Validation of the Icelandic version of the Neuropsychiatric Inventory with Caregiver Distress (NPI-D).

BACKGROUND: Dementia is a complex and often debilitating illness, presenting with not only wide-ranging cognitive impairment but also neuropsychiatric challenges, which can have diverse consequences in quality of life for both patient and caregiver.

AIM: Studying the validity and reliability of an Icelandic translation of the Neuropsychiatric Inventory with Caregiver Distress (NPI-D).

METHODS: NPI-D was administered to 38 primary caregivers of dementia patients. The concurrent validity was explored by statistically comparing the NPI-D to the Behavioural Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD) and the Geriatric Depression Scale (GDS). Regarding caregiver distress, concurrent validity was established between NPI-D, BEHAVE-AD Global Rating and two other caregiver distress scales.

RESULTS: Significant correlation was found when total score on the BEHAVE-AD was compared with total score on the NPI-D. All NPI-D subscales achieved significant correlation with the corresponding BEHAVE-AD subscales apart from the 'depression/dysphoria subscale'. This NPI-D subscale correlated however, significantly with the GDS depression scale, a frequent and well validated measure of depressive symptoms in the elderly population. Cronbach's alpha coefficient indicated a high degree of overall internal consistency among the items of the NPI-D. Interestingly, apathy was the most frequent neuropsychiatric disturbance and the only subscale that differed significantly between dementia severity levels. Finally, when studying caregiver distress, the NPI-D showed good concurrent validity with other measures of caregiver burden and distress.

CONCLUSIONS: The results demonstrate an acceptable level of validity and reliability; therefore the Icelandic translation of the NPI-D is well suited for identifying neuropsychiatric symptoms in dementia and associated caregiver burden.