What’s new in cognitive function in ICU survivors

Increasing numbers of patients survive a critical care admission, but many of them develop morbidities, including cognitive impairments, that have devastating consequences. Cognitive impairment affects 10–62 % of ICU survivors, with most studies reporting deficits in a third to half of patients [1]. Variability in the prevalence of cognitive impairments across studies is explained by heterogeneity in assessments (questionnaires, cognitive screening tests, or neuropsychological test batteries) and variable follow-up intervals [1]. While some patients have prior cognitive impairment, critical illness results in de novo cognitive deficits in previously healthy individuals. New or worsening cognitive impairment appears more prevalent in the critically ill than in other hospitalized patients. For example, one study found significantly higher odds of cognitive impairment after severe sepsis, compared to hospitalized patients without sepsis [2]. It is unclear if a “dose response” exists pertaining to the relationship between severity of illness and severity of cognitive impairment, although numerous studies have found that traditional markers of illness severity are not predictive of cognitive deficits or cognitive decline. …