NIHSS is not enough for cognitive screening in acute stroke: A cross-sectional, retrospective study

Area of Science:

• Neurology
• Cognitive Neuroscience

Background:

• Cognitive deficits are common after stroke.
• Early detection of cognitive impairment is crucial for timely intervention.
• The National Institute of Health Stroke Scale (NIHSS) cognitive subscale (Cog-4) is a potential screening tool.

Purpose of the Study:

• To evaluate the diagnostic accuracy of the Cog-4 for identifying cognitive deficits in acute stroke patients.
• To compare the performance of the Cog-4 against a reference standard, the Montreal Cognitive Assessment (MoCA).

Main Methods:

• Cross-sectional, retrospective study of 531 acute stroke patients.
• Cog-4 assessed using admission NIHSS scores.
• MoCA administered within 36-48 hours of admission.
• Non-parametric statistical analyses, including Cohen's kappa, were used.

Main Results:

• The Cog-4 failed to identify cognitive deficits in 53-65% of patients, depending on the MoCA threshold used.
• Agreement between Cog-4 and MoCA was poor (Cohen's kappa: -0.210 to -0.109).
• Cog-4 sensitivity ranged from 35% to 48% for detecting cognitive impairment.

Conclusions:

• The Cog-4 demonstrates limited ability to accurately detect cognitive deficits in the acute phase of stroke.
• Current evidence suggests the Cog-4 is insufficient as a standalone diagnostic tool for cognitive impairment post-stroke.
• More comprehensive and structured cognitive assessments are necessary for accurate diagnosis and management.