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Biomedical subjects

G R Marsh

Publications and source records attributed to G R Marsh.

17 recordsLinked to original sources
PubMed1992

A cognitive-behavioral therapy for sleep-maintenance insomnia in older adults.

Older adults (3 men, 4 women, aged 55 to 68 years) with chronic sleep-maintenance insomnia were treated sequentially with relaxation therapy (RT) and then with a cognitive-behavioral therapy (CBT) specifically designed for alleviating sleep maintenance problems. Sleep diaries and an objective measure of sleep, the sleep assessment device, showed only modest improvements in measures of wake time after sleep onset, sleep efficiency, and night-to-night sleep variability following RT. However, significant improvements in these measures were observed following CBT and at a 3-month follow-up. These findings, considered in conjunction with previous reports, suggest that CBT specifically addresses factors that sustain sleep maintenance complaints. Additional trials of CBT with larger samples are warranted.

Aged↗
PubMed1992

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.

Ambulatory Care↗
PubMed1992

Periodic limb movement variability in older DIMS patients across consecutive nights of home monitoring.

Older difficulty initiating and/or maintaining sleep (DIMS) patients who met criteria for periodic limb movement disorder (PLMD) were monitored for three consecutive nights in their homes using ambulatory polysomnography (PSG). Correlational analyses of the group data suggested little night-to-night variability in either movement indices or movement-related arousal indices for this sample. However, within-subjects comparisons suggested considerable variability in these indices and other sleep measures across nights. Nevertheless, for most subjects, the variability noted for these indices appeared to have little effect on PLMD severity classification or clinical treatment decisions derived from blind examinations of PSGs. Further, the initial PSG study generally led to a representative severity classification and clinical decision. Additional research is needed to determine the generalizability of these results to younger subjects, patients with complaints of excessive somnolence and other methods of home PSG monitoring.

Age Factors↗
PubMed1991

Sleep variability across consecutive nights of home monitoring in older mixed DIMS patients.

Twenty patients with difficulties initiating and maintaining sleep (DIMS) were monitored in their homes for three consecutive nights using ambulatory polysomnography (PSG). Following each night of monitoring, patients provided subjective ratings of sleep disturbance and tolerance of the PSG equipment. Friedman analyses of variance performed on the objective and subjective parameters showed that the sample, as a whole, evidenced no systematic first night effects (FNE) in response to monitoring. Inspection of the data from each individual subject, nevertheless, showed that half of the sample did experience multiple FNE. Further, several scales from the Minnesota Multiphasic Personality Inventory discriminated those patients who showed multiple FNE from those who did not. However, far more striking was the finding that clinically and statistically significant intrasubject variability across nights was observed for each sleep parameter measured. Given this finding, a single ambulatory PSG study may not fully convey the nature of the sleep disturbance experienced by the DIMS patient even when FNE are absent. We thus, recommend multiple ambulatory sleep studies for those clinical and research situations in which it is necessary to document patients' night-to-night sleep variability. In contrast, when the goal of the PSG study is that of determining a sleep diagnosis, a single ambulatory study, in combination with other clinical data, may be sufficient.

Aged↗
PubMed1990

Daytime functioning and nighttime sleep before, during, and after a 146-hour tennis match.

Two adult males (ages 31 and 35 years) were studied while they participated in a week-long marathon tennis match under conditions of extreme sleep restriction (4-5 h reductions per night). Polysomnographic monitoring was conducted on the two nights prior to the marathon, continuously throughout the match, and on two recovery nights. In addition, measures of daytime sleepiness, mood state, and cognitive performance were obtained during the course of the study. Despite undergoing marked sleep restriction, both players continued to obtain their usual (baseline) amounts of slow wave sleep throughout the marathon. Both players showed a gradually increasing tendency toward daytime dozing across the first few days of the marathon. This tendency decreased on the fifth day but increased again on the sixth day of the match. Also, both players showed a pre- to postmatch decline on some cognitive measures. However, the players differed markedly in their ratings of sleepiness, mood ratings, recovery sleep patterns, and endurance with respect to the demands of the match. Results appear to be consistent with previous laboratory studies in documenting the primacy of the "slow wave sleep drive." Given the marked differences observed between the players, research designed to identify factors that predict response to sleep loss seems to be warranted.

Adult↗
PubMed1989

Two methods of scoring sleep with the Oxford Medilog 9000: comparison to conventional paper scoring.

This study evaluated two methods of scoring taped polysomnographic data directly on the Medilog 9000 scanner: (a) screen-by-screen scoring, and (b) rapid screen scoring. Sixteen overnight polysomnograms recorded on Medilog 9000 recorders were scored using the above two methods and were also printed on paper for conventional paper scoring. Interscorer agreement was 87.8% for paper scoring, 85.5% for screen-by-screen scoring, and 84.2% for rapid screen scoring. Comparison of screen-by-screen scoring with paper scoring revealed small absolute deviations and correlations of r greater than 0.90 for all sleep parameters, with the exception of brief (less than 2 min) awakenings (r = 0.69). Rapid screen scoring resulted in slightly lower correlations and greater deviations from paper scoring on several sleep parameters, but appeared acceptable for most clinical purposes and greatly reduced the required scoring time. Although some statistically significant differences between scoring methods were observed, the size of effect was small and of doubtful clinical importance. These findings suggest that polysomnographic data recorded on Medilog 9000 recorders can be reliably and accurately scored on the Medilog scanner, obviating the laborious task of printing the taped data on paper.

Adolescent↗
PubMed1989

Polysomnographic assessment of DIMS: empirical evaluation of its diagnostic value.

This investigation examined the diagnostic value of polysomnography (PSG) for evaluating disorders of initiating and maintaining sleep (DIMS). The sample consisted of 100 outpatients who presented to the Duke Sleep Disorders Center with a complaint of chronic insomnia. All patients were given comprehensive medical, psychiatric, behavioral, and ambulatory PSG evaluations. Sleep disorder diagnoses were assigned using the criteria of the Association of Sleep Disorders Centers. Overall, PSG yielded important diagnostic information in 65% of the sample: 34% were given a primary sleep disorder diagnosis that was heavily dependent on PSG data [periodic movements of sleep (PMS) = 25%, apnea = 3%, and subjective insomnia = 6%]; 15% were given a secondary diagnosis of one of these three disorders; and PSG ruled out suspected PMS in 9% and sleep apnea in 7% of the sample. Patients greater than 40 years of age had a significantly higher rate of positive PSG findings than younger patients. Using only the clinical exam, two experienced sleep clinicians were able to predict only 14 of 25 PMS cases and one of three cases of sleep apnea. Based on these data, we suggest using PSG routinely with older insomniacs and with younger patients who fail initial treatment.

Adult↗
PubMed1985

Prediction and evaluation of memory performance by young and old adults.

Does the poorer performance of older people in laboratory tests of episodic memory result from metamemory problems? Memory of 20 young and 20 old adults for 60 "unrelated" paired associates was measured by an associative matching task. Two metamemory measures also were taken: Each pair was rated at the time of study for the likelihood that the person would recall it (prediction measure) and on the matching task each response pairing was judged as to its correctness (response evaluation measure). Young adults were correct on 50% of the associative matches, old only 30%. The two groups did not differ in the predictive metamemory measure: Both were able to predict relative memorability. Old persons, however, underestimated task difficulty (i.e., they overestimated the number of correct associative matches they would make, whereas the young did not). Both groups were quite accurate in the response evaluation measure.

Adolescent↗
PubMed1979

The effects of deanol on cognitive performance and electrophysiology in elderly humans.

Deanol (900 mg/day for 21 days) had no effect on learning a list of words when tested at weekly intervals. Tests of simple and complex reaction time and a test of continuous serial decoding of digits showed no enhancement with the drug. Several components of evoked potentials recorded from several scalp sites did show enhanced amplitude under drug treatment. These changes were not accompanied by changes in the EEG spectrum as are seen with some other psychoactive drugs. Deanol seems to be an ineffective treatment for the normal slowing of cognitive function seen in the normal elderly person or those elderly with only minimal cognitive decline and free of symptoms of dementia. Contrary to earlier reports, elderly persons were found to be able to benefit from warning signals in a complex reaction time task.

Aged↗
PubMed1979

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.

Brain↗
PubMed1975

Changes in alpha rhythm asymmetry during learning of verbal and visuospatial tasks.

Alpha activity in the two cortical hemispheres was examined during learning and overlearning of a verbal and a visuospatial task. Compared to a pretask baseline condition, the amount of alpha activity during the tasks was decreased. An increase in alpha activity was found from learning to overlearning in both tasks. A greater amount of alpha was found in the right hemisphere for both tasks. In addition, no difference in the degree of alpha asymmetry was found between the tasks. This was discussed in light of prior contrary findings. A significant positive correlation was found between change in learning rate and change in alpha asymmetry during the verbal task. An interpretation of this finding was offered in terms of the level of hemispheric activation reflecting the degree of task engagement.

Alpha Rhythm↗
PubMed1975

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.

Adult↗
PubMed1975

Age-dependent changes in hippocampal theta.

The hippocampal theta rhythm in rats exhibited an age-dependent slowing in modal frequency. However, the theta rhythm of young rats with chronic respiratory infections showed a similar slowing. Respiratory disease-free hamsters also exhibited an age-dependent slowing of modal frequencies. These findings emphasize that the health status of the animal must be examined carefully in order to establish an age-dependent slowing in hippocampal rhythm.

Age Factors↗
PubMed1975

Age differences in the speed of a spatial cognitive process.

Older subjects responded slower than younger subjects on a spatial task which required them to rotate mentally a perspectively drawn figure in order to judge whether it was congruent with a second figure. Decision time was partitioned into two components: (1) the time taken for the "mental rotation" process, (2) the time taken for the remaining processes such as stimulus encoding and motor output. Both components required more time in the elderly group. The increase with age in the component of decision time representing rotational processes was similar to those increases seen by other investigators examining age-dependent differences in time required for memory-scanning processes using verbal stimuli.

Adolescent↗