Olfactory impairment in Wilson’s disease

Introduction Olfactory dysfunction is a common and early sign of many neurodegenerative disorders, but little is known about olfactory dysfunction in Wilson’s disease (WD). We aimed to evaluate olfactory function in patients with WD and identify selective WD screening odors. Methods We measured olfactory identification ability in 25 patients with WD and 25 healthy controls using the University of Pennsylvania Smell Identification Test (UPSIT). Patients with WD were evaluated using the Global Assessment Scale for WD (GAS). Cognitive function was measured using the Mini–Mental State Examination. Results Patients with WD were worse at identifying smells in the simplified Chinese version of the UPSIT compared with healthy controls (t = 2.198, p = .033), but there was no difference in olfactory dysfunction severity between the groups (V = 136, p = .094). UPSIT scores negatively correlated with the GAS neurological scores in patients with WD (r = −0.571, p = .003). Using logistic regression with least absolute shrinkage and selection operator analysis, two models were screened. Receiver‐operating characteristic (ROC) curve analysis revealed that, to discriminate WD patients from healthy controls, the area under the ROC curve (AUC) for a combination of seven odors (motor oil, onion, licorice, strawberry, tire, jasmine, and natural gas) was 0.926, while the AUC for three odors (onion, licorice, and jasmine) was 0.852. Conclusions Patients with WD may have stable, selective olfactory impairments. This selective pattern may be a useful tool for disease diagnosis and prediction. Olfactory function and selective odor identification impairment has been explored in patients with WD. We found that the patients with WD were worse at identifying smells compared with healthy controls, but the hyposmia severity was milder than that found in PD or AD patients. A selective pattern of olfactory dysfunction was also detected in WD, and both the seven odor model and the three odor model showed good disease discrimination accuracy.