Natural History of Cognitive Impairment in Critical Illness Survivors. A Systematic Review

Abstract

Long-term cognitive impairment is common among ICU survivors, but its natural history remains unclear. In this systematic review, we report the frequency of cognitive impairment in ICU survivors across various time points after ICU discharge that were extracted from 46 of the 3,350 screened records. Prior studies used a range of cognitive instruments, including subjective assessments (10 studies), single or screening cognitive test such as Mini-Mental State Examination or Trail Making Tests A and B (23 studies), and comprehensive cognitive batteries (26 studies). The mean prevalence of cognitive impairment was higher with objective rather than subjective assessments (54% [95% confidence interval (CI), 51-57%] vs. 35% [95% CI, 29-41%] at 3 months after ICU discharge) and when comprehensive cognitive batteries rather than Mini-Mental State Examination were used (ICU discharge: 61% [95% CI, 38-100%] vs. 36% [95% CI, 15-63%]; 12 months after ICU discharge: 43% [95% CI, 10-78%] vs. 18% [95% CI, 10-20%]). Patients with acute respiratory distress syndrome had higher prevalence of cognitive impairment than mixed ICU patients at ICU discharge (82% [95% CI, 78-86%] vs. 48% [95% CI, 44-52%]). Although some studies repeated tests at more than one time point, the time intervals between tests were arbitrary and dictated by operational limitations of individual studies or chosen cognitive instruments. In summary, the prevalence and temporal trajectory of ICU-related cognitive impairment varies depending on the type of cognitive instrument used and the etiology of critical illness. Future studies should use modern comprehensive batteries to better delineate the natural history of cognitive recovery across ICU patient subgroups and determine which acute illness and treatment factors are associated with better recovery trajectories.

Protocol for the Prognostication of Consciousness Recovery Following a Brain Injury

“…Current neurocognitive tools are expensive and inconvenient; they are time consuming, require specially trained staff to administer, and subjects must attend testing sessions in person. As a result, the subject pool for current neurocognitive tools largely excludes patients who are institutionalized, have limited mobility, those who do not live near the testing center, or who have negatively associated traumatic memories due to their recent hospital experience, and are unwilling to return to the admitting hospital (Honarmand et al, 2020). Access to webbased neurocognitive battery therefore has valuable implications for this patient population.…”

“…Second, very little is known about the long-term outcomes of ICU survivors. While it is known that long-term cognitive impairments affect 40-100% of ICU survivors (Hopkins et al, 2005;Moulaert et al, 2009;Iwashyna et al, 2010;Wilcox et al, 2013;Honarmand et al, 2020), and affects people of all ages (Pandharipande et al, 2014), there is a lack of a systematic, patient-accessible method for accurately tracking cognitive recovery in these patients. Our group has recently established that a web-based cognitive battery that can be self-administered by patients is both feasible for use in ICU patients and accurately detects cognitive impairment across multiple cognitive domains (Honarmand et al, 2019).…”

“…This model has several limitations including the length of these testing sessions, patient inconvenience of traveling to clinic assessments, high costs associated with employing trained personnel, and high rates of patient attrition. As a result, traditional methods of comprehensive cognitive assessment cannot be used for a largescale multi-center natural history study that requires repeated measurement of cognitive function within individual patients during their recovery (Honarmand et al, 2020).…”

Could Virtual Reality play a role in the rehabilitation after COVID-19 infection?

“…Without intervention, such impairments can last for years after discharge. 19 Cognitive interventions, including memory exercises and exercises for building optimism, may reduce these symptoms. 20 These can easily be provided through VR, and allow for exercises to be completed at individualised pacing.…”

Impact of Graded Passive Cycling on Hemodynamics, Cerebral Blood Flow, and Cardiac Function in Septic ICU Patients

“…Sepsis is associated with short-and long-term complications, including physical and cognitive impairment (1,2). Although early active mobilization is associated with improvements in peripheral strength at hospital discharge (3,4) and shorter delirium duration (5), many patients are unable to participate in active mobilization during earlier stages of critical illness due to decreased levels of consciousness and ventilator dependence.…”