Olfactory Function In Patients With Mild Cognitive Impairment And Alzheimer’s Disease

ObjectiveTo analyze the relationship between olfactory bulb(OB) volume, depth of olfactory sulcus(OS) and olfactory function in patients with mild cognitive impairment (MCI) and Alzheimer’disease(AD). To explore the new diagnostic method of mild cognitive impairment, which would aid to early detection and intervention of mild cognitive impairment, for purpose of delay and prevent the development of Alzheimer’ disease.MethodsFifty patients with MCI patients, AD patients and healthy subjects were examined by olfactory function T&T testing, OB volume and depth of OS assessed with Magnetic resonance imaging (MRI).ResultsT&T olfactory testing revealed that MCI patients had higher scores than healthy subjects(2.90±0.32与1.40±0.18, P<0.05), AD patients had higher scores than MCI patients(3.35±0.41与2.90±0.32, P<0.05). The olfactory discriminate threshold were no difference between male and female patients with MCI, AD and control groups (P>0.05). Bilateral and average olfactory bulb volumes were smaller in AD group[(29.89±5.19) mm3,(30.15±4.99) mm3,(30.06±5.09)mm3] than in MCI group[(36.35±4.09) mm3,(36.57±4.13) mm3,(36.47±4.12)mm3](P<0.01). Bilateral and average olfactory bulb volumes were smaller in MCI group [(36.3±54.09) mm3,(36.57±4.13) mm3,(36.47±4.12)mm3] than in control group [(46.65±6.23)mm3,(46.83±6.27)mm3,(46.71±6.25)mm3](P<0.01). OS depth study revealed no statistical difference between AD patients, MCI patients and control groups(P>0.05). Olfactory discriminate threshold was negatively correlated with average olfactory bulb volumes (r=-0.701, P<0.05), and was not correlated with depth of OS(r=-0.123, P>0.05) in AD patients. Olfactory discriminate threshold was negatively correlated with average olfactory bulb volumes (r=-0.643, P<0.05), and was not correlated with depth of OS(r=-0.167, P>0.05) in MCI patients.ConclusionsThe olfactory function were both decreased in AD and MCI patients. The degree of olfactory dysfunction in AD patients were more significant than in MCI patients. The olfactory bulb volumes were both smaller in AD and MCI patients. The degree of olfactory bulb volumes’ diminution in AD patients were more significant than in MCI patients. The depth of olfactory sulus were no significant changes in AD and MCI patients; The olfactory bulb volume was correlated with olfactory function, the depth of olfactory sulus is no correlated with olfactory function in AD and MCI group; The olfactory dysfunction may be the early diagnosis marker for MCI patients.