Detection of Nocturnal Scratching Movements in Patients with Atopic Dermatitis Using Accelerometers and Recurrent Neural Networks

Abstract

Atopic dermatitis is a chronic inflammatory skin condition affecting both children and adults and is associated with pruritus. A method for objectively quantifying nocturnal scratching events could aid in the development of therapies for atopic dermatitis and other pruritic disorders. High-resolution wrist actigraphy (three-dimensional accelerometer sensors sampled at 20 Hz) is a noninvasive method to record movement. This paper presents an algorithm to detect nocturnal scratching events based on actigraphy data. The twofold process consists of segmenting the data into "no motion," "single handed motion," and "both handed motion" followed by discriminating motion segments into scratching and other motion using a bidirectional recurrent neural network classifier. The performance was compared against manually scored infrared video data collected from 24 subjects (6 healthy controls and 18 atopic dermatitis patients) demonstrating an score of 0.68 and a rank correlation of 0.945. The algorithm clearly outperformed a published reference method based on wrist actigraphy ( score of 0.09 and a rank correlation of 0.466). The results suggest that scratching movements can be discriminated from other nocturnal movements accurately.

Measurement of Nocturnal Scratching in Patients with Pruritus Using a Smartwatch: Initial Clinical Studies with the Itch Tracker App

“…The studies reported here provide evidence that the newly-developed app, Itch Tracker, in combination with Apple Watch enables measurement of nocturnal scratching in a simple and reliable manner. The algorithm used is different from other algorithms and systems used in previous studies (10)(11)(12). The validated high performance of the app shown by the high sensitivity and high positive predictive values fits the clinical use of this method.…”

“…Their common feature is that acceleration signals produced by wrist movement are recorded by a wristwatch-like device equipped with a built-in accelerometer, followed by analysis of data to quantify scratching. Some recent studies have attempted to differentiate signals caused by scratching signals from those caused by other types of movement, using a specific algorithm to accurately quantify scratching activity (10)(11)(12). However, all of the above actigraphy devices have been produced for specific purposes of measurement and are not general smartwatches that are widely used, thus hampering the spread of this method for daily use.…”

Incorporating patient-reported symptom assessments into routine care for people with chronic kidney disease

“…They allow longitudinal tracking of activity and can be worn around the wrist like a watch while minimizing disruption of everyday life; a pilot study with accelerometers in 29 haemodialysis patients reported that the majority of participants felt able to incorporate the device into their daily activities [ 42 ]. In terms of supporting symptom assessment, accelerometers have been shown to accurately detect scratching activity in patients with dermatologic conditions [ 43 ], which is likely to generalize to people with kidney disease who are bothered by itching. ‘Scratching reports’ generated from accelerometer data might provide a visual aid for patients and clinicians to discuss the severity and impact of itching.…”

Machine Learning in Dermatology: Current Applications, Opportunities, and Limitations

“…Data from personal monitoring devices can also be useful in dermatology for quantifying pruritus [83] or tracking skin over time [84]. One scientific method for assessing pruritus is through video recording of patients, which is tedious and not practical outside an experimental setting [85].…”

“…One scientific method for assessing pruritus is through video recording of patients, which is tedious and not practical outside an experimental setting [85]. Using a ML algorithm to analyze data from a wrist actigraphy device to quantify nocturnal scratching could lead to the creation of novel therapies for atopic dermatitis and other pruritic disorders [83].…”