Faculty Bibliography

BACKGROUND: This report describes the associations between sleep complaints and reported visual impairment in an urban community-residing older adult sample. METHODS: A total of 1118 volunteers from a biracial cohort participated in the study (mean age = 74 +/- 6; mean body mass index = 28 +/- 10). Volunteers were recruited using a stratified, cluster sampling technique. In a standard order, several questionnaires were administered, soliciting information on socioeconomic status, physical health, social support, and emotional experience. The physical health questionnaire included questions on whether or not the volunteer experienced sleep disorder, visual impairment, heart disease, respiratory disease, arthritis, and hypertension. In this report, we present data on the prevalence of reported sleep problems and visual impairment among older adults. RESULTS: Of the total sample, 9% used sleep medicine, 25% reported difficulty falling asleep, 52% indicated experiencing difficulty maintaining sleep, 28% reported waking up early in the morning, and 12% reported daytime sleep longer than 2 hours. Chi-square results showed greater sleep complaints for volunteers with visual impairment. Consistent with these results, analysis of variance revealed that visually impaired volunteers had a higher index rate of sleep disturbance (F((1, 1110)) = 35.32, p <.0001). CONCLUSIONS: These data provide evidence that older adults reporting visual impairment are also likely to report sleep complaints. This verifies laboratory findings of an association of ophthalmic diseases with sleep-wake problems and with circadian rhythm abnormalities.

OBJECTIVES: To examine whether dim illumination in the evening is a factor in sleep disturbances of aging, depression, and circadian phase advance. DESIGN: One-week continuous recordings were made to record illumination exposure and to infer 24-hour sleep patterns from wrist activity. SETTING: Recordings took place during normal home and community activities. PARTICIPANTS: Complete data of 154 postmenopausal women, mean age 66.7, were selected from a larger study of participants in the Women's Health Initiative. MEASUREMENTS: Illumination in lux was averaged for 4 hours before bedtime and over 24 hours. Mood was measured using a brief eight-item screen. RESULTS: Illumination in the 4 hours before bedtime was quite dim: median 24 lux. Nevertheless, evening light exposure was not significantly related to sleep amount (in bed or out of bed) sleep efficiency, sleep latency, wake within sleep, or mood. In contrast, the overall amount of light throughout the 24 hours was negatively correlated with sleep latency, wake within sleep, and depressed mood. CONCLUSIONS: Low evening lighting does not appear to be a crucial factor in sleep and mood disturbances of aging, but overall lighting may contribute to these disturbances.

STUDY OBJECTIVES: To date, conflicting observations have been made regarding ethnic differences in sleep patterns. Plausibly, differing sampling strategies and disparity in the cohorts investigated might help explain discrepant findings. To our knowledge population-based studies investigating ethnic differences in sleep complaints have not addressed within-group ethnic heterogeneity, although within-group health disparities have been documented. DESIGN: Volunteers (n =1118) in this study were community-residing older European Americans and African Americans residing in Brooklyn, New York, which were recruited by a stratified, cluster sampling technique. Trained interviewers of the same race as the respondents gathered data during face-to-face interviews conducted either in the respondent's home or another location of their choice. Data included demographic and health risk factors, physical health, social support, and emotional experience. Relationships of demographic and health risk factors to sleep disturbances were examined in multiple linear regression analyses. Within-group differences in sleep complaints were also explored. SETTING: N/A. PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Of the factors showing significant associations with sleep disturbance, European American ethnicity was the most significant predictor (r2 = 0.20). Worse sleep and greater reliance on sleep medicine were observed among European Americans. Caribbean Americans reported less sleep complaints than did U.S.-born African Americans, and immigrant European Americans reported greater complaints than did US-born European Americans. CONCLUSIONS: As expected several health risk factors were predictive of sleep disturbance among urban community-dwelling older adults, but ethnicity was the most significant predictor. The present data suggest both between-group and within-group ethnic differences in sleep complaints. Understanding of demographic and cultural differences between African Americans and European Americans may be critical in interpreting subjective health-related data

Progress in transducer design and empirical characterization of wrist movement has led to diverse wrist activity monitors, each with its unique features and modality of operation. This study compared sleep--wake estimates from nocturnal wrist activity quantified by different motion-quantifying algorithms. Healthy young adults wore an Actillume and a Mini Motionlogger on the same wrist while nocturnal polysomnography data were recorded simultaneously in the laboratory. Activity data were analyzed with ACTION3 using scoring algorithms independently calibrated for each measurement modality. Overall, each modality yielded accurate and reliable sleep estimates relative to polysomnographic estimates (agreement rates: 91.4--96.5%, correlations for sleep duration: 0.79--0.94). Estimates derived from Actillume modalities were comparable to those of Mini Motionloggers, suggesting that the transducers of these two devices performed comparably for monitoring sleep and wakefulness. Wrist movement quantified by the Mini Motionlogger proportional-integrating mode yielded the best accuracy for detection of sleep--wake states.

Two validation studies were conducted to optimize the sleep-detection algorithm of the Actillume. The first study used home recordings of postmenopausal women (age range: 51 to 77 years), which were analyzed to derive the optimal algorithm for detecting sleep and wakefulness from wrist activity data, both for nocturnal in-bed recordings and considering the entire 24 h. The second study explored the optimal algorithm to score in-bed recordings of healthy young adults (age range: 19 to 34 years) monitored in the laboratory. In Study I, the algorithm for in-bed recordings (n=39) showed a minute-by-minute agreement of 85% between Actillume and polysomnography (PSG), a correlation of.98, and a mean measurement error (ME) of 21 min for estimates of sleep duration. Using the same algorithm to score 24-h recordings with Webster's rules, an agreement of 89%, a correlation of.90, and 1 min ME were observed. A different algorithm proved optimal to score in-bed recordings (n=31) of young adults, yielding an agreement of 91%, a correlation of.92, and an ME of 5 min. The strong correlations and agreements between sleep estimates from Actillume and PSG in both studies suggest that the Actillume can reliably monitor sleep and wakefulness both in community-residing elderly and healthy young adults in the laboratory. However, different algorithms are optimal for individuals with different characteristics.

BACKGROUND: It is commonly believed that sleep duration in the population has been declining gradually. Whereas sleep restriction in the laboratory induces sleepiness and mood disturbances, it is not certain whether a short sleep duration impairs the quality of everyday life. METHODS: Using population-based data, we explored whether greater habitual sleep duration is a predictor of better health-related quality of life, measured by the Quality of Well-Being (QWB) scale. The relationships between QWB and several potential correlates were examined in a stepwise linear regression analysis. RESULTS: Neither subjective nor actigraphic sleep duration were associated with QWB. Greater quality of well-being was associated with greater sleep satisfaction, younger age, less obesity, non-Hispanic White ethnicity, and greater experienced illumination. CONCLUSION: These data suggest that increasing sleep duration may not directly improve quality of life, despite evidence that curtailment of nocturnal sleep is associated with fatigue.

PURPOSE: To report the onset and progression of retinal nerve fiber layer myelination in an adolescent patient. METHODS: Case report. RESULTS: A 7-year-old male was found to have myelination of the retinal nerve fiber layer in the left eye. When he was reexamined at age 14 years, he was found to have new myelination in the right eye, progression of the myelination in the left eye, and bilateral optic nerve drusen. CONCLUSION: Retinal nerve fiber layer myelination can occur spontaneously in adolescence, progress in adolescence, and be associated with optic nerve drusen.

Actigraphy has been used to monitor individuals' sleep and wakefulness patterns without laboratory confinement. To date, its validity in monitoring sleep and wakefulness among patients with major depressive episodes has not been systematically examined. The present study investigated whether the normative criteria of the Actigraph Data Analysis Software, initially optimized for healthy individuals, could score wrist-activity data accurately in a sample of depressed patients. Application of the normative algorithm yielded a correlation coefficient of 0.85 and an average error of 35 min, comparing actigraphic and polysomnographic sleep estimates. The algorithm optimized for this sample provided a correlation coefficient of 0.81 and an error of 6 minutes. For both algorithms, agreement for individual comparisons varied substantially. These findings suggest that scoring criteria optimized on wrist-activity data of healthy young adults may not produce optimal results for patients characterized with major depressive episodes.

A recent report that popliteal illumination shifted the circadian rhythms of body temperature and melatonin challenged the longstanding belief that light phase-shifting the circadian system in mammals is mediated only through the retina. The authors tested effects of popliteal illumination and illumination provided through the eyelids on melatonin suppression. In randomized, counterbalanced orders, healthy volunteers received three treatments from midnight until 2:00 AM, one on each of three visits to the laboratory. Treatments included (1) no illumination from light pads applied to the popliteal fossae, with light mask maintained at < 3 lux (control); (2) light mask illuminated at 1700 lux, with popliteal light pads extinguished; and (3) popliteal light pads illuminated (13,000 lux) and light mask at < 3 lux (control). Saliva specimens were sampled at midnight, at 1:00 AM, and at 2:00 AM. Mean salivary melatonin concentrations rose from an average of 30.8 (3.9) pg/ml at midnight (baseline), to 33.2 (4.0) pg/ml at 1:00 AM, and to 37.2 (3.8) pg/ml at 2:00 AM in all three conditions, but no statistical differences were found using repeated-measures ANOVA. No evidence of melatonin suppression by either popliteal or closed eyelid light stimulation was found. These data suggest that bright retinal illumination is necessary for suppression of melatonin mediated through the suprachiasmatic nuclei.