Reader Response: Prestroke Disability and Outcome After Thrombectomy for Emergent Anterior Circulation Large Vessel Occlusion Stroke
AskielBruno, Neurologist, Medical College of Georgia at Augusta University
JeffreySwitzer, Neurologist, Medical College of Georgia at Augusta University
FenwickNichols, Neurologist, Medical College of Georgia at Augusta University
Submitted March 16, 2022
We read this study with interest.1 However, we would like to point out a problem that could be expected when using the modified Rankin scale (mRS) outside of its designed setting. The mRS was designed to measure residual disability after stroke and using it before a stroke is undefined.2 Furthermore, comparing the standard post-stroke mRS scores to the undefined pre-stroke scores can produce peculiar results. This problem likely led to the unusual result of an association between a pre-stroke disability and less accumulated disability post-stroke in this study. This could be expected because the standard post-stroke mRS measures the consequences of only a stroke and not the pre-stroke disabilities, possibly resulting in lower post-stroke scores than pre-stroke scores in some patients. For example, a patient with a pre-stroke mRS somehow scored as 2 on the scale and excellent recovery from the stroke (post-stroke mRS of 1) might be classified as having no accumulated disability. However, a patient with a pre-stroke mRS somehow scored as 0 and a similar excellent recovery (post-stroke mRS of 1) might be classified as having accumulated disability. Given the nature of the mRS, this approach may “hide” the additional disability from a stroke in patients with pre-stroke disabilities.
Disclosure
The authors report no relevant disclosures. Contact journal@neurology.org for full disclosures.
References
de Havenon A, Castonguay A, Nogueira R, et al. Prestroke Disability and Outcome After Thrombectomy for Emergent Anterior Circulation Large Vessel Occlusion Stroke. Neurology. 2021;97(19):e1914-e1919. doi:10.1212/WNL.0000000000012827
Bruno A, Switzer JA, Durkalski VL, Nichols FT. Is a prestroke modified Rankin Scale sensible?. Int J Stroke. 2011;6(5):414-415. doi:10.1111/j.1747-4949.2011.00661.x
We read this study with interest.1 However, we would like to point out a problem that could be expected when using the modified Rankin scale (mRS) outside of its designed setting. The mRS was designed to measure residual disability after stroke and using it before a stroke is undefined.2 Furthermore, comparing the standard post-stroke mRS scores to the undefined pre-stroke scores can produce peculiar results. This problem likely led to the unusual result of an association between a pre-stroke disability and less accumulated disability post-stroke in this study. This could be expected because the standard post-stroke mRS measures the consequences of only a stroke and not the pre-stroke disabilities, possibly resulting in lower post-stroke scores than pre-stroke scores in some patients. For example, a patient with a pre-stroke mRS somehow scored as 2 on the scale and excellent recovery from the stroke (post-stroke mRS of 1) might be classified as having no accumulated disability. However, a patient with a pre-stroke mRS somehow scored as 0 and a similar excellent recovery (post-stroke mRS of 1) might be classified as having accumulated disability. Given the nature of the mRS, this approach may “hide” the additional disability from a stroke in patients with pre-stroke disabilities.
Disclosure
The authors report no relevant disclosures. Contact journal@neurology.org for full disclosures.
References