Thomas Hornick MD Patricia Higgins RN, PhD Rest-Activity and Light Exposure Patterns in Older Adults: Methodological Implications Thomas Hornick MD Patricia Higgins RN, PhD

Objectives Understand the influence of circadian rhythm disruptions on overall health. Identify clinical characteristics of circadian rhythm disturbances in older adults Recognize the importance of chronobiology in elders’ sleep-wake disturbances. Describe results from preliminary studies assessing the use of circadian light therapy in a nursing home unit and measurement of circadian light exposure in a case study of home-dwelling older adults. 

Biological Rhythms Types of rhythms Ultradian (heart beat, respirations, appetite) Infradian (menstrual cycle) Circannual (annual breeding cycles) Circadian (sleep-wake cycle) Rhythms allow organisms to time events and anticipate change! Biological rhythms are periodic biologic fluctuations that correspond to, or are in response to, environmental change Rhythms allow organisms to time events and anticipate change; i.e., rhythms allow organism to adapt to environmental change

Arendt 2006

With Zeitgeber

Disruption of circadian rhythm Poor performance/fatigue (Reinberg et al, 2007, Laposky et al 2008) Weight gain(Knutson et al, 2007) Breast cancer (Stevens et al 2001) Other conditions

Why older adults? Sleep disorders are common Complaints among caregivers of persons with dementia frequently revolve around disordered day/night cycles Medications for sleep are less safe in this population

Aging and light Older adults spend much of their time in muted indoor lighting. 35 minutes/day of bright light exposure compared to approximately 58 minutes of bright light per day for middle-aged adults. (Sanchez 1993) Reduced light exposure compounded due to physiologic changes senile meiosis, cataract formation, and/or increased light absorption by the crystalline lens. (Charmin 2003) Attenuation of light exposure by more than 80% in normal older adults relative to young adults.

Age related losses in retinal illumination Turner et al Br J Ophthalmol. 2008 November; 92(11): 1439–1444

Biological rhythms are endogenous but highly sensitive to environmental stimuli; i.e., light. The influence of light and darkness on circadian rhythms and related physiology and behavior through the SCN in humans . Wikipedia, accessed 10/30/09

Role of Retinal Receptors Three known retinal receptors: process visual and circadian timing information Rods and cones: visual data Intrinsically photosensitive retinal ganglion cells (iPRGC): primarily light-dark data process visual and circadian timing information

Spectral sensitivity of photopic, scotopic and circadian (melatonin suppression) photoreception Spectral sensitivity of photopic, scotopic and circadian (melatonin suppression) photoreception.5 7 Peak sensitivities of circadian, scotopic and photopic photoreception are 460 nm (blue), 506 nm (green) and 555 nm (green-yellow), respectively. Spectral absorptance is shown for 30D blue blocking (AcrySof SN60AT, Alcon Laboratories, Fort Worth, TX) and UV-only blocking (ClariFlex, Advanced Medical Optics, Santa Ana, CA) intraocular lenses (IOLs).8 The area between the two IOL curves is the violet, blue and green light blocked in comparison with a UV-only blocking IOL. Turner et al Br J Ophthalmol. 2008 November; 92(11): 1439–1444

iPRGCs: History 1998: Melanopsin in light-sensitive cells on frog skin (Provencio et al, Proc Natl Acad Sci ) 2000: Melanopsin-containing cells found in retinal ganglion cell layer (Provencio et al, J Neuroscience) Most likely comprise the retinohypothalamic tract Sensitive to wavelengths in the 484-500 nm (blue light) 2002: Light responses from melanopsin-containing ganglion cells in humans (Berson et al, Science) 1998: Ignacio Provencio, U VA, first published article on melanopsin, photopigment in light-sensitive cells of frog skin. (Provencio I, Jiang G, De Grip WJ, Hayes WP, Rollag MD (January 1998). "Melanopsin: An opsin in melanophores, brain, and eye". Proc. Natl. Acad. Sci. U.S.A. 95 (1): 340–5. doi:10.1073/pnas.95.1.340. PMID 9419377) 2000: A novel human opsin in the inner retina. Provencio I, Rodriguez IR, Jiang G, Hayes WP, Moreira EF, Rollag MD. J Neurosci. 2000 Jan 15;20(2):600-5. 2002: Don Berson, Brown University, (Berson DM, Dunn FA, Takao M (February 2002). "Phototransduction by retinal ganglion cells that set the circadian clock". Science 295 (5557): 1070–3. doi:10.1126/science.1067262. PMID 11834835)

Intrinsically photosensitive retinal ganglion cells (iPRGCs) Timing Photoreceptors Located throughout retina (~3000) Express melanopsin Blue light sensitive(peak 460nm) Regulate photoperiodism (sensitivity to length of day and night) Higher excitatory threshold than rods/cones Transmits to SCN 24-hour light-dark pattern on the retina is the most efficient stimulus for entrainment of circadian rhythms in humans ipRGC – intrinsically photosensitive retinal ganglion cells Neurons: repeatedly fire electrical impulses: reset, fire, reset– light adaptation thought to occur during this process [possibly in the reset timing] Photosensitive: Respond to contrast in light levels Berson DM, Dunn FA, Takao M. Phototransduction by retinal ganglion cells that set the circadian clock. Science. 2002 Feb 8;295(5557):1070-3. Melanopsin-containing cells found in monkey retinal ganglion cell layer (Provencio et al., 2000) Most likely comprise the retinohypothalamic tract Sensitive to wavelengths in the 484-500 nm (blue light)

Suprachiasmatic nucleus (SCN) is master pacemaker Activity in SCN correlates with circadian rhythms Lesions of SCN abolish free-running rhythms Isolated SCN continues to cycle Transplanted SCN imparts rhythm of the donor on the host SCN is known to be compromised in older adults with dementia. (Harper et al 2008) SCN drives daily cycles of activity, hormones SCN in humans have an intrinsic period slightly greater than 24 hours, and is modulated by the temporal pattern of light and dark on the retina. Disruption of this pattern leads from flying across times zones or from shift work can lead to sleep loss, weight gain or breast cancer ref Stevens RG, Rea MS. Light in the built environment: potential role of circadian disruption in endocrine disruption and breast cancer. Cancer Causes Control. 2001;12:279–87. doi: 10.1023/A:1011237000609. [PubMed] [Cross Ref] Figueiro MG, Rea MS, Bullough JD. Does architectural lighting contribute to breast cancer? J Carcinog. 2006;5:20. doi: 10.1186/1477-3163-5-20. [PMC free article] [PubMed] [Cross Ref]Lemmer B. Importance of circadian rhythms for regulation of the cardiovascular system: studies in animal and man. Conf Proc IEEE Eng Med Biol Soc. 2006;1:168–70. full_text. [PubMed] Maemura K, Takeda N, Nagai R. Circadian rhythms in the CNS and peripheral clock disorders: role of the biological clock in cardiovascular diseases. J Pharmacol Sci. 2007;103:134–8. doi: 10.1254/jphs.FMJ06003X2. [PubMed] [Cross Ref]Young ME, Bray MS. Potential role for peripheral circadian clock dyssynchrony in the pathogenesis of cardiovascular dysfunction. Sleep Med. 2007;8:656–67. doi: 10.1016/j.sleep.2006.12.010. [PMC free article] [PubMed] [Cross Ref]Kreier F, Kalsbeek A, Sauerwein HP, Fliers E, Romijn JA, Buijs RM. "Diabetes of the elderly" and type 2 diabetes in younger patients: possible role of the biological clock. Exp Gerontol. 2007;42:22–7. doi: 10.1016/j.exger.2006.07.004. [PubMed] [Cross Ref]Laposky AD, Bass J, Kohsaka A, Turek FW. Sleep and circadian rhythms: key components in the regulation of energy metabolism. FEBS Lett. 2008;582:142–51. doi: 10.1016/j.febslet.2007.06.079. [PubMed] [Cross Ref]Knutson KL, Spiegel K, Penev P, Van Cauter E. The metabolic consequences of sleep deprivation. Sleep Med Rev. 2007;11:163–78. doi: 10.1016/j.smrv.2007.01.002. [PMC free article] [PubMed] [Cross Ref]

Role of Melatonin Melatonin Primary role in humans is to convey information about the daily light-dark cycle to physiological systems Peaks during sleep, suppressed by light. Melatonin is a methoxyindole synthesized and secreted principally by the pineal gland at night under normal environmental conditions. The endogenous rhythm of secretion is generated by the suprachiasmatic nuclei and entrained to the light/dark cycle. Light is able to either suppress or synchronize melatonin production according to the light schedule. The nycthohemeral rhythm of this hormone can be determined by repeated measurement of plasma or saliva melatonin or urine sulfatoxymelatonin, the main hepatic metabolite. The primary physiological function of melatonin, whose secretion adjusts to night length, is to convey information concerning the daily cycle of light and darkness to body physiology. This information is used for the organisation of functions, which respond to changes in the photoperiod such as the seasonal rhythms. Seasonal rhythmicity of physiological functions in humans related to possible alteration of the melatonin message remains, however, of limited evidence in temperate areas in field conditions. Also, the daily melatonin secretion, which is a very robust biochemical signal of night, can be used for the organisation of circadian rhythms. Although functions of this hormone in humans are mainly based on correlative observations, there is some evidence that melatonin stabilizes and strengthens coupling of circadian rhythms, especially of core temperature and sleep-wake rhythms. The circadian organisation of other physiological functions could depend on the melatonin signal, for instance immune, antioxidative defenses, hemostasis and glucose regulation. Since the regulating system of melatonin secretion is complex, following central and autonomic pathways, there are many pathophysiological situations where the melatonin secretion can be disturbed. The resulting alteration could increase predisposition to disease, add to the severity of symptoms or modify the course and outcome of the disorder.

Melatonin Rhythms and Aging Average (±SEM) plasma melatonin in young (top, n=90) and older (bottom, n=29) subjects during a normally phased sleep episode (closed boxes) and a constant routine where they remained awake at the same clock hours (open circles). Data were aligned such that each subject's wake time was graphically adjusted to 08:00 and the data from the baseline day and night and from the CR(constant routine) expressed relative to wake time; sleep time is from 24:00 to 08:00. Melatonin data were averaged hourly within and then across subjects Age 65-81, mean 68 Average (±SEM) plasma melatonin in young (top, n=90) and older (bottom, n=29) subjects during a normally phased sleep episode (closed boxes) and a constant routine where they remained awake at the same clock hours (open circles). Data were aligned such that each subject's wake time was graphically adjusted to 08:00 and the data from the baseline day and night and from the CR expressed relative to wake time; sleep time is from 24:00 to 08:00. Melatonin data were averaged hourly within and then across subjects. Zeitzer et al Sleep. 2007 November 1; 30(11): 1437–1443.

Plasma melatonin suppression by bright light in 65 year old man Plasma melatonin data from subject 19G7, a 65 year old man who was exposed to a 3,527 lux light stimulus. Upper panel: plasma melatonin data from the initial circadian phase estimation procedure (CR1); middle panel: plasma melatonin data from the intervention day, with the 6.5-h experimental light exposure indicated by the open box; lower panel: plasma melatonin data from the final circadian phase estimation procedure (CR2) shown in the solid symbols, with data from CR1 replotted from above in the open symbols. During CR1, the fitted peak of the melatonin secretion (MELmax) occurred at 03:45, 3.5 h before habitual wake time. During CR2 MELmax occurred at 06:30, a 3.5 h phase delay. Melatonin was suppressed by 78% during the 6.5-h 3,527 lux light stimulus. Plasma melatonin data from subject 19G7, a 65 year old man who was exposed to a 3,527 lux light stimulus. Upper panel: plasma melatonin data from the initial circadian phase estimation procedure (CR1); middle panel: plasma melatonin data from the intervention day, with the 6.5-h experimental light exposure indicated by the open box; lower panel: plasma melatonin data from the final circadian phase estimation procedure (CR2) shown in the solid symbols, with data from CR1 replotted from above in the open symbols. During CR1, the fitted peak of the melatonin secretion (MELmax) occurred at 03:45, 3.5 h before habitual wake time. During CR2 MELmax occurred at 06:30, a 3.5 h phase delay. Melatonin was suppressed by 78% during the 6.5-h 3,527 lux light stimulus. Duffy et al Neurobiol Aging. 2007 May; 28(5): 799–807.

Melatonin suppression with bright light Phase shift of fitted plasma melatonin peak (MELmax) vs. illuminance of experimental light stimulus. Data from each of the ten subjects are plotted individually and shown with square symbols. Solid line represents the 4-parameter logistic model fit to the data, with the 95% confidence interval of the model shown in the dotted lines. For comparison, the 4-parameter logistic model fit to the data from our previous study in younger adults [64] is shown in the dashed line. Phase shift of fitted plasma melatonin peak (MELmax) vs. illuminance of experimental light stimulus. Data from each of the ten subjects are plotted individually and shown with square symbols. Solid line represents the 4-parameter logistic model fit to the data, with the 95% confidence interval of the model shown in the dotted lines. For comparison, the 4-parameter logistic model fit to the data from our previous study in younger adults [64] is shown in the dashed line. Duffy et al Neurobiol Aging. 2007 May; 28(5): 799–807.

Circadian light transfer function Figueiro, et al. 2006

Clinical applications

Light levels in contemporary and natural environments39 54–57 and also in phototherapy for seasonal affective disorder, which is typically 2500 lux for 2 h/day or 10 000 lux for 30 min/day.44 Illuminances are given in units of photopic lux. Photopic lux accurately describe the effectiveness of a particular light exposure for overall cone photoreception, which has a peak sensitivity at 555 nm in the green–yellow part of the spectrum (cf, fig 1). A standard circadian lux unit is needed10 40 but has not been adopted yet for comparing the effectiveness of different light exposures for circadian photoreception, which has peak sensitivity at 460 nm in the blue part of the spectrum (cf, fig 1). Turner et al Br J Ophthalmol. 2008 November; 92(11): 1439–1444

Therapeutic light 2 Hours bright light in AM Improved sleep efficiency in NH residents Fetveit et al, 2003 30 minutes sunlight for five days Decreased napping Increased participation Alessi et al, 2005 Daytime bright light Improved sleep/wake cycle in persons with dementia (van Someren et al,1997) Studies using bright white light have demonstrated that light treatment can help reduce the negative impact of aging on circadian rhythms of sleep and wake, and thus, improve the quality and quantity of sleep in older adults, including those with dementia. Bright white light exposure in the morning improved sleep in institutionalized older adults. Fetveit et al12 demonstrated that exposure to 2 hours of bright light in the morning for at least 2 weeks substantially improved sleep efficiency of older adults living in nursing homes. Alessi et al.11 showed that five consecutive days of 30-minute exposure to sunlight, increased physical activity, structured bedtime and control of light and noise at night resulted in a significant decrease in daytime sleeping in intervention participants compared to controls. Further, they showed that intervention participants had increased participation in social and physical activities as well as social conversation. Murphy and Campbell49 have shown that light exposure in the evening can delay the circadian clock and help older adults sleep better at night and be more awake during the day.

Riemersma-van de Lek et al JAMA 2008 6/12 Homes randomized for lighting intervention Installed fluorescent fixtures, both real and sham 1000 lux horizontal at eyes in intervention Caregivers unaware which arm randomized to Melatonin randomized by patient 3.5 year follow up Light exposure was manipulated by installing a large number of ceilingmounted fixtures with Plexiglas diffusers containing an equal amount of Philips TLD 840 and 940 fluorescent tubes (Philips Lighting BV, Eindhoven, the Netherlands) in the common living room. Lights were on daily between approximately 9 AM and 6 PM. The aim was an exposure of ±1000 lux, measured before the eyes in the gaze direction. This intensity is technically feasible and has in previous studies been confirmed to synchronize circadian rhythms in healthy people in temporal isolation31 and to improve circadian activity rhythm disturbances in elderly patients with moderate to severe dementia.32

MMSE, Depression ADLs improved Less irritability, less inability to sleep in those with the lighting. 5%without decelerating the progressive cognitive worsening (as is also the case foracetylcholinesteraseinhibitors8).Light also reduced depressive symptoms by a relative 19% and attenuated the gradual increase in functional limitationsby53%. A similar increase in efficacy over time by 2% was found fo Riemersma-van der Lek, R. F. et al. JAMA 2008;299:2642-2655.

Schedule change: Shift work Light at night (LAN) Nurses’ Health Study (Willet, PI) Effects of Light at Night on Circadian System in Nurses (Schernhammer, PI, RO1-OH008171) 30 year study Evaluate light exposure in rotating shift workers based on the recent information on the specific wavelengths that affect melatonin levels in humans, and will relate those measures to the response of their circadian system, as measured by melatonin levels in urine. Specifically, we will measure light exposure by applying a new device, a circadian light meter that captures the short wavelength portion of visible light, which has been described to most strongly suppress melatonin levels and phase shift the circadian pace maker as part of the light's influence on non-image forming function in humans. Urine collections will be conducted during three of the overall 7 days of study period. Sample 180 Approx 15 million shift workers in US: self selecting nurses, safety officers

Circadian phase shifters Can have negative effects on health Abrupt: jet lag, shift work Gradual: institutionalization Timed light exposure: reset clock Sensitivity age-related Bright light in morning advances the clock Bright light in evening delays the clock Delays easier than advances Jet lag: Adjusting to new schedule can cause daytime sleepiness, insomnia, irritability, stomach upset

Circadian Lighting in Long-term Care: A feasibility study

Methods 3 participants, residents of Ward 62B Lighting: GE fluorescent ceiling lamps 14,000 K Instruments Sleepwatch-L© (AMI, Ardsley, NY) Neuropsychiatric Inventory-Nursing Home Version DaysimeterTM (Lighting Research Center, Rensselear Polytechnic Institute) 29

Methods/Instrumentation for Sleep/Light Data Subject wore Sleep Watch-L© for 7 days Wrist-worn electronic measure of body movement and light Software calculates activity/inactivity and light © Ambulatory Monitoring Inc

Lighting Installation VAMC safety standards 1st phase: 3 ‘blue lamp’ prototypes by GE: 8000 Kelvin (K); 14,000K;16,000K 2nd: 13 standard fluorescent lighting ceiling light fixtures in Dayroom 7 of 13 changed to 14,000 K (6 remained @ 5000 K) Timer controlled blue lighting on, 8a-6p Lighting after 6pm: sufficient for visual acuity Regular lighting is 5000 Kelvin (color correlated temperature, hot body radiation)

Mean of light measurements taken at eye level (horizontally) at 8 points in the room in the 4 cardinal directions, using PMA 2200 Photoradiometer, SnP Meter Photopic SL3103-001, S/N 9829 Light Conditions Photopic (cones) Lux Scotopic (rods) Lux S/P Ratio Brightness Visual Effectiveness all on 517 1178 2.24 781 1818 14,000 K only 381 918 2.26 606 759 standard 333 725 2.14 491 609 all off 222 489 2.17 328 412 Lux – SI unit of illuminance [human brightness perception] as measured by a light meter 1 lux = 1 lumen/square meter Two types of photoreceptors: Rods/cones ratio = ~10/1 Photopic - brightness perceived by cones Scotopic – brightness perceived by rods [more sensitive to bluish-white light] Historically, light meters measured eye’s cone sensitivity to lamps/lighting = photopic data More accurate measure combines the two [rods and cones] into a measure that more reflects what the human eye perceives in terms of light  S/P ratio Studies indicate that lighting that provides higher S/P ratio provides better visual acuity http://www.lightenergysource.com/Scotopic.htm Visual effectiveness: “a measure of how the appearance of information and the use of visual elements within it affect the ease with which users can find, understand, and use the information. Because most… users use their eyes to access your information, the visual impact of that information can be an important factor in its general quality.” http://proquest.safaribooksonline.com/0131477498/ch10

Results & Conclusions Wrist actigraph well accepted Light sensor on wrist covered much of the time by clothing? New blue lighting well received 3 subjects exposure to blue lighting (time in Dayroom/ 10 hr period): 77 minutes, 371 mins, 373 mins Next time: Change installation pattern?, use DaysimeterTM

Rest-Activity and Light Exposure Patterns in the Home Setting: A Methodological Study P. Higgins, T. Hornick, M. Figueiro American J Alzheimer’s Disease and Other Dementias, 2010

Purpose Assess the feasibility and reliability of using a circadian light meter (DaysimeterTM) in a field setting and use the human circadian phototransduction model’s analyses to provide clinically relevant results

Dyad Caregiver – Wife, 73 years, “good health”, no vision problems, no sleep-aid meds. Primary caregiver Elder – Husband, 80 years, vascular dementia plus multiple co-morbidities, continent, needed assistance for all ADL’s and IADL’s, multiple meds included antidepressant but no sleep-aid Elder received all primary care from the Cleveland VA Geriatrics Clinical team. The couple had been married for approximately 50 years. Mr. X was diagnosed with probable vascular dementia three years previously and the couple had recently moved into an independent housing community for elders. Neither had significant visual problems and neither were taking medications for sleep or behavior disorders. Mr. X, who was continent, needed assistance for bathing, dressing, transfer, toileting and feeding and was dependent in all independent activities of daily living. His last Mini Mental Status Exam, 25/30, was completed more than three years before the study and he had resisted all repeat attempts at testing. Besides dementia syndrome, Mr. X had aortic stenosis, hyperaldosteronism, s/p CVA with right hemiparesis, diabetes mellitus, hypertension, gastritis, hyperlipidemia, and a history of depression. Mr X was on ASA, losartan, metformin, omeprazole, simvastatin, and citalopram, and no over the counter agents. Mrs. X, who was not a patient in the LSCVAMC geriatrics clinic, rated her health as good and reported that she was on medications for hypertension and hyperlipidemia but did not take any sleep-aid medication. She provided all care for her husband. Recruited on a routine visit to clinic. Informed written consent obtained from wife for both parties. Assent obtained for elder.

Methods Procedure - Light exposure and rest-activity data were collected over 7 consecutive days in November, 2007 Instruments Assessment of sleep quality and habits Home visit Sleepwatch-L© (AMI, Ardsley, NY) DaysimeterTM (Lighting Research Center, Rensselear Polytechnic Institute) Mrs. X’s initial scores: Pittsburgh Sleep Quality Index was 6, indicating that she rated her previous month’s sleep as ‘poor.’ PSQ ITEMS: how often have you had trouble sleeping because you…can’t get to sleep within 30 mins, get up to use the BR, can’t breath comfortably? Taken meds to help you sleep, staying awake while driving, eating meals, social activities? Problem to get up enthusiasm to get things done? Rating on Epworth Sleepiness scale: 3, indicating she got ‘enough sleep’. ITEMS: how likely are you to doze while sitting & reading, watch TV, lying down to rest in the afternoon, sitting inactive in a public place, in a car while stopped at a traffic light. During the 7-day trial, she reported that she did not take any daytime naps, regularly went to bed about 10 pm and got up once during the night to use the bathroom. In the mornings she was up and out of bed for the day between 7-8 a.m. and did not nap during the day. In daily TC, she evaluated her previous night’s sleep quality as ‘fair or very good’ with only 1 of 7 nights rated as ’fairly poor.’ She reported that Mr. X was up for the day between 8-8:30 a.m., spent most of the day in his recliner, and that she considered him a “a good night-time sleeper” who did not disturb her own sleep even though she was aware of when he used the urinal.

DaysimeterTM Research prototype Two light meters measure photopic and circadian light exposure Actigraph measures movement

Results

Built Environment Independent living complex for seniors Apartment: 640 square feet Brown paneling and beige paint and carpet One south facing window in bedroom Sliding glass door onto porch (south facing) Standard florescent lighting: kitchen and bath Incandescent lighting: floor and table lamps

Ambient light exposure/24 hrs when out of bed (lux) Range Mean mins: > 20 lux > 500 lux >1000 lux Elder 0-449 191.5 0.0 Caregiver 0-3990 635.5 18.0 8.0 Dyad data Light Norms (in lux)* Sunlight /reflective surfaces 150,000 Overcast Day 1,000 Avg nursing home 50 Avg living room 50-200 Twilight 10 Full Moon 1 *From Turner, 2008. Br J Opthalmology

- Mean sleep efficiency % - Mean night sleep (mins) ACTIGRAPHY Caregiver wife Demented husband Sleep-rest - Mean sleep efficiency % - Mean night sleep (mins) - Mean sleep latency (mins) - Mean wake after sleep onset [WASO] (mins) - Mean napping/24 hr (mins) 70 257 81 119 31 446 17 105 96 Intra-daily variability (0-2) 0.71 0.95 Inter-daily stability (0-1) 0.69 0.76 Caregiver 4.3 hours Elder – 7.4 hours Nighttime sleep: number of minutes scored as sleeping at night. Sleep latency: number of minutes until sleep onset scored (first interval with > 20 minutes sleep). >60 minsimpaired* Sleep efficiency: percent of time scored as sleep beginning with first sleep interval. <70%impaired* Napping: number of minutes scored as sleeping when not in bed. WASO: number of minutes scored as awake after sleep onset to end of sleep; indication of sleep fragmentation. >90 minutesimpaired sleep* Intra-daily variability (IV): indication of fragmentation of rest-activity/24 hours; theoretical range 0-2; a good r-a rhythm has low IV (Carvalho-Bos et al 2007) Inter-daily stability (IS): indication of the strength of the coupling between the light-dark cycle and rest-activity cycle; theoretical range 0-1; good r-a rhythm\ has high IS (Carvalho-Bos et al 2007) *”Cutpoints” used to provide “clinically meaningful” norms per Yaffee et al, p 238.

24-hour Sleep and Light Caregiver Elder Caregiver 1112 wake minutes 328 sleep minutes (7 episodes) 22.8% sleep

Caregiver Per Daysimeter: caregiver phasor magnitude of 0.17 [norms 0.5-0.6] Indication of circadian entrainment/disruption

Entrained vs Disrupted Human Would like to talk about two specific environmental phase shifters: jet lag and shift work

Conclusions Daily light levels are very low Little variation in light levels Sleep Neither caregiver or elder sleep well Caregiver: poor circadian entrainment Sleep disruption causes Low lighting, little contrast Frequent wake times at night

Support VISN 10 GRECC, Cleveland VAMC Frances Payne Bolton School of Nursing, Case Western Reserve University, Cleveland, OH Lighting Research Center, Rensselear Polytechnic Institute, Troy NY General Electric Company, Nela Park, East Cleveland, OH 49

Team Tom Hornick, MD1,2 Patricia Higgins, PhD1,2 Mariana Figueiro, PhD3 Mark Rea, PhD3 Andy Bierman, MS3 John Bullough, PhD3 Bill Biers, PhD4 Mark Duffy, PhD4 Ed Yandek, BS4 1Case Western Reserve University 2Cleveland Veterans Affairs Medical Center 3Lighting Research Center, Rensselaer Polytechnic Institute 4General Electric Lighting, Nela Park

Next Steps “Methodology issues in a tailored light treatment for persons with dementia" R01 – M. Figueiro, PI

Wikipedia, accessed 5/2010