In a recent study published on the Research Square preprint server*, researchers assessed functional and microstructural brain abnormalities, fatigue, and cognitive impairment following mild coronavirus disease 2019 (COVID-19).
Study: Functional and microstructural brain abnormalities, fatigue and cognitive dysfunction after mild COVID-19. Image credit: GEMINI PRO STUDIO/Shutterstock
Studies have identified neurological symptoms of COVID-19, but little is known about the long-term neurological effects of severe acute respiratory syndrome (SARS-CoV-2) infection. Although most people recover from respiratory symptoms, the prognosis of post-COVID-19 exhaustion and cognitive dysfunction is questionable.
Although neuroinvasion following SARS-CoV-2 has been confirmed in some brain autopsies, the neural processes that generate neuropsychiatric and neurological symptoms remain unknown.
About the study
In the present study, the researchers revealed abnormalities of functional connectivity, clinical assessment and neuropsychological assessments.
The team performed a cross-sectional analysis of data from an observational study to examine post-acute neurological signs and neuroimaging changes associated with COVID-19. used social media to publicize their online survey. The first 87 participants who did not require hospitalization and had a confirmed diagnosis of COVID-19 were required to visit the center and complete the four steps of the protocol: a personal interview and neurological assessment, a 3T magnetic resonance (MR) acquisition along with a neuropsychological evaluation. , and blood sample collection at the Campinas University Hospital. COVID-19 was diagnosed by polymerase chain reaction (PCR) or verified immunoglobulin (Ig)-M or IgG antibodies. A total of 55 healthy volunteers had no symptoms of COVID-19 and had never tested SARS-CoV-2-positive.
The team performed an exploratory neuropsychological assessment on recovered patients. Tests were chosen to examine different cognitive areas, including language with the phonemic verbal fluency test and the verbal categorical fluency test, episodic memory with the logical memory subtest of the Wechsler Memory Scale-Revised, and cognitive flexibility with the track creation test.
The team determined z-scores corresponding to neuropsychological test results using the Brazilian standard and scaled scores. Supplementary analysis was also performed with multiple linear regression residuals to adjust for the impact of age or education. For each test, function was classified as conserved, low average, below average, or very low. We measured anxiety and depression symptoms using the Beck Anxiety Inventory (BAI) and the Beck Depression Inventory-II, respectively (BDI-II). The Chalder Exhaustion Questionnaire (CFQ-11) and the Epworth Sleepiness Scale were also used to assess fatigue and excessive daytime sleepiness (ESS), respectively.
results
The study results showed an average latency of 54 days between diagnosis and personal interview for the 87 patients we investigated. Patients had an average of four symptoms during the acute phase, while they had an average of two symptoms in the post-acute phase. Fatigue, headache, memory problems, anosmia and somnolence were the most common post-acute effects. In addition, 38 participants felt exhaustion, often accompanied by other symptoms such as a headache in 25 respondents, memory problems in 17 subjects and sleepiness in 14 subjects.
The team discovered abnormalities in 11 individuals based on post-COVID-19 neurological tests and interviews. Along with personal interviews, 65 respondents scored an average of 15 points on the CFQ-11 and 9 points on the ESS. In contrast to the number of symptoms noted in the interview, symptoms indicated exhaustion in 44 of 65 people and excessive daytime sleepiness in 23 of 65 people.
The neuropsychological assessment was performed on a subgroup of 78 people. Almost 18% of people had symptoms of depression, while 29% had symptoms of anxiety. The team discovered a relationship between BDI-II and CFQ-11 scores. In terms of cognitive function, the team observed abnormal phonological fluency performance among 33% of patients, abnormal performance on the Trail Making Test (TMT)-A in 30% of patients, and abnormal TMT-B in 40% of patients. An association was also observed between higher values of fractional anisotropy (FA) in patients and lower values of axial diffusivity (AD), mean diffusivity (MD) and radial diffusivity (RD).
conclusion
The results of the study showed that SARS-CoV-2 affected the brains of patients who did not require hospitalization, with chronic fatigue, headache, memory impairment and sleepiness even two months after infection by SARS-CoV-2. The team identified these patients’ cognitive impairment, mild white matter and connectivity abnormalities. Brain changes and the severity of cognitive impairment warrant substantial longitudinal research on persistent neuropsychiatric symptoms in patients recovered from COVID-19, even in those with minimal acute symptoms. After the initial phase, specific symptom treatments and neurorehabilitation procedures may be required to improve cognitive function and quality of life for patients with permanent disabilities.
*Important news
Research Square publishes preliminary scientific reports that are not peer-reviewed and therefore should not be considered conclusive, guide clinical practice or health-related behavior, or be treated as established information.