Table 1.

Self-reported pain assessment tools for older adults with cognitive impairment

Scale	Description	Psychometric properties
Numeric Rating Scale (NRS) [204]	A line with numbers 0 to 10 displayed at equal intervals, where 0 means no pain and 10 means the worst pain imaginable.	NRS has been validated among older adults [300, 311, 312]. The completion rate was high for people with cognitive impairment. The completion rate decreased in people with mild (76%) to moderate (58%) cognitive impairment [313].
Faces Pain Scale (FPS) Revised Faces Pain Scale (FPS-R) [206, 207]	Consists of different facial expressions to indicate different severity of pain experienced by patients.	Both are reliable and valid in older people with cognitive impairments and with different cultural background [204, 209, 210, 314, 315] For patients with deficits in facial recognition, the results should be interpreted with care [316].
Iowa Pain Thermometer (IPT) [204]	A descriptor scale presented with a graphic thermometer showing a color gradient from white to red in order to help patients rate their pain intensity as temperature. Additional choices between words are available to improve the sensitivity of the scale.	Older adults with cognitive impairment are more likely to correctly complete IPT as compared to NRS, Verbal Descriptor Scale, FPS, and visual analog scale [204]. IPT is the most preferred scale by both young and older adults (with osteoarthritic pain) [204].
Verbal Descriptor Scale (VDS) [317]	Consists of seven verbal descriptions to indicate different severity of pain ranging from 0 to 6, where 0 means “no pain” and 6 means “pain as bad as it could be.”	VDS score agrees with the ratings of FPS or NRS but their associations are not linearly related [317]. The majority (90%) of people with moderate cognitive impairment can accurately use VDS [313]. A simplified version has been developed for people with severe dementia [318]
Visual Analog Scale (VAS) [319]	A 10-cm line with 0 means no pain and 10 means the worst possible pain.	VAS has significantly higher error (approximately 20%) among older adults as compared to NRS and VDS [203, 320, 321].