Non Invasive Smell Aids Tested in Clinical Trial: May Offer Some Improvement to Olfactory Ability
By Stephanie Feuer
A pair of non-invasive smell aids may improve the ability to smell according to the results of a recent clinical trial. Researchers from Ohio State University tested a nasal plug and a nasal clip designed to improve intranasal air and odorant delivery. The results,reported in BMC Medicine, show some promise.
The “Smell Aids”
Researchers tested smell sensitivity with two devices: a "pinch" and a "nasal plug." The pinch was a nasal clip, similar to those used by swimmers, that pinches a nasal valve area and intensifies nasal airflow. The plug was a prototype made from foam ear plugs that redirects air and odor flow to the nasal cavity.
Study Design
Fifty-eight normosmic people and 54 patients with acquired smell loss participated in the trial. Participants without smell loss sniffed two bottles and had to identify which bottle contained the odor. The patients with smell deficits were tested with a nine odor scratch and sniff test.
Smell Loss Subject Breakdown
Of the subjects with smell deficits, 69% suffered from post-COVID olfactory dysfunction, including parosmia The remaining had loss or distorted sense of smell due to head trauma, head and neck cancer and surgery, or nasal polyps.
Key Results for Patients with Smell Loss
Overall, both smell aids improved patients' ability to identify odors:
Baseline score: 4.30 ± 2.27
With pinch device: 4.82 ± 2.06 (improvement of 0.52 points)
With nasal plug: 5.11 ± 2.32 (improvement of 0.81 points)
The nasal plug device worked better than the pinch device
For COVID long haulers, only the nasal plug showed significant improvement
Non-COVID patients had worse baseline smell scores than COVID long haulers
Patients with diminished smell had worse scores than those with distorted smell
Healthy Subject Breakdown
Subjects were divided into two groups - normal and super smeller - based on a baseline smell sensitivity test.
Key results for Normosmic Subjects
There was a significant correlation between baseline smell sensitivity and improvement with devices
People with less sensitive smell at baseline showed greater improvement
Normal sensitivity group showed significant improvements:
Baseline score: 12.49 ± 2.8
With pinch device: 14.73 ± 5.44 (improvement of 2.24 points)
With nasal plug upwards: 14.42 ± 4.87 (improvement of 1.93 points)
Super smeller group did not show significant improvements with either device
Key Takeaways
Overall, the trial indicates that modulating intranasal airflow may support increased olfactory ability. One key question the study did not address is if the effectiveness of nasal pinches or plugs would vary with particular nasal anatomy.
Still, researchers are optimistic that this avenue will lead to a non-invasive way to treat smell loss. Kai Zhao, PhD, professor in the Ohio State Department of Otolaryngology said “The smell aids our team developed hold the promise of becoming effective, over-the-counter therapies like eyeglasses and hearing aids.”
