October 23, 2024, 8:44 am | Read time: 3 minutes
Previous studies have already shown that the coronavirus can cause long-term damage to the brain. These were mostly based on severe courses of the disease and older COVID-19 patients. However, even mild coronavirus diseases can change the brain – especially in young people.
The list of long-term effects of coronavirus is long. They range from a loss of smell and/or taste to exhaustion or feeling unwell after physical exertion. However, studies have also shown that the virus can have an impact on the brain. For example, it is said to lower cortisol levels in the brain and thus promote inflammation. Researchers from Italy have now identified further structural changes in the brain that can be associated with a mild course of coronavirus disease in young people.
MRI scans and cognitive tests
As part of the longitudinal cohort study “Public Health Impact of Metal Exposure (PHIME),” the researchers recruited adolescents and young adults from northern Italy as participants.1 They focused on this region because it was considered a hotspot during the pandemic. The following exclusion criteria were applied:
- Neurological diseases
- Hepatic diseases
- Metabolic diseases
- Endocrine diseases
- Psychiatric diseases
- Clinically diagnosed motor deficits
- Clinically diagnosed cognitive impairments
- Insufficiently corrected visual deficits
On this basis, a total of 207 subjects aged between twelve and 25 years were suitable for the study, who completed MRI scans and cognitive tests. The so-called standard “Cambridge Neuropsychological Test Automated Battery” was carried out by trained neuropsychologists. In this way, the cognitive and motor memory functions of the adolescents and young adults were assessed.
After the Covid-19 restrictions were lifted, 40 people took part in a follow-up study in which the same tests and MRI scans were repeated. In addition, each participant underwent a COVID-19 assessment, a multimodal MRI, a cognitive function test, a blood sample, and further information on the COVID-19 diagnosis (positive PCR test within twelve months). This resulted in a total of 13 adolescents or young adults with a previous mild corona disease whose brains were examined using standardized methods.
The results
The scientists were able to observe significant differences in the time between examinations, corona symptoms, and vaccination status. Using various statistical methods, they identified five localized functional connectivity nodes that differed greatly between the two groups and primarily influenced cognitive functions. In adolescents who tested positive for coronavirus, a significant reduction in the left hippocampus volume in the brain was observed. This part is responsible for encoding verbal and visual-spatial memories. However, the connectivity of the entire brain remained unchanged.
The left amygdala, which is involved in the storage of memory content, was also affected in Covid patients. “We found connectivity differences in five cortical and subcortical brain areas between participants with and without mild SARS-CoV-2 infection. Furthermore, we observed reduced volume in the left hippocampus in positive Covid patients compared to negative Covid individuals. We observed a significant correlation between mild SARS-CoV-2 infection and functional measures in a subcortical brain area, the left amygdala,” the scientists summarize their findings.
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Limitations of the study
The study shows that even mild coronavirus disease can have an impact on the brains of adolescents and young adults. However, further studies need to be carried out to understand and explain the mechanisms behind this. This is the only way to actually ensure to what extent coronavirus could have negatively affected the brains of adolescents and young adults.
Furthermore, the study only examined young people from the hotspot of northern Italy. Other regions were not included, which means that the results may not apply to other population groups with different socio-demographic backgrounds. In addition, the study size of 40 participants in the follow-up examinations was very small. For this reason, the cohort should be larger in subsequent research work.