Cognitive impairment at the acute stroke phase
Cognitive impairment (MoCA score < 25) appeared more in patients with new-onset anterior circulation cerebral infarction than in controls (56.3 versus 27.6%; p = 0.007). As shown in Figure 2A, the proportion of mild cognitive impairment (MoCA score: 20 to 24) in patients was similar to controls (20.8 versus 20.7%). However, the proportion of severe cognitive impairment (MoCA score: 0 to 19) was higher (35.4 versus 6.9%). Additionally, the cognitive impairment of the left infarction group did not differ from the right infarction group (Figure 2B).
Moreover, no significant differences in the abstraction MoCA score were detected among participants (Table 2). Compared to controls, the visuospatial/executive, attention, and orientation MoCA scores in both left and right infarction patients significantly decreased. Nevertheless, the MoCA scores for naming, language, and delayed recall significantly decreased only in left infarction patients.
Cerebrovascular reserve
The CBF, CBV, MTT, and TTP in different brain areas, including frontal, temporal, parietal, and occipital lobes, the basal ganglia, and the semioval center were used to assess the CVR of patients with new-onset anterior circulation cerebral infarction (Table 3). In the frontal lobe of patients, only MTT significantly increased compared to controls, and the other CVR predictors such as CBF, CBV, and TTP did not differ.
In the temporal lobe of patients, the CBF, CBV, and MTT significantly differed compared to controls. Interestingly, significant differences for CBF and MTT were detected only in left infarction patients. In these patients, the left vessels CBF significantly decreased and the MTT significantly increased. However, the CBF and MTT of right infarction patients were similar to controls. The right vessels CBV significantly increased in right infarction patients but, for left infarction patients, it was similar to controls.
Regarding the parietal lobe of patients, significant differences were detected for CBF and MTT compared to controls. For right infarction patients, the CBF in both left and right vessels significantly decreased compared to controls. The left vessels CBF significantly decreased and the MTT significantly increased in left infarction patients. MTT of right vessels also significantly increased in right infarction patients.
In the occipital lobe of patients, significant differences regarding CBV and MTT were detected compared to controls. The left vessels MTT significantly increased in left infarction patients, similar to the right vessels of right infarction patients. Additionally, compared to controls, the right vessels CBV significantly increased in right infarction patients but did not differ in left infarction patients.
Moreover, in the semioval center of patients, there were significant differences in CBF and MTT compared to controls. The left vessels CBF significantly decreased in left infarction patients. A significant increase was also detected for the MTT right vessels of right infarction patients. Similarly, the left vessels MTT significantly increased in both right and left infarction patients.
Finally, in the basal ganglia, the left vessels CBF significantly decreased in left infarction patients. On the other hand, the left vessels MTT significantly increased in the left infarction patients, similar to the right vessels of right infarction patients. Also, the left vessels TTP significantly decreased in right infarction patients.
Associations between cognitive impairment and cerebrovascular reserve
The data from left infarction patients were selected during linear regression analyses to assess the relationship between cognitive impairment and cerebrovascular reserve. This analysis indicated that the right vessels CBF and left vessels CBV in the frontal lobe, the left vessels CBF in the parietal lobe, the left vessels MTT in the occipital lobe were risk factors and composed the regression equation (p < 0.0001, Table 4). Especially, the right vessels CBF in the frontal lobe and the left vessels MTT in the occipital lobe were negatively related to the MoCA scores of left infarction patients. On the other hand, the left vessels CBV in the frontal lobe and the left vessels CBF in the parietal lobe were positively related to the MoCA scores of left infarction patients.
The data from right infarction patients was also used in a linear regression analysis to evaluate the relationship between cognitive impairment and cerebrovascular reserve. The results indicated that the CBF in the temporal lobe was a risk factor, included in the regression equation (p = 0.010, Table 4). Especially, the right vessels CBF in the temporal lobe was negatively related to the MoCA scores of right infarction patients. Besides, the left vessels CBF in the temporal lobe was positively related to the MoCA scores of these patients.