves a restorative role for neurocognitive functioning. The current study, which examined the relationship between SWS and reaction time performance among middle-aged adults with and without insomnia complaints, was conducted to further explore this possibility. A sample of 31 noncomplaining middle-aged (ages 40 to 59 years) normal sleepers and a like-aged sample of 27 insomnia sufferers, provided data for the current investigation. All participants underwent nocturnal sleep monitoring immediately prior to undergoing a battery of daytime tests that measured simple reaction time, vigilance/signal detection, and complex reaction time. Results showed relationships between reaction time performances on some tasks and some SWS measures among both the normal sleepers and insomnia sufferers. Findings supported our prediction that the presence of sleep pathology (e.g., insomnia) alters the SWS-performance relationship observed, but the results failed to show a consistent relationship between SWS and subsequent performance within either sample. The findings suggest that the specific performance demands of the task in question as well as physiological parameters other than SWS may determine performance as well. Findings for this and previous studies do provide some support for the contention that the neurocognitive restorative value of SWS may change across the lifespan. Possible implications of the studys findings are discussed and directions for future research are considered.

Changes in Event Related Potentials During Processing of Stroop Stimuli

In a simplified Stroop test, subjects responded with a button press to either the color or word dimension of Stroop stimuli. Response times were analyzed as a function of condition (color or word), stimulus type (congruent or noncongruent color-word pairing) and visual field of presentation (left or right). Changes in the stimulus evoked potential (Experiment I) and the preresponse (premotor) potential (Experiment II) were measured as a function of the independent variables and hemisphere of recording site. Stimulus type had the expected Stroop effect on response time, with noncongruent stimuli associated with longer RTs. The pattern of changes in the event related potentials suggested that the typical Stroop interference effect (color condition) is localized in the response selection stage of processing. However, the less common reverse Stroop effect (word condition) probably results from more complex processing interactions during encoding of the color and word dimensions.

Daytime testing after laboratory or home-based polysomnography: comparisons of middle-aged insomnia sufferers and normal sleepers

Many studies have shown only modest differences between insomnia sufferers and matched, non‐complaining normal controls in regard to their levels of daytime sleepiness and diurnal performances. The current study was conducted to determine whether such daytime comparisons might be affected by the setting (home vs. sleep lab) in which study participants sleep on the nights before such testing. The study used a counter‐balanced, matched‐group design in which participants underwent three consecutive nocturnal polysomnographs (PSG) conducted either in the sleep lab or in their homes prior to undergoing daytime multiple sleep latency test (MSLT) and computer‐administered performance testing. The study participants were 35 (18 women and 17 men) middle‐aged (40–59 years) non‐complaining normal sleepers and 33 middle‐aged insomnia sufferers (17 women and 16 men) who met structured interview criteria for persistent primary insomnia. Use of a hierarchical linear statistical model showed only insomnia sufferers who underwent nocturnal home PSG were more alert on the MSLT than were normal sleepers who underwent lab PSG. However, these insomnia sufferers showed a greater propensity toward attention lapses on selected reaction time tests than did either of the two normal control groups (i.e. either those who slept in the lab or those who slept at home). The results suggest the nocturnal sleep setting (home vs. lab) may affect subsequent MSLT and performance test comparisons of insomnia sufferers and normal sleepers.

Ambulatory polysomnography: Technical aspects and normative values

Ambulatory polysomnographic (APSG) assessment of sleep disorders is now possible, but the technique of APSG is sufficiently different from in-laboratory PSG that normative data from in-laboratory PSG may not apply to APSG. This paper reviews the technical aspects of APSG and presents normative APSG data from 20 older healthy males. Subjects underwent medical and psychiatric screening before completing APSG in their homes. Total sleep time and the rapid-eye-movement sleep latency (RL) were both shorter than those reported by others using traditional in-laboratory techniques. The shorter total sleep may be related to behaviors at home that impinge upon sleep. The shorter RL may be related to differences in calculation methods. Periodic limb movements were common in our subjects but did not contribute to sleep disturbance. We conclude that APSG is sufficiently different from traditional PSG as to warrant collection of a large normative data base.

Hemispheric asymmetry in the processing of Stroop stimuli

Subjects responded to Stroop (incongruent color and color word) and non-Stroop (congruent color and color word) stimuli, presented to the left or right visual field, under four instructional conditions (color, word, memory color, memory word). The typical Stroop effect was present in the simple conditions (color, word) with no hemispheric asymmetry. In the memory conditions, there was hemispheric asymmetry in the Stroop effect, with reduced interference in the right hemisphere for memory color responses, and in the left hemisphere for memory word responses. The difference in results was attributed to the possibility for selective attention to a target, rather than a dimension, in the memory conditions.

Some Relationships between CNV, P300, and Task Demands

Publisher Summary The relatively slow electrocortical phenomena Contingent Negative Variation (CNV) and P300 have been found to be related to various psychological/cognitive demands of the testing situation rather than to the physical dimensions of the stimuli involved. Recent results have shown topographical shifts of the CNV in an anterior or posterior direction with changes in “cognitive set” with eye movement artifact eliminated as a factor. This chapter describes an experiment in which an initial habituation set of alternating red and green lights was given, followed immediately by a more complex repeating pattern of G, G, R, G, R. This was continued until the subject correctly guessed one complete five-element pattern. Four iterations of this pattern were then given as overtraining. Silver disk electrodes placed above and below the left eye and at the outer canthus of each eye provided information on eye movements. Any eye movements or blinks during a trial period caused that trial to be excluded from further data analysis.