A Multi-Modal Combination Intervention to Promote Cognitive Function in Older Intensive Care Unit Survivors

Up to 25% of intensive care unit (ICU) survivors experience cognitive impairment comparable in severity to mild Alzheimer's disease and related dementias after hospital discharge. Older ICU survivors (ages 60 and older) are at highest risk for delirium and subsequent cognitive impairment, which contribute to higher risk for cognitive decline related to Alzheimer's disease and related dementias. Sleep and activity are essential for recovery from critical illness, yet ICU survivors experience both sleep deficiency and profound inactivity. About 75-80% of ICU patients experience circadian dysrhythmia, which contributes to cognitive decline and increases likelihood of developing Alzheimer's disease and related dementias. The scientific premises of the proposed study are: 1) a combined sleep promotion and cognitive training intervention will have synergistic effects to mitigate the risk of cognitive impairment and development of Alzheimer's disease and related dementias in older ICU survivors; and 2) chronotherapeutic timing of interventions (i.e., adjusting timing of interventions according to circadian rhythm) may improve intervention efficacy.

Using a 2 x 2 factorial design, 100 English- or Spanish-speaking older ICU survivors will be enrolled after discharge out of ICU and randomized to one of 4 combinations of two interventions: SLEEP and COG. We propose that the combination of a nighttime sleep promotion intervention \[SLEEP: nighttime use of earplugs and eye masks\] and a daytime computerized cognitive training intervention \[COG: daily 30-minute cognitive training sessions\] may produce synergistic effects on cognitive function to mitigate delirium and reduce risk of incident Alzheimer's disease and related dementias. Because circadian dysrhythmia contributes to cognitive decline, chronotherapeutic timing of the COG intervention could maximize intervention efficacy. Specific Aim 1: Test the separate and combined effects of SLEEP and COG \[SLEEP + COG, SLEEP, COG\] versus an active control \[AC\] in improving cognitive function for older ICU survivors. Specific Aim 2: Examine circadian rhythm parameters of continuous body temperature (iButton: wearable sensor) to determine the optimal window for timing of the COG intervention. Specific Aim 3: Examine if the effects of each intervention on cognitive function are mediated by sleep and activity, and examine if selected biological and clinical factors moderate intervention effects. Exploratory Aim 4: Explore the effect of each intervention on cognitive function at 1 month and incident Alzheimer's disease and related dementias at 6 months and 12 months post-hospital discharge.