Papers by Kathiresan Manickam
This work describes the complexity found in the normal and the deaf crying acoustic waves. Using ... more This work describes the complexity found in the normal and the deaf crying acoustic waves. Using approximate entropy, in a single figure, the complexity of the auto-covariance of the signal is computed. Thus, using this complexity value, we are able to discriminate the normal and the deaf infants crying domains with
Approximate entropy (ApEn) adapted to quantify the pattern complexity across the electro-glottogr... more Approximate entropy (ApEn) adapted to quantify the pattern complexity across the electro-glottogram (EGG) spectral domain characterizes normal male vowel phonation in two groups, a majority group (G1) with high ApEn and a minority group (G2) with low ApEn. Using the ApEn measure of normality a sample of post-treatment male oncology patients with adult onset growth hormone deficiency (GHD) shows distinctive spectral entropy signatures. These are consistent with either disrupted larynx development in relative youth, with high normal-group G1 complexity and elevated pitch, or loss of conscious control in middle age, with low normal group G2 or worse complexity. This is at least initial evidence that speech perturbation may be of value in detecting the adult GHD in oncology.
Context: Adult males with congenital, untreated, severe GH deficiency (GHD) due to genetic GHRH r... more Context: Adult males with congenital, untreated, severe GH deficiency (GHD) due to genetic GHRH receptor deficiency exhibit distinctive, high-pitched, and raspy voice characteristics. Objective/Design: To determine the physical underpinning of this phenomenon, we performed voice recordings, translarynx impedance measurements, spectral analysis, and estimates of spectral complexity [approximate entropy (ApEn)] in four affected men. Results were compared with those obtained in four men with untreated adult-onset GHD and a normal male population. Results: Congenital GHD subjects had a high-pitched voice with a fundamentalfrequencytypicalofnormalfemales(174–266Hz).Their frequency spectra were characterized by abnormal harmonics, with reversal/interruption of the normal amplitude decay among higherorder harmonics, findings consistent with a creaky quality of the voice. Patients with adult-onset GHD, acquired at ages 31, 38, and 40 yr,hadanormalmalepitch(fundamentalfrequency,117–154Hz)but...
December 13-15, 2007: Firenze, Italy, ed. by C. Manfredi, ISBN 978 88-8453-673-3 (print) ISBN 978... more December 13-15, 2007: Firenze, Italy, ed. by C. Manfredi, ISBN 978 88-8453-673-3 (print) ISBN 978-88-8453-674-7 (online) © Firenze university press, 2007. Abstract: The approximate entropy of vowel phonation spectra has been used to reveal two normal voicing groups in healthy males. An analysis of the corresponding open and closed quotients for the groups shows the first with balanced quotients and the second with asymmetric quotients characterised by pronounced vocal fold open phases. This indicates the second group is impacted by turbulent air flow, which reduces both the spectral structure in and approximate entropy of vowel phonation. The corresponding spectra are presented to confirm the effect. This provides a physiological explanation for the success of approximate entropy as a single figure of merit for voicing quality.
Larynx cancer patients receive radiotherapy as a non-invasive alternative to surgery and cure rat... more Larynx cancer patients receive radiotherapy as a non-invasive alternative to surgery and cure rates are high. Inevitably this impacts vocal fold functionality. Hence, voice recovery as a pre-requisite for resuming normal life is of special interest. Voicing recovery following radiotherapy is studied in this paper. Complexity analysis, using approximate entropy to concisely quantify the collective spectral pattern derived from the electro-glottogram, has revealed a double banded male normal voicing reference standard. Forty-eight male larynx cancer patients have been studied by applying this technique in parallel with an unrestricted perceptual analysis before and one year after radiotherapy. Two thirds of radiotherapy patients had improved voice quality one year after treatment. Approximate entropy increased to reach normal population reference levels. These patients were predominantly in the less aberrant perceptual categories. However, a quarter of patients showed reduced approxim...
A non-parametric iterative model is developed to predict the EGG from the acoustic normalised har... more A non-parametric iterative model is developed to predict the EGG from the acoustic normalised harmonic spectrum. This study is a follow up from the previous work in quantifying EGG harmonic complexity pattern using single figure computed Approximate Entropy. This single figure computation aids in understanding the voice quality changes and vocal functionality. EGG measurements are not widely available so consequently a need to estimate EGG characteristics from the acoustic spectrum is inevitable. 30 % of the healthy male population recovered with the same pattern complexity and 65 % have shown little changes in complexity and the remaining 5 % showed substantial changes in complexity.
ABSTRACT POSTER Workplace Safety and Health Institute 1500 Bendemeer Road #04-01, Ministry of Man... more ABSTRACT POSTER Workplace Safety and Health Institute 1500 Bendemeer Road #04-01, Ministry of Manpower Services Centre, Singapore 339946 . E [email protected] www.wshi.gov.sg Global Estimates of Occupational Accidents and Work-‐related Illnesses 2014. Introducton, Results, Methods, Conclusion. We reviewed employment figures, mortality rates, occupational burden of diseases and injuries, reported accidents, surveys on self-‐reported occupational illnesses and injuries, attributable fractions, economic cost, estimates of work related injuries and ill-‐health, and the most recent information on the problems from published papers, documents, and electronic data sources of international and regional organizations, in particular ILO, WHO, EU and ASEAN, institutions, agencies, and public websites.
IEE Seminar Medical Applications of Signal Processing, 2002
Trans-larynx impedance waveforms or electroglottograms (EGG) are used by speech and language ther... more Trans-larynx impedance waveforms or electroglottograms (EGG) are used by speech and language therapists (SALT) in the management of larynx cancer patients, a population dominated by males. EGG is known to be perturbed by the presence of malignant disease in and around the vocal folds and its treatment by radiotherapy. These perturbations have defied concise interpretation in terms of 'normality'. Hence, this study reports the use of approximate entropy (ApEn) complexity analysis in a fundamental-harmonic normalised (FHN) EGG spectral domain that is free from the effects of pitch variability, to characterise phonation in a single parameter. The approach was first used on waveforms from 89 healthy male volunteers in order to quantify 'normality' of phonation, and then on 48 larynx cancer patients, presenting with varying degrees of voice impairment, before and 12 months after treatment. Results are compared to subjective ranking by a senior SALT. FHN-spectral features divided the healthy volunteers into two statistically distinct groups, one with high, the other with moderate, but both with consistent complexity values. Two thirds of larynx cancer patients presenting with at least some residual vocal fold functionality showed an improvement in their complexity values from pretreatment lows to post treatment highs that were clearly normal. A comparison of complexity changes with expert SALT categorisation demonstrated 70 % agreement, with exceptions concentrated in the most severely affected pre-treatment individuals. (5 pages)
Proceedings Sixth International Conference on Information Visualisation, Feb 1, 2002
Background The International Labour Organization (ILO) estimated that about 2.3 million workers d... more Background The International Labour Organization (ILO) estimated that about 2.3 million workers die from occupational accidents and diseases worldwide every year. This is equivalent to 4 per cent of annual global GDP, or USD2.8 trillion, being lost to direct and indirect costs of accidents and diseases. Other researchers have also reported that about 5 per cent of the burden of all diseases and injuries in established market economies could be attributed to work. Methods The Workplace Safety and Health (WSH) Institute reviewed the methodologies and cost models from different countries when developing this preliminary economic cost model for Singapore. In this model, the WSH Institute determined the cost of work-related injuries and ill health that would be borne by employers, workers and the community. Cost items linked to staff turnover, training of replacement workers, loss of worker output, insurance premium and legal costs incurred were computed as cost borne by employers. The c...
Medical engineering & physics, 2004
Vocal fold functionality may alter in response to direct radiotherapy or indirectly by perturbati... more Vocal fold functionality may alter in response to direct radiotherapy or indirectly by perturbation of the hypothalamic-pituitary axis. Perceptual assessment of voice quality is difficult to summarise in a single, reliable figure of normality and normality itself is undefined. In this study spectral analysis of vocal fold vibration, based on impedance variations measured across the larynx using an electro-glottogram, is used to build a single parameter description of standard vowel phonation in the normal male population. Patient data and perceptual assessment are then compared to this standard. The spectral pattern of the vowel/i/ electro-glottogram time series is analysed using approximate entropy after dynamic fundamental-harmonic frequency normalisation. The approximate entropy provides a single estimate of the spectral pattern complexity. A cohort of 89 normal males formed two statistically distinct groups, G1, with strong spectral pattern and high complexity 0.338 (+/-0.036), ...
Recording occupational accidents and occupational diseases is one of the central demands for good... more Recording occupational accidents and occupational diseases is one of the central demands for good occupational health and safety. Western industrial countries have already for a long time recorded their occupational accidents and occupational diseases, but the established practices of recording differ from country to country. In many developing countries the recording of occupational accidents and diseases has only recently been established or is still absent. Variation in recording due to, e.g. differences in definitions and branch of compensation system is challenging in terms of understanding recorded cases. In addition, work-related diseases are typically excluded from the recording system. Work-related diseases are diseases caused by work, at least partly, but not classified as occupational diseases. For example, musculoskeletal disorders, mental diseases and occupational cancers have received increasing interest. Occupational accidents and work-related diseases are a worldwide problem. They cause a lot of suffering and losses for the individual, organisation, community and society. Statistics of occupational accidents and work-related diseases are needed for prevention work at the enterprise and nation level. Statistics help to focus on specific areas and affect political decision-making. Especially increasing awareness in developing countries and directing limited resources to the right places is easier. The objective of this doctoral thesis was to develop models to estimate the global number of occupational accidents and fatal work-related diseases. The study was done in three parts: the initial study and two update studies. The first one was carried out in 2001-2002. It concentrated on creating a model to estimate the number of occupational accidents for the year 1998 and fatal work-related diseases for the year 2000. The second (2003-2004) and the third (2005-2006) studies were more like update studies. The methods used in these update studies were the same as in the first study to keep the estimated numbers comparable. The number of occupational accidents was calculated for the years 2001 and 2003 as well as the number of fatal work-related diseases for the year 2002. In the second update study fatal work-related diseases figures were given for the first time by country level. In the world approximately 2.3 million deaths occur every year because of occupational accidents and work-related diseases. It means that over 6,000 workers die every day because of their work. There were 330 million non-fatal accidents causing at least four days absence from work during one year. Deaths have remained quite the same during a five year PREFACE My doctoral thesis was like a triathlon which includes three parts done quite separately: three research projects done for the International Labour Organization (ILO), six scientific review articles and the summary of my thesis. The time I used to this academic triathlon was not the world record, partly because I used time also for interesting bypaths. These bypaths helped me better to understand the general view of the theme and to assess methods and results. I would like to thank Professor Kaija Leena Saarela for guiding and supporting me during this process. Especially I am grateful for Kaija Leena that she trusted me and gave me the most interesting research I have ever done and which I have not yet get tired. I am also grateful for Dr., Docent Jukka Takala who gave this project for our unit, who supervised and supported me during this long process. Dr., Docent Hannu Tarvainen and Dr. Tuula Räsänen I would like to thank for the time they used to examine this thesis and ensured that the demands of the doctoral thesis are fulfilled. I have had in luck to work on an environment, where I have met such nice people. I would like to thank my present and former colleagues. Especially discussions with Professor Jouni Kivistö-Rahnasto, Ms. Noora Nenonen M.Sc., Ms. Sanna Nenonen M.Sc. and Mr. Pertti Palukka M.Sc. have taken my work forward. What would I have done without Ms. Heli Kiviranta during these years; thank you for everything. I would like to acknowledge the ILO department of Programme on Safety and Health at Work and the Environment (SAFEWORK), Academy of Finland and Tampere University of Technology for funding. I would also like to thank the Finnish Work Environment Fund for giving me a scholarship which gave me the possibility to work as a part time and wrote articles. Also financial support from Finnish Doctoral Program in Industrial Engineering and Management gave me possibility to write summary and finalise my thesis. I would like to thank my parents Maija and Jarke, my sister Outi and my brother Pete. They trusted me and brought me down to earth. They also taught me that I cannot always be right. My loving thanks for my husband Jari, who always knew that I got this thesis ready even it took time. My daughter Siiri and sons Eero and Aapo, now it is over.
Speech Communication, 2005
Vocal fold vibration during vowel phonation can be used to characterise voice quality. This vibra... more Vocal fold vibration during vowel phonation can be used to characterise voice quality. This vibration can be measured using a laryngograph, which produces a waveform of highly correlated trans-larynx impedance variations, collectively termed the electroglottogram (EGG). Using ...
Journal of Occupational and Environmental Hygiene, 2014
This article reviews the present indicators, trends, and recent solutions and strategies to tackl... more This article reviews the present indicators, trends, and recent solutions and strategies to tackle major global and country problems in safety and health at work. The article is based on the Yant Award Lecture of the American Industrial Hygiene Association (AIHA) at its 2013 Congress. We reviewed employment figures, mortality rates, occupational burden of disease and injuries, reported accidents, surveys on self-reported occupational illnesses and injuries, attributable fractions, national economic cost estimates of work-related injuries and ill health, and the most recent information on the problems from published papers, documents, and electronic data sources of international and regional organizations, in particular the International Labor Organization (ILO), World Health Organization (WHO), and European Union (EU), institutions, agencies, and public websites. We identified and analyzed successful solutions, programs, and strategies to reduce the work-related negative outcomes at various levels. Work-related illnesses that have a long latency period and are linked to ageing are clearly on the increase, while the number of occupational injuries has gone down in industrialized countries thanks to both better prevention and structural changes. We have estimated that globally there are 2.3 million deaths annually for reasons attributed to work. The biggest component is linked to work-related diseases, 2.0 million, and 0.3 million linked to occupational injuries. However, the division of these two factors varies depending on the level of development. In industrialized countries the share of deaths caused by occupational injuries and work-related communicable diseases is very low while non-communicable diseases are the overwhelming causes in those countries. Economic costs of work-related injury and illness vary between 1.8 and 6.0% of GDP in country estimates, the average being 4% according to the ILO. Singapore's economic costs were estimated to be equivalent to 3.2% of GDP based on a preliminary study. If economic losses would take into account involuntary early retirement then costs may be considerably higher, for example, in Finland up to 15% of GDP, while this estimate covers various disorders where work and working conditions may be just one factor of many or where work may aggravate the disease, injury, or disorders, such as traffic injuries, mental disorders, alcoholism, and genetically induced problems. Workplace health promotion, services, and safety and health management, however, may have a major preventive impact on those as well. Leadership and management at all levels, and engagement of workers are key issues in changing the workplace culture. Vision Zero is a useful concept and philosophy in gradually eliminating any harm at work. Legal and enforcement measures that themselves support companies and organizations need to be supplemented with economic justification and convincing arguments to reduce corner-cutting in risk management, and to avoid short-and long-term disabilities, premature retirement, and corporate closures due to mismanagement and poor and unsustainable work life. We consider that a new paradigm is needed where good work is not just considered a daily activity. We need to foster stable conditions and circumstances and sustainable work life where the objective is to maintain your health and work ability beyond the legal retirement age. We need safe and healthy work, for life.
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Papers by Kathiresan Manickam