Recommended Stroke Assessment Tools for Early Recognition and Intervention
The FAST (Face, Arm, Speech, Time) or CPSS (Cincinnati Prehospital Stroke Scale) are the recommended stroke assessment tools for first aid providers and emergency medical services personnel to identify suspected stroke patients. 1
Primary Stroke Assessment Tools
FAST Assessment Tool
- FAST evaluates facial drooping, arm weakness, speech difficulty, and time to call emergency services 1
- High sensitivity (81%) for stroke detection in prehospital settings 1
- Simple to use, easily remembered, and takes minimal time to complete 1
- Recommended for first aid providers and initial stroke screening 1
Cincinnati Prehospital Stroke Scale (CPSS)
- Similar components to FAST with high pooled sensitivity of 80% 1
- Widely used in emergency medical services 1
- Demonstrated benefit in increasing rates of fibrinolytic therapy for stroke patients 1
Enhanced Stroke Assessment Options
Stroke Scales with Blood Glucose Measurement
- Stroke assessment systems that include blood glucose measurement (LAPSS, OPSS, ROSIER, KPSS) have similar sensitivity (80%) but higher specificity (93%) compared to FAST/CPSS (47%) 1
- Recommended when glucometers are available to increase diagnostic accuracy 1
- Los Angeles Prehospital Stroke Screen (LAPSS) has demonstrated high sensitivity and specificity for confirming stroke diagnosis 2
Hospital-Based Assessment Tools
- National Institutes of Health Stroke Scale (NIHSS) is strongly recommended for hospital settings 1
- NIHSS should be performed at hospital admission or within 24 hours after presentation 1
- NIHSS score strongly predicts recovery probability after stroke (score >16 forecasts high probability of death or severe disability; score <6 forecasts good recovery) 1
Implementation Considerations
First Aid and Prehospital Setting
- EMS personnel should use validated stroke assessment tools as part of on-scene assessment 1
- Initial screening with FAST/CPSS, followed by a second screen using a validated stroke severity tool for possible endovascular treatment candidates 1
- On-scene time should be minimized to a median of 20 minutes or less for patients within the treatment window 1
- Training first aid providers in stroke assessment systems has shown significant improvement in stroke recognition (from 76.4% to 94.4% immediately after training) 1
Emerging Assessment Approaches
- Recent research has investigated adding Balance and Eyes assessments to FAST (BE-FAST) to improve detection of posterior circulation strokes 3
- BE-FAST shows higher sensitivity (97.8% vs 58.7%) but lower specificity (10.0% vs 39.8%) than FAST for posterior circulation strokes 3
- However, adding coordination and diplopia assessments did not significantly improve overall stroke detection in another prehospital study 4
Pitfalls and Caveats
- FAST may miss approximately 39% of posterior circulation strokes 3
- Stroke scales without glucose measurement have lower specificity, potentially leading to more false positives 1
- FAST assessment performed by ambulance personnel has higher positive predictive value (73%) compared to when used by emergency medical communication center staff (56%) 5
- No single stroke scale is perfect - all have limitations in sensitivity and specificity 6
Algorithm for Stroke Assessment Tool Selection
- For first aid providers and initial screening: Use FAST or CPSS 1
- If glucometer available: Use LAPSS, OPSS, ROSIER, or KPSS for improved specificity 1
- In hospital setting: Use NIHSS for comprehensive assessment and prognosis 1
- For suspected posterior circulation stroke: Consider BE-FAST if available 3
The primary goal is early recognition to minimize time to treatment, as this directly impacts morbidity, mortality, and quality of life outcomes for stroke patients 1.