Although individuals with dementia who reside in nursing homes are particularly susceptible to developing delirium, this condition is rarely recognised in these settings. Detection of delirium requires validated and reliable tools for this setting that can be applied by nursing staff. The primary objective of the study is to assess the comprehensibility, practicality and inter-rater reliability of two delirium detection tools (4 A’s test (4AT) and 4-item delirium superimposed on dementia (4-DSD)) and one tool for assessing both the diagnosis and severity of delirium (Delirium Rating Scale-Revised-98 (DRS-R-98)) in people with dementia who reside in nursing homes when used by nurses.

The comprehensibility and practicality of the German versions of the 4AT, 4-DSD and DRS-R-98 will be evaluated using cognitive interviews in accordance with the consensus-based standards for the selection of health measurement instruments framework. On the basis of the results of the cognitive interviews, a manual for each of the three tools will be developed and finalised by an expert panel. Finally, the inter-rater reliability and measurement error of the three tools will be determined using the manuals. For this purpose, a total of 70 residents from six nursing homes will be assessed by at least two nurses. The data analysis will include descriptive statistics and inter-rater reliability assessment for individual items (kappa value) and total scores (Intraclass correlation coefficients).

This study will assess the comprehensibility, practicality and inter-rater reliability of the 4AT, 4-DSD and DRS-R-98 for use in residents with dementia in nursing homes. The project was approved by the medical ethics committee of the University of Oldenburg (reference number: 2025-093).

The inter-rater reliability study was registered in the German Clinical Trials Register. Registration number: DRKS00037458 (https://www.drks.de/search/de/trial/DRKS00037458/details).