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[Validation of Allen's scale for the diagnosis of stroke]
E Valiente1, R Martín, F Gracia
1Departamento. de Medicina y Psiquiatria, Facultad de Medicina, San Juan, Alicante.
Insights
The Allen scale is not a reliable tool for diagnosing stroke types, showing low sensitivity and specificity, particularly for hemorrhagic stroke. Further validation is needed for accurate cerebrovascular pathology assessment.
Area of Science:
- Neurology
- Medical Diagnostics
- Cerebrovascular Diseases
Context:
- Accurate diagnosis of cerebrovascular pathology is crucial.
- Computerized tomography (CT) is a key diagnostic tool.
- Clinical scales aim to aid stroke diagnosis.
Purpose:
- To validate the Allen scale against CT scans for differentiating hemorrhagic and ischemic stroke.
- To assess the diagnostic accuracy of the Allen scale.
Summary:
- The study evaluated 62 stroke patients using the Allen scale and CT scans.
- The Allen scale demonstrated low overall sensitivity (61%) and specificity (40%).
- Diagnostic accuracy varied by stroke type, with poor performance for hemorrhagic stroke.
Impact:
- The Allen scale's low sensitivity and specificity limit its utility in stroke diagnosis.
- Clinical decision-making requires more reliable diagnostic methods.
- This study highlights the need for improved diagnostic tools for cerebrovascular events.
Introduction:
The importance of cerebrovascular pathology demands the most exact and complete diagnosis possible, by general physical and neurological examination and complementary techniques including computerized tomography (CT). Without CT, diagnosis may be delayed, for which reason such authors as Allen have put forward scales which by means of diagnostic scoring distinguish between stroke types.
Aim:
To validate the Allen scale as opposed to CT scan in a series of patients suffering from haemorrhagic and ischaemic stroke.
Materials And Method:
Sixty-two consecutive hospitalized patients suffering from stroke were studied, who all underwent CT scan within fifteen days of admission.
Results:
The group consisted of 62 patients, 33 males (53%) and 29 females (47%) having an average of 70.2 +/- 11.2 years. The most frequent type of stroke was ischaemic (63%) as opposed to haemorrhagic (37%). Globally for all strokes we obtained the following results: Sensitivity (S) = 61%, Specificity (Sp) = 40%, positive predictive value ( + PV) = 84% and negative predictive value (-PV) = 17%. For ischaemic stroke the results were as follows: S = 76%, Sp = 66%; +PV = 67% and -PV = 76%. Finally for haemorrhagic stroke the results were S = 43%; Sp = 100%; +PV = 100% and -PV = 75%.
Conclusions:
The Allen scale has not proved to be a valid instrument in stroke diagnosis due to its low sensitivity and specificity especially in cases of haemorrhagic stroke.