Online Analysis of Handwriting For Disease Diagnosis: A Review
Online Analysis of Handwriting For Disease Diagnosis: A Review
Research paper
Abstract
Background/Objectives: Handwriting is an action governed by brain like any other action. This process is usually unconscious and is
closely tied to impulses from brain. Any kind of disease affects the kinetic movement and reflects in subject’s handwriting. To understand
the health and mental problems, it is important to focus on how subject writes instead of what subject writes. This also makes the process
of handwriting analysis independent of any language. Handwriting analysis is a pseudo-science used to study physical and behavioral
characteristics of handwriting. In this paper, the general approach used for the disease diagnosis based on digital handwriting analysis has
been presented. The research work carried out to diagnose diseases such as Alzheimer, Mild Cognitive Impairment, Dysgraphia,
Schizophrenia, Autism, Parkinson’s disease and Mental illness based on digital handwriting analysis has been reviewed in this paper. The
features related to motion, time and pressure have been used for diagnosis of disease. The experiments and results are also summarized in
this paper.
Copyright © 2018 Authors. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
506 International Journal of Engineering & Technology
There are two phases of system namely learning phase and testing
phase. The goal of learning phase is to build the model of
classification. Machine learning algorithms are used to build this
model [12]. The ANOVA test [13], Naive Bayes [14], Support
Vector Machine (SVM), Decision Tree, K-Nearest Neighbors, K-
Means [15] are most commonly used algorithms to model the
data.
sheet and on a blank sheet. The statistical study was carried out features were classified using linear support vector machine. They
based on orientation, slant, ordering, and baseline of letters to obtained 89.9% accuracy [24].
derive writing score. This score was obtained using interrater
reliability coefficient of statistical program SPSS and the median 4.3. Schizophrenia
score of the three separate evaluations computed for each subject.
The results showed that patients having a writing score upto five Schizophrenia (SZ) is found in 1% of population in people of age
never had a MODA greater than 60 nor a MMSE greater than 20 around 20’s. Schizophrenia patients often behave quite different
[19]. They concluded that handwriting is a useful for evaluating and strange as compared to normal people and sometimes they
the posthumous of testamentary capacity. could not able to relate themselves with real world. Schizophrenia
Murad Badarna et. al. studied pen motion patterns in patients patients can be distinguished by using kinetic features of
having low MCI and high MCI. The handwriting analysis was handwriting like velocity or jerk [25].
based on spatial measures like width, height, displacement, and Alexander B et. al. studied Schizophrenia patient’s handwriting
curve length, kinematic measures like mean, median, and standard movements to measure drug-induced motor side effects. Six
deviation in acceleration, in-air and on-paper duration, pressure schizophrenia subjects who have not received any antipsychotic
and angles. They obtained classification accuracy of 95.23% for medication, 27 schizophrenia subjects treated with risperidone and
patients with low MCI based on the on-surface pen motion pattern 46 healthy subjects were enrolled for study. Participants were
and accuracy of 85.80% for patients having high MCI [20]. given exercise to draw loops of different size and writing a
sentence. The data was recorded and analysed using MovAlyzeR
4.2. Dysgraphia tool. The up and down successive movements were segmented
into strokes. For each stroke, peak vertical velocity, velocity
Dysgraphia is found in school-aged children. Children with scaling (VS), vertical size, and average normalized jerk (ANJ)
Dysgraphia face difficulties in organizing letters and produce across a trial were measured. Results showed that patients treated
uneven patterns of disordered handwriting. Using spatial and with risperidone exhibited significantly greater dysfluent
temporal measures, children with Dysgraphia can be identified handwriting movements than healthy or untreated SZ participants.
easily [21]. Differences were observed in some handwriting kinematic
Zdenek Mzourek et. al. analyzed sequential writing of 27 children measures like ANJ between unmediated SZ patients and healthy
having Dysgraphia, with 27 age-matched controls having participants. The sentences produced by unmediated SZ patients
experience of two years of writing in school. The parameters were were smoother than medicated patients, and their handwriting
based on 51 features, divided into three groups: non-linear movements were more dysfluent [26].
dynamic features, kinematic features and other features. The M. Ahmadlou et. al. performed analysis of kinetic features of
observations were based on altitude/tilt and pressure. The features handwriting among group of healthy people and SZ patients.
based on pressure found more useful for diagnosis of Dysgraphia. Subjects were asked to write ‘hello’ word three times in different
They observed that pressure applied was higher by 17% in case of scales of height 1cm, 2cm and 4cm. Eight different features were
children having Dysgraphia. To improve accuracy, they proposed extracted out of which three related to vertical peak velocity (PV)
an intra-writer normalization method based on subtraction. This and others are related to velocity scaling slope (VSS), normalized
method showed increase in accuracy by 4% and decrease in HPSQ jerk (NJ) and ANJ. An artificial neural network (ANN) of N nodes
score estimation error by 3.48%. This proposed automatic system (N equals to number of selected features) was created with three
had 96% sensitivity and specificity towards diagnosis of layers. The first layer was an input layer, next was hidden layer
Dysgraphia and also the system was able to rate developmental with 1 to 20 nodes and output layer with one node. The results
Dysgraphia with estimated HPSQ total score with 10% error [22]. were obtained through 100 different runs. In each run, four data
Patrice L. Weiss et. al. studied and compared both, online samples were used for testing purpose and other seventeen for
handwriting obtained using digital tablet and traditional learning purpose. The system was able to differentiate SZ subjects
handwriting analysis obtained from a pen and paper, among group from normal people with accuracy of 97.5% [27].
of children having Dysgraphia and group of children with Theo Wayne S. Fenton et. al. suggested a method to analyze
proficient handwriting. Handwriting samples of 50 proficient performance of lateralized motor in SZ subjects. Patients were
students and 50 students of 3rd grade with Dysgraphia were asked to draw two straight lines with each hand. These lines were
collected. The results showed that both digital and conventional scanned using HP Plotter. To measure deviation in straight line,
evaluations were able to differentiate between children with root mean squared (RMS) error of regression equation was
Dysgraphia and children with proficient handwriting. By calculated for each line. To measure overall degree of disorder, the
combining both the methods, they got improved understanding of average of RMS error of all four lines was taken. Also the
writing difficulties. The spatial and temporal measures of difference in RMS values was measured between two hands to
handwriting kinematics were used as primary features. The total compare performance index of motoric laterality. The writing
length paragraph and total length of in-air and on-paper movement samples were collected from 86 SZ patients diagnosed using
constitute spatial measures whereas total time recorded to finish statistical and diagnostic manual of mental disorders test. Fourteen
writing tasks, in-air and on-paper time, were also included as employees from housekeeping staff were included as control
temporal measures. The digital analysis of handwriting showed subjects. To obtain reliable image of scanned drawing sample,
significantly higher in-air time among the Dysgraphia handwrites four lines drawn by each control subject were selected randomly
as compared to proficient writers. The pencil travelled above from database and scanned twice and scores were compared using
writing surface between successive character segments, letters and one-tailed Pearson Correlation for each line drawn by each control
words among the non-proficient writers as compared to proficient subject. The SZ patients and control subjects were compared
writers. These results provided clues of underlying difficulties based on lateralization and motor disorder indices with the help of
limiting performance of children with Dysgraphia [23]. one-tailed T-tests. The SZ patients poorly performed motor
Gideon Dror et. al. proposed a system for characterization and movements than control subjects [28].
automatic identification of Dysgraphia in third-grade children. The
system was based on analysis of child’s writing movements. The 4.4. Autism
pressure applied on pen, it’s orientation and position were
measured using a standard digital writing pad. The samples of Autism occurs in school-aged children. Children with Autism
ninety-nine Dysgraphia writers and proficient writers were often face difficulties in communicating with other people. Also it
collected. The features extracted were based on wide range of is difficult to understand their feelings and read their mind.
dynamic and visual properties of handwriting. The extracted Children with Autism can be identified by analyzing speed, slant
509 International Journal of Engineering & Technology
and size of handwriting [29]. lengths, 9.22mm (SD = 1.60) whereas in positive and neutral
Sara Rosenblum studied behavior of children’s handwriting with subjects they were longer 10.67mm (SD = 2.46) and 10.74mm
autism spectrum disorder. Sixty children aged 9-12 years from (SD = 2.89) respectively. The width of strokes was narrower in the
third to sixth grades from different schools were included in the negative subjects, 3.03mm (SD = 0.44) as compared to 3.60mm
study. Out of sixty, half children had high-functioning autism (SD = 0.85) and 3.43mm (SD = 0.77) in positive and neutral
spectrum disorder having Intelligence Quotient above 80 whereas subjects respectively. In group of negative subjects, the height of
other 30 were normal children. The degree of pressure applied by strokes produced was shorter 4.52mm (SD = 0.9) in comparison
subject on paper, the rhythm and speed of handwriting, in-air time, with negative and neutral subjects 5.32mm (SD = 1.34) and
slant and some other features were measured for each subject. The 5.53mm (SD = 1.41) respectively. The duration of on-paper
system correctly identified children with autism with accuracy of strokes was shorter in the positive and negative moods, 144ms
91.5%. The letters produced by children with Autism were taller (SD = 19.2) and 143.5ms (SD = 18.4) respectively, whereas for
and broader, and degree of pen’s slant on paper was smaller, also neutral subjects it was 157 ms (SD = 32.5). Also strokes produced
on-paper and in-air waiting times were longer as compared to by subjects with negative mood had lower pressure than those
normal students [30]. made in neutral or positive moods [36].
A study by Beth Patricia Johnson et. al. was aimed to characterize Perla Werner et. al. examined functional disorder in performance
handwriting performance in children with Autism Spectrum of handwriting between elder people with Mild Major Depressive
Disorder(ASD) by using digitized handwriting tasks. The study Disorder (MDD). Twenty elder people diagnosed with DSM-IV
included 52 boys with 8 to 12 years of age, 29 typically test of mild MDD were included along with twenty healthy
developing (TD) children from control group and 23 patients of subjects recruited among MDD participant’s relatives having
ASD. The efficiency of motor movements was measured using similar gender, age and educational level. The space, time and
MABC-2 test. Five writing sequences were given to each subject pressure were measured based on four handwriting tasks such as
in cursive letters (1. emem, 2. elel, 3. eeem, 4. eeel, 5. eeee) copying a paragraph, writing one’s name and surname, writing all
having transition movements among similar (e-to-e) and different alphabets sequentially and filling in a check. The pressure applied
letters (e-to-m, e-to-l) with variation in direction and sizing. by depressed patients was significantly lower and proven to be
Tortuosity, size, writing speed and average peak velocity for a major factor affecting the writing performance. Also the time
writing sequence were measured. The results showed that ASD required to plan and execute movement of hands was higher. This
children were facing greater difficulty in writing as compared to feature was measured using in-air duration on pen [37].
group of TD children of similar age. Also the letters/words were
spaced unevenly by ASD children [31]. 4.6. Parkinson Disease
A review by Evdokia Anagnostou et. al. analyzed existing
evidences showing dysfunction in writing movements of children Parkinson Disease (PD) is a disorder in motor functions due to
with ASD and documented their handwriting difficulties. They damage in central nervous system. It is found in people with age
collected and analysed data from January 1943 to January 2011 around 50 years and it gets worse over the time. By measuring the
from ISI Web of Science, PubMed, Google Scholar, Scopus and jerk and acceleration pattern of handwriting produced PD can be
all English-language related to ASD children [32]. identified [38].
The Quantitative measurement of handwriting was carried out by
4.5. Mental Illness David Song et. al. to analyse discriminate in every-day
handwriting tasks among group of people having Parkinson’s
Handwriting Analysis has also been used to find people with disease, people with psychotropic-induced Parkinsonism and
negative emotions like Stress, Anxiety and Depression. normal people. The aim was to find some psycho-parameter to
Depression is increasingly affecting people world-wide. It affects measure degree of Parkinsonism. The experiment included ten
motivation, concentration and many other aspects of human life. subjects (1 female and 9 males) meeting DSM-IV criteria of
Stress depends on two things: psychological perception of schizophrenia having clinically observable drug-induced
pressure and body’s response to it which involves multiple Parkinsonism, thirteen patients (4 females and 9 males) diagnosed
systems, from metabolism to muscles to memory. Anxiety is with idiopathic PD and Twelve (2 females and 10 males) normal
reaction to stressful situations which occurs in threatening healthy comparison subjects (NC). The velocity analysis of
circumstances. Person with negative emotions show difference in handwriting samples showed that peak velocities of vertical
pressure applied on pen while writing, also the strokes are strokes from middle to bottom were nearly doubled, whereas for
abnormal in time and space [33, 34]. SZ patient’s velocities were constant. In addition, to find degree of
Anna Esposito et. al. proposed a system to detect of negative smoothness of handwriting, NJ was calculated based on
emotions through writing and drawing tasks. The time-based normalized size and duration of strokes. Results showed that both
features were used as they are more efficient to determine the state SZ and PD patients had lower velocities than normal people,
of mental illness. They measured in-air and on-paper duration, particularly for stokes larger than 4cm. Significant reduction in VS
total time and various characteristics of stokes using digitalizing was observed in both PD and SZ subjects whereas on SZ subjects
tablet. For each writing or drawing task, in-air, on-paper, and total exhibited lack of smoothness [39].
time taken by candidate was recorded along with number of stokes Rifat Sipahi et. al. introduced method based on analysis of static
and ranked using Random Forest approach. The results were images of subject’s signature or handwriting samples to detect
validated against DASS [35] and repeating the experiment N times changes in micrographic of subjects with therapeutic response or
on K candidates by excluding one candidate from population each symptomatic progression in Parkinson’s disease. Twelve samples
time to form subset of K-1 candidates. The results showed that of signature of different subjects corresponding to symptomatic
stress and anxiety can be recognized more correctly than PD conditions, normal health and artificially generated signature
depression using digital handwriting analysis [11]. with reduced size were used for comparison. Matrices sensitive to
Gil Luria et. al. studied relationship between handwriting and the properties of micrographic were chosen with minimal
mood. Sixty-two subjects from University of Haifa were included sensitivity to confounding handwriting properties. These metrics
in the study with average age of 24.8 ranging between 21 to 29 included ink utilization, character size-reduction and pixel density
years. The Computerized Penmanship Evaluation Tool and of writing samples from left to right. The signatures of subjects
Software (ComPET) was used for analysis of features. The were collected and scored for each group before and after clinical
variation in length, width, height of strokes, duration and pressure diagnosis of subjects. Significant difference was observed in Pixel
applied were measured among group of positive, negative and Density among signature recordings, before versus after [40].
neutral people. In negative subjects the strokes had shorter M. Naumann et. al. studied kinetic features of handwriting
510 International Journal of Engineering & Technology
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Autism In-air time and slant, Sizing, IQ
machine-learing/
Tortuosity
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[18] Perla Werner, Sara Rosenblum, Gady Bar-On, Jeremia Heinik and
Parkinson Velocity Jerk, Kinetic Measures UPDRS
Amos Korczyn, “Handwriting Process Variables Discriminating
Mild Alzheimer’s Disease and Mild Cognitive Impairment”, The
Journals of Gerontology: Series B, vol 61, Issue 4, Pages P228–
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[19] Paola Fontana, Francesca Dagnino, Leonardo Cocito and Maurizio
Handwriting is also called as brain writing. It is used to predict Balestrino, “Handwriting as a gauge of cognitive status: a novel
physical, emotional and mental health of an individual. In this forensic tool for posthumous evaluation of testamentary capacity”,
Neurol Sci., 29(4):257-61, 2008.
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[20] Murad Badarna, Ilan Shimshoni, Gil Luria and Sara Rosenblum,
diagnosis of health and mental issues has been presented. A model “The Importance of Pen Motion Pattern Groups for Semi-
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