Headache and cognitive disturbance correlate with ganglion cell layer thickness in patients who recovered from COVID-19.

BACKGROUND: Retinal abnormalities are being increasingly reported in COVID-19, in addition to the well-known symptoms of this disease accounting for the neurological involvement. In this study, we aimed to investigate whether ganglion cell layer thickness (GCLT) was different in recovered COVID-19 patients compared to controls in the subacute stage and to determine whether it correlated with COVID-19-related neurological symptoms or pneumonia. METHODS: This study involved 40 patients who had recovered from COVID-19 and 40 age- and sex-matched healthy controls. All the participants underwent ophthalmological examination, spectral domain optical coherence tomography and neurological examination. The clinical and biochemical properties of the patients were noted and their correlations with GCLT were sought. RESULTS: The duration after COVID-19 infection was 113 ± 62 (mean ± SD) days. At this subacute stage, there was no significant difference between the GCLT measurements of the COVID-19 patients and the controls (14 ± 4.0 µm [median ± IQR] vs 16 ± 4.8 µm, respectively). When we analyzed the relationships with neurological symptoms in the patient group, we found that patients with cognitive symptoms had lower GCLT values compared to those without (13 ± 3 µm vs. 16 ± 4 µm, respectively; p = 0.002). Patients who suffered headache during the acute infection also had lower GCLT values compared to those without (14 ± 4 µm vs. 18 ± 5 µm, respectively; p = 0.015). The GCLT values did not differ significantly with respect to anosmia, ageusia, sleep disturbances, having had COVID-19 pneumonia, or smoking status. Age, duration after COVID-19, and blood levels of thyroid stimulating hormone, glucose, vitamin D and vitamin B12 were not in correlation with GCLT in our study. CONCLUSION: Our findings highlight an association between GCLT values and neurological symptoms such as cognitive disturbance (brain fog) and headache in patients who had recovered after non-severe COVID-19 infection. Neuroretinal involvement by SARS-CoV2 might be linked to central neurological symptoms. The patients with lower GCLT values may benefit from close monitoring for neurological problems.

Subacute neurological sequelae in mild COVID-19 outpatients.

Introduction: Neurological aspect of COVID-19 is less understood compared to its respiratory and systemic effects. We aimed to define subacute neurological sequelae in patients who recovered from mild COVID-19. Materials and Methods: This study enrolled long COVID patients who had mild infection, were non-hospitalized, and admitted to our hospital with neurological complaints occurring after COVID-19. The evaluation included detailed history of the symptoms, neurological examination, blood tests and necessary investigations relevant to their personal medical situation, and also a retrospective inquiry about their respiratory and neurological status during the acute phase of infection. Descriptive statistical measures, Chi-square and Student's t-test were utilized. Result: We identified 50 patients (29F/21M) with a mean age of 36.9 ± 1.6 (mean ± SEM). The average time from COVID-19 to admission was 99 days(min-max= 15-247). Most frequent neurological complaints were headache (42%) and cognitive dysfunction (42%). Sleep disturbance (36%), prolonged anosmia (30%), prolonged ageusia (22%), fatigue (22%), and dizziness (8%) followed. Most patients with headache experienced headache also as an acute manifestation of COVID-19 (p= 0.02). Acute-stage sleep disorders were found to be more associated with subacute cognitive symptoms than other central symptoms (p= 0.008). The most common neurological symptom in the acute phase was headache (74%). Six patients, despite the absence of any acute-stage neurological symptoms, presented with emergence of subacute neurological sequela. There were only five patients with pulmonary involvement during the acute stage, who were not different from the rest of the cohort in terms of neurological sequelae. There was no increase of inflammatory markers in the blood tests at the subacute stage, or no association of the symptoms to biochemical parameters. Conclusions: This study gives a description of neurological sequelae of mild COVID-19 at the subacute stage, in a relatively young group, and reveals that cognitive disturbances, as well as headache, are quite frequent.