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

Abstract

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