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Objectives: To describe clinical characteristics, hospitalization flow and outcomes in a cohort of patients with coronavirus disease 2019 (COVID-19) in a Brazilian hospital in the first and second waves of the pandemic. Methods: This retrospective, observational study included patients with confirmed COVID-19 who were evaluated in the emergency department (ED) between 1 March 2020 and 30 June 2021. Descriptive statistics have been used to report clinical characteristics, admissions and outcomes. Comparison between the two waves was inferred using hypothesis test techniques. Results: During the study period, 7723 (86.54%) patients were evaluated in the ED, of which 1908 (24.70%) were admitted. Of these, 476 (24.95%) patients were initially allocated to the intensive care unit (ICU) and 1432 (75.05%) to the general ward. Of the patients initially allocated to the general ward, 349 (24.37%) were later transferred to the ICU. One hundred and fifty-eight patients were intubated (19.15% of ICU admissions) and 110 patients died (5.77% of all admissions). In the second wave, the admission rates decreased in both the ICU (from 13.84% to 9.56%; P<0.01) and the general ward (from 22.41% to 17.16%; P<0.01). The average age in the second wave decreased from 44.06 to 41.87 years (P<0.01). Patients with severe symptoms, such as dyspnoea, decreased from 25.51% to 13.13% (P<0.01) in the second wave. The death rate among admitted patients decreased by 17.84% (from 6.52% to 5.38%; P<0.01). Conclusion: Despite the greater number of patients in the second wave, the admission and death rates were lower compared with the first wave. The mean age of patients was lower in the second wave, and patients arrived at the hospital with less severe symptoms compared with the first wave.
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Background: How the prefrontal cortex (PFC) recovers its functionality following lesions remains a conundrum. Recent work has uncovered the importance of transient low-frequency oscillatory activity (LFO; < 4 Hz) for the recovery of an injured brain. We aimed to determine whether persistent cortical oscillatory dynamics contribute to brain capability to support 'normal life' following injury. Methods: In this 9-year prospective longitudinal study (08/2012-2021), we collected data from the patient E.L., a modern-day Phineas Gage, who suffered from lesions, impacting 11% of his total brain mass, to his right PFC and supplementary motor area after his skull was transfixed by an iron rod. A systematic evaluation of clinical, electrophysiologic, brain imaging, neuropsychological and behavioural testing were used to clarify the clinical significance of relationship between LFO discharge and executive dysfunctions and compare E.L.´s disorders to that attributed to Gage (1848), a landmark in the history of neurology and neuroscience. Findings: Selective recruitment of the non-injured left hemisphere during execution of unimanual right-hand movements resulted in the emergence of robust LFO, an EEG-detected marker for disconnection of brain areas, in the damaged right hemisphere. In contrast, recruitment of the damaged right hemisphere during contralateral hand movement, resulted in the co-activation of the left hemisphere and decreased right hemisphere LFO to levels of controls enabling performance, suggesting a target for neuromodulation. Similarly, transcranial magnetic stimulation (TMS), used to create a temporary virtual-lesion over E.L.'s healthy hemisphere, disrupted the modulation of contralateral LFO, disturbing behaviour and impairing executive function tasks. In contrast to Gage, reasoning, planning, working memory, social, sexual and family behaviours eluded clinical inspection by decreasing LFO in the delta frequency range during motor and executive functioning. Interpretation: Our study suggests that modulation of LFO dynamics is an important mechanism by which PFC accommodates neurological injuries, supporting the reports of Gage´s recovery, and represents an attractive target for therapeutic interventions. Funding: Fundação de Amparo Pesquisa Rio de Janeiro (FAPERJ), Universidade Federal do Rio de Janeiro (intramural), and Fiocruz/Ministery of Health (INOVA Fiocruz).