Discussions:
In the contemporary COVID-19 era, the local burden of POD increased a
surprising two-fold. Thus, COVID-19-related POD has indeed caused a
non-negligible threat to the quality of life of the affected, as well as
the Japanese public health system. Surprisingly, 5 of 7 COVID-19
patients lacked an acute diagnosis and were later diagnosed
serologically. This may reflect the local situation in Japan, which once
faced a severe shortage of molecular diagnostics. Comparisons to
preceding findings from the UK, also indicated that seroprevalence of
the COVID-19-related impairment in the odor sensation5had relied on subjective assessment of impairment lacking quantitative
data. Our findings confirmed the previously reported magnitude of an
increase in the disease burden, by further using robust indices of both
qualitative and quantitative features (SAOQ, OE, IO).
The intranasal trigeminal system, like the gustatory system, is now
recognized as a frequent neuronal target of the
SARS-CoV-26. OE, which is widely used in Japan,
contains menthol as one of the 12 odorants and allows for the screening
of any coexisting intranasal trigeminal dysfunction. In line with
previous research, non-recognition of the cooling sensation in menthol,
which is an expression of trigeminal dysfunction, rather than olfactory
dysfunction, was more commonly observed in our cohort of patients with
COVID-19-related POD. However, some participants reported a subjective
improvement in their POD during interviews, despite inconsistent
unimprovement in the OE scoring. This could be due to the patient’s
difficulty in distinguishing trigeminal sensation from olfaction. Thus,
assessing POD in the clinic must use pleiotropic approaches and robust
measures. The prognostic value of differentiating the POD etiologies in
the era of COVID-19 shall be studied further in the future.