Introduction to the Apathy Evaluation Scale

Apathy is a common problem following traumatic brain injury (TBI). The Apathy Evaluation Scale (AES) was developed by Marin (1991) as a method for measuring apathy resulting from brain-related pathology. He defined apathy as “lack of motivation not attributable to diminished level of consciousness, cognitive impairment, or emotional distress.” (Marin, 1991). He also relates an operational definition: “a state characterized by simultaneous diminution in the overt behavioral, cognitive, and emotional concomitants of goal-directed behavior.” (Marin et al, 1991) Stemming from this definition, Marin described three domains of apathy:

• ‘deficits in goal-directed behavior’
• ‘a decrement in goal-related thought content’
• emotional indifference with flat affect (Marin, 1996)

Although it was originally used in people with stroke, Alzheimer’s disease, and depression, Kant et al. (1998) used the AES to study people with traumatic brain injury (TBI). He found that 85% of those who were apathetic according to AES also met their criteria for depression using the Beck Depression Inventory-II. Because this study implies that the AES may not distinguish the apathy of depression from neurologically-based apathy, Glenn et al. (2002) modified Marin’s definition of apathy, deleting the exclusion due to "emotional distress" and adding some other clarifications as well: "lack of motivation not attributable to diminished level of consciousness, cognitive impairment, or motor dysfunction; and manifested by decreased initiative, akinesia, emotional indifference, and flat affect.” (adapted from Marin, 1991). Stuss et al (2000) have questioned whether apathy is a single construct.

There are three versions of the AES for use by the person with the neurological problem, i.e., self (AES-S); by an informant such as a family member (AES-I), or by a clinician (AES-C). They are essentially the same, with only the pronoun referring to the subject changed. However the AES-C requires a semi-structured interview. (Marin, 1991) The 3 scales can be found in Table 1 in Marin (1996).

Information regarding the AES was contributed by Spaulding/Partners at Harvard Medical School. Please contact Mel Glenn, M.D., at for more information.

If you find the information in the COMBI useful, please mention it when citing sources of information. The information on the Apathy Evaluation Scale may be cited as:

Glenn, M. (2005). The Apathy Evaluation Scale. The Center for Outcome Measurement in Brain Injury. http://www.tbims.org/combi/aes ( accessed ).