Background
Behavioral and psychological symptoms of dementia (BPSD) are a well‐known risk factor for an increased burden of care for staff in long‐term care facilities and family caregivers. The factors that contribute to BPSD development are multifaceted, and it is difficult to establish universal solutions for the different types of BPSD in different individuals. This study investigated the characteristics of each symptom and people with dementia using latent trait of BPSD appearance by item response theory.
Method
We conducted a cross‐sectional survey of older residents with dementia in 2015 at 10 selected long‐term care facilities in Hokkaido, Japan. Data were collected with a questionnaire completed by care staff. The questionnaire included a brief questionnaire form of the Neuropsychiatric Inventory (NPI‐Q), a standardized scale to assess 12‐item BPSD. Of the participants (n=312), we excluded 11 who had severe disability in daily living or were almost bed‐ridden and 104 for whom no medical records on cause of dementia were available. The two‐parameter logistic model was used to estimate an item difficulty and item discrimination for each symptom. We examined the association between the person parameters, latent BPSD score, and sociodemographic characteristics of the participants using Welch’s t test or ANOVA.
Result
Of the 197 residents with dementia (women: 81.7%, mean age: 86.4±7.7 years), agitation was the most prevalent symptom in BPSD, followed by irritability and apathy. The difficulty of symptoms was lower in agitation, irritability, aberrant motor behaviors, and disinhibition. This means that those having even lower latent BPSD scores could appear these symptoms. Conversely, hallucinations, euphoria, anxiety, and delusions, which showed higher difficulty, could be exhibited in those with higher latent BPSD scores. Apathy, night‐time disturbances, depression, and appetite disturbances showed too high difficulty and too low discrimination. The latent BPSD scores were not associated with sex, age, place of residence, cause of dementia, but with ADL and cognitive functions.
Conclusion
We demonstrated that some of BPSD symptoms could be characterized by latent trait on BPSD appearance. The characteristics based on latent BPSD trait might be useful to consider the measures of addressing BPSD.