Since pruritus is defined as an unpleasant sensation that provokes the desire to scratch, the assessment of scratching can provide indirect but objective data about itch intensity. Unlike scratching during the daytime, nocturnal scratching is expected to be less influenced by psychosocial factors so as to reflect the extent of itch more reliably. It is also less confounded by other body movements, which makes its measurement easier. Several methods have been devised to record nocturnal scratching since 1970s. Among them wrist actigraphy has advantages as being a portable lightweight device easily tolerated by patients, allowing for longitudinal recording at home with a simple method of data collection and analysis. The amount of wrist activity is reported to correlate with the amount of nocturnal scratching measured by video recording, subjective evaluation of itch, scoring of skin lesions of atopic dermatitis and serum levels of certain inflammatory cytokines, which suggest potential of actigraphy as a useful device to measure nocturnal scratching for the evaluation of itch. On the other hand it is challenged by inability of actigraphy to discriminate scratching from other body movements, discrepancy between the subjective score of itch and actigraphy values, and inter-individual variation in scratching.
KeywordsActigraphy Accelerometer Measurement of itch Scratching Nocturnal scratching Measurement of scratching Atopic dermatitis Objective Wrist activity Sleep Chronic pruritus
- 1.Stander S, Augustin M, Reich A, Blome C, Ebata T, Phan NQ, Szepietowski JC. Pruritus assessment in clinical trials: consensus recommendations from the International Forum for the Study of Itch (IFSI) Special Interest Group Scoring Itch in Clinical Trials. Acta Derm Venereol. 2013;93(5):509–14.CrossRefPubMedGoogle Scholar
- 29.Wootton CI, Koller K, Lawton S, O’Leary C, Thomas KS, SWET study team. Are accelerometers a useful tool for measuring disease activity in children with eczema? Validity, responsiveness to change, and acceptability of use in a clinical trial setting. Br J Dermatol. 2012;167(5):1131–7.CrossRefPubMedGoogle Scholar
- 31.Noro Y, Omoto Y, Umeda K, Tanaka F, Shiratsuka Y, Yamada T, Isoda K, Matsubara K, Yamanaka K, Gabazza EC, Nishikawa M, Mizutani H. Novel acoustic evaluation system for scratching behavior in itching dermatitis: rapid and accurate analysis for nocturnal scratching of atopic dermatitis patients. J Dermatol. 2014;41(3):233–8.CrossRefPubMedGoogle Scholar