The apathy inventory: assessment of apathy and awareness in Alzheimer's disease, Parkinson's disease and mild cognitive impairment.

Objective: This study was designed to establish the validity and reliability of the apathy inventory (IA), a rating scale for global assessment of apathy and separate assessment of emotional blunting, lack of initiative, and lack of interest.

Method: Information for the IA can be obtained from the patient or from a caregiver. We evaluated 115 subjects using the IA, consisting of 19 healthy elderly subjects, 24 patients with Mild Cognitive Impairment (MCI), 12 subjects with Parkinson's disease (PD) and 60 subjects with Alzheimer's disease (AD).

Results: Internal consistency, item reliability, and between-rater reliability were high. A test-retest reliability study demonstrated that caregiver responses to IA questions were stable over short intervals. A concurrent validity study showed that the IA assesses apathy as effectively as the Neuro Psychiatric Inventory apathy domain. In the caregiver-based evaluation, AD subjects had significantly higher scores than controls, both for global apathy score and for the lack of interest dimension. When the AD patients were subdivided according to diagnostic criteria for apathy, apathetic patients had significantly higher scores than non apathetic patients. With the patient-based evaluations, no differences were found among the AD, MCI and control groups. The scores in the patient-based evaluations were only higher for the PD group versus the control subjects. The results also indicated that AD patients had poor awareness of their emotional blunting and lack of initiative.

Conclusions: The IA is a reliable method for assessing in demented and non-demented elderly subjects several dimensions of the apathetic syndrome, and also the subject's awareness of these symptoms.