Stroke Scale Score

Stroke Scale Scores: Predictive Value and Clinical Applications

Baseline NIH Stroke Scale (NIHSS) Score and Stroke Outcomes

The National Institutes of Health Stroke Scale (NIHSS) is a critical tool for assessing the severity of a stroke and predicting patient outcomes. Research has shown that the baseline NIHSS score is a strong predictor of recovery after an ischemic stroke. Specifically, each additional point on the NIHSS decreases the likelihood of an excellent outcome by 24% at 7 days and by 17% at 3 months. Patients with NIHSS scores of 7 to 10 have a 46% chance of excellent outcomes at 3 months, while those with scores of 11 to 15 have only a 23% chance. A score of 16 or higher forecasts a high probability of death or severe disability, whereas a score of 6 or lower predicts a good recovery.

Comparative Prognostic Value of Stroke Scales

Several stroke scales are used to evaluate the prognosis of stroke patients, including the NIHSS, Acute Physiology and Chronic Health Evaluation (APACHE II and III), Chinese Stroke Scale (CSS), activities of daily living (ADL) (Barthel Index, BI), and Glasgow Coma Scale (GCS). Among these, the NIHSS has been shown to provide significant prognostic information, with an area under the ROC curve (AUC) of 0.859, indicating good predictive value. However, APACHE II was found to be superior among the six scales evaluated.

European Stroke Scale (ESS) and Its Reliability

The European Stroke Scale (ESS) is another tool designed to measure stroke severity, particularly for patients with middle cerebral artery stroke. The ESS has demonstrated good interrater and intrarater reliability, with high internal consistency (Cronbach's α coefficient of 0.92). It correlates well with other neurological scales and has shown strong prognostic validity for neurological, functional, and handicap status at 1 and 8 months post-stroke.

Japan Stroke Scale: A Weighted Approach

The Japan Stroke Scale (JSS) offers a unique approach by providing weighted variables to quantify stroke severity. This scale includes factors such as consciousness, language, and motor function, with consciousness being the most heavily weighted at 49.8%. The JSS has shown excellent reliability and responsiveness, making it a potentially universal and standardized system for stroke severity assessment.

Interconversion of Stroke Scales

The ability to convert scores between different stroke scales is limited. While conversion between the Canadian Neurological Scale and the middle cerebral artery Neurological Score is satisfactory, conversion from the NIHSS to these scales is less reliable, particularly for patients with dysphasia and total anterior circulation strokes. This suggests that meta-analyses using different stroke scales may face significant challenges.

Retrospective NIHSS Scoring

Retrospective assessment of stroke severity using the NIHSS is feasible and reliable, even when some physical examination elements are missing from the written record. An algorithm developed for this purpose has shown near-perfect interrater reliability and excellent agreement with prospective NIHSS scores. This method allows for the adjustment of stroke outcomes based on initial stroke severity in retrospective studies.

Scandinavian Stroke Scale (SSS)

The Scandinavian Stroke Scale (SSS) is a clinical measure of functional impairment and activity limitations in acute stroke patients. It includes nine items such as consciousness, motor power, and speech, with high internal consistency (Cronbach’s α: 0.91) and good to excellent interrater reliability. The SSS is widely used and available in multiple languages, making it a practical tool for global application.

Recognition of Stroke in the Emergency Room (ROSIER) Scale

The ROSIER scale is an effective tool for identifying strokes and transient ischemic attacks (TIAs) in emergency settings. With a sensitivity of 0.89 and specificity of 0.76, the ROSIER scale is considered an excellent method for rapid stroke diagnosis, applicable across diverse settings and by various healthcare providers.

Conclusion

Stroke scales such as the NIHSS, ESS, JSS, and SSS play a crucial role in assessing stroke severity and predicting patient outcomes. Each scale has its strengths and specific applications, with the NIHSS being particularly notable for its strong predictive value. Understanding the nuances and comparative effectiveness of these scales can significantly enhance clinical decision-making and patient care in stroke management.

Summary

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