Montreal Cognitive Assessment score correlates with regional cerebral blood flow in post-stroke patients

Objective: Valid and reliable measures are needed to assess post-stroke cognitive impairment. The Montreal Cognitive Assessment (MoCA) has been considered a superior screening test to the Mini-Mental State Examination (MMSE) for patients with post-stroke cognitive impairment, particularly in executive function, which may be related to reduction in regional cerebral blood flow (rCBF). In this study, we determined whether MoCA and MMSE scores correlate with rCBF assessed with SPECT in the subacute phase after ischemic stroke. Patients and methods: We retrospectively enrolled 28 patients who were admitted to the Red Cross Otsu Hospital with acute cerebral infarction, which was confirmed by magnetic resonance imaging (MRI), if they underwent cognitive assessment (MoCA/MMSE) and I-123-IMP SPECT imaging within 3 weeks post-stroke during a study period of 5 months. Correlation analyses between rCBF and MoCA or MMSE scores were performed by statistical parametric mapping (SPM) and volume-of-interest (VOI) analyses. Results: Total MoCA score correlated with the rCBF in the prefrontal cortex, cingulate cortex, caudate nucleus and thalamus by SPM analysis (uncorrected p < 0.001; cluster-level corrected p < 0.05). Among the subtest scores of MoCA, visuoexecutive function, attention, language and delayed recall scores were positively correlated with rCBF in the prefrontal cortex by VOI analysis (p < 0.05). However, total MMSE score did not correlate significantly with any of the rCBF measures. Conclusions: Post-stroke cognitive performance assessed with MoCA positively correlated with rCBF in brain regions mainly comprising the prefrontal-subcortical circuits. The findings of this hypothesis-generating study support the notion that MoCA is useful for assessing post-stroke cognitive status.