Observer-rated pain assessment instruments improve both the detection of pain and the evaluation of pain intensity in people with dementia.

BACKGROUND: Observer-rated pain assessment instruments for people with dementia have proliferated in recent years and are mainly effective in identifying the presence of pain. The objective of this study was to determine whether these tools can also be used to evaluate intensity of pain.

METHOD: Quasi-experimental design. Cognitively intact [Mini Mental State Examination (MMSE) ≥ 24, n = 60] and impaired people (MMSE < 20, n = 65) in nursing home facilities took part in the study. Participants were observed at rest and during a movement protocol. Directly afterwards, the observer, blinded to cognitive status, completed three behavioural pain assessment instruments (Abbey Pain Scale, Pain Assessment in Advanced Dementia Scale (PAINAD), Non-communicative Patient's Pain Assessment Instrument (NOPPAIN) ], before interviewing the resident about pain self-report.

RESULTS: Significant correlations were found between observer-rated and self-rated measures of pain and were stronger in persons with dementia than in cognitively intact adults. Discriminant function analysis (DFA) revealed: (1) that the use of observer-rated instruments improved recognition of the presence or absence of pain by up to 25.4% (in dementia) and 28.3% (in cognitively intact adults) above chance; and (2) the same instruments improved the classification of residents into the correct self-reported level of pain intensity by up to 42.5% (in dementia) and 34.1% (in cognitively intact adults) above chance. However, DFA also reveals a considerable rate of 'false alarms' for pain in cognitively intact and 'misses' in cognitively impaired people.

CONCLUSIONS: The use of the Abbey Pain Scale, PAINAD or NOPPAIN improves both the recognition of pain presence/absence as well as rating pain severity in older people with impaired cognition.