Clinical Utility and Psychometric Properties of the Apathy Evaluation Scale

The Apathy Evaluation Scale (AES) is a tool utilized with individuals with brain injury, neurocognitive disorders, and other mixed populations, to quantify and characterize apathy in adults.¹ The scale “treats apathy as a psychological dimension defined by simultaneous deficits in the overt behavioral, cognitive, and emotional concomitants of goal-directed behavior.”¹ It has three versions: self-rated (AES-S), clinician-rated (AES-C), and informant-rated (AES-I). Using factor analysis, three factors were identified for the scale, including general apathy, disinterest/amotivation, and lack of concern.¹ The psychometric properties of the AES have been examined in various clinical cohorts, including individuals with Alzheimer’s disease (AD),¹ traumatic brain injury (TBI),^2,3 acquired brain injury,⁴ multiple sclerosis,⁵ severe mental illness⁶, and cognitively healthy middle-aged cohort who are at risk for AD.⁷

The scale consists of 18 items, and each item is scored on a 4-point Likert scale. The total score ranges from 18 to 72, with higher scores indicating more apathy. Three items are reverse scored. The AES has been reported to have good internal consistency (α = .86-.94), test-retest reliability (r =.76-.94), and interrater reliability (ICC = .94).¹ The scale’s content validity was tested in the original study.¹ From hundreds of possible items collected from literature review, authors selected items that were most clear and demonstrated item-total correlations of 0.4 or above in pilot testing.¹ In addition, during scale development, the scale’s face validity was supported by expert review.¹ In terms of construct validity, the AES was found to have high correlation (r = 0.71) with apathy subscale of the Frontal Systems Behavior Scale in a sample of individuals with TBI.² The scale also demonstrates acceptable convergent (e.g., the correlation between AES-C and the Hamilton Scales for Depression was .53) and discriminant validity (see below).¹ Marin et al. reported that (a) the intercorrelation between the AES-S and AES-I was .43, the intercorrelation between the AES-S and AES-C was .72, and the intercorrelation between the AES-I and AES-C was .62, (b) the clinician-rated and self-rated versions of the AES were able to discriminate apathy from depression (r = 0.39 to 0.42) and anxiety (r = 0.35 to 0.42), and (c) the informant-rated version of the AES was not able to discriminate apathy from depression.¹ The mean scores on the AES-S for individuals with brain injury and young adult controls were 37 (SD = 8.6) and 24.4 (SD = 4.5), respectively.^8,9 A score of 34 indicates apathy on the AES-C for people with brain injury.⁴

In summary, the AES is a useful, reliable, and valid instrument to quantify and measure severity of apathy symptoms in adults. It is important to note that the AES-C and AES-S were able to discriminate apathy from depression and anxiety better than the AES-I. It has been translated into Japanese, Portuguese, German, and Turkish.^10,11,12,13As a neuropsychiatric symptom, apathy should be measured in examining problems of relevance to psychology, psychiatry, and neurology, which may aid in understanding motivation, prognosis, and differential diagnosis.¹