ASSESSING THE IMPACT OF NEUROPSYCHIATRIC SYMPTOMS IN ALZHEIMERS-DISEASE - THE NEUROPSYCHIATRIC INVENTORY CAREGIVER DISTRESS SCALE

OBJECTIVES: To develop an adjunct scale to the Neuropsychiatric Invent ory (NPI) for assessing the impact of neuropsy chiatric symptoms in Al zheimer's disease (AD) patients on caregiver distress, DESIGN: Cross-s ectional descriptive and correlational study. SETTING: University out- patient memory disorders clinics. PARTICIPANTS: Eighty-five AD subject s and their caregivers (54 spouses, 31 children). MEASUREMENTS: The NP I and NPI Caregiver Distress Scale (NPI-D) were used to assess neurops ychiatric symptoms in AD patients and related caregiver distress, resp ectively. Criterion validity of the NPI-D tvas examined(N = 69) by com parison with an abridged version of the Relatives' Stress Scale (RSS') , a general measure of sari giver stress, using item clusters that had previously been correlated to behavioral disturbances in demented pat ients. Test-retest in = 20) and inter-rater reliability (n = 16) of th e NPI-D were also assessed. RESULTS: Test-retest and interrater reliab ility of the NPT-D were both adequate, Overall, caregiver NPI-D distre ss ratings were correlated significantly with the RSS' (r = .60, P < . 001), RSS' ratings correlated strongly with NPI scores (r .64, P < .00 1), even after controlling for degree of cognitive impairment based on the Mini-Mental State Exam (MMSE) score (r = .61). MMSE scores showed a moderate correlation to RSS' ratings (-.30, P = .02), but this asso ciation was markedly attenuated when controlling for the degree of neu ropsychiatric disturbance based on the NPI score (r = -.14). NPI-D rat ings for 9 of 10 NPI symptom domains correlated most strongly with eit her NPI symptom severity or total (frequency X severity) scores. Agita tion, dysphoria, irritability, delusions, and apathy were the symptoms most often reported to be severely distressing to caregivers. CONCLUS IONS: The NPI-D provides a reliable and valid measure of subjective ca regiver distress in relation to neuropsychiatric symptoms measured by the NPI. Neuropsychiatric alterations are more strongly associated tha n cognitive symptoms to caregiver distress. The NPI-D may be useful in both clinical and research settings for assessing the contribution to caregiver distress of neuropsychiatric symptoms in AD patients.