***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The frequencies of five common sleep complaints -- trouble falling asleep , waking up , awaking too early , needing to nap and not feeling rested -- were assessed in over 9,000 participants aged 65 years and older in the National Institute on Aging 's multicentered study entitled " Established Population s for Epidemiologic Studies of the Elderly " ( EPESE ) . Less than 20 % of the participants in each community rarely or never had any complaints , whereas over half reported at least one of these complaints as occurring most of the time . Between 23 % and 34 % had symptoms of insomnia , and between 7 % and 15 % percent rarely or never felt rested after waking up in the morning . In multivariate analyses , sleep complaints were associated with an increasing number of respiratory symptoms , physical disabilities , nonprescription medications , depressive symptoms and poorer self-perceived health . Sleep disturbances , particularly among older persons , oftentimes may be secondary to coexisting diseases . Determining the prevalence of specific sleep disorders , independent of health status , will require the development of more sophisticated and objective measures of sleep disturbances STUDY OBJECTIVE To investigate the associations between sleep stage distributions and subsequent decline in cognitive function in older men over time . DESIGN A population -based prospect i ve sub study of the Osteoporotic Fractures in Men Study . SETTING S Six sites in the United States . PARTICIPANTS Community-dwelling men aged 67 y or older ( n = 2,601 ) , who were free of probable dementia at sleep visit . Follow-up averaged 3.4 y. MEASUREMENT AND RESULTS Sleep stages were identified by in-home polysomnography  at the initial sleep visit ( 2003 - 2005 ) . Cognitive outcomes were assessed with the  Trail Making Test Part B and Modified Mini-Mental State Examination ( 3MS ) at sleep visit and two follow-up visits . After adjusting for multiple confounders compared with men in the lowest quartile of percent of sleep time spent in Stage N1 , those in the highest quartile had a twofold increase in cognitive decline for both cognitive tests ( adjusted annualized percent change/y : Trail Making Test Part B Q1 = 1.06 , Q4 = 2.45 , P = 0.01 ; 3MS Q1 = -0.27 , Q4 = -0.48 , P = 0.03 ) . In addition , compared with men in the highest quartile , men in the lowest quartile of percent of sleep time in Stage R revealed more cognitive decline on the 3MS ( adjusted annualized percent change/y : Q1 = -0.49 , Q4 = -0.22 , P = 0.003 ) . These findings were consistent even after further adjustment of total sleep time and sleep disordered breathing . No significant relationships between other sleep stages ( N2 , N3 ) and cognitive change were found . CONCLUSION Increased time in Stage N1 and less time in Stage R are associated with worsening cognitive performance in older men over time Sleeping brain activity reflects brain anatomy and physiology . The aim of this study was to use high density ( 256 channel ) electroencephalography ( EEG ) during sleep to characterize topographic changes in sleep EEG power across normal aging , with high spatial resolution . Sleep was evaluated in 92 healthy adults aged 18–65 years old using full polysomnography and high density EEG .  After artifact removal , spectral power density was calculated for st and ard frequency b and s for all channels , averaged across the NREM periods of the first 3 sleep cycles . To quantify topographic changes with age , maps were generated of the Pearson ’s coefficient of the correlation between power and age at each electrode . Significant correlations were determined by statistical non-parametric mapping . Absolute slow wave power declined significantly with increasing age across the entire scalp , whereas declines in theta and sigma power were significant only in frontal regions . Power in fast spindle frequencies declined significantly with increasing age frontally , whereas absolute power of slow spindle frequencies showed no significant change with age . When EEG power was normalized across the scalp , a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp . This partial preservation was particularly significant in the slow wave and sigma b and s. The effect of age on sleep EEG  varies substantially by region and frequency b and . This non-uniformity should inform the design of future investigations of aging and sleep . This study provides normative data on the effect of age on sleep EEG topography , and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor OBJECTIVE To investigate whether age-related and experimental reductions in SWS and sleep continuity are associated with increased daytime sleep propensity . METHODS Assessment of daytime sleep propensity under baseline conditions and following experimental disruption of SWS .  Healthy young ( 20 - 30 y , n = 44 ) , middle-aged ( 40 - 55 y , n = 35 ) and older ( 66 - 83 y , n = 31 ) men and women , completed a 2-way parallel group study . After an 8-h baseline sleep episode , subjects were r and omized to 2 nights with selective SWS disruption by acoustic stimuli , or without disruption , followed by 1 recovery night .  Objective and subjective sleep propensity were assessed using the  Multiple Sleep Latency Test ( MSLT ) and the Karolinska Sleepiness Scale ( KSS ) . FINDINGS During baseline sleep , SWS decreased ( P < 0.001 ) and the number of awakenings increased ( P < 0.001 ) across the 3 age groups . During the baseline day , MSLT values increased across the three age groups ( P < 0.0001 ) with mean values of 8.7 min ( SD : 4.5 ) , 11.7 ( 5.1 ) and 14.2 ( 4.1 ) in the young , middle-aged , and older adults , respectively . KSS values were 3.7 ( 1.0 ) , 3.2 ( 0.9 ) , and 3.4 ( 0.6 ) ( age-group : P = 0.031 ) . Two nights of SWS disruption led to a reduction in MSLT and increase in KSS in all 3 age groups ( SWS disruption vs. control : P < 0.05 in all cases ) . CONCLUSIONS Healthy aging is associated with a reduction in daytime sleep propensity , sleep continuity , and SWS . In contrast , experimental disruption of SWS leads to an increase in daytime sleep propensity . The age-related decline in SWS and reduction in daytime sleep propensity may reflect a lessening in homeostatic sleep requirement . Healthy older adults without sleep disorders can expect to be less sleepy during the daytime than young adults STUDY OBJECTIVE Examine the effects of donepezil on sleep and rapid eye movement ( REM ) sleep electroencephalogram ( EEG ) in patients with Alzheimer disease , using polysomnography , and the correlation between REM sleep EEG parameters and cognitive scores . DESIGN R and omized , double-blind , placebo-controlled design . SETTING S Two sleep research centers , University Hospital . PARTICIPANTS Thirty-five patients with mild to moderate Alzheimer disease , allocated to 2 groups : donepezil treated ( n=17 ) and placebo treated ( n=18 ) . INTERVENTION Patients were administered donepezil or placebo . OUTCOME MEASURES  Polysomnography with REM sleep EEG spectral analysis and cognitive evaluation using the Alzheimer Disease Assessment Scale , cognitive subscale , were performed at baseline and after 3 and 6 months . Slowing ratio was the ratio between slow and fast EEG frequency b and s. Cognitive and sleep data were analyzed using analysis of variance . Correlations between cognitive improvement and REM sleep EEG were also calculated . RESULTS REM sleep increased significantly after 3 and 6 months of donepezil treatment compared with baseline and placebo ( p < .01 ) . Overall theta ( p = .04 ) , frontal theta ( p < .01 ) and frontal delta ( p = .03 ) absolute power during REM sleep decreased after 6 months of donepezil treatment . The occipital slowing ratio decreased during treatment ( p = .04 ) . REM sleep overall and frontal and centroparietal alpha absolute power significantly correlated with the cognitive improvement rate on the Alzheimer Disease Assessment Scale , cognitive subscale ( r = 0.75 , r = 0.71 , r = 0.78 ) ; p < .01 ) . CONCLUSIONS Donepezil treatment enhanced REM sleep and reduced slow frequencies of REM sleep EEG , suggesting a possible action upon REM sleep-related cholinergic neurons in patients with Alzheimer disease . Furthermore , REM sleep alpha power may predict the cognitive response to donepezil The effect of age on sleep and the  sleep EEG  was investigated in middle-aged men ( mean age : 62.0 years ) and in young men ( mean age : 22.4 years ) . Even though the older men reported a higher number of nocturnal awakenings , subjective sleep quality did not differ . Total sleep time , sleep efficiency , and slow wave sleep were lower in the middle-aged , while stage 1 and wakefulness after sleep onset were higher . The differences in wakefulness within nonREM-REM sleep cycles was most pronounced in the third and fourth cycle . In the older men , EEG power density in nonREM sleep was reduced in frequencies below 14.0 Hz , whereas in REM sleep age-related reductions were limited to he delta-theta ( 0.25 - 7.0 Hz ) and low alpha ( 8.25 - 10.0 Hz ) b and . Slow-wave activity ( SWA , power density in the 0.75 - 4.5 Hz range ) decreased in the course of sleep in both age groups . The between-group difference in SWA diminished in the course of sleep , whereas the difference in activity in the frequency range of sleep spindles ( 12.25 - 14.0 Hz ) increased . It is concluded that frequency and state specific changes occur as a function of age , and that sleep dependent decline in SWA and increase in sleep spindle activity are attenuated with age The effects of age and gender on sleep EEG power spectral density were assessed in a group of 100 subjects aged 20 to 60 years . We propose a new statistical strategy ( mixed-model using fixed-knot regression splines ) to analyze quantitative EEG measures . The effect of gender varied according to frequency , but no interactions emerged between age and gender , suggesting that the aging process does not differentially influence men and women . Women had higher power density than men in delta , theta , low alpha , and high spindle frequency range . The effect of age varied according to frequency and across the night . The decrease in power with age was not restricted to slow-wave activity , but also included theta and sigma activity . With increasing age , the attenuation over the night in power density between 1.25 and 8.00 Hz diminished , and the rise in power between 12.25 and 14.00 Hz across the night decreased . Increasing age was associated with higher power in the beta range . These results suggest that increasing age may be related to an attenuation of homeostatic sleep pressure and to an increase in cortical activation during sleep Objective : Sleep disturbance is common in dementia , although it is unclear whether differences in sleep architecture precede dementia onset . We examined the associations between sleep architecture and the prospect i ve risk of incident dementia in the community-based Framingham Heart Study ( FHS ) . Methods : Our sample comprised a subset of 321 FHS Offspring participants who participated in the Sleep Heart Health Study between 1995 and 1998 and who were aged over 60 years at the time of sleep assessment ( mean age 67 ± 5 years , 50 % male ) .  Stages of sleep were quantified using home-based polysomnography . Participants were followed for a maximum of 19 years for incident dementia ( mean follow-up 12 ± 5 years ) . Results : We observed 32 cases of incident dementia ; 24 were consistent with Alzheimer disease dementia . After adjustments for age and sex , lower REM sleep percentage and longer REM sleep latency were both associated with a higher risk of incident dementia . Each percentage reduction in REM sleep was associated with approximately a 9 % increase in the risk of incident dementia ( hazard ratio 0.91 ; 95 % confidence interval 0.86 , 0.97 ) . The magnitude of association between REM sleep percentage and dementia was similar following adjustments for multiple covariates including vascular risk factors , depressive symptoms , and medication use , following exclusions for persons with mild cognitive impairment at baseline and following exclusions for early converters to dementia . Stages of non-REM sleep were not associated with dementia risk . Conclusions : Despite contemporary interest in slow-wave sleep and dementia pathology , our findings implicate REM sleep mechanisms as predictors of clinical dementia BACKGROUND / OBJECTIVES  Obstructive sleep apnea ( OSA ) has been linked to an increased risk for Alzheimer 's disease ( AD ) , but little prospect i ve evidence exists on the effects of OSA treatment in pre clinical AD . The objective was to determine if continuous positive airway pressure ( CPAP ) treatment adherence , controlling for baseline differences , predicts cognitive and everyday function after 1 year in older adults with mild cognitive impairment ( MCI ) and to determine effect sizes for a larger trial . DESIGN Quasi-experimental pilot clinical trial with CPAP adherence defined as CPAP use 4 hours or more per night over 1 year . SETTING Sleep and geriatric clinics and community . PARTICIPANTS Older adults , aged 55 to 89 years , with an apnea-hypopnea index of 10 or higher participated : ( 1 ) MCI , OSA , and CPAP adherent ( MCI + CPAP ) 
    Output:
    
Findings show that compared to healthy controls , those with MCI have pronounced changes in sleep macro-architecture with greater wake after sleep onset , reduced total sleep time , lower sleep efficiency , longer sleep onset latency , longer rapid eye movement sleep ( REM ) latency , reduced REM sleep , greater N1 sleep , and worse severity of hypoxemia .
Pooling of sleep micro-architecture EEG measures was not possible due to limited studies , however reduced spindles in non-REM sleep and greater EEG slowing in REM sleep were reported