Sleep Pattern Differences Between Older Adult Dementia Caregivers and Older Adult Noncaregivers Using Objective and Subjective Measures

The majority of persons with dementia (PWD) are cared for in the home setting by informal caregivers, usually a female relative. Researchers have reported a variety of changes in caregiver sleep including changes in sleep quantity and quality.1 Because the results are variable, however, research is needed to determine whether there are factors that predict which caregivers are at risk for poor sleep. Accurate assessment and prevention is critical, because poor sleep in caregivers has been associated with sympathoadrenal medullary arousal,2 changes in immune function,3 poorer psychological state,4,5 and early institutional placement of the PWD.6,7 Additionally, interventions could be better targeted to the factors associated with poor sleep in dementia caregivers. While caregivers consistently report poorer sleep quality than noncaregivers,5,8–11 the picture is not as clear when sleep is measured objectively or subjectively.1,4 In some studies, sleep quantity was considered normal because it was similar to age-matched controls,3 while in other studies, poorer sleep was attributed to causes such as depression or caregiver burden rather than caregiver status.1,12 One reason for inconsistent findings may be the sampling strategy used in previous studies, namely, that all dementia caregivers were sampled regardless of the nighttime activity in the PWD. Approximately 25% to 54% of PWD have significant changes in their sleep-wake cycle, causing awakenings at night. These awakenings could have a significant impact on caregiver sleep quantity, since the PWD often requires supervision when up at night. This supervision is critical to prevent injuries, such as falls13 or inappropriate actions, such as home exits,14 associated with cognitive impairments typically seen in dementia. Thus caregivers who supervise PWD with nighttime activity are potentially most at risk for substantial sleep changes or disturbances. Secondly, inconsistent findings may be due to inadequate measurement of sleep. Thus research on caregiver sleep, using commonly accepted sleep measurements (e.g., sleep diaries and actigraphy over a period of time), is needed to fill this gap in knowledge.15 Caregivers of PWD may develop night-to-night sleep deficits caused by the need to provide supervision or other caregiving tasks, and they may attempt to make up for this by sleeping longer in subsequent nights. If, however, researchers only examine the week's mean values of sleep and wake variables, values may appear normal, and the pattern of high variability in night-to-night sleep would be lost. The perception of sleep adequacy may be affected by this inconsistent pattern of sleep over the week. Hence, analysis of the intra-individual variability of night-to-night sleep may help explain why most caregivers complain of poor sleep quality even if sleep times are in a normal range. The purposes of this study were threefold: 1. To quantify sleep parameters in older adult caregivers of PWD with nighttime activity over a 7-day period in the natural caregiving setting (using both objective and subjective sleep measurement methods) and to compare these findings to a group of noncaregiving older adults. The following measurements and variables were used: Actigraphy (objective): total sleep time (TSTo), sleep onset latency (SOLo), wake after sleep onset (WASOo), and sleep efficiency (SEo). Sleep diary (subjective): total sleep time (TSTs), sleep onset latency (SOLs), wake after sleep onset (WASOs), sleep efficiency (SEs), and sleep quality (SQs) rating. Daytime functioning: Epworth Sleepiness Scale (ESS) and Fatigue Severity Scale (FSS). 4. To examine the night-to-night variability in caregivers' sleep patterns and to compare these with sleep patterns of noncaregiving adults. 5. To explore the correlation patterns of sleep measured subjectively and objectively between caregivers and noncaregivers.