Public Release: 

Monell Center awarded grant to evaluate role of nasal airflow obstruction in smell loss

New technology may help surgeons predict chance of reversing anosmia

Monell Chemical Senses Center

PHILADELPHIA (January 22, 2015) - Monell Center scientist Kai Zhao, PhD, is principal investigator on a $1.5M 4-year grant from the National Institute on Deafness and Other Communication Disorders (NIDCD), part of the National Institutes of Health, to further develop clinical methodology that can predict the path of air flow through a person's nasal passages. The methodology may someday help physicians evaluate treatment outcomes for patients undergoing surgery to reverse nasal obstruction and associated loss of smell (anosmia).

"Our proposed research intends to validate a clinical tool that can determine whether blockage of nasal airflow contributes to a patient's smell loss," said Zhao, a biological engineer at Monell. "This knowledge will assist both patients and clinicians in planning effective treatment options and potentially save millions of dollars in healthcare costs each year by eliminating unnecessary surgeries."

The project adds to the Monell Center's expanding list of research focused on anosmia, the clinical term for lack of the sense of smell. Anosmia has several causes, including physical nasal obstruction due to chronic nasal sinus disease. Such obstruction, which can be caused by inflamed tissues, polyps, or other physical causes, is thought to block airflow, thus preventing odor molecules from reaching smell receptors high inside the nose.

Approximately one quarter of anosmia cases are related to chronic nasal sinus disease, which affects an estimated 30 million people in the United States each year, making it one of the country's most common medical conditions.

Patients with nasal sinus disease often report congestion and accompanying feelings of airflow blockage or obstruction. However, in earlier studies, Zhao and his collaborators found that self-reports of airflow blockage often are not related to airflow resistance from physical obstruction, but may instead be due to abnormal sensory feedback from within the nose.

The new studies funded by the NIDCD grant will use computational fluid dynamics (CFD) modeling, a branch of physics originally developed to predict fluid movement through complex passageways. Zhao previously has shown that CFD methodology can be applied to a CAT scan of a person's upper airways to predict nasal airflow patterns, which vary appreciably from person to person.

In a 2014 paper, Zhao and his collaborators used their CFD model in patients with chronic nasal sinus disease to relate nasal airflow patterns with olfactory loss. The study revealed that CFD can help determine whether smell loss in these patients is associated with blocked airflow.

Now, Zhao and fellow researchers from Monell are teaming with clinicians from the University of Pennsylvania and Thomas Jefferson University to assess the clinical effectiveness of CFD modeling in predicting surgical outcomes.

The new studies will evaluate whether CFD methodology allows physicians to better predict the chances of restoring the sense of smell when operating to remove blockages. Prior to surgery, CFD modeling will allow a surgeon to evaluate which nasal blockages could be contributing to the patient's loss of smell. For patients whose anosmia actually is related to a nasal obstruction, pinpointing the responsible blockage should lead to targeted surgery with better success rates for restoring the sense of smell.

Similarly, surgery to alleviate complaints of nasal obstruction independent of smell loss will likely be more successful when it is possible to identify beforehand whether the contributing factor is due to blockage rather than sensory-based.

Other investigators on the grant include Pamela Dalton, PhD, and Bruce Bryant, PhD, from Monell; Noam Cohen, MD, PhD, David Kennedy, MD, James Palmer, MD, and Nithin Adappa, MD, from the University of Pennsylvania; Edmund Pribitkin, MD, from Thomas Jefferson University; and Issa Zakeri, PhD, from Drexel University. The grant, entitled "Objective evaluation of conductive olfactory losses & nasal obstruction symptoms," is funded by NIH DC013626-01A1.

In 2014, the Monell Center launched "A Sense of Hope: The Monell Anosmia Project," a three-year campaign to support a research and advocacy program focused on anosmia, which affects six million Americans and many more worldwide. The research goal is to identify the biological causes of anosmia in order to develop potential treatment approaches for this under-recognized condition. Other ongoing research includes studies to develop fundamental knowledge of how to isolate, grow, and transplant human olfactory stem cells. A third focus involves sequencing DNA from individuals with hereditary anosmia and their relatives in an effort to identify the genetic basis underlying some forms of anosmia.

"Dr. Zhao's novel research demonstrates the Monell Center's commitment to understanding the causes of anosmia so that we can develop effective treatments for this pervasive disease," said Monell Director Robert F. Margolskee, MD, PhD. "We are proud of how 'A Sense of Hope' has grown over its first year and will add yet more research on anosmia as we increase our funding base."


Monell has incorporated educational material about anosmia into its website, including an explanation of what is known about the underlying biologic causes of smell loss and information on the limited treatment options currently available. To learn more about anosmia, visit

The Monell Chemical Senses Center is an independent nonprofit basic research institute based in Philadelphia, Pennsylvania. For over 46 years, Monell has advanced scientific understanding of the mechanisms and functions of taste and smell to benefit human health and well-being. Using an interdisciplinary approach, scientists collaborate in the programmatic areas of sensation and perception; neuroscience and molecular biology; environmental and occupational health; nutrition and appetite; health and well-being; development, aging, and regeneration; and chemical ecology and communication. For more information about Monell, visit

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