Olfactory Dysfunction and Cognitive Impairment

Background: The aim of the current study was to investigate the changes of the olfactory function in the Korean elderly population related to cognitive decline by using the CDR (Clinical Dementia Rating scale) and KVSS Test (Korean Version of Sniffin ’ Sticks Test). Methods: 41 subjects between the ages of 65-85 years, were included in this study. All subjects were screened to exclude conditions affecting olfactory functions. These subjects were divided into three groups according to CDR. 23 subjects belonged to the CDR 0 group, 9 to the CDR 0.5 group and 9 to the CDR 1 group. The KVSS Test consisted of the olfactory threshold test and olfactory identification test. Results: Significant differences were found among the CDR 0 group, CDR 0.5 group and CDR 1 group (p<0.001) in the olfactory identification test. Scores in the olfactory identification test was lower in the CDR 1 group than in the CDR 0.5 group and CDR 0 group. There were no significant differences between the scores of subjects in the CDR 0 group and those in the CDR 0.5 group on the olfactory identification test. Scores in the olfactory threshold test were not different in the CDR 0 group, CDR 0.5 group and CDR 1 groups (p>0.05). Conclusions: These results suggest that the cognitive deficits were associated with the decrease of scores in the olfactory identification test and that the olfactory identification test may have clinical utility in the diagnosis o