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Biomedical subjects

L Rosenthal

Publications and source records attributed to L Rosenthal.

At least 19 recordsLinked to original sources
PubMed1999

Psychometric evaluation of daytime sleepiness and nocturnal sleep onset scales in a representative community sample.

BACKGROUND: The public health importance of daytime sleepiness as a risk factor for accidents, interpersonal problems, and decreased productivity has been recognized. However, epidemiologic research on this topic has been limited by the reliance on laboratory measures (i.e., the Multiple Sleep Latency Test-MSLT). Two scales, daytime sleepiness and nocturnal sleep onset, have been identified from the self-report Sleep-Wake Activity Inventory (SWAI) in a clinic sample and validated against the MSLT. This study evaluates the replicability of the two scales in a population sample and assesses potential thresholds in scale scores that distinguish normal from pathologic levels of daytime sleepiness and difficulty falling asleep. METHODS: The sample consisted of 2181 subjects 18-45 years old in the Detroit metropolitan area. All sleep characteristic information covered the 2 weeks prior to interview. Split-half sample factor analyses were conducted to assess replicability of the results. Distribution of scale scores and their relation to construct validity variables were used to evaluate possible thresholds. RESULTS: A two-factor model appeared to best account for the variation among the 12 items from the SWAI. The two factors accounted for 50% of the variance in both split-half sample analyses. The revised eight-item daytime sleepiness and two-item nocturnal sleep onset scales showed good and fair internal consistency respectively across both split-half samples. There appeared to be a "natural break" in daytime sleepiness scale scores that was associated with a substantial and consistent change in number of hours slept. No breaks appeared in nocturnal sleep onset scores. CONCLUSIONS: This study replicated the results of the clinic-based study and suggested a potentially useful diagnostic threshold for self-report excessive daytime sleepiness. Epidemiology of sleep depends on the ability to move from the laboratory to population surveys in reliable and valid ways. Development of self-report is a step in that direction.

Adolescent↗
PubMed1999

The detection of brief daytime sleep episodes.

INTRODUCTION: In the present study we evaluated the characteristics of sleep-onset detection (during daytime nap opportunities) as a function of differing sleep lengths among healthy, asymptomatic subjects. METHODS: Twenty subjects were randomized into a Latin square design in which each subject received 1, 5, 10, and 20 minutes of sleep during an MSLT. Subjects were asked after each nap if they fell asleep. The rate of sleep detection was analyzed as a function of sleep duration. RESULTS: Three subjects detected sleep onset after 1 minute of sleep, 7 subjects after 5 minutes of sleep, 10 subjects after 10 minutes of sleep, and 14 after 20 minutes of sleep (chi 2 = 9.63, p < .05). CONCLUSIONS: The present data indicate the importance of sleep duration in an individual's ability to detect the occurrence of sleep. Importantly, only three subjects detected sleep after 1 minute of sleep, emphasizing the dangerous nature of brief sleep episodes in the context of public safety.

Adult↗
PubMed1999

Ethanol as a hypnotic in insomniacs: self administration and effects on sleep and mood.

The purpose of this study was to assess the effects of low ethanol doses on sleep and mood and to assess its reinforcing effects used as a hypnotic. Twenty healthy adults, aged 21-45 yrs, all moderate social drinkers, were studied: eleven subjects had insomnia and nine were normal sleepers, as documented by clinical polysomnography. On two sampling nights each, ethanol (0.5 g/kg) or placebo was administered before sleep in color-coded cups presented in three doses (0.2, 0.2, and 0.1 g/kg) separated by 15 min. On three subsequent nights subjects chose their preferred presleep beverage (0.2 g/kg ethanol or placebo) based on cup color and were given an opportunity for 3 additional refills (0.2 g/kg each) of the chosen beverage at 15 min intervals, yielding a total possible dose of 0.8 g/kg. Insomniacs chose ethanol 67% of nights and normals 22%. Insomniacs chose significantly more ethanol refills than normals for an average nightly dose of 0.45 g/kg and normals took significantly more placebo refills. On the sampling nights 0.5 g/kg ethanol reduced REM sleep for both groups for the 8-hr sleep period and in insomniacs increased stage 3-4 sleep and reduced stage 1 sleep during the first half of the night to the level seen in the normals. Other sleep variables were not altered in either group or halves of the night. Presleep improvements in the Profile of Mood States tension and concentration factors were also associated with ethanol administration. Thus, acutely, both sleep and mood effects appear to be associated with the reinforcing effects of ethanol as a hypnotic for insomniacs.

Adult↗
PubMed1999

Sleepiness and the reinforcing and subjective effects of methylphenidate.

On 4 days, 6 volunteers received 10 mg methylphenidate or placebo at 0900 after 4 or 8 hr time in bed (TIB) and then on 4 days after 4 or 8 hr TIB chose their preferred capsule. On sampling days, 4 hr TIB increased multiple sleep latency test (MSLT) scores and Fatigue scale scores on the Profile of Mood States (POMS). In both TIBs, the drug increased the MSLT and POMS Vigor and Tension scale scores. It reduced POMS Fatigue scores and improved divided attention performance to a greater extent after 4 versus 8 hr. Drug was chosen on 88% of days after 4 hr, but only 29% of days after 8 hr. Preference for the drug depends on sleepiness and is mediated by performance-enhancing and fatigue-altering effects.

Adult↗
PubMed1999

Group supervision of groups: a modern analytic perspective.

This article is introduced by historical references to Freud's Wednesday Evening Society and to relevant sources in the literature on group supervision. The aims of group supervision are defined: helping supervisees to understand the individuals who comprise their groups, helping the supervisee become a group-oriented therapist, alerting supervisees to the critical task of monitoring and regulating the amount of emotional excitation within their groups, helping supervisees deal with the range of feelings induced in them by their groups, and helping them become familiar with the principles and become proficient in the techniques of modern analysis. Major aspects of the group-supervisory process are delineated and illustrated through the use of relevant vignettes. Resistance in supervisory groups is discussed with examples of the resolution of some resistances. The author's method and style of leading supervisory groups is presented, as are observations on the boundaries of supervisory groups.

Humans↗
PubMed1998

The effects of REM sleep deprivation on the level of sleepiness/alertness.

STUDY OBJECTIVES: The purpose of this study was to evaluate the effects of acute REM deprivation on daytime sleepiness/alertness, as measured by the MSLT. PARTICIPANTS: Twenty-six healthy, normal volunteers (14 males and 12 females) participated in this study. Participating subjects were in good physical and psychological health and were asymptomatic as to sleep/wake complaints. INTERVENTIONS: Subjects spent 5 nights and 5 days in the laboratory. The first night and day were utilized for screening purposes. The remaining stay in the laboratory consisted of a baseline night and day, 2 deprivation nights and days, and a recovery night and day. Each night, a nocturnal polysomnogram was employed to monitor subjects' sleep. Each day, subjects underwent an MSLT to evaluate their sleepiness/alertness. Subjects were randomized into REM-deprivation (RD) and yoked-control (YC) groups. On deprivation nights, RD subjects were awakened each time they entered stage REM sleep, and the YC subjects were awakened concomitantly with the RD subjects, assuming they were not in stage REM sleep. RESULTS: The REM-deprived subjects did not demonstrate any changes in MSLT scores across experimental days. In contrast, the YC subjects documented significantly lower MSLT scores on deprivation days due to decreased total sleep time. CONCLUSION: The REM-deprivation procedure antagonized the effects of sleep loss on daytime sleepiness, resulting in increased alertness for RD subjects compared to YC subjects. The mechanism by which REM deprivation exerts its alerting effects is unknown and will require future research.

Adult↗
PubMed1998

Relation between impedance and electrode temperature during radiofrequency catheter ablation of accessory pathways and atrioventricular nodal reentrant tachycardia.

OBJECTIVES: Impedance monitoring has been proposed as a method to assess the adequacy of tissue heating during catheter ablation procedures. The purpose of this study was to evaluate the relation among initial impedance, fall in impedance, and electrode temperature during catheter ablation procedures. METHODS AND RESULTS: Data from 248 applications of radiofrequency energy in 45 consecutive patients (26 with accessory pathways and 19 with atrioventricular nodal reentrant tachycardia) referred for catheter ablation were analyzed. The initial impedance was higher during ablation of accessory pathways than during atrioventricular nodal reentrant tachycardia (116+/-66 versus 106+/-80 omega, P < .001). In both groups, a significant correlation was observed between the initial impedance and temperature (R = 0.98, P < .001). After accounting for differences between patients and ablation targets, an even closer correlation was observed (accessory pathways: R = 0.95, P < .0001; atrioventricular nodal reentrant tachycardia: R = 0.94, P < .0001). CONCLUSION: These data suggest that monitoring of the initial impedance and the fall in impedance during ablation procedures may provide clinically valuable information to assess the efficacy of tissue heating and lesion formation.

Adolescent↗
PubMed1998

The siesta culture concept is not supported by the sleep habits of urban Mexican students.

Evidence in support for the concept of the so-called 'siesta culture' is not well developed and has, to date, relied largely on qualitative anthropological data. Presumably such cultures are characterized by a strong tendency for daytime naps and daytime sleepiness, phenomena which may partially represent the effects of geographic, climatic or light conditions and/or cultural influences. In this study we surveyed the nocturnal sleep habits and daytime sleep tendencies of 577 Mexican college students residing in Mexico City (19 degrees N latitude). Results indicated a number of parallels between the reported sleep habits of these students and those reported from other cultures at latitudes far to the north (North America, Europe), such as longer sleep at the weekends, an association between snoring and daytime sleepiness and a lack of relationship between nocturnal sleep duration and the reported tendency to nap. There was some suggestion that these Mexican students may actually nap less when compared to other college student populations. Taken together, these results call into question what is meant by the concept of a 'siesta culture', at least in this urban, educated, upper social economic scale (SES) population, and suggest that future studies in equatorial regions be undertaken to further appreciate the role of climate, photoperiod and/or culture in the tendency for humans to nap during the day.

Adolescent↗
PubMed1998

Relationship between the upper limit of vulnerability determined in normal sinus rhythm and the defibrillation threshold in patients with implantable cardioverter defibrillators.

The upper limit of vulnerability is the strength above which ventricular fibrillation is no longer inducible with a shock delivered during the vulnerable phase of the cardiac cycle. It has been demonstrated that the upper limit of vulnerability correlates with the defibrillation threshold in a paced rhythm. The purpose of this study is to evaluate the correlation of the upper limit of vulnerability determined in normal sinus rhythm with the defibrillation threshold using a simplified protocol in patients undergoing placement of an ICD. We studied 28 patients who underwent ICD implantation. CPI generators and Endotak leads were used in all patients. Device-based testing was used to determined the defibrillation threshold and the upper limit of vulnerability. The upper limit of vulnerability was tested with three shocks delivered at 0, 20, and 40 ms before the peak of the T wave during normal sinus rhythm. The defibrillation threshold was determined by a simple step up-down protocol. The upper limit of vulnerability (9.0 +/- 4.5 J) did not significantly differ from the defibrillation threshold (9.9 +/- 4.0 J), P = NS. A close correlation was present, correlation coefficient = 0.75, P < 0.0001. The upper limit of vulnerability was within 5 J of the defibrillation threshold in 27 (96%) of the 28 patients. The upper limit of vulnerability underestimated the defibrillation threshold by 10 J in one patient who had a defibrillation threshold of 15 J. The upper limit of vulnerability determined in normal sinus rhythm correlates significantly with the defibrillation threshold in patients undergoing ICD implantation. The protocol is simple and easily implemented clinically.

Anti-Arrhythmia Agents↗
PubMed1998

Daytime CPAP titration: a viable alternative for patients with severe obstructive sleep apnea.

OBJECTIVE: Continuous positive airway pressure (CPAP) is the treatment of choice for patients diagnosed with severe obstructive sleep apnea (OSA). The implementation of CPAP therapy has traditionally been based on full-night titration studies or split-night protocols. This study compared a group of patients who received a regular nocturnal CPAP titration with patients who received a daytime CPAP titration. The objective of the study was to determine if daytime CPAP titration is a viable alternative for the implementation of CPAP treatment in patients with severe OSA. STUDY DESIGN: Fourteen patients (13 men and one woman) received a daytime CPAP titration (day group). The day group was matched to 18 patients (17 men and one woman) who were titrated under a full-night regular nocturnal study (night group). Eligible patients were those with severe OSA (respiratory event index > 40). The groups were matched by age, sex, and body mass index. RESULTS: Daytime and nocturnal CPAP titration studies yielded sufficient amounts of rapid eye movement (REM) and non-REM sleep to help determine CPAP settings. Importantly, the diurnal and nocturnal CPAP titrations resulted in comparable therapeutic pressures as well as comparable resolution of sleep-disordered breathing. After 1 week of treatment, the groups exhibited similar CPAP use and comparable improvements in subjective sleepiness as indicated by their increase in sleep/wake activity inventory scores. CONCLUSIONS: Daytime CPAP titration studies may be a viable alternative for the efficient and expedient implementation of CPAP therapy among some patients with severe OSA.

Adult↗
PubMed1997

Safety and effectiveness of placement of pacemaker and defibrillator leads in the axillary vein guided by contrast venography.

Despite evidence of an increased incidence of lead fracture, the infraclavicular subclavian approach remains the dominant approach for placement of pacemaker and implantable defibrillator leads. Although this complication can be prevented by lead placement in the cephalic vein or by recently described approaches for lead placement in the axillary vein, these approaches have not gained widespread acceptance. The purpose of this study was to evaluate the safety and efficacy of an alternative technique for lead placement that uses contrast-guided venipuncture of the axillary vein with a 5Fr micropuncture introducer set. A total of 50 patients underwent an attempt at placement of pacemaker or implantable defibrillator leads via the axillary vein using this new technique. Patients were randomized into 2 groups based on whether the initial attempt at axillary vein access was performed medial or lateral to the rib cage margin. Lead placement was successfully accomplished in 49 of the 50 patients using this technique. Initial success was achieved in each of 25 patients randomized to the medial approach compared with 18 of 24 patients randomized to the lateral approach to the axillary vein (75%). In each of the 6 patients in whom the initial technique failed, lead placement was subsequently achieved with the medial approach. In addition to a higher initial success rate, the medial approach was determined to be preferable as evidenced by a shorter lead placement time, a smaller number of contrast injections, and a reduced requirement for additional micropuncture guidewires. There were no major complications associated with either approach. Contrast-guided venipuncture of the axillary vein is a safe and effective approach to placement of endocardial leads.

Aged↗
PubMed1997

Hypnotic self administration: forced-choice versus single-choice.

Twenty-four men and women with insomnia, age 21-50 years, self administered hypnotics under a single-choice with placebo, single-choice with triazolam (0.25 mg), or forced-choice of placebo versus triazolam (0.25 mg) paradigm. Subjects received 4- sampling nights of placebo or triazolam in the single-choice conditions or 2 nights of each in the forced-choice condition. Then on 7 choice nights they could self administer a capsule, or not, in the single-choice conditions, or were required to choose one of two color-coded capsules in the forced-choice condition. In the single-choice conditions, subjects chose placebo 80% of nights and triazolam 77% of nights, while in the forced-choice condition triazolam was chosen on 86% of nights. Thus, the self administration of triazolam did not vary significantly between single or forced choice conditions, but that of placebo did. Placebo rate was high when it was the only alternative, but low when competing with triazolam. On sampling nights, compared to placebo, triazolam produced a significant increase in total sleep time, a reduction in latency to sleep, wake after sleep onset, and percentage stage 1 sleep. Triazolam, relative to placebo, also improved mood in the morning on some sampling nights. For subjects choosing capsules < 100% of opportunities (n = 14), on nights a capsule was chosen versus nights none was chosen (regardless of whether placebo or triazolam was the choice), self-ratings 30 min before bedtime on the Profile of Mood States vigor scale were significantly higher.

Adult↗
PubMed1997

Closure of permanent tracheostomy in patients with sleep apnea: a comparison of two techniques.

A "permanent" skin-lined tracheostomy is used for patients with severe obstructive sleep apnea syndrome who fall, refuse, or can't tolerate continuous positive airway pressure. Closure of the stoma may be performed if the apnea has been controlled by surgeries that enlarge and stabilize the upper airway, if adequate weight loss occurs, or if the patient decides to accept continuous positive airway pressure. Two different closure techniques are compared. Sixty-nine three-layer closures were performed in 66 patients from 1980 to 1990. Postoperative complications, including stridor, subcutaneous emphysema, pneumomediastinum, tracheal granuloma, hematoma, and respiratory arrest, occurred in 30% of patients, and three required reopening of their tracheostomy sites. After 1990 a simple deepithelialization technique was used in 10 patients without any major complications. This technique is simpler and quicker and can be performed with the patient under local anesthesia.

Adult↗
PubMed1997

Alerting effects of methylphenidate under basal and sleep-deprived conditions.

Six men and 3 women on each of 4 days received 10 mg of methylphenidate or placebo (2 times a day) at 0800 and 1200 after 8 hr or 0 hr of sleep. Sleep latency was measured by the Multiple Sleep Latency Test (MSLT) at 0930, 1130, 1330, 1530, and 1730. Participants also completed divided-attention and auditory vigilance tasks at 1000 and 1400 and the Profile of Mood States (POMS) and the Addiction Research Center Inventory (ARCI) after the 0930 and 1330 latency tests. The drug increased mean latency on the MSLT in both sleep conditions. Performance only showed drug effects after prior sleep deprivation. On the POMS, the drug increased Vigor and reduced Fatigue and Depression scale scores, primarily after sleep deprivation. The drug increased the ARCI Amphetamine and Morphine-Benzedrine scores only in the basal state. The ARCI Pentobarbital score was increased by sleep deprivation and decreased by the drug.

Adult↗