Age-Based Differences in Sleep Quality, Pre-Sleep Arousal, and Psychosocial Factors during the Second Wave Lockdown of the COVID-19 Pandemic in Georgia-A Higher Vulnerability of Younger People.

The COVID-19 pandemic has deeply disrupted sleep and mental health of people around the world. We aimed to investigate age-based differences in the prevalence of and relationship between sleep quality, pre-sleep arousal, and psychosocial factors during the second wave lockdown of the COVID-19 pandemic in Georgia. Data were collected through an online survey (n = 1117). Participants were categorized into four age groups: 18-29, 30-41, 42-53, and 54-70 years. The youngest participants reported the most prevalent disruption of sleep behavior. Overall, 58.3% of respondents were poor sleepers. The Pittsburgh Sleep Quality Index (PSQI) global score was highest in the youngest age group but the difference was not significant. There was a significant difference in the PSQI component scores for subjective sleep quality, sleep latency, and daytime dysfunction, all being worse in young respondents. We also observed a significantly higher prevalence rate of worse sleep quality in the youngest age group, relative to the pre-pandemic period. On the other hand, the oldest respondents showed significantly greater use of sleeping medications. Significantly higher levels of somatic and cognitive pre-sleep arousal, perceived stress, feeling depressed, anxious, and socially isolated were reported by the youngest age group. Study findings indicate a higher vulnerability of younger people to the impact of the COVID-19 pandemic. Assessment of pre-sleep arousal and implementation of specific, age-based interventions may prove beneficial to improve possible consequences of the pandemic on sleep and mental health.

Sleep electroencephalogram evidence of delayed brain maturation in attention deficit hyperactivity disorder: a longitudinal study.

STUDY OBJECTIVES: This study investigates whether longitudinally measured changes in adolescent brain electrophysiology corroborate the maturational lag associated with attention deficit hyperactivity disorder (ADHD) reported in magnetic resonance imaging (MRI) studies and cross-sectional sleep electroencephalogram (EEG) data. METHODS: Semiannually nine adolescents diagnosed with ADHD (combined presentation, DSM-V criteria, mean age 12.39 ±â€…0.61 years at first time-point, two females) and nine typically developing controls (12.08 ±â€…0.35 years, four females) underwent all-night laboratory polysomnography, yielding four recordings. RESULTS: Sleep macrostructure was similar between groups. A quadratic model of the age change in non-rapid eye movement (NREM) delta (1.07-4 Hz) power, with sex effects accounted for, found that delta power peaked 0.92 ±â€…0.37 years later in the ADHD group. A Gompertz function fit to the same data showed that the age of most rapid delta power decline occurred 0.93 ±â€…0.41 years later in the ADHD group (p = 0.037), but this group difference was not significant (p = 0.38) with sex effects accounted for. For very low frequency (0.29-1.07 Hz) EEG, the ADHD lag (1.07 ±â€…0.42 years later, p = 0.019) was significant for a Gompertz model with sex effects accounted for (p = 0.044). Theta (4-7.91 Hz) showed a trend (p = 0.064) toward higher power in the ADHD group. Analysis of the EEG decline across the night found that standardized delta and theta power in NREMP1 were significantly (p < 0.05 for both) lower in adolescents with ADHD. CONCLUSIONS: This is the first longitudinal study to reveal electrophysiological evidence of a maturational lag associated with ADHD. In addition, our findings revealed basically unaltered sleep macrostructure but altered sleep homeostasis associated with ADHD.

Sleep restriction and age effects on waking alpha EEG activity in adolescents.

Study Objectives: To understand how sleep need changes across adolescence our laboratory is carrying out a longitudinal dose-response study on the effects of sleep duration on daytime sleepiness and performance. This report focuses on the relation of the waking alpha (8-12 Hz) electroencephalogram (EEG) to prior sleep duration, whether this relation changes with age, and whether decreased waking alpha power is related to changes in daytime sleepiness, vigilance, and executive functioning. Methods: Study participants (n = 77) entered the study at ages ranging from 9.86 to 13.98 years and were studied annually for 3 years. Each year participants completed each of three time in bed (TIB) conditions (7, 8.5, or 10 h) for four consecutive nights. Waking EEG was recorded on the day following the fourth night. Results: TIB restriction and resultant sleep loss were associated with reduced alpha power with the effect being stronger for the eyes closed condition. TIB restriction altered the power spectrum within the alpha range by increasing the frequency of maximum alpha power. Alpha power decreased with age, but the effect of TIB restriction did not decrease with age. Reduced alpha power was associated with small but significant increases in subjective and objective sleepiness but was not associated with changes in vigilance or executive functioning. Conclusions: We interpret the alpha depression following sleep loss as incomplete sleep dependent recuperation that contributes to daytime sleepiness. The absence of a decrease in TIB effects with age indicates that this sleep need measure does not decrease over early to mid-adolescence.

Longitudinal assessment of NREM sleep EEG in typically developing and medication-free ADHD adolescents: first year results.

OBJECTIVE: Clinical observation and structural MRI studies suggest that delayed brain maturation is a major cause of attention deficit hyperactivity disorder (ADHD). Sleep electroencephalogram (EEG) which exhibits major changes across adolescence provides an opportunity to investigate brain electrophysiology evidence for maturational delay. We present data from an ongoing longitudinal study of sleep EEG in medication-free ADHD and typically developing adolescents to investigate brain electrophysiological evidence for this maturational delay. METHODS: Nine adolescents diagnosed with ADHD (combined presentation, DSM-V criteria, mean age 12.39 ± 0.61 years, 2 females), and nine typically developing controls (12.08 ± 0.35 years, 4 females) were recruited. Subjects underwent an adaptation night and all night polysomnography twice yearly at the Laboratory. RESULTS: Basic sleep structure did not differ between the ADHD and control groups. In addition, we found no group differences on delta power (p = 0.77), but found a possible trend toward higher theta power (p = 0.057) for the ADHD group. The decline of standardized delta power across the 4 non-rapid eye movement (NREM) periods differed by group (p < 0.05) with the percent delta power in the first NREM period being lower in the ADHD group. CONCLUSIONS: Our data support the preponderant evidence that basic sleep structure is unaltered with ADHD. Our data do suggest altered sleep homeostatic recuperative processes in ADHD. The theta findings from the first two recordings are suggestive of a maturational delay associated with ADHD, but follow-up data-points are needed.

Effects of sleep restriction on the sleep electroencephalogram of adolescents.

STUDY OBJECTIVES: This report describes findings from an ongoing longitudinal study of the effects of varied sleep durations on wake and sleep electroencephalogram (EEG) and daytime function in adolescents. Here, we focus on the effects of age and time in bed (TIB) on total sleep time (TST) and nonrapid eye movement (NREM) and rapid eye movement (REM) EEG. METHODS: We studied 77 participants (41 male) ranging in age from 9.9 to 16.2 years over the 3 years of this study. Each year, participants adhered to each of three different sleep schedules: four consecutive nights of 7, 8.5, or 10 h TIB. RESULTS: Altering TIB successfully modified TST, which averaged 406, 472 and 530 min on the fourth night of 7, 8.5, and 10 h TIB, respectively. As predicted by homeostatic models, shorter sleep durations produced higher delta power in both NREM and REM although these effects were small. Restricted sleep more substantially reduced alpha power in both NREM and REM sleep. In NREM but not REM sleep, sleep restriction strongly reduced both the all-night accumulation of sigma EEG activity (11-15 Hz energy) and the rate of sigma production (11-15 Hz power). CONCLUSIONS: The EEG changes in response to TIB reduction are evidence of insufficient sleep recovery. The decrease in sigma activity presumably reflects depressed sleep spindle activity and suggests a manner by which sleep restriction reduces waking cognitive function in adolescents. Our results thus far demonstrate that relatively modest TIB manipulations provide a useful tool for investigating adolescent sleep biology.

Insomnia, Pre-Sleep Arousal, Psychosocial Factors and Changes in Sleep Pattern during the Second Wave Lockdown of the COVID-19 Pandemic in Georgia.

Studies performed across the COVID-19 pandemic waves point to the persistent impact of the pandemic on sleep and mental health. We expand these data by examining insomnia, pre-sleep arousal, psychosocial factors, and retrospective changes in sleep pattern during the COVID-19 second wave lockdown period in Georgia. Data were collected through an online survey (n = 1117). The prevalence rate of probable insomnia disorder was 24.2%. Clinically relevant somatic and cognitive pre-sleep arousal was present in 49.8% and 58.0% of participants, and high levels of anxiety, depression and social isolation were found in 47.0%, 37.3%, 47.2% of respondents, respectively. We observed high prevalence rates of worse sleep quality, delayed bedtimes and risetimes, longer sleep latencies, higher awakenings and shorter sleep durations, relative to the pre-pandemic period. COVID-19-infected participants showed more severe sleep and mental problems. Specific predictors differentially affected insomnia, somatic and cognitive pre-sleep arousal. Depression and COVID-19 infection emerged as vulnerability factors for pre-sleep arousal, which, in turn, was associated with a higher predisposition to insomnia disorder. We confirm the strong deteriorating impact of the COVID-19 pandemic on sleep and psychosocial well-being during the second wave lockdown period. The specific association between pre-sleep arousal, insomnia, and psychosocial factors is of clinical relevance for the prevention of severity and persistence of sleep and mental problems across the repeated lockdown/reopening waves. Modulation of pre-sleep arousal may prove beneficial to implement targeted interventions.

Sleep and psycho-behavioral problems in internally displaced children in Georgia.

OBJECTIVE: The aim of this study was to examine sleep and psycho-behavioral variables in Georgian Internally Displaced (ID) Children and their population-based controls. METHODS: One hundred and sixty one children (10.85 ± 0.9) from ID families escaped from Shida Kartli, Georgia, and 161 non-ID children (10.94 ± 0.9) were studied after seven years of displacement. Children completed the Pre-Sleep Arousal Scale, Buss-Perry Aggression Questionnaire (BPAQ), Children's Depression Inventory (CDI), and the Child Trauma Screening Questionnaire (CTSQ). In addition, we assessed the children's appraisal of the family environment. Moreover, parents reported socio-demographic information, their children's academic excellence, and completed the Sleep Disturbance Scale for Children (SDSC), Beck Depression Inventory II (BDI), and Perceived Stress Scale (PSS). RESULTS: Compared with the control group, ID children had a lower level of academic excellence and family environment (p < 0.01) as well as higher scores in all SDSC dimensions with the significant difference for breathing (p < 0.001), hyperhidrosis and SDSC total scores (p < 0.05). Cognitive pre-sleep arousal was significantly higher in non-IDs (p < 0.01), while there was no difference between groups in somatic pre-sleep arousal level. All BPAQ component and total scores were higher in IDs than in non-IDs but the difference was significant only in Physical Aggression (p < 0.01). Mean scores for BDI and PSS were significantly higher in ID than non-ID parents (p < 0.001). Both cognitive and somatic pre-sleep arousal predicted SDSC total score in non-IDs (p < 0.01) while cognitive but not somatic arousal was significant predictor in IDs (p < 0.01). CONCLUSION: Sleep and psycho-behavioral problems are noticeable even in those ID children who were very young at the time of displacement. Psycho-social environment in which children are growing up warrants major consideration in ID population.

Relationship between Sleep Disorders and Health Related Quality of Life-Results from the Georgia SOMNUS Study.

The extent to which sleep disorders are associated with impairment of health-related quality of life (HRQoL) is poorly described in the developing world. We investigated the prevalence and severity of various sleep disorders and their associations with HRQoL in an urban Georgian population. 395 volunteers (20⁻60 years) completed Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, STOP-Bang questionnaire, Insomnia Severity Index, Beck Depression Inventory-Short Form, and Short Form Health Survey (SF-12). Socio-demographic data and body mass index (BMI) were obtained. The prevalence of sleep disorders and their association with HRQoL was considerable. All SF-12 components and physical and mental component summaries (PCS, MCS) were significantly lower in poor sleepers, subjects with daytime sleepiness, apnea risk, or insomnia. Insomnia and apnea severity were also associated with lower scores on most SF-12 dimensions. The effect of insomnia severity was more pronounced on MCS, while apnea severity-on PCS. Hierarchical analyses showed that after controlling for potential confounding factors (demographics, depression, BMI), sleep quality significantly increased model's predictive power with an R² change (ΔR²) by 3.5% for PCS (adjusted R² = 0.27) and by 2.9% for MCS (adjusted R² = 0.48); for the other SF-12 components ΔR² ranged between 1.4% and 4.6%. ESS, STOP-Bang, ISI scores, all exerted clear effects on PCS and MCS in an individual regression models. Our results confirm and extend the findings of studies from Western societies and strongly support the importance of sleep for HRQoL. Elaboration of intervention programs designed to strengthen sleep-related health care and thereof HRQoL is especially important in the developing world.

Sleep-wake patterns and sleep quality in urban Georgia.

OBJECTIVES: Sleep problems represent a worldwide health concern but their prevalence and impacts are unknown in most non-European/North American countries. This study aimed to evaluate sleep-wake patterns, sleep quality and potential correlates of poor sleep in a sample of the urban Georgian population. METHODS: Analyses are based on 395 volunteers (267 females, 128 males, aged 20-60 years) of the Georgia Somnus Study. Subjects completed the Pittsburgh Sleep Quality Index (PSQI) and the Beck Depression Inventory-Short Form. Sociodemographic information and self-reported height and weight were collected. RESULTS: 43% of subjects had poor sleep quality (PSQI > 5). Further, 41% had low sleep efficiency, 27.6% slept 6 hours or less, 32.4% went to bed after midnight, 27.6% snored, 10.6% were taking sleep medication, and 26.8% had sleep maintenance problems as occurring three or more times a week. The latest bedtime, rise time, and gender effect on these variables were found in the age group 20-29 years. PSQI global score showed a significant age but not gender difference. The economic status and the depression score were two significant predictors of sleep quality. CONCLUSIONS: Poor sleep quality has a high prevalence and is strongly linked to the economic status. Study findings call for a global assessment of sleep problems in countries where sleep disturbances represent an insufficiently recognized public health issue.

Sleep quality among internally displaced Georgian adolescents and population-based controls.

Sleep problems in children and adolescents are a significant public health concern and may be linked to a variety of psychoemotional difficulties. This study aimed to evaluate sleep quality and associated factors in conflict-affected Georgian adolescents after 9 months of forced displacement. Thirty-three internally displaced adolescents (mean age 11.4 years) and 33 adolescents (mean age 10.8 years) from the general population completed the Epworth Sleepiness Scale and the Children's Depression Inventory (CDI). Parents completed the Children's Sleep-Wake Scale and provided information on their socioeconomic status (SES) and the adolescents' sleep behavior, academic performance, and peer social relationships. The groups differed significantly in sleep quality, peer relationships, SES, and CDI scores. In the internally displaced group, the only significant predictor of sleep quality was SES, which increased the predictive capacity of the model (demographic and psychosocial variables) by 20% in the hierarchical analyses. The most significant predictor in the non-internally displaced group was CDI. This research indicates that displacement may affect sleep quality and psychosocial functioning. The importance of family SES as a contributing factor to displaced adolescents' poor sleep quality is highlighted. An integrated approach designed to improve the psychosocial environment of internally displaced adolescents is needed for their protection.

The journey through the world of adolescent sleep.

Sleep-wake patterns and the electroencephalogram (EEG) during sleep undergo fundamental changes during adolescence. Scientific evidence indicates that these changes represent components of an extensive maturational brain remodeling process. Sleep during periods of brain maturation appears to be particularly important for health and behavior. Adolescents' sleep problems affect their cognitive and psychobehavioral functioning, making insufficient sleep during this developmental stage a significant international health concern. In this review, we summarize some key data concerning developmental changes in sleep behavior and regulation, and the association between sleep EEG changes and brain maturation. This review extends our understanding of adolescent sleep and highlights its significance for healthy development. We discuss the possibility to follow brain maturation and to detect errors in this maturational process by monitoring the developmental sleep EEG changes.

Insomnia in a displaced population is related to war-associated remembered stress.

Although traumatic events are presumed to cause sleep disturbances, particularly insomnia, sleep in populations subjected to forced displacement has received little attention. The present study examined the prevalence of insomnia and associated factors in internally displaced persons (IDPs) from Abkhazia 15 years after displacement to Tbilisi. Detailed subjective information about sleep-wake habits, sleep-related and stress-related parameters were obtained from 87 IDPs categorized into good sleepers and insomniacs. The Insomnia Severity Index, Perceived Stress Scale and Beck Depression Inventory were administered. The incidence of insomnia was 41.4%. The majority of insomniacs strongly believed that war-related stress accounted for the onset of their insomnia. Stepwise regression (95% confidence interval) revealed four variables significantly associated with insomnia status: self-estimated influence of war related stress (odds ratio (OR) = 2.51), frequency of nightmares (OR = 1.6), Perceived Stress Scale score (OR = 1.14) and Beck Depression Inventory score (OR = 1.12). Insomnia in IDPs was strongly related to war-associated remembered stress. ?Over thinking' about major stress exposure enhanced IDPs' vulnerability to insomnia. These findings have implications for the management of insomnia and associated impairment of daytime functioning in IDPs.

Adolescent changes in homeostatic regulation of EEG activity in the delta and theta frequency bands during NREM sleep.

STUDY OBJECTIVES: Slow wave EEG activity in NREM sleep decreases by more than 60% between ages 10 and 20 years. Slow wave EEG activity also declines across NREM periods (NREMPs) within a night, and this decline is thought to represent the dynamics of sleep homeostasis. We used longitudinal data to determine whether these homeostatic dynamics change across adolescence. DESIGN: All-night sleep EEG was recorded semiannually for 6 years. SETTING: EEG was recorded with ambulatory recorders in the subjects' homes. PARTICIPANTS: Sixty-seven subjects in 2 cohorts, one starting at age 9 and one starting at age 12 years. MEASUREMENTS AND RESULTS: For NREM delta (1-4 Hz) and theta (4-8 Hz) EEG, we tested whether the proportion of spectral energy contained in the first NREMP changes with age. We also tested for age changes in the parameters of the process S exponential decline. For both delta and theta, the proportion of energy in the first NREMP declined significantly across ages 9 to 18 years. Process S parameters SWA(0) and TWA(0), respectively, represent slow wave (delta) activity and theta wave activity at the beginning of the night. SWA(0) and TWA(0) declined significantly (P < 0.0001) across ages 9 to 18. CONCLUSIONS: These declines indicate that the intensity of the homeostatic or restorative processes at the beginning of sleep diminished across adolescence. We propose that this change in sleep regulation is caused by the synaptic pruning that occurs during adolescent brain maturation.

Kinetics of NREM delta EEG power density across NREM periods depend on age and on delta-band designation.

STUDY OBJECTIVES: (1) To determine whether children and elderly exhibit the atypical kinetics of very low frequency (VLF) power found in young adults, (2) to test the hypothesis that variations in "delta" bandwidth designations can explain discrepancies in whether normalized delta power density declines across non-rapid eye movement periods (NREMPs) linearly or shows the curvature expected of exponential change, and (3) to test our hypothesis that the decline in normailized delta power density in children across NREMPs would have a slope similar to that which we had previously found in young adults and elderly. METHODS: In 3 age groups (mean ages 11, 22, and 71 years) NREM electroencephalograms were analyzed with fast Fourier transform for frequencies between 0.3 and 4 Hz in bands. Across-NREMP trends of normalized power density for various "delta" bands were analyzed by analyses of variance for linearity, curvature, and age interactions. RESULTS: We replicated the atypical kinetics of VLF power (-0.3-0.9 Hz) in young adults reported by others and showed that this pattern exists in children and normal elderly. As frequencies increased above 0.7 Hz, power showed first a linear and then a concave-upward curvilinear decline across NREMPs in children and young adults; the decline across NREMPS in the elderly became linear but never developed curvilinearity. For all designations of delta, the across-NREMP decline in children was significantly steeper than in young adults. CONCLUSIONS: The findings that all normalized "delta" electroencephalogram bands in children showed a curvilinear decline across NREMPs that was steeper than that in young adults confirms observations of others and refutes our hypothesis that the decline would be linear with the same slope we found in young adults and elderly. Whether the decline in normalized power in young adults appears linear or curvilinear depends on whether the convex trend of VLF power is included.

Sleep EEG evidence of sex differences in adolescent brain maturation.

STUDY OBJECTIVES: The steep decline in slow-wave (delta) electroencephalogram (EEG) intensity across adolescence is a prominent feature of late brain maturation. As a first step in determining whether the adolescent delta decline is similar in both sexes, we compared cross-sectional sleep EEG data from 9- and 12-year-old boys and girls. DESIGN: All-night EEG recordings, 6 months apart, were conducted on each subject. SETTING: EEG was recorded in the subjects' homes. PARTICIPANTS: Thirty-two 9-year-olds and 38 12-year-olds are enrolled in a 4-year longitudinal study of adolescent sleep. There are equal numbers of each sex in both age cohorts. INTERVENTIONS: N/A. MEASUREMENTS: Using ambulatory recorders, EEG was recorded in the subjects' homes on their normal sleep schedule. For each of the 2 semi-annual recording periods, data from the 10 subjects from each age-sex group with the cleanest (fewest artifacts) signals were selected for crosssectional comparisons of visual scoring and EEG variables. All artifact-free 20-second non-rapid eye movement epochs were analyzed with power spectral and period-amplitude analysis. RESULTS: In the 12-year-old cohort, delta power per minute was 37% higher in boys than girls. The 9-year-old cohort showed no sex difference. A second recording 6 months later produced similar results. CONCLUSION: These cross-sectional data indicate that girls begin the steep adolescent decline in slow-wave EEG earlier than boys. We hypothesize that this reflects an earlier onset of adolescent synaptic pruning in females.

Rapid eye movement density shows trends across REM periods but is uncorrelated with NREM delta in young and elderly human subjects.

Saccade-like eye movements are the most prominent phasic component of rapid eye movement (REM) sleep. Eye movement density (EMD) appears to be negatively related to sleep depth. Thus, EMD is depressed by sleep deprivation. We sought to determine in 19 young normal (YN) and 19 elderly normal (EN) subjects: (a) whether EMD is correlated with delta EEG in baseline sleep; (b) whether EMD is increased by daytime naps; and (c) whether EMD patterns across sleep cycles differ in the two age groups. Subjects participated in four separate 2-day recording sessions, each consisting of a baseline night, a daytime nap, and post nap night. EMD was measured as 0.3-2 Hz integrated amplitude (IA)/20 s stage REM. EMD was not correlated with rate of non rapid eye movement (NREM) delta production (power/min) in the baseline sleep of either group. Changes in EMD and delta power/min on post nap nights also were uncorrelated. These data indicate that very strong changes in sleep depth (state) are required to overcome the individual stability (traits) of NREM delta and eye movement density. ANOVA for EMD across REM periods 1-4 showed a significant cycle effect and a significant age x cycle interaction. These effects were mainly due to YNs having depressed EMD in the first REM period, likely due to the low arousal level early in sleep in these subjects. Compared with waking saccades the saccade eye movements of REM sleep have received little investigation. Further study of these movements could shed new light on neurophysiology of REM sleep. Such studies might also be clinically useful because the density of these movements appears to be related to depression and (independently) to cognitive function in individuals with brain impairment.

Rapid eye movement density is reduced in the normal elderly.

STUDY OBJECTIVES: While there is general agreement on the age changes in non-rapid eye movement sleep, there is conflicting evidence on whether eye movement density (EMD) in rapid eye movement sleep is affected by aging. We therefore performed computer measurement of EMD in young and elderly normal subjects. DESIGN: Sleep electroencephalogram and electrooculogram were recorded in each subject on 4 nonconsecutive baseline nights. Eye movement density in the elderly subjects was compared to that in young adults. SETTING: A sleep research laboratory with 4 separate bedrooms. INTERVENTIONS: Not applicable. PARTICIPANTS: Subjects were 19 young normal adults and 19 elderly normal adults. MEASUREMENTS AND RESULTS: Digitized electrooculograms were analyzed with the extensively validated zero-cross period-amplitude module of PASS PLUS software. The EMD was measured as 0.3 to 2 Hz integrated amplitude per 20-second stage of rapid eye movement sleep. Eye-movement incidence was the number of half waves. Eye-movement amplitude was the sum of peak-trough excursions (curve length) in the average half wave. We also counted visually the number of 2-second epochs with eye movements for 1 baseline night in both groups. The EMD in the elderly subjects was substantially and significantly lower than in the young subjects. Visual scoring of EMD on 1 baseline night confirmed the statistically significant difference between age groups. Period-amplitude analysis revealed that a lower eye-movement incidence rather than reduced amplitude caused the lower EMD in the elderly. The EMD was significantly correlated within subjects across the nonconsecutive baseline nights in both groups; in both, subjects' EMD average across 2 nights provided a correlation greater than .90 with the 4-night mean. CONCLUSIONS: The incidence of eye movements during rapid eye movement sleep is substantially reduced in the elderly. We hypothesize that this reduction is due to degenerative (aging) rather than developmental brain changes. The correlation analysis indicates that EMD is a reasonably stable individual trait in both young and elderly adults. These results encourage normative studies of EMD over a wider age span and continued exploration of the relation of EMD to cognitive function in the elderly.