Olfactory dysfunction is more common among patients with Wilson disease than healthy individuals, according to a new study published in the Polish Journal of Neurology and Neurosurgery. This is especially the case in older patients. 

“Predominantly neurological symptoms, and the presence of typical brain [magnetic resonance imaging] changes, predisposed patients with [Wilson disease] to smell disorders,” the authors of the study wrote. 

Read more about the symptoms of Wilson disease

It is already known that neurodegenerative disorders often affect the sense of smell. However, the effect of Wilson disease on olfaction is not well understood.

Here, a team of researchers led by Anna Członkowska, MD, PhD, from the Second Department of Neurology at the Institute of Psychiatry and Neurology in Warsaw, Poland, evaluated the olfactory function of 68 patients with Wilson disease and compared it to that of 70 sex- and age-matched healthy volunteers.

The researchers used “Sniffin’ Sticks” to test the participants’ odor detection thresholds and odor discrimination and identification abilities. “Sniffin’ Sticks” are a new olfactory test comprising pen-like odor-dispensing devices. They consist of 3 olfactory function tests, including odor threshold, odor discrimination, and odor identification.

The results of the study showed that patients with Wilson disease were worse than healthy controls at discriminating and identifying odors. However, there was no difference between patients with Wilson disease and healthy individuals in terms of odor detection thresholds. 

Patients who had predominantly neurological symptoms had higher olfactory dysfunction. Moreover, the presence of pathological lesions in the brain and generalized brain atrophy predisposed patients to olfactory dysfunction. 

The researchers also found inverse correlations, although weak, between age and odor detection threshold and odor discrimination ability in patients with Wilson disease. 

Finally, male sex was a risk factor for abnormal threshold discrimination identification in both patients with Wilson disease and healthy people, the researchers found.


Piechal A, Bembenek J, Baranowska, Litwin T, Mirowska-Guzel D, Członkowska A. Olfactory dysfunction in patients with Wilson’s disease. Neurol Neurochir Pol. Published online March 20, 2023. doi:10.5603/PJNNS.a2023.0020