Which objective itch-assessment tools are applicable to patients with advanced cognitive impairments? A scoping review

Background: Itching is an irritating and uncomfortable sensation that has a profound effect on patients' physical and mental health. It is a major under-recognised problem in older patients who cannot express their pain due to advanced cognitive impairment. Therefore, objective itch-assessment tools that do not rely on patients' reports of itching may be of value for this patient group. Objective: To summarise the characteristics of validated objective itch-assessment tools for patients with advanced cognitive impairment. Methods: This scoping review was conducted according to the PRISMA extension for scoping reviews checklist. The PubMed, CINAHL and Cochrane Library databases were searched, via database-specific search strategies, for articles published in English between January 1, 1990 and March 11, 2020. Based on the eligibility criteria, two authors independently screened the articles for inclusion. Thereafter, the lead author performed data extraction and analysis. Results: Three validated scratch-monitoring using accelerometers and a sound sensor and one validated scratch-mark assessment have been reported. The Actiwatch Plus, ActiTrac (R), body-conducted sound sensor and Scoring Atopic Dermatitis index for scratching (SCORAD-scratch) had positive criterion validity outcomes. The Actiwatch Plus, ActiTrac (R) and body-conducted sound sensor were significantly correlated with scratch behaviour (r = 0.91, p < 0.001; r = 0.71, p = 0.042; r = 0.99, and p-value not shown, respectively). The SCORAD-scratch was significantly correlated with subjective itch-assessment scores (r = 0.78-0.80, p = <0.0001-0.010). Conclusions: This scoping review summarises the characteristics of validated objective itch-assessment tools to investigate which of these are applicable to older patients with advanced cognitive impairments. Although there are limitations and further verification is required, the ActiTrac (R), Actiwatch Plus and body-conducted sound sensor may be useful for measuring scratch movements and itching.