Brief screening tests during acute admission in patients with mild stroke are predictive of vascular cognitive impairment 3-6 months after stroke

Objectives To determine the prognostic value of brief cognitive screening tests administered in the subacute stroke phase (initial 2 weeks) for the detection of significant cognitive impairment 3-6 months after stroke, the authors compared the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE). Methods Patients with ischaemic stroke and transient ischaemic attack were assessed with both MoCA and MMSE within 14 days after index stroke, followed by a formal neuropsychological evaluation of seven cognitive domains 3-6 months later. Cognitive outcomes were dichotomised as either no-mild (impairment in <= 2 cognitive domains) or moderate-severe (impairment in >= 3 cognitive domains) vascular cognitive impairment. Area under the receiver operating characteristic (ROC) curve analysis was used to compare discriminatory ability. Results 300 patients were recruited, of whom 239 received formal neuropsychological assessment 3-6 months after the stroke. 60 (25%) patients had moderate-severe VCI. The overall discriminant validity for detection of moderate-severe cognitive impairment was similar for MoCA (ROC 0.85 (95% CI 0.79 to 0.90) and MMSE (ROC 0.83 (95% CI 0.77 to 0.89)), p=0.96). Both MoCA (21/22) and MMSE (25/26) had similar discriminant indices at their optimal cutoff points; sensitivity 0.88 versus 0.88; specificity 0.64 versus 0.67; 70% versus 72% correctly classified. Moreover, both tests had similar discriminant indices in detecting impaired cognitive domains. Conclusions Brief screening tests during acute admission in patients with mild stroke are predictive of significant vascular cognitive impairment 3-6 months after stroke.