1 INTRODUCTION
Olfaction is an important sense of organisms that can regulate emotions,
affect cog-nition and behaviour1,2, and also remind us
of dangers in the environment3. It can be imp-aired by
chronic rhinosinusitis, head trauma, infections, ageing, long-term
smoking, alco-holism, metabolic diseases, and autoimmune
diseases4. Olfactory dysfunction can signifi-cantly
affect patients’ quality of life5, and it is an early
marker of neurodegenerative dise-ases such as Alzheimer’s disease and
Parkinson’s disease6,7.
The diagnosis and classification of olfactory dysfunction mainly depend
on olfacto-ry psychophysical tests such as the Sniffin’ Sticks
test8, the Connecticut Chemosensory Clinical Research
Center test9, the University of Pennsylvania Smell
Identification Test10, T&T test11,
and so on. Among them, the Sniffin’ Sticks test has been the most widely
us-ed. The test comprises an olfactory threshold test, olfactory
discrimination test, and olfa-ctory identification test (SSOI test).
According to the research of Chrea et al.12,
differences in culture, customs, and other factors in different
countries and regions can lead to different people’s familiarity with
th-e same smell. When subjects receive olfactory identification tests
that are not suitable for their region, they may be unfamiliar with the
odor itself or its distractors, which may aff-ect the results of
olfactory tests. Therefore, many researchers designed olfactory test
met-hods suitable for local people by changing odors and distractors.
Among them, the modi-fied scheme for the Sniffin’ Sticks test is the
most common. Dozens of countries and reg-ions, including Spain,
Malaysia, Congo, and Turkey, have put forward the modified sche-me for
the Sniffin’ Sticks test suitable for local people13-16.
In recent years, some researchers in China also have been committed to
putting for-ward modified schemes of olfactory tests suitable for
Chinese people. The Institute of Ps-ychology of the Chinese Academy of
Sciences and the Beijing Anzhen Hospital, Affiliat-ed with Capital
Medical University, have put forward the modified scheme of olfactory
t-ests suitable for Chinese people, CSIT and
COIT17,18. Although these two modified sche-mes used
odors familiar to Chinese people to modify the olfactory identification
test, the-y ignored two problems. First, both schemes only changed some
odors but did not adjust the distractors of other options. Second,
researchers mostly choose pleasant or neutral od-ors instead of
unpleasant odors in most olfactory test modification schemes, including
th-ese two modification schemes. The warning function is an important
olfactory function, and most of the odors with warning functions are
unpleasant odors, such as burnt smell in case of fire, special smells in
case of natural gas leakage, etc.
To detect the olfactory function of subjects more comprehensively, it is
necessary to introduce some unpleasant odors with warning function into
olfactory tests. In this study, we modified the distractors in an
olfactory identification test appropriately, and some un-pleasant odors
with warning functions were introduced to modify the olfactory
identifica-tion test. We aimed to design the Chinese Modified Olfactory
Identification (CMOI) test based on the SSOI test and to present
participants’ sensitivity to unpleasant
odors.
2MATERIALS
AND METHODS
For the development of this report, the STROBE guide for observational
studies has been followed.