Date Published: April 12, 2019
Publisher: Public Library of Science
Author(s): Kimia Honarmand, Sabhyata Malik, Conor Wild, Laura E. Gonzalez-Lara, Christopher W. McIntyre, Adrian M. Owen, Marat Slessarev, Sheila Alexander.
To assess the feasibility of using a widely validated, web-based neurocognitive test battery (Cambridge Brain Sciences, CBS) in a cohort of critical illness survivors.
We conducted a prospective observational study in two intensive care units (ICUs) at two tertiary care hospitals. Twenty non-delirious ICU patients who were mechanically ventilated for a minimum of 24 hours underwent cognitive testing using the CBS battery. The CBS consists of 12 cognitive tests that assess a broad range of cognitive abilities that can be categorized into three cognitive domains: reasoning skills, short-term memory, and verbal processing. Patients underwent cognitive assessment while still in the ICU (n = 13) or shortly after discharge to ward (n = 7). Cognitive impairment on each test was defined as a raw score that was 1.5 or more standard deviations below age- and sex-matched norms from healthy controls.
We found that all patients were impaired on at least two tests and 18 patients were impaired on at least three tests. ICU patients had poorer performance on all three cognitive domains relative to healthy controls. We identified testing related fatigue due to battery length as a feasibility issue of the CBS test battery.
Use of a web-based patient-administered cognitive test battery is feasible and can be used in large-scale studies to identify domain-specific cognitive impairment in critical illness survivors and the temporal course of recovery over time.
Long-term cognitive impairment is a common complication in critical illness survivors [1–3] but its natural history and the temporal profile of cognitive recovery in individual patients remain unknown. Understanding these features is critical for identifying optimal therapeutic windows and selecting patient subgroups most likely to benefit from targeted interventions.
Of 45 patients approached, 25 declined to participate in this study, most commonly due to self-reported inability to participate or limited availability due to required clinical care activities (e.g., diagnostic tests). Twenty patients (7 females) were included in the analysis (Fig 1). Patient demographic and clinical characteristics are presented in Table 1. We reached family members or friends of 15 patients for completion of the IQCODE. None of these patients were found to have pre-morbid dementia as assessed by the IQCODE.
We demonstrated that a comprehensive, web-based neurocognitive testing platform is feasible for use in critical illness survivors and detects domain-specific cognitive impairment. We identified battery length as a potential challenge to wider scale use of the CBS battery, which we believe can be addressed by shortening the battery length. Further studies using the CBS cognitive battery are needed to determine its feasibility in assessing cognition and cognitive recovery over time. Further optimization of this tool for ICU patients may possibly establish a novel frontier in ICU cognition research by enabling remote monitoring of cognitive recovery in critical illness survivors, correlation of cognitive scores with neuroimaging data to help identify underlying neural mechanisms, and objective assessment of outcomes associated with preventative, therapeutic, and rehabilitative interventions.