A recent study has revealed that chemosensory loss due to the coronavirus disease or COVID-19 appears to recover partially or substantially with time. Recovery process is impacted by age and the degree of chemosensory loss.
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What Is Chemosensory Loss?
Chemosensory loss
is defined as the loss or distortion of the sense of smell and/or taste. The
ability to smell and taste start when molecules of substances stimulate sensory
cells high inside the nose called the olfactory nerve cells or food and
beverage stimulate the taste buds of the mouth or throat called the gustatory
nerve cells. Stimulated sensory cells send out messages to the brain to
identify as a particular taste or smell.
Current clinical study has concluded that the onset of
symptoms of loss of smell and taste, that is correlated with COVID-19, takes
place 4 to 5 days after other symptoms, and that these symptoms would last from
7 to 14 days. Outcomes, however, differed and there is a need for further
studies to clarify the existence of these symptoms.
Experts extracted their data from the Global Consortium
of Chemosensory Research or GCCR, which is a crowdsourced online study that
looks at self-reported smell, taste, and nasal blockage, among other factors,
in participants with respiratory diseases. The survey responses from 974
patients with confirmed or suspected COVID-19 were covered and evaluated for
chemosensory loss and recovery.
A rating scale of 0-100 was utilized to quantify
smell, taste, and chemesthesis, and were compared between pre- and post-
disease states. The respective average ratings while sick with COVID-19 were
11.90, 20.39, and 40.81. Following the resolution of symptoms, scores improved
to 53.05, 60.75, and 69.52, correspondingly.
But, such improvement observed was not homogenous,
with the two main recovery profiles emerging: partial (48.6%) and substantial
(51.64%). The participants with partial recovery of chemosensation inclined to
be older and had been infected earlier than counterparts who attained a
substantial recovery.
A clustering analysis further unveiled that the degree
of chemosensory loss impacted the path to recovery. For example, most patients
with moderate smell/taste of loss yet preserved chemesthesis experienced a
partial recovery. However, those who had substantial loss of all 3
chemosensations revealed the highest rate of recovery.
Researchers said that, “Our work provides indications
on the recovery process on which we shaped a scientific-based approach for the healthcare
professionals to characterize the clinical picture of patients reporting
chemosensory loss due to COVID-19 infection.”
Source: Sci Rep 2021;11:17504