- Researchers reviewed over 80 studies containing EEG scan findings to investigate the effects of COVID-19 on the brain.
- Results showed 88% of the patients had brain scan abnormalities.
- The most common abnormality among the patients was a diffuse slowing.
Researchers from Baylor College of Medicine and the University of Pittsburgh conducted a systematic review to analyze the common EEG findings among COVID-19 patients. Along with an analysis of the brain scan abnormalities, researchers also collected data on age, gender, indication for EEG, and co-morbid neurological conditions.
They compiled data from over eighty COVID-19 studies containing EEG scan findings. The review included 617 patients with a median age of 61 years. They published their findings in the journal Seizure: European Journal of Epilepsy.
Brain Scan Abnormalities Seen in One-Third of Patients
They discovered the most common reason for requesting an EEG scan was an altered mental status. Around 61.7% of patients experienced some level of confusion and disorientation that warranted an imaging scan. Seizures and Cardiac events were also among the most common EEG indications.
EEG, or an electroencephalogram, is a test that detects the brain’s electrical activity. Abnormal activity occurs as a result of infections and other brain abnormalities. Thus, making it useful for detecting neurological complications. Previous studies have shown that around 34.6% of patients with severe COVID-19 experience neurological effects.
Average age of those affected was 61, one-third were female and two-thirds were males. This suggests that brain involvement in COVID-19 could be more common in older males. More research is needed but these findings show us these are areas to focus on as we move forward.
Dr. Zulfi Haneef, assistant professor of neurology/neurophysiology at Baylor.
Approximately one-third of the patients in the review had EEG Scan abnormalities within the frontal lobe of the brain. Dr. Zulfi Haneef believes this is likely due to the virus gaining an entry through the nose and thus affecting the brain at a location next to the entry point.
Implications of the Findings
Approximately 69% of the patients’ EEG findings showed diffuse slowing which generally occurs due to cerebral pathology. It is characterized by slowing or impairment of memory, attention, and awareness. Certain sedatives, neurodegenerative disorders, and brain infections can result in diffuse slowing.
Factors such as the severity of the disease, duration of monitoring, and pre-existing neurological conditions, all directly correlate with the extent of EEG abnormalities.
However, abnormal EEG findings are not always the result of the virus gaining entry into the brain. According to Dr. Haneef, reduced oxygen supply due to cardiac complications of COVID-19 can also cause EEG abnormalities. Furthermore, it is important to note that some patients had pre-existing neurological conditions which can influence EEG results.
Due to the predominance of frontal lobe abnormalities in patients, it is proposed as a potential biomarker for COVID-19 encephalopathy. Furthermore, the authors of the study suggest hospitals perform more imaging studies along with EEG scans. This is to clarify whether these abnormalities only occur in hospitalized patients or also in people with mild symptoms.
Reference:
Arun Raj Antony, Zulfi Haneef, Seizure: European Journal of Epilepsy, https://doi.org/10.1016/j.seizure.2020.10.014
Mao L, Jin H, Wang M, Hu Y, Chen S, He Q, et al. Neurologic manifestations of hospitalized patients with coronavirus disease 2019 in Wuhan, China. JAMA Neurol 2020;77:683–90. https://doi.org/10.1001/jamaneurol.2020.1127.
