Reliability, validity, and diagnostic accuracy of the apathy evaluation scale in chronic stroke survivors

Background We aimed to determine the psychometric properties of the Apathy Evaluation Scale (AES) in chronic stroke survivors. Methods In this study, 112 non-cognitive impairment stroke survivors participated. Acceptability, inter-rater, and test-retest reliability of the three Persian versions of AES (clinician, informant, and self-rated) were evaluated. The correlation of three AES versions with the Hospital Anxiety and Depression Scale (HADS), Modified Rankin Scale (mRS), and Barthel Index (BI) was evaluated. To assess the diagnostic accuracy of the three AES versions, stroke survivors were classified as apathetic (n = 43) and non-apathetic (n = 69) groups using the 'diagnostic criteria of apathy'. Results The floor and ceiling effect, skewness, and kurtosis were within acceptable range for three AES versions. Internal consistency (alpha = 0.88-0.91) and test-retest and inter-rater reliability (ICC2,1 >0.90) were acceptable for all AES versions. Standard Error of Measurement and Minimal Detectable Change values for test-retest and/or inter-rater reliability ranged 1.6-2.5 and 4.42-6.93 for three versions of AES, respectively. Significant moderate to high correlation (r or p = -0.34-0.69) was found between three AES versions and HADS-D, HADS-A, BI, and mRS. The cut-off point > 34 (sensitivity = 87.5%, specificity = 72.22%, and AUC = 0.80) was derived for discriminating apathetic from non-apathetic stroke survivors based on the AES- self-rated total score. Conclusion All three AES versions are reliable and valid screening tools to evaluate and characterize apathy in stroke survivors. The AES-self-rated had good discriminative validity for discriminating apathetic from non-apathetic subjects in non-cognitive impairment stroke survivors.