Diagnostic accuracy of cognitive screening tools under different neuropsychological definitions for poststroke cognitive impairment.

Objectives: The accuracy of cognitive screening tools to detect poststroke cognitive impairment (PSCI) was investigated using various neuropsychological definitions.

Methods: Hospital-based stroke patients underwent a comprehensive neuropsychological assessment. The rate of PSCI was estimated using thresholds of 1, 1.5, or 2 standard deviations below the normal control and memory impairment defined by a single or multiple tests. Meanwhile, the diagnostic accuracy of cognitive screening through face-to-face assessment using the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment Scale (MoCA), and telephone assessment using a 5-minute NINDS-Canadian Stroke Network (NINDS-CSN) scale and a six-item screener (SIS), was both tested under different definitions, with the optimal cutoff selected based on the highest Youden index.

Results: In stroke patients, the rate of PSCI ranged from 46.3% to 76.3% upon different definitions. The face-to-face MoCA was more consistent with the comprehensive cognitive assessment compared to MMSE. The optimal cutoff of PSCI was MMSE ≤ 27 and MoCA ≤ 19. For the telephone tests, the 5-minute NINDS-CSN assessment was more reliable, and the optimal cutoff was ≤23, while for SIS ≤ 4.

Conclusions: Cognitive screening tools including the face-to-face MMSE and MoCA, together with the telephone assessment of NINDS-CSN 5-minute protocol and SIS, were simple and effective for detecting PSCI in stroke patients. The corresponding threshold values for PSCI were 27 points, 19 points, 23 points, and 4 points.