Olfactory and gustatory dysfunctions in COVID-19 outpatients: A prospective cohort study

OBJECTIVES

To describe the characteristics, evolution and risk factors for long-term persistence of olfactory and gustatory dysfunctions (OGD) in COVID-19 outpatients.

PATIENTS AND METHODS

We conducted a prospective study in SARS-CoV-2 infected outpatients with OGD. Weekly phone interviews were set up starting from COVID-19 onset symptoms and over the course of 60 days, using standardized questionnaires that included a detailed description of general symptoms and OGD. The primary outcome was the proportion of patients with complete recovery of OGD at D30. Rate and time to recovery of OGD, as well as risk factors for late recovery (>30 days), were evaluated using Cox regression models.

RESULTS

Ninety-eight outpatients were included. The median time to onset of OGD after first COVID-19 symptoms was 2 days (IQR 0-4). The 30-day recovery rate from OGD was 67.5% (95% CI 57.1-75.4) and the estimated median time of OGD recovery was 20 days (95% CI 13-26). Risk factors for late recovery of OGD were a complete loss of smell or taste at diagnosis (HR=0.26, 95% CI 0.12-0.56, P=0.0005) and age over 40 years (HR=0.56, 95% CI 0.36-0.89, P=0.01).

CONCLUSIONS

COVID-19 patients with complete loss of smell or taste and over age 40 are more likely to develop persistent OGD and should rapidly receive sensorial rehabilitation.

Multimodal neurometabolic investigation of the effects of zolpidem on leukoencephalopathy-related apathy

BACKGROUND AND PURPOSE

The symptomatic effect of zolpidem on apathy has been reported in neurological disorders such as strokes and post-anoxic brain injuries, but not in white-matter disease of the brain.

METHODS

A 38-year-old patient presenting with severe apathy related to a genetic leukoencephalopathy but showing marked improvement of apathy after taking 10 mg of zolpidem was studied. To understand what may mediate such a clinical effect, a multimodal neurometabolic approach using ¹⁸ F fluorodeoxyglucose positron emission tomography (FDG-PET) and a dedicated magnetic resonance spectroscopy (MRS) sequence for gamma aminobutyric acid (GABA) and glutamine + glutamate metabolism was undertaken.

RESULTS

Pre-zolpidem FDG-PET showed hypometabolism in the orbitofrontal cortex, dorsolateral cortex and basal ganglia compared to healthy controls. Post-zolpidem, FDG-PET displayed increased metabolism in the orbitofrontal cortex together with improvement in the emotional and auto-activation domains of apathy. There was no improvement in the cognitive domain of apathy, and no change in metabolism in the dorsolateral frontal cortex. Post-zolpidem, MRS showed increased GABA and glutamine + glutamate levels in the frontal cortex and pallidum.

CONCLUSION

Our multimodal neurometabolic study suggests that the effects of zolpidem on apathy are related to increased metabolism in the orbitofrontal cortex and basal ganglia secondary to GABA modulation. Zolpidem may improve apathy in other white-matter disorders.