Kevin O’Connor, MD
Alemseged F, Rocco A, Arba F, Schwabova JP, Wu T, Cavicchia L, Ng F, Ng JL, Zhao H, Williams C, et al. Posterior National Institutes of Health Stroke Scale Improves Prognostic Accuracy in Posterior Circulation Stroke. Stroke. 2021.
The NIH Stroke Scale (NIHSS) is an indispensable part of acute stroke evaluations, but its components focus more on anterior circulation deficits than posterior circulation deficits. Alemseged et al. developed the POST-NIHSS to augment the NIHSS with additional posterior circulation deficits based on retrospective analysis of 202 patients with clinical and radiographic evidence of posterior circulation stroke and NIHSS score <10 who did not undergo mechanical thrombectomy from the Basilar Artery Treatment and Management registry. They then validated their POST-NIHSS with 65 prospectively recruited patients.
Clinical features of posterior circulation strokes may include gait/truncal ataxia, diplopia, ptosis, nystagmus, internuclear ophthalmoplegia, vertical gaze impairment, Horner syndrome, palatal palsy, tongue deviation, and abnormal cough. The retrospective analysis identified gait/truncal ataxia (OR, 3.14 [95% CI, 1.24–7.92], P=0.02), dysphagia (OR, 5.22 [95% CI, 1.63–16.7], P=0.005), and abnormal cough (OR, 8.17 [95% CI, 1.49–44.8], P=0.02) as significantly associated with poor outcome. To the standard NIHSS, the POST-NIHSS adds 3 points for gait/truncal ataxia when assessing item 7 and a new item 12 to assess for abnormal cough (5 points) and dysphagia (4 points). In a ROC analysis for age-adjusted poor outcome, POST-NIHSS performed better than NIHSS (POST-NIHSS AUC, 0.80 [95% CI, 0.73–0.87] versus NIHSS AUC, 0.73 [95% CI, 0.64–0.83]). In a subgroup sensitivity analysis of 156 of the 202 patients with NIHSS 0-5 (77%), POST-NIHSS remained associated with age-adjusted poor outcome (OR, 1.40 [95% CI, 1.14–1.70], P=0.01) while NIHSS was not (OR, 1.12 [95% CI, 0.82–1.56], P=0.46).