Cognitive Impairment After COVID-19—A Review on Objective Test Data

Abstract

Objective: The aim was to conduct a review on the literature on objective cognitive impairment in patients after COVID-19.Methods: We performed a literature review and searched Ovid Medline in February 2021 based on a PECO scheme.Results: Twelve articles met all inclusion criteria. Total patient sample was <1,000. All studies on global cognitive function found impairment, ranging from 15 to 80% of the sampled patients. Seven studies on attention and executive functions reported impairment, with varying results depending on sub-domain and different tests. Three out of four studies reported memory difficulties, with two studies reporting short-term memory deficits. Although results indicate possible language impairment, only one study used domain-specific language tasks. Two out of four studies on visuospatial function did not report any impairment.Conclusion: Patients with recent SARS-CoV-2 infection appear to experience global cognitive impairment, impairment in memory, attention and executive function, and in particular verbal fluency. Based on the current results, we recommend clinicians to evaluate the need for cognitive assessment of patients with a recent COVID-19 infection, regardless of the severity of the disease, treatment methods and length of ICU stay. We need studies with larger sample and control group.

Episodic long-term memory in post-infectious SARS-CoV-2 patients

“…Episodic LTM sub-clinical/clinical deficits proved to be mildly-to-moderately prevalent in post -infectious SARS-CoV-2 patients—the higher rate being found in those already at risk for cognitive decline [ 5 ]. LTM deficits could be detected by both I- and II-level measures of verbal LTM, although the latter proved to be slightly more sensitive than the former, especially with respect to RCD+ patients.…”

“…Cognitive sequelae of COVID-19 within the dysexecutive-inattentive and amnesic spectrum have been attributed to neurotropic properties of SARS-CoV-2 and featured neuroinflammatory processes [ 5 ], as well as to iatrogenic confounders (e.g., steroidal treatments) [ 4 ] and premorbid risk factors for cognitive impairment [ 1 ]. To screen for cognitive deficits in this population has been stressed as relevant due to their adverse impact on rehabilitative and ecological outcomes [ 5 ].…”

“…Subjective episodic long-term memory (LTM) difficulties are frequently reported by COVID-19-recovered patients [ 8 ] also yielding at psychometric testing [ 5 ] and neuroradiological examinations of LTM-related structures [ 6 ]. However, little is known about the semiology and prevalence of post -COVID-19 LTM difficulties, being still debated whether such deficits arise from primary amnesic features due to medial temporal dysfunctions [ 7 ] or are secondary to non-instrumental processes of a prefrontal etiology [ 10 ].…”

“Brain Fog” by COVID-19 or Alzheimer’s Disease? A Case Report

“…Specifically, cognitive issues are among the most frequent neurological symptoms reported by patients after the acute phase ( Bliddal et al, 2021 ; Vanichkachorn et al, 2021 ). Evidence regarding the prevalence, characteristics, and mechanisms associated with cognitive dysfunction after COVID-19 is still scarce ( Daroische et al, 2021 ). To date, heterogeneous findings have been found in several cognitive domains, especially concerning attention and executive functioning and episodic memory ( Almeria et al, 2020 ; Woo et al, 2020 ; Zhou et al, 2020 ).…”

“…To date, heterogeneous findings have been found in several cognitive domains, especially concerning attention and executive functioning and episodic memory ( Almeria et al, 2020 ; Woo et al, 2020 ; Zhou et al, 2020 ). However, studies have used mainly brief cognitive tests or online surveys, which are not designed to characterize the neuropsychological profile associated with COVID-19 ( Daroische et al, 2021 ). Furthermore, most studies do not include a healthy control group, which can hinder obtaining reliable conclusions.…”