Zoltán Galáž

Zoltán Galáž
Brno University of Technology · Department of Telecommunications

Ph.D.
Focusing on interpretable machine learning applied in the field of neurodegenerative and neurodevelopmental disorders.

About

54
Publications
11,039
Reads
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675
Citations
Citations since 2016
49 Research Items
672 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
Introduction
Zoltan Galaz (https://www.zoltan.galaz.eu) is a leading data scientist at the Brain Diseases Analysis Laboratory (BDALab). He deals with the research and development of methodology and non-invasive tools for diagnosing, rating, monitoring, and treatment of neurodegenerative and neurodevelopmental disorders based on advanced signal processing and machine learning techniques. See: https://www.youtube.com/watch?v=_4Jo8mmdhxw
Additional affiliations
September 2015 - April 2020
Brno University of Technology
Position
  • Researcher
September 2015 - present
Brno University of Technology
Position
  • Analyst
Education
September 2014 - December 2018
Brno University of Technology
Field of study
  • Signal Processing
September 2011 - June 2014
Brno University of Technology
Field of study
  • Signal Processing
September 2008 - June 2011
Brno University of Technology
Field of study
  • Signal Processing

Publications

Publications (54)
Preprint
Full-text available
Motor speech disorders in patients with Parkinson’s disease (PD), collectively referred to as hypokinetic dysarthria, are the early markers of the disease. Acoustic speech features are, therefore, suitable digital biomarkers for the diagnosis and monitoring of this pathological phenomenon. At the same time, it is clear that language plays an essent...
Article
Full-text available
Parkinson's disease dysgraphia (PDYS), one of the earliest signs of Parkinson's disease (PD), has been researched as a promising biomarker of PD and as the target of a noninvasive and inexpensive approach to monitoring the progress of the disease. However, although several approaches to supportive PDYS diagnosis have been proposed (mainly based on...
Preprint
This paper deals with a~complex acoustic analysis of phonation in patients with Parkinson's disease (PD) with a~special focus on estimation of disease progress that is described by 7 different clinical scales (e.\,g. Unified Parkinson's disease rating scale or Beck depression inventory). The analysis is based on parametrization of 5 Czech vowels pr...
Preprint
Full-text available
Up to 90% of patients with Parkinson's disease (PD) suffer from hypokinetic dysathria (HD) which is also manifested in the field of phonation. Clinical signs of HD like monoloudness, monopitch or hoarse voice are usually quantified by conventional clinical interpretable features (jitter, shimmer, harmonic-to-noise ratio, etc.). This paper provides...
Preprint
This paper deals with a~complex acoustic analysis of phonation in patients with Parkinson's disease (PD) with a~special focus on estimation of disease progress that is described by 7 different clinical scales (e.\,g. Unified Parkinson's disease rating scale or Beck depression inventory). The analysis is based on parametrization of 5 Czech vowels pr...
Preprint
Full-text available
Up to 90 % of patients with Parkinson's disease (PD) suffer from hypokinetic dysarthria (HD). In this work, we analysed the power of conventional speech features quantifying imprecise articulation, dysprosody, speech dysfluency and speech quality deterioration extracted from a specialized poem recitation task to discriminate dysarthric and healthy...
Preprint
Full-text available
This paper deals with a complex acoustic analysis of phonation in patients with Parkinson's disease (PD) with a special focus on estimation of disease progress that is described by 7 different clinical scales ,e. g. Unified Parkinson's disease rating scale or Beck depression inventory. The analysis is based on parametrization of 5 Czech vowels pron...
Article
Introduction Hypokinetic dysarthria (HD) is common in Parkinson’s disease (PD). Our objective was to evaluate articulatory networks and their reorganization due to PD pathology in individuals without overt speech impairment using a multimodal MRI protocol and acoustic analysis of speech. Methods A total of 34 PD patients with no subjective HD comp...
Article
Full-text available
Background: Diffusion kurtosis imaging has been applied to evaluate white matter and basal ganglia micro-structure in mixed Parkinson's disease (PD) groups with inconclusive results. Objectives: To evaluate specific patterns of kurtosis changes in PD and to assess the utility of diffusion imaging in differentiating between healthy subjects and cogn...
Article
Full-text available
Automatic objective non-invasive detection of pathological voice based on computerized analysis of acoustic signals can play an important role in early diagnosis, progression tracking, and even effective treatment of pathological voices. In search towards such a robust voice pathology detection system, we investigated three distinct classifiers wit...
Article
Full-text available
The Table 3 was published incorrectly in the original publication of the article.
Article
Full-text available
School-aged children spend 31–60%of their time at school performing handwriting, which is a complex perceptual-motor skill composed of a coordinated combination of fine graphomotor movements. As up to 30% of them experience graphomotor difficulties (GD), timely diagnosis of these difficulties and therapeutic intervention are of great importance. At...
Article
Full-text available
Dysgraphia (D) is a complex specific learning disorder with a prevalence of up to 30%, which is linked with handwriting issues. The factors recognized for assessing these issues are legibility and performance time. Two questionnaires, the Handwriting Proficiency Screening Questionnaire (HPSQ) for teachers and its modification for children (HPSQ-C),...
Article
Full-text available
Graphomotor disabilities (GD) are present in up to 30% of school-aged children and are associated with several symptoms in the field of kinematics. Although the basic kinematic features such as velocity, acceleration, and jerk were proved to effectively quantify these symptoms, a recent body of research identified that the theory of fractional calc...
Preprint
Full-text available
Automatic objective non-invasive detection of pathological voice based on computerized analysis of acoustic signals can play an important role in early diagnosis, progression tracking and even effective treatment of pathological voices. In search towards such a robust voice pathology detection system we investigated 3 distinct classifiers within su...
Preprint
Full-text available
This paper describes a preliminary investigation of Voice Pathology Detection using Deep Neural Networks (DNN). We used voice recordings of sustained vowel /a/ produced at normal pitch from German corpus Saarbruecken Voice Database (SVD). This corpus contains voice recordings and electroglottograph signals of more than 2 000 speakers. The idea behi...
Conference Paper
The majority of Parkinson's disease (PD) patients suffer from handwriting abnormalities commonly called as Parkinsonic dysgraphia. Several approaches of PD dysgraphia analysis exist, e.g. based on online handwriting processing. However, a small and unilingual cohort of PD patients is often an issue in quantitative PD dysgraphia analysis studies. Th...
Presentation
Full-text available
The majority of Parkinson’s disease (PD) patients suffer from handwriting abnormalities commonly called as Parkinsonic dysgraphia. Several approaches of PD dysgraphia analysis exist, e.g. based on online handwriting processing. However, a small and unilingual cohort of PD patients is often an issue in quantitative PD dysgraphia analysis studies. Th...
Article
Full-text available
Parkinson's disease dysgraphia affects the majority of Parkinson's disease (PD) patients and is the result of handwriting abnormalities mainly caused by motor dysfunctions. Several effective approaches to quantitative PD dysgraphia analysis, such as online handwriting processing, have been utilized. In this study, we aim to deeply explore the impac...
Article
Full-text available
Hypokinetic dysarthria (HD) and freezing of gait (FOG) are both axial symptoms that occur in patients with Parkinson’s disease (PD). It is assumed they have some common pathophysiological mechanisms and therefore that speech disorders in PD can predict FOG deficits within the horizon of some years. The aim of this study is to employ a complex quant...
Article
Full-text available
Hypokinetic dysarthria, which is associated with Parkinson's disease (PD), affects several speech dimensions, including phonation. Although the scientific community has dealt with a quantitative analysis of phonation in PD patients, a complex research revealing probable relations between phonatory features and progress of PD is missing. Therefore,...
Conference Paper
Parkinson's disease (PD) is one of the most frequent neurodegenerative disorder with progressive decline in several motor and non-motor skills. Due to time-consuming and partially subjective conventional PD diagnosis, several more effective approaches based on signal processing and machine learning, e.g. online handwriting analysis, have been propo...
Conference Paper
Full-text available
Determining the place of origin of the musical compositions is a modern area of research in the field of music information retrieval (MIR). The musical interpretation of one piece carries a variety of author's intentions that influence the musical character of the resulting composition. These aspects may include rhythm, dynamics, timbre, or tonalit...
Article
Full-text available
Introduction: Hypokinetic dysarthria (HD) is a common symptom of Parkinson's disease (PD) which does not respond well to PD treatments. We investigated acute effects of repetitive transcranial magnetic stimulation (rTMS) of the motor and auditory feedback area on HD in PD using acoustic analysis of speech. Methods: We used 10 Hz and 1 Hz stimula...
Article
Full-text available
Neurodegenerative pathologies as Parkinson's Disease (PD) show important distortions in speech, affecting fluency, prosody, articulation and phonation. Classically, measurements based on articulation gestures altering formant positions, as the Vocal Space Area (VSA) or the Formant Centralization Ratio (FCR) have been proposed to measure speech dist...
Conference Paper
Parkinson’s disease (PD) is the second most frequent neurodegenerative disorder. One typical hallmark of PD is disruption in execution of practised skills such as handwriting. This paper introduces a new methodology of kinematic features calculation based on fractional derivatives applied on PD handwriting. Discrimination power of basic kinematic f...
Poster
Full-text available
In search towards a robust voice pathology detection system (VPD), we investigated three distinct classifiers within supervised learning and anomaly detection paradigms on data from four different databases with the aim to: 1) Investigate whether it is possible to build a robust VPD system using currently available resources and mentioned classifie...
Article
Introduction Hypokinetic dysarthria (HD) is a common symptom of Parkinson’s disease (PD) which does not respond well to PD treatments. We investigated short-term effects of repetitive transcranial magnetic stimulation (rTMS) on HD in PD using acoustic analysis of speech. Methods We used both high and low frequency rTMS applied over the right poste...
Presentation
Full-text available
Lots of voice pathologies are not being diagnosed and treated due to a lack of training, time or appropriate equipment of general practitioners. We are aiming for early diagnosis using quick preventive tests, without extensive training and without the need for expensive equipment. Which would point the patient to a specialized voice therapist if ne...
Article
Full-text available
Aim: The research described is intended to give a description of articulation dynamics as a correlate of the kinematic behavior of the jaw-tongue biomechanical system, encoded as a probability distribution of an absolute joint velocity. This distribution may be used in detecting and grading speech from patients affected by neurodegenerative illness...
Conference Paper
Full-text available
This paper describes a preliminary investigation of Voice Pathology Detection using Deep Neural Networks (DNN). We used voice recordings of sustained vowel /a/ produced at normal pitch from German corpus Saarbruecken Voice Database (SVD). This corpus contains voice recordings and electroglottograph signals of more than 2 000 speakers. The idea behi...
Conference Paper
Hypokinetic dysarthria (HD) and freezing of gait (FOG) are frequent symptoms of Parkinson's disease (PD). The aim of this work is to reveal pathological mechanisms common for HD and FOG, and use acoustic analysis of dysarthric speech to assess the gait difficulties in PD. We used a correlation analysis to investigate a relationship between speech f...
Conference Paper
Up to 90% of patients with Parkinson's disease (PD) suffer from hypokinetic dysarthria (HD). In this work, we analysed the power of conventional speech features quantifying imprecise articulation, dysprosody, speech dysfluency and speech quality deterioration extracted from a specialized poem recitation task to discriminate dysarthric and healthy s...
Article
Full-text available
Hypokinetic dysarthria (HD) occurs in 90% of Parkinson's disease (PD) patients. It manifests specifically in the areas of articulation, phonation, prosody, speech fluency, and faciokinesis. We aimed to systematically review papers on HD in PD with a special focus on (1) early PD diagnosis and monitoring of the disease progression using acoustic voi...
Article
Developmental dysgraphia, being observed among 10–30% of school-aged children, is a disturbance or difficulty in the production of written language that has to do with the mechanics of writing. The objective of this study is to propose a method that can be used for automated diagnosis of this disorder, as well as for estimation of difficulty level...
Code
Objective analysis of Parkinson’s disease (PD) based on quantification of hypokinetic dysarthria (HD) is a modern and prospective method of diagnosis, assessment, monitoring and treating of the disease. It has been shown that approximately 60 – 90% of patients with PD suffer from HD. HD is characterized by impaired respiration, phonation, articulat...
Chapter
Up to 90 % of patients with Parkinson’s disease (PD) suffer from hypokinetic dysathria (HD) which is also manifested in the field of phonation. Clinical signs of HD like monoloudness, monopitch or hoarse voice are usually quantified by conventional clinical interpretable features (jitter, shimmer, harmonic-to-noise ratio, etc.). This paper provides...
Article
Background and objective: Hypokinetic dysarthria (HD) is a frequent speech disorder associated with idiopathic Parkinson's disease (PD). It affects all dimensions of speech production. One of the most common features of HD is dysprosody that is characterized by alterations of rhythm and speech rate, flat speech melody, and impairment of speech inte...
Code
Analysis of dysarthric speech is usually performed in combination with some form of visualization of parametric space computed in direction of extracting clinically interpretable information about speech production deterioration. This toolbox (Dysarthric Speech Visualization tool – DSV tool) enables users to visualize several world-renown methods s...
Conference Paper
Full-text available
This paper deals with an acoustic analysis of hypokinetic dysarthria in patients with Parkinson's disease (PD). The analysis is based on parametrization of five basic Czech vowels using conventional features and parameters based on empirical mode decomposition (EMD). Experimental dataset consists of 84 PD patients with different disease progress an...
Code
In the field of biomedical signal processing (such as the speech signal processing, hand-written text processing, etc.), it often happens that the result of the parametrization process (parametrization serves us to quantify the useful information stored in the data with so called parameters) is a high-dimensional parametrization space. It describes...
Code
Preliminary statistical analysis is used as a tool to obtain a statistical insight into the analysed dataset. In the field of pathological signal processing the common methodology is to perform so called parametrization process in order to extract clinically useful information from the data to describe the deterioration of the speech production. Th...
Conference Paper
Full-text available
This paper deals with a complex acoustic analysis of phonation in patients with Parkinson's disease (PD) with a special focus on estimation of disease progress that is described by 7 different clinical scales (e. g. Unified Parkinson's disease rating scale or Beck depression inventory). The analysis is based on parametrization of 5 Czech vowels pro...

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Projects

Projects (4)
Project
The goal of the project is to develop a psychological diagnostic method for evaluation of graphomotor disabilities. Currently, the dysgraphia diagnosis is based on the subjective assessment of experts. The proposed software will provide the objective acquisition and interpretation of parameters linked to graphomotor disabilities, based on children’s drawings and handwriting. This data will be processed by mathematical modeling of behavioral, socio-demographic and clinical data, which will be used to produce a visualization that displays the severity of the disability on a scale. The outcome will be objective, accurate, and valid diagnostics of handwriting disabilities. Project outcomes will be the psycho-diagnostic method and its methodology, software, several publications, and a workshop.
Archived project
The main goal of this multidisciplinary project is to research the handwriting/drawing parameterization in relation to the developmental dysgraphia (DD) symptoms and as a result to introduce a new concept/methodology of computerized DD diagnosis and rating.