Hypoechogenicity of brainstem raphe in long-COVID syndrome–less common but independently associated with depressive symptoms: a cross-sectional study

Abstract

Objective: Long coronavirus disease (Long-COVID) syndrome is a hitherto poorly understood phenomenon with a broad spectrum of symptoms, including depression and anxiety. Depressive symptoms have been associated with brainstem raphe (BR) alterations in transcranial sonography (TCS) that might reflect dysfunction of the serotonergic system. The primary aim was to investigate the connection of BR alterations with depressive and anxiety symptoms in patients with Long-COVID syndrome. Methods: In a cross-sectional study design, we included outpatients fulfilling the criteria of Long-COVID syndrome. All patients were examined by TCS in the axial plane with focus on BR signal alterations. The Hospital Anxiety and Depression Scale (HADS) was used to test for symptoms of anxiety and depression. Results: We included n = 70 patients with Long-COVID syndrome, of which 28.6% (n = 20) exhibited a reduced echogenicity of BR in the TCS examination. Patients with hypoechogenic BR had higher subscores for anxiety and depression compared to normoechogenic patients (HADS depression: median 8 versus 5.5, p = 0.006; HADS anxiety: median 9 versus 6.5, p = 0.006). After adjustment for reasonable confounders, only the odds ratio (OR) for relevant depressive symptoms was higher among Long-COVID patients with hypoechogenic raphe (adjusted OR 3.884, 95% CI 1.244–12.123). Discussion: Hypoechogenic BR alterations are independently associated with depressive symptoms in Long-COVID patients but are not highly frequent. Future studies should investigate whether the hypoechogenicity of the BR is a direct consequence or whether it reflects a priori a higher susceptibility to depressive symptoms after COVID-19, thus enabling to identify COVID-19 patients at higher risk of developing Long-COVID depressive symptoms.