Study on the correlation between cerebral hemodynamics and cognitive function in patients with mild cognitive impairment

Objective To study the characteristics of cerebral hemodynamics and the correlation with cognitive function in patients with mild cognitive impairment (MCI). Methods A total of 80 cases were divided into MCI group (N = 40) and control group (N = 40). Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were used to evaluate the cognitive function of 2 groups. Bilateral middle cerebral artery (MCA) and basilar artery (BA) were examined by means of transcranial Doppler (TCD) ultrasound to obtain mean flow velocity (MFV), pulsatility index (PI), resistance index (RI) and the ratio of peak systolic velocity to end-diastolic velocity (S/D) in all subjects. Results Compared with control group, PI ( P = 0.023) and RI ( P = 0.035) of MCA were significantly increased in MCI group. The differences in MFV, S/D and hemodynamic indexes of BA had no significance between 2 groups ( P > 0.05, for all). The rate of abnormal PI of MCA in MCI group was higher than that in control group [45% (18/40) vs. 20% (8/40); χ 2 = 4.615, P = 0.032]. Pearson correlation analysis showed that PI of MCA had negative correlation with MoCA score in MCI group ( r = -0.382, P = 0.036), and no correlation with MMSE score ( P > 0.05). MFV, RI and S/D of MCA and MFV, PI, RI and S/D of BA had no correlation with MoCA and MMSE scores ( P > 0.05, for all). MCI group was further divided into subgroups according to PI, and MoCA score was significantly lower in abnormal PI subgroup than that in normal PI subgroup [(18.57 ± 3.02) score vs. (23.41 ± 2.78) score; t = 3.914, P = 0.015]. Conclusions Cerebral hemodynamics in MCI patients was changed. The cognitive impairment was closely related to the increase of PI in MCA. DOI: 10.3969/j.issn.1672-6731.2017.01.011