Each year, an estimated two million individuals experience a traumatic brain injury (TBI) in the United States, with many experiencing cognitive difficulties such as memory impairment, challenges in focusing, and problem solving. TBI can be classified as mild (mTBI), moderate, or severe, but all have been associated with self-reported cognitive challenges, with varying degrees of severity. The self-reported symptom of “brain fog” has become increasingly relevant in recent years, as it also has been used to describe the lack of mental clarity commonly associated with COVID-19. Clinicians have previously noted brain fog as a key diagnostic symptom of mTBI, as well as a significant health challenge for those who experience it.
Because the field of TBI research lacks a consistent definition of brain fog, most existing TBI studies have focused instead on related symptoms, such as impairment in memory and concentration. To address this gap in the literature, a team of researchers conducted a study using individuals with mTBI, moderate-to-severe TBI, and healthy controls. All participants were evaluated for symptoms of depression, post-concussion syndrome, and brain fog using the Mental Clutter Scale.
The study found that individuals with symptomatic mTBI and moderate-to-severe TBI reported increased brain fog as compared to healthy controls, which did not differ significantly by TBI severity. Brain fog was strongly correlated with depression in individuals with mTBI but not those with moderate-to-severe TBI. Despite the association of brain fog with depressive symptoms for mTBI, there were few associations between brain fog and other objective measures of cognition, suggesting that depressive symptoms may contribute to cognitive impairment.
The results of this study indicate that brain fog may have both biological and psychological origins and can be a valid measure in TBI outcomes. These results suggest that brain fog is a useful clinical tool for understanding patients’ own perception of their cognitive abilities, as well as their risk for developing depressive symptoms. Brain fog has been largely overlooked despite being a common symptom of TBI, and should be considered by clinicians as both a diagnostic measure, as well as an indicator of residual functional concerns for patients in TBI recovery.
Bell T, Crowe M, Novack T, et al. Severity and correlates of brain fog in people with traumatic brain injury. Research in Nursing & Health. (November 2022).