Olfactory dysfunction is related to postoperative delirium in Parkinson's disease.

Operations often lead to delirium in elderly patients, particularly those with impaired cognition, suggesting that underlying neuropathology may play a role in the development of postoperative delirium. Olfactory dysfunction is a well-known marker of underlying Lewy body pathology in Parkinson's disease (PD). However, the prognostic value of olfaction for the development of postoperative delirium in PD remains unclear. 34 PD patients with or without postoperative delirium following surgery under general anesthesia were included in this study (n = 17 for each group). Cross-Cultural Smell Identification scores were lower in PD patients with postoperative delirium (4.4 ± 1.5) relative to the delirium-free controls (6.8 ± 2.4, p < 0.005). Multivariate logistic regression analysis revealed that olfaction and operation time were significant predictors of the development of postoperative delirium. Impaired olfaction is significantly associated with postoperative delirium in PD. Olfaction may be useful for identifying PD patients susceptible to postoperative delirium.