***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: This study examined the effects of bright light exposure on three measures of depression and four measures of agitation in persons with dementia residing in long-term care . Using a r and omized controlled design , participants were r and omly assigned to receive either bright light ( n = 30 ) or low intensity light ( n = 30 ) for eight weeks . Bright light exposure was associated with significant improvement in depression and agitation , while participants receiving low intensity light displayed higher levels of depression and agitation or no significant change . Findings support the use of bright light exposure to reduce depression and agitation in this population BACKGROUND Disturbances in rest-activity rhythm are prominent and disabling symptoms in Alzheimer 's disease ( AD ) . Nighttime sleep is severely fragmented and daytime activity is disrupted by multiple napping episodes . In most institutional environments , light levels are very low and may not be sufficient to enable the circadian clock to entrain to the 24-hour day . The purpose of this r and omized , placebo-controlled , clinical trial was to test the effectiveness of morning bright light therapy in reducing rest-activity ( circadian ) disruption in institutionalized patients with severe AD . METHOD Subjects ( n = 46 , mean age 84 years ) meeting the NINCDS-ADRDA ( National Institute of Neurological and Communicative Disorders and Stroke -- the Alzheimer 's Disease and Related Disorders Association ) AD diagnostic criteria were recruited from two large , skilled nursing facilities in San Francisco , California . The experimental group received one hour ( 09:30 - 10:30 ) of bright light exposure ( > or = 2500 lux in gaze direction ) Monday through Friday for 10 weeks . The control group received usual indoor light ( 150 - 200 lux ) . Nighttime sleep efficiency , sleep time , wake time and number of awakenings and daytime wake time were assessed using actigraphy . Circadian rhythm parameters were also determined from the actigraphic data using cosinor analysis and nonparametric techniques . Repeated measures analysis of variance ( ANOVA ) was used to test the primary study hypotheses . RESULTS AND CONCLUSION Although significant improvements were found in subjects with aberrant timing of their rest-activity rhythm , morning bright light exposure did not induce an overall improvement in measures of sleep or the rest-activity in all treated as compared to control subjects . The results indicate that only subjects with the most impaired rest-activity rhythm respond significantly and positively to a brief ( one hour ) light intervention We investigated whether low intensity dawn-dusk simulation ( DDS ) , a ' naturalistic ' form of light therapy design ed to embed sleep in its accustomed phase , could improve the disturbed circadian rest-activity cycle , nocturnal sleep and and /or cognitive functions in dementia . A protocol of 3 weeks each of baseline , treatment and follow-up was completed by 13 patients ( 85yr old+/-5yr , MMSE 14+/-5 ; n=9 DDS versus n=4 ' placebo ' dim red light ) who wore an activity/lux monitor throughout . There were no significant changes in clinical or cognitive status , nor modification of circadian stability or amplitude characteristics of the rest-activity cycle . However , two aspects of sleep responded to DDS but not to dim red light . The main sleep episode was 1:14h earlier during treatment ( p=0.03 ) compared with before and after DDS . With respect to actimetry-determined sleep variables , the DDS group tended to have shortened ' sleep latency ' , longer ' sleep duration ' , more nocturnal immobility and less nocturnal activity than the dim red group ( p<0.1 ) . In parallel , nighttime light exposure tended to be reduced ( p=0.07 ) . These promising findings -after only 3 weeks of light treatment in elderly patients with advanced dementia-suggest that the circadian timing system remains functionally responsive even to low intensity DDS light . Increasing zeitgeber strength is an important strategy for improving sleep quality and timing in dementia , and DDS light therapy may provide one of the appropriate means to do so OBJECTIVE Preliminary data suggest that morning bright light might improve symptoms of agitation , a serious problem in patients with dementia . The authors exp and on an earlier pilot study by evaluating the effect of bright light therapy on agitated behavior in a large sample of patients with severe dementia . METHODS Ninety-two patients were r and omly assigned to morning bright light , morning dim red light , or evening bright light .  Agitation was rated by research staff who observed the patients every 15 minutes throughout the treatment period and by caregivers at one time-point before and one time-point after treatment . RESULTS Morning bright light delayed the acrophase of the agitation rhythm by over 1.5 hours . Bright light was associated with improved caregivers ' ratings but had little effect on observational ratings of agitation . CONCLUSION Although the result that light shifted the peak of the agitated behavior might be generalizable to patients with milder forms of AD , the fact that agitation was not ameliorated might not be . Because the suprachiasmatic nucleus ( SCN ) of patients with severe AD is likely to be more degenerated , and the circadian activity rhythms deteriorate as the disease progresses , it is still possible that patients with more intact SCNs , that is , patients with mild or moderate AD , might benefit from light treatment even more than those with severe AD OBJECTIVES To test the effects of walking , light exposure , and a combination intervention ( walking , light , and sleep education ) on the sleep of persons with Alzheimer 's disease ( AD ) . DESIGN R and omized , controlled trial with blinded assessors . SETTING Independent community living . PARTICIPANTS One hundred thirty-two people with AD and their in-home caregivers . INTERVENTIONS Participants were r and omly assigned to one of three active treatments ( walking , light , combination treatment ) or contact control and received three or six in-home visits . MEASUREMENTS Primary outcomes were participant total wake time based on wrist actigraphy and caregiver ratings of participant sleep quality on the Sleep Disorders Inventory ( SDI ) . Secondary sleep outcomes included additional actigraphic measurements of sleep percentage , number of awakenings , and total sleep time . RESULTS Participants in walking ( P=.05 ) , light ( P=.04 ) , and combination treatment ( P=.01 ) had significantly greater improvements in total wake time at posttest ( effect size 0.51 - 0.63 ) than controls but no significant improvement on the SDI . Moderate effect size improvements in actigraphic sleep percentage were also observed in active treatment participants . There were no significant differences between the active treatment groups and no group differences for any sleep outcomes at 6 months . Participants with better adherence ( 4 d/wk ) to walking and light exposure recommendations had significantly less total wake time ( P=.006 ) and better sleep efficiency ( P=.005 ) at posttest than those with poorer adherence . CONCLUSION Walking , light exposure , and their combination are potentially effective treatments for improving sleep in community-dwelling persons with AD , but consistent adherence to treatment recommendations is required Sleep disorders are problematic for persons with dementia and their family caregivers . This r and omized controlled trial with crossover evaluated the effects of an innovative blue-white light therapy on 17 pairs of home-dwelling persons with dementia and their caregivers . Subjects with dementia received blue-white light and control ( ‘ red-yellow ’ light ) for six weeks separated by a four-week washout . Neither actigraphic nor most self-reported sleep measures significantly differed for subjects with dementia . For caregivers , both sleep and role strain improved . No evidence of retinal light toxicity was observed . Six weeks of modest doses of blue-white light appear to improve sleep in caregivers but not in persons with dementia . Greater or prolonged circadian stimulation may be needed to determine if light is an effective treatment for persons with dementia Neuropsychiatric behaviors are common in people with Alzheimer 's disease ( AD ) and make both professional and lay caregiving difficult . Light therapy has been somewhat successful in ameliorating disruptive behaviors . This r and omized trial tested the effects of morning or afternoon bright light exposure compared with usual indoor light on the presence , frequency , severity , and occupational disruptiveness of neuropsychiatric behaviors in nursing home residents with AD .  Light was administered for 1 hr daily ( Monday-Friday ) for 10 weeks . The Neuropsychiatric Inventory — Nursing Home was used to assess behavior at baseline and end of the intervention . Analyses revealed statistically significant differences between groups on agitation/aggression , depression/dysphoria , aberrant motor behavior , and appetite/eating disorders . The magnitude of change was small and may not represent clinical ly significant findings . Agitation/aggression and nighttime behaviors commonly occurred and were highly correlated with occupational disruptiveness . Interventions that decrease the presence and /or severity of neuropsychiatric behaviors have the potential to significantly decrease caregiver burden BACKGROUND Agitation is common in people with dementia , is distressing to patients and stressful to their carers . Drugs used to treat the condition have the potential to cause particularly severe side effects in older people with dementia and have been associated with an increased death rate . Alternatives to drug treatment for agitation should be sought . The study aim ed to assess the effects of bright light therapy on agitation and sleep in people with dementia . METHODS A single center r and omized controlled trial of bright light therapy versus st and ard light was carried out . The study was completed prior to the m and atory registration of r and omized controls on the clinical trials registry data base and , owing to delays in writing up , retrospective registration was not completed . RESULTS There was limited evidence of reduction in agitation in people on active treatment , sleep was improved and a suggestion of greater efficacy in the winter months . CONCLUSIONS Bright light therapy is a potential alternative to drug treatment in people with dementia who are agitated OBJECTIVES To determine whether fragmented sleep in nursing home patients would improve with increased exposure to bright light . DESIGN R and omized controlled trial . SETTING Two San Diego-area nursing homes . PARTICIPANTS Seventy-seven ( 58 women , 19 men ) nursing home residents participated . Mean age + /- st and ard deviation was 85.7 + /- 7.3 ( range 60 - 100 ) and mean Mini-Mental State Examination was 12.8 + /- 8.8 ( range 0 - 30 ) . INTERVENTIONS Participants were assigned to one of four treatments : evening bright light , morning bright light , daytime sleep restriction , or evening dim red light . MEASUREMENTS Improvement in nighttime sleep quality , daytime alertness , and circadian activity rhythm parameters . RESULTS There were no improvements in nighttime sleep or daytime alertness in any of the treatment groups . Morning bright light delayed the peak of the activity rhythm ( acrophase ) and increased the mean activity level ( mesor ) . In addition , subjects in the morning bright light group had improved activity rhythmicity during the 10 days of treatment . CONCLUSION Increasing exposure to morning bright light delayed the acrophase of the activity rhythm and made the circadian rhythm more robust . These changes have the potential to be clinical ly beneficial because it may be easier to provide nursing care to patients whose circadian activity patterns are more socially acceptable Sleep in the nursing home environment is extremely fragmented , possibly in part as a result of decreased light exposure . This study examined the effect of light on sleep and circadian activity rhythms in patients with probable or possible Alzheimer 's disease . Results showed that both morning and evening bright light result ed in more consoli date d sleep at night , as measured with wrist actigraphy . Evening light also increased the quality of the circadian activity rhythm , as measured by a 5-parameter extended cosine model ( amplitude , acrophase , nadir , slope of the curve , and relative width of the peak and trough ) . Increasing light exposure throughout the day and evening is likely to have the most beneficial effect on sleep and on circadian rhythms in patients with dementia . It would behoove nursing homes to consider increasing ambient light in multi purpose rooms where patients often spend much of their days BACKGROUND Dementia is a progressive neurological disorder that causes a high degree of dependency . This dependency has been defined as an increased need for assistance due to deterioration in cognition and physical functioning , and changes in behavior . Highly dependent people with dementia are more likely to be institutionalized . OBJECTIVES To investigate the association between specific categories of physical dependency and the presence of neuropsychiatric symptoms in people with dementia admitted to a long-term care institution . DESIGN A prospect i ve observational cohort study . SETTING S Home care and long-term care institutions in eight European countries . PARTICIPANTS People with dementia living at home but at risk of institutionalization and recently institutionalized people with dementia . METHOD Baseline and 3-month follow-up interviews were performed between November , 2010 and April , 2012 . The sample consisted of 116 recently institutionalized dementia sufferers and 949 people with dementia still living at home .  Physical dependency was measured using the Katz Activity of Daily Living index , and neuropsychiatric symptoms were assessed through The  Neuropsychiatric Inventory  . Specific categories of dependency were analyzed by performing a logistic regression analysis . This followed examination of baseline characteristics to define the degree of physical dependency , as factors associated with institutionalization , and evaluation of the same characteristics at 3-month follow-up to detect changes in the degree of physical dependency and neuropsychiatric symptoms associated with recent admission to a long-term care institution . RESULTS Toileting , dressing and continence dependency was higher in institutionalized people than in those receiving home-care . Delusion , hallucination , agitation , anxiety , apathy , motor-disturbances , night-time behavior and eating disorders were also worse in the institutionalized . Logistic regression analysis showed that independent factors significantly associated with being recently institutionalized were toileting ( odds ratio=2.3 ; 95 % confidence interval=1.43 - 3.71 ) 
    Output:
    
Light therapy can relieve BD , improve sleep quality , and alleviate symptoms of depression for cognitively impaired persons