Incidence of Aphasia in Ischemic Stroke.

INTRODUCTION: A decrease in ischemic stroke (IS) incidence has been observed in high income countries during the last decades. Whether this has influenced the occurrence of aphasia in IS is uncertain. We therefore examined the incidence rate and potentially related determinants of aphasia in IS. METHODS: We prospectively examined consecutive patients admitted to hospital with first-ever acute IS between March 1, 2017, and February 28, 2018, as part of the Lund Stroke Register (LSR) Study, comprising patients from the uptake area of Skåne University Hospital, Lund, Sweden. Patients were assessed with National Institutes of Health Stroke Scale (NIHSS) at stroke onset. Presence of aphasia was evaluated with NIHSS item 9 (language). We registered IS subtypes and risk factors. To investigate possible temporal changes in aphasia incidence, we made comparisons with corresponding LSR data from 2005 to 2006. Incidence rates were calculated and adjusted to the European Standard Population (ESP) and to the Swedish population. RESULTS: Among 308 included IS patients, 30% presented with aphasia (n = 91; 95% CI: 25-35), a proportion of aphasia in IS that was similar to 2005-2006. The incidence rate of aphasia was 31 per 100,000 person-years adjusted to the ESP (95% CI: 25-38 per 100,000 person-years) corresponding to a significant decrease of 30% between 2005-2006 and 2017-2018. The decrease was significantly more pronounced in men. The initial severity of aphasia remained unchanged, with the majority of patients having severe to global aphasia. No significant differences between vascular stroke risk factors were noted among stroke patients with or without aphasia. CONCLUSION: Even though the overall IS incidence rate has decreased during the first decades of the 21st century, the proportion of IS patients with aphasia at stroke onset remains stable at 30%. Aphasia continues to be an important symptom that needs to be considered in stroke care and rehabilitation.

Accuracy of NIH Stroke Scale for diagnosing aphasia.

OBJECTIVES: The National Institutes of Health Stroke Scale (NIHSS) has not been validated to diagnose aphasia in the stroke population. We therefore examined the diagnostic accuracy of NIHSS for detecting aphasia in acute ischemic stroke. METHODS: Consecutive patients with acute first-ever ischemic stroke were included prospectively in Lund Stroke Register Study at Skåne University Hospital, Sweden. Exclusion criteria were: (a) non-native Swedish; (b) obtundation (c) dementia or psychiatric diagnosis. Patients were assessed with NIHSS item 9 (range 0-3, where 1-3 indicate aphasia) by a NIHSS certified research nurse in the acute phase after stroke onset (median 3 days). Within 24 h after this assessment, a speech therapist evaluated the patients' language function with the comprehensive language screening test (LAST, range 0-15 where 0-14 indicates aphasia). Data were analyzed using LAST as 'reference standard'. RESULTS: We examined 221 patients. Among these, 23% (n = 50) had aphasia according to NIHSS (distribution of scores 0, 1, 2, 3 were n = 171, n = 29, n = 12, n = 9) compared to 26% (n = 58) with aphasia according to LAST (score ≤14; median = 11). Assuming LAST as reference standard, NIHSS gave 16 false negatives (NIHSS item 9 = 0) for aphasia (LAST scores range 8-14), and 8 false positives (NIHSS item 9 score = 1) for aphasia, yielding a sensitivity of 72% (0.59-0.83) and a specificity of 95% (0.91-0.98). CONCLUSIONS: When using NIHSS for screening and diagnosing aphasia in adults with acute ischemic stroke, patients with severe aphasia can be detected, however, some mild aphasias might be misclassified. Given the 72% sensitivity, absence of aphasia on the NIHSS should not be used to guide stroke treatment.