Objective We characterized the evolution of neurologic symptoms and self‐perceived recovery of non‐hospitalized COVID‐19 “long haulers” 6–9 months after their initial Neuro‐COVID‐19 clinic evaluation. Methods In this follow‐up study on the first 100 patients, 50 SARS‐CoV‐2 laboratory‐positive (SARS‐CoV‐2 + ), and 50 laboratory‐negative (SARS‐CoV‐2 − ), evaluated at our Neuro‐COVID‐19 clinic between May and November 2020, patients completed phone questionnaires on their neurologic symptoms, subjective impression of recovery and quality of life. Results Of 52 patients who completed the study (27 SARS‐CoV‐2 + , 25 SARS‐CoV‐2 − ) a median 14.8 (range 11–18) months after symptom onset, mean age was 42.8 years, 73% were female, and 77% were vaccinated for SARS‐CoV‐2. Overall, there was no significant change in the frequency of most neurologic symptoms between first and follow‐up evaluations, including “brain fog” (81 vs. 71%), numbness/tingling (69 vs. 65%), headache (67 vs. 54%), dizziness (50 vs. 54%), blurred vision (34 vs. 44%), tinnitus (33 vs. 42%), and fatigue (87 vs. 81%). However, dysgeusia and anosmia decreased overall (63 vs. 27%, 58 vs. 21%, both p < 0.001). Conversely, heart rate and blood pressure variation (35 vs. 56%, p = 0.01) and gastrointestinal symptoms (27 vs. 48%, p = 0.04) increased at follow‐up. Patients reported improvements in their recovery, cognitive function, and fatigue, but quality of life measures remained lower than the US normative population ( p < 0.001). SARS‐CoV‐2 vaccination did not have a positive or detrimental impact on cognitive function or fatigue. Interpretation Non‐hospitalized COVID‐19 “long haulers” continue to experience neurologic symptoms, fatigue, and compromised quality of life 14.8 months after initial infection.

Background and ObjectivesAlthough patients hospitalized with COVID-19 frequently present with encephalopathy, those with mild initial COVID-19 disease who never required hospitalization also often develop neurologic symptoms as part of postacute sequelae of severe acute respiratory coronavirus type 2 (SARS-CoV-2) infection (neuro-PASC). The pathogenic mechanisms of COVID-19 encephalopathy and neuro-PASC are unknown. We sought to establish biochemical evidence of CNS injury in those patients and their association with neuropsychiatric manifestations and SARS-CoV-2 antigenemia.MethodsWe recruited hospitalized, posthospitalized, and nonhospitalized patients with confirmed diagnosis of COVID-19 with neurologic symptoms in addition to healthy control (HC) subjects. Plasma neurofilament light chain (pNfL), plasma glial fibrillary acidic protein (pGFAP), and plasma SARS-CoV-2 Nucleocapsid antigen (pN Ag) were measured by HD-X Simoa analyzer (Quanterix) and compared with neuropsychiatric symptoms, patient-reported quality-of-life measures, and standardized cognitive assessments. Neuroglial scores (pGFAP/pNfL) were calculated to estimate the relative contribution of astroglial and neuronal involvement.ResultsWe enrolled a total of 64 study participants, including 9 hospitalized patients with COVID-19 encephalopathy (CE), 9 posthospitalization neuro-PASC (PNP) patients, 38 nonhospitalized neuro-PASC (NNP) patients, and 8 HC subjects. Patients with CE were older, had higher pNfL and pGFAP concentrations, and more frequent pN Ag detection than all neuro-PASC groups. PNP and NNP patients exhibited similar PASC symptoms, decreased quality-of-life measures, and cognitive dysfunction, and 1 of the 38 (2.6%) NNP patients had pN Ag detectable 3 weeks postsymptoms onset. Patients with neuro-PASC presenting with anxiety/depression had higher neuroglial scores, which were correlated with increased anxiety on quality-of-life measures.DiscussionpNfL, pGFAP, and pN Ag measurements indicate neuronal dysfunction and systemic involvement in hospitalized COVID-19 patients with encephalopathy. Detection of SARS-CoV-2 N Ag in blood 3 weeks after symptoms onset in a nonhospitalized patient suggests that prolonged antigenic stimulation, or possibly latent infection, may occur. Anxiety was associated with evidence of astroglial activation in patients with neuro-PASC. These data shed new light on SARS-Cov-2 neuropathogenesis and demonstrate the value of plasma biomarkers across the COVID-19 disease spectrum.

SUMMARY Compelling evidence links amyloid beta (Aβ) peptide accumulation in the brains of Alzheimer’s disease (AD) patients with the emergence of learning and memory deficits; yet a clear understanding of the events that drive this synaptic pathology are lacking. We present evidence that neurons exposed to Aβ are unable to form new synapses, resulting in learning deficits in vivo. We demonstrate the Nogo receptor family (NgR1-3) act as Aβ receptors mediating an inhibition of synapse assembly, plasticity and learning. Live imaging studies reveal Aβ activates NgRs on the dendritic shaft of neurons triggering an inhibition of calcium signaling. We define T-type calcium channels as a target of Aβ-NgR signaling, mediating Aβ’s inhibitory effects on calcium, synapse assembly, plasticity and learning. These studies highlight deficits in new synapse assembly as a potential initiator of cognitive pathology in AD, and pinpoint calcium dysregulation mediated by NgRs and T-type channels as key components.