Smell test might help predict DMT effectiveness

Published 04 April 2022

A smell test could be used to tell whether treatments for multiple sclerosis (MS) are working or not, a new study suggests.

Researchers in Austria teste whether measuring olfactory threshold (OT) could be a way to detect whether a person is responding to a particular disease-modifying therapy (DMT). OT is a test of how sensitive to smells someone’s nose is. Experts have noted that OT can worsen when a person’s MS is active and there is inflammation in the brain, but generally remains unaffected while the disease is stable.

DMTs have been demonstrated to be effective overall in helping prevent relapses, but every person is individual and there is no easy way to tell if someone will respod to a particular therapy.

“There is an urgent need for biomarkers enabling a reliable and easy evaluation of the impact of therapeutic interventions, ideally indicating not only an absence of signs of disease activity but rather a positive change,” the researchers wrote.

The study looked at 123 people with relapsing remitting MS who were at the beginning of first-time DMT treatment. Researchers assessed their OTs at the start of the study, after three months and then after one year.

During the study, almost half (48%) of the participants had a relapse. The OT scores of these patients was significantly worse among those who relapsed at the start of the study, with a score of 4.75 vs 6.75 for those who hadn’t relapsed, and also after three months – 4.50 vs 7.37, and after a year – 5.75 vs 7.5.

The strongest predictor of relapse risk was the OT at three months after the beginning of DMT treatment, with patients who had an OT score of higher than 6.5 around 90% less likely to have a relapse over the course of the year-long study.

The team said that more research is needed to validate the findings as this was a relatively small study.