Psychometric Properties of an Abbreviated Version of the Apathy Evaluation Scale for Parkinson Disease (AES-12PD)

Background Apathy is a frequent symptom in Parkinson's disease (PD), substantially aggravating the course of PD. Regarding the accumulating evidence of the key role of apathy in PD, time-efficient assessments are useful for fostering progress in research and treatment. The Apathy Evaluation Scale (AES) is widely used for the assessment of apathy across different nosologies. Objective To facilitate the application of the AES in PD, we reduced the AES to two-thirds its length and validated this abbreviated version. Design Data sets of 339 PD patients of the DEMPARK/LANDSCAPE study without dementia and depression were randomly split into two samples. Data of sample 1 were used to develop a brief version of the AES (AES-12PD). A cross-validation was conducted in sample 2 and in a subsample of 42 PD patients with comorbid dementia and depressive symptomatology. Receiver operating characteristic analysis was applied to determine the optimal cutoff of the AES-12PD as an indicator of apathy. Results The AES-12PD featured high internal consistency that was better compared to the AES. The abbreviated scale was well differentiated from motor impairment and cognitive deficits. The AES-12PD cutoff of 27/28 was the optimal cutoff for apathy in PD patients without dementia and depression. The cutoff of 25/26 indicated apathy in PD patients with comorbid dementia and depression. Conclusion Results confirm a high internal consistency and good discriminant validity of the AES-12PD. The AES-12PD represents a reliable tool for the efficient assessment of apathy that can be applied in PD patients with and without dementia and depression.