Objectives: To compare 2 samples of patients with Alzheimer disease (AD), from Italy and the United States, in order to determine transcultural differences in the manifestation of noncognitive symptoms. To analyze the concurrent validity, internal consistency reliability, between-rater reliability, and test-retest reliability of the Neuropsychiatric Inventory Scale (NPI).
Methods: The NPI was given to 50 Italian and 50 US patients with AD. To demonstrate the validity and reliability of the Italian version of the instrument, several different methods of analysis were used. The total score on the NPI and the score of single items in the different stages of the disease were compared in the 2 samples of patients.
Results: A high level of internal consistency reliability was confirmed, the between-rater reliability was very high, and the test-retest reliability was significantly correlated. Apathy was the most frequently recorded behavior in the Italian sample. Five of 10 NPI item scores showed a significant relation with the Mini-Mental State Examination scores in both samples. The Italian patients showed an increasing and significantly higher mean NPI total score at all levels of dementia severity when compared with the US patients. The scores on some NPI subscales, such as apathy, aberrant motor behavior, disinhibition, and agitation, were significant higher in Italian patients at different levels of severity covarying with educational level.
Conclusions: These results indicate that NPI is a reliable instrument with which to study transcultural differences in the presentation of neuropsychiatric disturbances in patients with AD. The described similar pattern of behaviors between Italians and US patients with AD suggests a biological origin of the disorders. However, cultural influences must be taken in account when the focus of the study is on psychopathological aspects of dementia.