New Term Request - Parosmia

[danteXmachina]

Preferred term label: Parosmia

Synonyms Olfaction Disorder Smell Disorders Smell Disorder Cacosmia Cacosmias Dysosmia Dysosmias Paraosmia Paraosmias Smell Dysfunction Dysfunction, Smell Olfactory Impairment Impairment, Olfactory

References: https://www.ncbi.nlm.nih.gov/mesh/?term=parosmia, MeSH Unique ID: D000857

Definition (free text, please give PubMed ID) Inability of the brain to properly identify an odors natural smell. Distinct from anosmia (PMID: 32741085) and hyposmia (PMID:31356735) , parosmia has been identified as a post-infectious consequence of olfactory nerve injury by respiratory tract pathogens (PMID: 33210732), including SARS-CoV-2 (PMID: 32605712). Parosmia can arise by incomplete or aberrant regeneration of the injured olfactory nerves (PMID:31356735), or by defects in the central processing hubs of olfactory input independently of hyposmia (PMID: 31238309). Neurodegenerative causes of parosmia include network degeneration extending from the olfactory nerve to its projections in hippocampi and cortical grey matter (PMID: 21241781). As a symptom, parosmia is coincident with several neurological disorders including dementias (PMID: 33240192).

See also: https://www.ncbi.nlm.nih.gov/medgen/307133

Parent term (use hpo.jax.org/app)

Abnormality of the sense of smell

Diseases characterized by this term ? (e.g. Orphanet or OMIM number)

Upper respiratory tract infections PMID:31356735 COVID-19 PMID: 32605712 Alzheimer's disease PMID: 33240192

Please not that Orphanet and OMIM have not catalogued anosmia.

Your nano-attribution (ORCID)

ORCID: 0000-0002-0413-4028 , Google Scholar: https://scholar.google.com/citations?user=bYO5hS4AAAAJ&hl=en

[pnrobinson]

@danteXmachina it is unclear to me exactly what the clinical difference is. In the article cited above, the patient is described as having complete anosmia due to COVID-19 infection, but the authors then go on to call it parosmia, but it seems they are using it synonymously. We have been working on the long COVID phenotype (https://www.medrxiv.org/content/10.1101/2021.06.23.21259416v1), and from this I believe that COVID can be characterized by anosmia, hyposmia, and phantosmia -- is there anything else?

[danteXmachina]

@pnrobinson anosmia and hyposmia refer to complete or partial loss of the olfactory perception (i.e. quantitative disorders); phantosmia is olfactory perception without stimuli. Parosmia is altered olfactory perception in the presence of known stimuli, such as the smell of coffee; along with phantosmia, it is a qualitative disorder. It is clinically and phenomenologically distinct, and although bundled in with anosmia, it is separate clinical entity which involves cortical circuits, not just receptors. I've included two somewhat better references on COVID-19 and parosmia.

https://pmj.bmj.com/content/early/2021/03/31/postgradmedj-2021-139855 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8141364/

[danteXmachina]

@pnrobinson PS.: if it would help, I could summarize studies of parosmia (specifically) in COVID-19 as a mini review in a subsequent comment, and its associations with neurological complications in the LongCOVID spectrum. It's easy to do, and more or less our taskforce's fieldwork and its theoretical framework put into use (https://www.alz.org/aaic/downloads2021/COVID-19_and_Long-Term_Cognitive_Dysfunction.pdf)

[pnrobinson]

@danteXmachina -- I have added the term with the following definition: Misperception of existing odor, that is, distorted or altered olfactory perception in the presence of known stimuli. comment: Parosmia should be distinguished from anosmia (lack of sense of smell), hyposmia (reduced sense of smell), and phantosmia (olfactory perception without a stimulus).

Please contact me by email about the long COVID analysis! Here are my contact data https://robinsongroup.github.io/contact.html

[danteXmachina]

Thank you for the immediate response and the accurate representation of the term! I have sent an email at the indicated address.

Best,

George