Cognitive consequences of COVID-19: results of a cohort study from South America

ABSTRACT Background: Neurological and psychiatric manifestations associated with SARS-CoV-2 infection have been reported throughout the scientific literature. However, studies on post-COVID cognitive impairment in people with no previous cognitive complaint are scarce. Objective: We aim to investigate the impact of COVID-19 on cognitive functions in adults without cognitive complaints before infection and to study cognitive dysfunction according to disease severity and cognitive risk factors. Methods: Forty-five post-COVID-19 patients and forty-five controls underwent extensive neuropsychological evaluation, which assessed cognitive domains such as memory, language, attention, executive functions, and visuospatial skills, including psychiatric symptomatology scales. Data were collected on the severity of infection, premorbid medical conditions, and functionality for activities of daily living before and after COVID-19. Results: Significant differences between groups were found in cognitive composites of memory (p=0.016, Cohen’s d= 0.73), attention (p<0.001, Cohen’s d=1.2), executive functions (p<0.001, Cohen’s d=1.4), and language (p=0.002, Cohen’s d=0.87). The change from premorbid to post-infection functioning was significantly different between severity groups (WHODAS, p=0.037). Self-reported anxiety was associated with the presence of cognitive dysfunction in COVID-19 subjects (p=0.043). Conclusion: Our results suggest that the presence of cognitive symptoms in post-COVID-19 patients may persist for months after disease remission and argue for the inclusion of cognitive assessment as a protocolized stage of the post-COVID examination. Screening measures may not be sufficient to detect cognitive dysfunction in post-COVID-19 patients.

Subjective cognitive complaints and relations to objective cognitive performance among Lebanese patients with schizophrenia

Background Patients with schizophrenia have a particularly low level of insight into their illness compared to people with other mental health disorders. The objectives of the study were to evaluate: 1) subjective cognitive complaints in individuals with schizophrenia in comparison with health controls, 2) the relation between subjective cognitive complaint (SCC) and objective cognitive performance in the patients group, and 3) factors related to cognitive complaint, such as depression, insight, autonomy, and psychological symptoms. Methods Cross-sectional study was conducted between July 2019 and March 2020 enrolled 120 patients with schizophrenia disorders, selected from the Psychiatric Hospital of the Cross (HPC) – Lebanon and 60 healthy controls. The Self-Assessment Scale of Cognitive Complaints in Schizophrenia (SASCCS) was used to measure people living with schizophrenia perception of their cognitive impairment, while the Brief Assessment of Cognition in Schizophrenia (BACS) was used to evaluate their cognitive functioning. Results A significant difference was found between schizophrenia patients and healthy controls in all neurocognition and SASCCS tests. The hierarchical regression analysis showed that the BACS total score (Beta = −.06, p = .04), the PANSS general psychopathology (Beta = .29, p = .003), higher depression (Beta = .75, p = .003) were significantly associated with higher SCC. However, higher autonomy (Beta = − 6.35, p = .001) was significantly associated with lower SCC. A Structural equation model showed that the two most contributing variables were general psychopathology (Standardized Beta (SB): .33, p < 0.001) and autonomy (SB: −.29, p < 0.001). Conclusion A significant proportion of patients with schizophrenia could estimate their cognitive impairment. It also showed a positive correlation between depression and activity of daily living with SCC, suggesting that this aspect should be investigated alongside the clinical symptoms when a patient with schizophrenia presents with SCC.

PREPRINT: Mechanisms of Motoric Cognitive Risk: hypotheses based on a systematic review and meta-analysis of longitudinal cohort studies of older adults

We aimed to refine the hypothesis that Motoric Cognitive Risk (MCR), a syndrome combining measured slow gait speed and self-reported cognitive complaints, is prognostic of incident dementia and other major causes of morbidity in older age. We propose mechanisms on the relationship between motor and cognitive function and describe a roadmap to validate these hypotheses. We systematically searched major electronic databases from inception to August 2021 for original longitudinal cohort studies of adults aged ≥60 years that compared an MCR group to a non-MCR group with any health outcome. Fifteen cohorts were combined by meta-analysis. Participants with MCR were at an increased risk of cognitive impairment (adjusted hazard ratio [aHR] 1.76, 95%CI 1.49-2.08; I2=24.9%), dementia (aHR 2.12, 1.85-2.42; 33.1%), falls (adjusted Relative Risk 1.38, 1.15-1.66; 62.1%), and mortality (aHR 1.49, 1.16-1.91; 79.2%). The prognostic value of MCR is considerable and mechanisms underlying the syndrome are proposed. Keywords: Motoric cognitive risk, gait, dementia, review, meta-analysis, mechanism, pathophysiology, falls, mortality, subjective cognitive complaint, prognostic, prevention Systematic review registration: PROSPERO CRD42020225183.

Late-Life Depressive Symptomatology, Motoric Cognitive Risk Syndrome, and Incident Dementia: The “NuAge” Study Results

Background: Late-life depressive symptomatology and motoric cognitive risk syndrome (MCR) have independently been associated with an increased risk for incident dementia. This study aimed to examine the association of late-life depressive symptomatology, MCR, and their combination on incident dementia in community-dwelling older adults living in Quebec (Canada).Methods: The study was carried out in a subset of 1,098 community dwellers aged ≥65 years recruited in the “Nutrition as a determinant of successful aging: The Quebec longitudinal study” (NuAge), an observational prospective cohort study with 3 years follow-up. At baseline, MCR was defined by the association of subjective cognitive complaint with slow walking speed, and late-life depressive symptomatology with a 30-item Geriatric Depression Scale (GDS) score &gt;5/30. Incident dementia, defined as a Modified Mini-Mental State score ≤79/100 test and Instrumental Activity Daily Living score &lt;4/4, was assessed at each annual visit.Results: The prevalence of late-life depressive symptomatology only was 31.1%, of MCR only 1.8%, and the combination of late-life depressive symptomatology and MCR 2.4%. The combination of late-life depressive symptomatology and MCR at baseline was associated with significant overall incident dementia (odds ratio (OR) = 2.31 with P ≤ 0.001) but not for MCR only (OR = 3.75 with P = 0.186) or late-life depressive symptomatology only (OR = 1.29 with P = 0.276).Conclusions: The combination of late-life depressive symptomatology and MCR is associated with incident dementia in older community dwellers. The results suggested an interplay between late-life depressive symptomatology and MCR exposing them to an increased risk for dementia.

Stimulating Memory: Reviewing Interventions Using Repetitive Transcranial Magnetic Stimulation to Enhance or Restore Memory Abilities

Human memory systems are imperfect recording devices that are affected by age and disease, but recent findings suggest that the performance of these systems may be modifiable through interventions using non-invasive brain stimulation such as repetitive transcranial magnetic stimulation (rTMS). The translational potential of these rTMS interventions is clear: memory problems are the most common cognitive complaint associated with healthy aging, while pathological conditions such as Alzheimer’s disease are often associated with severe deficits in memory. Therapies to improve memory or treat memory loss could enhance independence while reducing costs for public health systems. Despite this promise, several important factors limit the generalizability and translational potential of rTMS interventions for memory. Heterogeneity of protocol design, rTMS parameters, and outcome measures present significant challenges to interpretation and reproducibility. However, recent advances in cognitive neuroscience, including rTMS approaches in addition to a new understanding of functional brain networks and related insights, may offer methodological tools necessary to design new interventional studies with enhanced experimental rigor, improved reproducibility, and greater likelihood of successful translation to clinical settings. In this review, we first discuss the current state of the literature on memory modulation with rTMS, then offer a commentary on developments in cognitive neuroscience that are relevant to rTMS interventions, and finally close by offering several recommendations for the design of future investigations using rTMS to modulate human memory performance.

Subjective Cognitive Dysfunction in Patients with Dizziness and Vertigo

<b><i>Introduction:</i></b> Patients with vestibular disorders sometimes report cognitive difficulties, but there is no consensus about the type or degree of cognitive complaint. We therefore investigated subjective cognitive dysfunction in a well-defined sample of neuro-otology patients and used demographic factors and scores from a measure of depression, anxiety, and stress to control for potential confounding factors. <b><i>Methods:</i></b> We asked 126 neuro-otology clinic outpatients whether they experienced difficulties with thinking, memory, or concentration as a result of dizziness or vertigo. They and 42 nonvertiginous control subjects also completed the Neuropsychological Vertigo Inventory (NVI, which measures cognitive, emotional, vision, and motor complaints), the Everyday Memory Questionnaire (EMQ), and Depression, Anxiety, and Stress Scales (DASS). <b><i>Results:</i></b> In the initial interview questions, 60% of patients reported experiencing cognitive difficulties. Cognitive questionnaire scores were positively correlated with the overall DASS score and to a lesser extent with age and gender. Therefore, we compared patients and controls on the NVI and EMQ, using these mood and demographic variables as covariates. Linear regression analyses revealed that patients scored significantly worse on the total NVI, NVI cognitive composite, and 3 individual NVI cognition subscales (Attention, Space Perception, and Time Perception), but not the EMQ. Patients also scored significantly worse on the NVI Emotion and Motor subscales. <b><i>Conclusions:</i></b> Patients with dizziness and vertigo reported high levels of cognitive dysfunction, affecting attention, perceptions of space and time. Although perceptions of cognitive dysfunction were correlated with emotional distress, they were significantly elevated in patients over and above the impact of depression, anxiety, or stress.

Self-reported word-finding complaints are associated with cerebrospinal fluid beta-amyloid and atrophy in cognitively normal older adults

Background and Objectives: Self-reported language complaints, and more specifically word-finding difficulties, are among the most frequent cognitive complaints in cognitively normal older adults (CN). The clinical significance of elevated self-reported word-finding complaints in CN is still a matter of debate. The present study aims at characterizing word-finding complaints in CN, establish their sociodemographic and psychological correlates, determine if they are predictive of lower levels of cerebrospinal fluid Aβ levels and finally, investigate if they are associated with brain atrophy in regions associated with naming impairments. Methods: In this observational case-control study, 239 CN from the Alzheimer Disease Neuroimaging Initiative (ADNI) database were selected. All participants completed the self-reported version of the Everyday Cognition (ECog) questionnaire, as well as a lumbar puncture for Aβ and a MRI. Results: Word-finding complaints were rated equally severe as a few other memory items and significantly more severe compared to all the other cognitive complaints. Ecog-Lang1 (Forgetting the names of objects) was not related to any demographic (age, sex, years of education) or psychological variable (depression-related symptoms, anxiety-related symptoms), while Ecog-Lang3 (Finding the right words to use in a conversation) was significantly negatively associated with years of education and positively associated with depression-related symptoms. Ecog-Lang1 severity significantly predicted CSF Aβ levels in CN, and this result remained significant even when controlling for all demographic and psychological variables as well as general level of cognitive complaint. Individuals with high Ecog-Lang1 complaints showed atrophy in the left fusiform gyrus and the left rolandic operculum in comparison to CN with no or low Ecog-Lang1 complaints. Discussion: Overall, our results support the fact that word-finding complaints are significant in CN and should be taken seriously. They have the potential to identify CN at risk of AD and support the need to include other cognitive domains in the investigation of subjective cognitive decline.