The study authors wanted to further understand post-COVID-19 infection “brain fog” and sought a new name for the phenomenon.
A small study showed that dementia progressed rapidly following infection with COVID-19, according to an article published in the Journal of Alzheimer's Disease Reports.
The ambiguous “brain fog” terminology is typically used to describe this phenomenon or feeling of memory loss and fatigue following COVID-19 infection, but the study authors proposed a new term in their paper for it: “FADE-IN MEMORY” (Fatigue, and decreased Fluency, Attention deficit, Depression, Executive dysfunction, slowed INformation processing speed, and subcortical MEMORY impairment).
Investigators from India studied 14 patients to assess this “brain fog” in terms of cognitive functioning and neuroimaging in patients with pre-existing dementia following COVID-19 infection. The cohort included 4 patients with Alzheimer’s disease, 5 with vascular dementia, 3 with Parkinson’s disease, and 2 with what the study authors described as the behavioral variant of frontotemporal dementia.
Most of the existing studies that explore the relationship between COVID-19 and “brain fog” have examined previously healthy individuals who did not experience any cognitive decline prior to their infection, the study authors said. Many symptoms described in these such studies include decreased attention and concentration, executive dysfunction, memory impairment, and delay in information processing speed. Studies like these were the impetus behind the study authors’ desire to evaluate these effects in patients with pre-existing dementia.
“The most noteworthy observation was that all 14 (100%) patients, 1 year after SARS-CoV-2 infection, had fatigue, depression, objective attention/concentration difficulties, executive dysfunctions, slowed information processing speed, and sub-cortical type memory impairments, irrespective of their previous cognitive status,” the study authors wrote.
The mean age of the patients with pre-existing dementia was 65 years. Most of the patients (10 of 14) required hospitalization during their follow-up period, but none of them had a stroke.
Following COVID-19 infection, these patients experienced a significant increase in measures of fatigue and depression, while there was a worsening in attention, memory, fluency, language, and visuospatial measures. After neuroimaging, the investigators determined there was an increase of periventricular white matter and deep white matter hyperintensities, and global cortical atrophy in these patients.
The study authors were able to match some of the cognitive decline to specific patterns in dementia diseases. For example, they wrote that fatigue is a predominant symptom of multiple sclerosis and is considered a new symptom of dementia. Fatigue following COVID-19 could suggest similarities between multiple sclerosis and COVID-19. After looking at the patients’ MRIs, the investigators found that all of them had white matter hyperintensities involving periventricular deep white matter which mimicked lesions observed in multiple sclerosis, too.
Depression was also observed in the dementia/post-COVID patients, but the study authors noted that depression can be impacted by several other factors including loss, loneliness, financial burden, and uncertainty. These factors were found across different studies, they added.
“We saw that rapid progression of dementia, the addition of further impairments/deterioration of cognitive abilities (mostly subcortical type), and increase or new appearance of white matter lesion burden were common in our patients, irrespective of dementia type, the severity of COVID-19, presence of vascular risk factors, oxygen or ventilator support,” the study authors wrote.
The investigators concluded that psychological factors such as depression, loneliness, uncertainty, loss, fear, and others should be further assessed for their impact on cognitive abilities.