Dynamic time warping: A new method in the study of poor handwriting

Abstract

Poor handwriting is a diagnostic criterion for developmental coordination disorder. Typical of poor handwriting is its low overall quality and the high variability of the spatial characteristics of the letters, usually assessed with a subjective handwriting scale. Recently, Dynamic Time Warping (DTW), a technique originally developed for speech recognition, was introduced for pattern recognition in handwriting. The present study evaluates its application to analyze poor handwriting. Forty children attending Dutch mainstream primary schools were recruited and based on their scores on the Concise Evaluation Scale for Children's Handwriting (Dutch abbreviation: BHK), 20 good and 20 poor writers (of whom 13 were scheduled for handwriting intervention) were identified. The groups were matched for age (7-9 years), school grade (grades 2 and 3) and handedness. The children subsequently wrote sequences of the letter 'a' on a graphics tablet in three conditions (normal, fast, and accurate). Classical kinematics were obtained and for each individual letter DTW was used to calculate the distance from the mean shape. The DTW data revealed much higher variability in the letter forms of the poor writers that was independent of the kinematic results of larger trajectories, faster movements, and higher pen pressure. The current results suggest that DTW is a valid and objective technique for letter-form analysis in handwriting and may hence be useful to evaluate the rehabilitation treatments of children suffering from poor handwriting. In education research it may be exploited to explore how children (should) learn to write.

The Assesment of Spatial Features and Kinematics of Characters: an Analysis of Subjective and Objective Measures

“…Thus, order of strokes production (not always respected in children handwriting, seen as a dynamic characteristic, is taken into account in the DTW computation. Same kind of relation between DTW methods and kinematics has been found by Di Brina (2008). We make the assumption that this index could be used as an overall indicator of the quality of handwriting production in is double assessment of spatial characteristics and kinematics features, as already suggested by several researches (Niels, 2004;Di Brina, 2008).…”

“…The assessment of spatial features and kinematics of characters: an analysis of subjective and objective measures 127 Di Brina, 2008;Bluteau et al, 2008). This algorithm has a real application in character recognition as shown by this citation from Di Brina and colleagues (2008): "By objectively analyzing the spatial-temporal patterns, DTW captures the essential character of writing, i.e., the overall shape of its graphic output".…”

Fall Detection for Mobile Phone based on Movement Pattern

“…When this value is lower than the threshold we computed before, non-fall result can be labeled to this sample. Since dynamic time warping (DTW) was developed for spoken-word recognition [11] and has used to temporally align various types of biometric data [12], we apply it to measure the similarity of real fall events with a new sample. The similarity of two templates in our collecting phase is performed as figure 7.…”

Low-cost movement analysis in children with specific learning disorders: A two-case report

“…This implies that motor coordination disorders are to be searched also in those patients presenting for ADHD, especially when they are dysgraphic (Di Brina, Nielsb, Overvelde, Levi & Hulstijn, 2008). The study of writing skills generally relies on neuropsychological pen-and-paper tests, but the need for well standardised and reliable tools has been underlined (Chiappedi, De Bernardi, Dalla Toffola & Bejor, 2010).…”