***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: There is increasing evidence that sleep promotes off-line enhancement of a variety of explicitly learned motor tasks in young adults . However , whether sleep promotes off-line consolidation of implicitly learned motor tasks is still under question . Furthermore , the role of sleep in promoting transfer of learning remains unknown . This study examined the role of sleep in learning and transfer of learning of an implicit continuous motor task . Twenty-three neurologically intact individuals ( mean age 26.4 years ) were r and omly assigned to either a sleep group or a no-sleep group . The sleep group practice d a continuous tracking task in the evening and underwent retention and transfer testing the following morning , while the no-sleep group practice d the tracking task in the morning and underwent retention and transfer testing in the evening . The results show that in both the sleep and no-sleep groups , performance improved off-line without further practice for both the general skill and the sequence-specific skill . The results also indicate that sleep and time promote transfer of learning of both sequence-specific and general skill learning to a spatial and temporal variation of the motor task . These findings demonstrate that sleep does not play a critical role in promoting off-line learning and transfer of learning of an implicit continuous motor task Decline in cognitive functions , including impaired acquisition of novel skills , is a feature of older age that impacts activities of daily living , independence , and integration in modern societies Background and Purpose : The purpose of this study was to identify which characteristics of a multidimensional sequence containing motor , spatial , and temporal elements would be most salient for motor sequence learning and whether age might differentially affect this learning . Subjects : Younger ( n=11 , mean age=26.0 years ) , middle-aged ( n=13 , mean age=50.7 years ) , and older ( n=11 , mean age=77.5 years ) adults who were neurologically intact participated in the study . Methods : Participants practice d a sequencing task with repeated motor , spatial , and temporal dimensions for 2 days ; on a separate third day , participants completed retention and interference tests design ed to assess sequence learning and which elements of the sequence were learned . The mean median response time for each block of responses was used to assess motor sequence learning . Results : Younger and middle-aged adults demonstrated sequence-specific motor learning at retention testing via faster response times for repeated sequences than r and om sequences ; both of these groups showed interference for the motor dimension . In contrast , older adults demonstrated nonspecific learning ( ie , similar improvements in response time for both r and om and repeated sequences ) . These findings were shown by a lack of difference between r and om and repeated sequence performance in the older adult group both at retention testing and during interference tests . Conclusion and Discussion : Our data suggest that , when younger and middle-aged adults practice sequences containing multiple dimensions of movement , the motor element is most important for motor learning . The absence of sequence-specific change demonstrated by an older adult group that was healthy suggests an age-related impairment in motor learning that may have profound implication s for rehabilitation 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 OBJECTIVE The present study examined whether the combination of a short daytime nap with caffeine , bright light and face washing was effective against  mid-afternoon sleepiness .  METHODS Ten young healthy adults participated in 5 experimental conditions ; those experiments were-Nap only : taking a 20 min nap ; Caffeine+Nap : taking 200 mg of caffeine followed by a nap ; Nap+Bright-light : being exposed to 2000 lx of bright light for 1 min immediately after napping ; Nap+Face-washing : washing their faces immediately after napping ; and No-Nap : taking a rest without sleep . These naps were taken at 12:40 hours . The subjects engaged in computer tasks for 15 min before napping and for 1 h after napping . RESULTS Caffeine+Nap was the most effective for subjective sleepiness and performance level ; its effects lasted throughout 1 h after napping . Nap+Bright-light was comparable with Caffeine+Nap , except for performance level .  Nap+Face-washing showed mild and transient effects , however , it suppressed subjective sleepiness immediately after napping . CONCLUSIONS The effects of a short nap against mid-afternoon sleepiness could be enhanced by combining caffeine intake , exposure to bright light , or face washing . SIGNIFICANCE The present study would provide effective counter measures against mid-afternoon sleepiness and sleepiness related accidents Memory consolidation is facilitated by sleep . Specifying the functional domain of sleep-dependent consolidation ( SDC ) is important for identifying the neural mechanisms underlying this phenomenon . Previous work indicates that SDC may be limited to conditions in which learning is explicit . In the present study , we tested the hypothesis that SDC may also occur with implicit learning when learning benefits from the formation of context ual associations , a function associated with the hippocampus . Three versions of the serial-reaction-time task ( SRTT ) were examined , and SDC was assessed by comparing performance after 12 hr breaks that included or did not include sleep .  SDC was observed in the Explicit condition . Two implicit conditions were compared . In the Implicit Non context ual condition , participants performed a concurrent tone-counting task with the pitch of each tone selected at r and om , precluding cross-dimensional associations . In the Implicit Context ual condition , participants responded to the color of the cues while the spatial location of the cues followed a correlated sequence . Whereas learning was observed in both implicit conditions , SDC was restricted to the context ual condition . Given that the formation of context ual associations is dependent on the hippocampus , we suggest that SDC is a hippocampus-mediated process OBJECTIVES To determine whether sleep benefits motor memory in healthy elderly adults and , if so , whether the observed sleep-related benefits are comparable with those observed in healthy young adults . DESIGN Repeated- measures cross-over design . SETTING Boston , Massachusetts ( general community ) and Harvard University . PARTICIPANTS Sixteen healthy older and 15 healthy young participants . MEASUREMENTS  Motor sequence task ( MST ) performance was assessed at training and at the beginning and end of the retest session ;  polysomnographic sleep studies  were recorded for the elderly participants . RESULTS After 12 hours of daytime wakefulness , elderly participants showed a dramatic decline in MST performance on the first three retest trials , and only a nonsignificant improvement by the end of retest ( the last 3 retest trials ) . In contrast , when the same participants trained in the morning but were retested 24 hours after training , after a day of wake plus a night of sleep , they maintained their performance at the beginning of retest and demonstrated a highly significant 17.4 % improvement by the end of the retest session , essentially identical to the 17.3 % improvement seen in young participants . These strikingly similar improvements occurred despite the presence of other age-related differences , including overall slower motor speed , a lag in the appearance of sleep-dependent improvement , and an absence of correlations between overnight improvement and sleep architecture or sleep spindle density in the elderly participants . CONCLUSION These findings provide compelling evidence that sleep optimizes motor skill performance across the adult life span BACKGROUND Studies in young healthy volunteers provided evidence of a beneficial impact of an anodal time-varied transcranial direct current stimulation ( tDCS ) during early slow wave rich sleep on declarative memory but not on procedural memory . OBJECTIVE /HYPOTHESIS The present study investigated whether sleep-dependent memory consolidation can also be affected by slow oscillating tDCS in a population of elderly subjects . METHODS 26 subjects ( 69.1 years ± 7.7 years ) received bi-frontal anodal stimulation ( max . current density : 0.331 mA/cm(2 ) ) during early NREM sleep in a double-blind placebo-controlled r and omized crossover study . Stimulation effects on offline consolidation were tested by using a declarative and a procedural memory task . Furthermore , sleep stages were scored , EEG power was analyzed and spindle densities were assessed . RESULTS Independently from stimulation condition , performance in both memory tasks significantly decreased overnight . Stimulation revealed no significant effect on sleep-dependent memory consolidation . Verum tDCS was accompanied by significantly more time awake and significantly less NREM stage 3 sleep during five 1-min stimulation free intervals . CONCLUSIONS The results of the present study are in line with other studies showing that offline consolidation during sleep varies with age and is less pronounced in the elderly than in young or middle-aged subjects . Contrary to an almost identical positive study in young adults , slow oscillatory tDCS applied to the elderly failed to show a beneficial effect on memory consolidation in the present study Background Sleep has been demonstrated to enhance simple motor skill learning “ offline ” in young adults . “ Offline learning ” refers to either the stabilization or the enhancement of a memory through the passage of time without additional practice . It remains unclear whether a functional motor task will benefit from sleep to produce offline motor skill enhancement . Physical therapists often teach clients functional motor skills ; therefore , it is important to underst and how sleep affects learning of these skills . Objective The purpose of this study was to determine whether sleep enhances the learning of a functional motor task . Design A prospect i ve , cross-sectional , repeated- measures design was used . Methods Young participants who were healthy ( N=24 ) were r and omly assigned to either a sleep group or a no-sleep group . The sleep group practice d a novel walking task in the evening and underwent retention testing the following morning , and the no-sleep group practice d the task in the morning and underwent retention testing in the evening . Outcome measures included time around the walking path and spatiotemporal gait parameters . Results Only participants who slept after practicing the novel walking task demonstrated a significant offline improvement in performance . Compared with the no-sleep group , participants in the sleep group demonstrated a significant decrease in the time around the walking path , an increase in t and em velocity , an increase in t and em step length , and a decline in t and em step time . Limitations Time-of-day effect and inability to ensure a certain amount of sleep quantity and quality of participants were limitations of the study . Conclusions This study is the first to provide evidence that sleep facilitates learning clinical ly relevant functional motor tasks . Sleep is an important factor that physical therapists should consider when teaching clients motor skills A worksite study was conducted to examine whether a 15-min nap during a post-lunch rest period would affect subsequent alertness , performance , and nocturnal sleep in eight factory workers under a 3-week protocol . Subjects were asked to take the nap at 12:30 h on a reclining chair during the nap week , and to remain awake during the no-nap week . The order of these 2 weeks was counterbalanced between the subjects . During the third , follow-up week , each subject determined whether or not she/he would nap . Alertness on the job and nocturnal sleep were assessed using a sleep diary .  Wrist activity was also recorded during sleep at night . Choice reaction time task ( RT ) was performed at 10:00 and 15:00 h every day of the nap week and every other day of the no-nap and follow-up weeks . Perceived alertness was significantly higher in the afternoon after nap than after no nap at the end of the week . Similar effects were observed during the follow-up week where almost half of the subjects napped . No significant differences between the three weeks were found for RT performance or nocturnal sleep . Workers ' attitudes toward the nap were favourable . Although further intervention research is required , our results suggest that post-lunch napping may have the potential to promote daytime alertness at work Background and Purpose : Although sleep has been shown to enhance motor skill learning , it remains unclear whether sleep enhances learning of a functional motor task in middle-aged and older individuals . The purpose of this study was to examine whether sleep enhances motor learning of a functional motor task in middle-aged and older adults . Methods : Twenty middle-aged and 20 older individuals were r and omly assigned to either the sleep condition or the no-sleep condition . Participants in the sleep condition practice d a novel walking task in the evening , and returned the following morning for retesting . Participants in the no-sleep condition practice d the walking task in the morning and returned the same day in the evening for a retest . Outcome measures included time around the walking path and spatiotemporal gait parameters . Results : Only the middle-aged and older adults in the sleep condition demonstrated significant off-line improvement in performance , measured as a decline in time to walk around the novel path and improvement in spatiotemporal gait parameters . The middle-aged and older adults in the no-sleep condition failed to demonstrate off-line improvements in performance of this functional task . Conclusions : This is the first study to provide evidence that sleep facilitates learning a clinical ly relevant functional motor task in middle-aged and older adults . Because many neurologic conditions occur in the middle-aged and older adults and sleep issues are very prevalent in many neurologic conditions , it is imperative that physical therapists consider sleep as a factor that may impact motor learning and recovery in these individuals . Video Abstract available . ( See Video , Supplemental Digital Content 1 , http://links.lww.com/JNPT/A73 ) for more insights from the authors 
    Output:
    
Overall , sleep was found to enhance motor performance in people after stroke in comparison to an equivalent time of wakefulness .
In addition , although evidence is limited , sleep only enhanced motor performance in people after stroke and not in age-matched healthy older adults .
In older adults the effect of a  sleep intervention  did - in general - not differ from equivalent periods of wakefulness .
The results suggest a delayed retention effect after longer breaks including sleep , hinting towards a changed learning strategy as a result of aging .
Current evidence for sleep dependent learning in people after stroke is promising , however sparse