Tag: cognitive processing

Long COVID is associated with severe cognitive slowing: a multicentre cross-sectional study

Abstract:

Background: COVID-19 survivors may experience a wide range of chronic cognitive symptoms for months or years as part of post-COVID-19 conditions (PCC). To date, there is no definitive objective cognitive marker for PCC. We hypothesised that a key common deficit in people with PCC might be generalised cognitive slowing.

Methods: To examine cognitive slowing, patients with PCC completed two short web-based cognitive tasks, Simple Reaction Time (SRT) and Number Vigilance Test (NVT). 270 patients diagnosed with PCC at two different clinics in UK and Germany were compared to two control groups: individuals who contracted COVID-19 before but did not experience PCC after recovery (No-PCC group) and uninfected individuals (No-COVID group). All patients with PCC completed the study between May 18, 2021 and July 4, 2023 in Jena University Hospital, Jena, Germany and Long COVID clinic, Oxford, UK.

Findings: We identified pronounced cognitive slowing in patients with PCC, which distinguished them from age-matched healthy individuals who previously had symptomatic COVID-19 but did not manifest PCC. Cognitive slowing was evident even on a 30-s task measuring simple reaction time (SRT), with patients with PCC responding to stimuli ∼3 standard deviations slower than healthy controls. 53.5% of patients with PCC’s response speed was slower than 2 standard deviations from the control mean, indicating a high prevalence of cognitive slowing in PCC. This finding was replicated across two clinic samples in Germany and the UK. Comorbidities such as fatigue, depression, anxiety, sleep disturbance, and post-traumatic stress disorder did not account for the extent of cognitive slowing in patients with PCC. Furthermore, cognitive slowing on the SRT was highly correlated with the poor performance of patients with PCC on the NVT measure of sustained attention.

Interpretation: Together, these results robustly demonstrate pronounced cognitive slowing in people with PCC, which distinguishes them from age-matched healthy individuals who previously had symptomatic COVID-19 but did not manifest PCC. This might be an important factor contributing to some of the cognitive impairments reported in patients with PCC.

Source: Zhao S, Martin EM, Reuken PA, Scholcz A, Ganse-Dumrath A, Srowig A, Utech I, Kozik V, Radscheidt M, Brodoehl S, Stallmach A, Schwab M, Fraser E, Finke K, Husain M. Long COVID is associated with severe cognitive slowing: a multicentre cross-sectional study. EClinicalMedicine. 2024 Jan 25;68:102434. doi: 10.1016/j.eclinm.2024.102434. PMID: 38318123; PMCID: PMC10839583. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10839583/ (Full text)

COVID-19 and Cognitive Function: Evidence for Increased Processing Speed Variability in COVID-19 Survivors and Multifaceted Impairment with LongCOVID Symptoms

Abstract:

Background: There is increasing evidence for cognitive function to be negatively impacted by COVID-19. There is, however, limited research evaluating cognitive function pre- and postCOVID-19 using objective measures.

Methods: We examined processing speed, attention, working memory, executive function and memory in adults (≤69 years) with a history of COVID-19 (n=129; assessed ≥20 days after diagnosis, none acutely unwell), compared to those with no known history of COVID-19 (n=93). We also examined cognitive changes in a sub-group of COVID (n=30) and non-COVID (n=33) participants, compared to their pre-COVID-19 pandemic level (data available through the MyCognition database).

Results: Cross-sectionally, the COVID group showed significantly larger intra-individual variability in processing speed, compared to the non-COVID group. The COVID sub-group also showed significantly larger intra-individual variability in processing speed, compared to their
pre-COVID level; no significant change occurred in non-COVID participants over the same time scale. Other cognitive indices were not significantly impacted in the cross-sectional or withinsubjects investigations, but participants (n=20) who had needed hospitalisation due to COVID19 showed poor attention and executive function relative to those who had not required hospitalisation (n=109). Poor health and long-COVID symptoms  correlated with poor cognitive function across domains in the COVID group.

Conclusions: The findings indicate a limited cognitive impact of COVID-19 with only intraindividual variability in processing speed being significantly impacted in an adult UK sample. However, those who required hospitalisation due to COVID-19 severity and/or experience long-COVID symptoms display multifaceted cognitive impairment and may benefit from repeated cognitive assessments and remediation efforts.

Source: Vakani K, Ratto M, Sandford-James A, Antonova E, Kumari V. COVID-19 and Cognitive Function: Evidence for Increased Processing Speed Variability in COVID-19 Survivors and Multifaceted Impairment with Long-COVID Symptoms. Eur Psychiatry. 2023 May 12:1-34. doi: 10.1192/j.eurpsy.2023.25. Epub ahead of print. PMID: 37170616. https://www.cambridge.org/core/services/aop-cambridge-core/content/view/AE8EFA3BF7DC84334EEBC3039427801C/S0924933823000251a.pdf/covid-19-and-cognitive-function-evidence-for-increased-processing-speed-variability-in-covid-19-survivors-and-multifaceted-impairment-with-long-covid-symptoms.pdf (Full text available as PDF file)

Brain function characteristics of chronic fatigue syndrome: A task fMRI study

Abstract:

The mechanism underlying neurological dysfunction in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is yet to be established. This study investigated the temporal complexity of blood oxygenation level dependent (BOLD) changes in response to the Stroop task in CFS patients. 43 CFS patients (47.4 ± 11.8 yrs) and 26 normal controls (NCs, 43.4 ± 13.9 yrs) were included in this study. Their mental component summary (MCS) and physical component summary (PCS) from the 36-item Short Form Health Survey (SF-36) questionnaire were recorded. Their Stroop colour-word task performance was measured by accuracy and response time (RT). The BOLD changes associated with the Stroop task were evaluated using a 2-level general linear model approach. The temporal complexity of the BOLD responses, a measure of information capacity and thus adaptability to a challenging environment, in each activated region was measured by sample entropy (SampEn).

The CFS patients showed significantly longer RTs than the NCs (P < 0.05) but no significant difference in accuracy. One sample t-tests for the two groups (Family wise error adjusted PFWE < 0.05) showed more BOLD activation regions in the CFS, although a two sample group comparison did not show significant difference. BOLD SampEns in ten regions were significantly lower (FDR-q < 0.05) in CFS patients. BOLD SampEns in 15 regions were significantly associated with PCS (FDR-q < 0.05) and in 9 regions were associated with MCS (FDR-q < 0.05) across all subjects. SampEn of the BOLD signal in the medioventral occipital cortex could explain 40% and 31% of the variance in the SF-36 PCS and MCS scores, and those in the precentral gyrus could explain an additional 16% and 7% across all subjects.

This is the first study to investigate BOLD signal SampEn in response to tasks in CFS. The results suggest the brain responds differently to a cognitive challenge in patients with CFS, with recruitment of wider regions to compensate for lower information capacity.

Source: Shan ZY, Finegan K, Bhuta S, Ireland T, Staines DR, Marshall-Gradisnik SM, Barnden LR. Brain function characteristics of chronic fatigue syndrome: A task fMRI study. Neuroimage Clin. 2018 Apr 25;19:279-286. doi: 10.1016/j.nicl.2018.04.025. eCollection 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6051500/ (Full study)

Research on cognitive complaints and cognitive functioning in patients with chronic fatigue syndrome (CFS): What conclusions can we draw?

Abstract:

People with chronic fatigue syndrome (CFS) complain of difficulties with concentration and memory yet studies suggest that they do not suffer gross deficits in cognitive functioning. Depressed patients make similar cognitive complaints, and there is symptomatic overlap between CFS and depression.

Cognitive complaints and depressed mood are positively correlated in CFS patients but, except on tasks which are particularly sensitive to depression, cognitive performance and depression are not.

The inconsistency between cognitive complaints and results of tests of cognitive functioning resembles that found in other subject groups and may be due in part to the inappropriate use of laboratory memory tests for assessing “everyday” cognitive functioning.

Even when cognitive capacity is intact, cognitive performance may be affected by factors such as arousal, mood, and strategy. In CFS patients, everyday cognitive tasks may require excessive processing resources leaving patients with diminished spare attentional capacity or flexibility.

 

Source: Wearden AJ, Appleby L. Research on cognitive complaints and cognitive functioning in patients with chronic fatigue syndrome (CFS): What conclusions can we draw? J Psychosom Res. 1996 Sep;41(3):197-211. http://www.ncbi.nlm.nih.gov/pubmed/8910243