Headache and brain fog are the most frequent and persistent symptoms in a cohort of neurological post-COVID-19 patients, regardless of the severity of the acute infection.

Objectives: Neurological symptoms are increasingly recognized as part of the clinical spectrum of COVID-19, both during the acute phase and in the post-acute phase, some- times persisting over time and configuring a neurological phenotype of Long COVID. The aim of this study was to establish a standardized Regional Registry to collect data from individuals diagnosed with COVID-19 who experienced neurological manifestations, in order to estimate the frequency, types, and prognostic impact of neurological involvement related to SARS-CoV-2 infection. The ultimate goal was to deepen understanding of NeuroCOVID and contribute to the improvement of clinical management and the development of future care strategies. Materials and Methods: A standardized Regional Registry was created to collect demographic, clinical, and instrumental data from patients with a confirmed diagnosis of COVID-19 and neurological symptoms that emerged either during hospitalization or in the outpatient setting, both in the acute phase and at follow-up. Results: At the enrolling center in Florence (AOU Careggi), 76 patients were included (53% male, mean age 54±13 years). Multiple comorbidities were present in 80% of patients. The most common neurological symptoms were cognitive deficits (67%), anosmia/dysgeusia (26%), headache (22%), and sensory disturbances/ paresthesias (28%). Some of these symptoms, such as hyposmia/ageusia and sensory disturbances, showed partial or complete resolution at 1-year follow-up. Others, particularly cognitive deficits and headache, tended to persist over time. Cognitive deficits often presented as subjective, nonspecific complaints referred to as "brain fog", which were not always confirmed by neurological examination or global cognitive screening tests (MMSE, MOCA). The frequency of these symptoms was similar in hospitalized and non-hospitalized patients. Discussion: Neurological symptoms are a frequent and clinically significant component of SARS-CoV-2 infection, presenting with heterogeneous patterns. Our data show that while some symptoms may be mild and reversible, others may result in persistent functional impairment up to one year after infection. Among these, brain fog and headache were the most frequent and long- lasting, regardless of the initial severity of COVID-19. Conclusion: These findings support the need for careful neurological monitoring in COVID-19 patients and for targeted, long-term follow-up, given the possibility that these symptoms may persist and negatively impact quality of life and functional performance.