Introduction
Aims and Results of Indo-European Research Activities
“Studies of Neurological Induced Skin Perfusion Dynamics”
In recent years, the investigation and understanding of the interaction between
tissue perfusion, brain activity and human hemodynamic are receiving much
attention. Such investigations have been generally confined to few premier research
institutions where expensive and sophisticated facilities like PET, MRI, etc., are
available. However, recent advancements in optoelectronics and computer technology have accelerated the development of new measuring systems and methodologies for use in this medical field. Specifically, transcutaneous assessment of skin
perfusion changes (blood volumetric measurement) through optical-sensor-based
photoplethysmography (PPG) has rapidly gained an important role. This basically
non-invasive measuring procedure is devoid of harmful radiation and ionizing
phenomena, simple in construction and connection to the measuring set-up and is
easy to use in all areas of human body. The relatively low cost of these sensors has
resulted in their use in various medical fields and clinical applications. In the past,
though, the application of PPG had been limited by technical difficulties involving
calibration of the data.
The development of the quantitative PPG technique based on computer-aided
data processing has removed this obstacle. In cooperation between the Indian
Institute of Technology at Chennai and RWTH Aachen University, an
Indo-German Project was initiated in 1996 for advanced studies in this research
area. Measuring system designs, experimental details and some preliminary results
obtained within the framework of this project are presented in this book. From the
investigations carried out so far using the PPG sensors in conjunction with
breathing sensors, it has been possible to monitor the 0.1–0.15 Hz rhythms in the
arterial blood volumetric changes and to study the influence of breathing on them.
These rhythms, which according to medical experts have relevance to psychosomatic conditions like stress or relaxation, can also be addressed to quantify the
benefits or lack of ancient Indian practices like yoga and meditation. Using the PPG
ix
Aims and Results of Indo-European Research Activities
“Studies of Neurological Induced Skin Perfusion Dynamics”
In recent years, the investigation and understanding of the interaction between
tissue perfusion, brain activity and human hemodynamic are receiving much
attention. Such investigations have been generally confined to few premier research
institutions where expensive and sophisticated facilities like PET, MRI, etc., are
available. However, recent advancements in optoelectronics and computer technology have accelerated the development of new measuring systems and methodologies for use in this medical field. Specifically, transcutaneous assessment of skin
perfusion changes (blood volumetric measurement) through optical-sensor-based
photoplethysmography (PPG) has rapidly gained an important role. This basically
non-invasive measuring procedure is devoid of harmful radiation and ionizing
phenomena, simple in construction and connection to the measuring set-up and is
easy to use in all areas of human body. The relatively low cost of these sensors has
resulted in their use in various medical fields and clinical applications. In the past,
though, the application of PPG had been limited by technical difficulties involving
calibration of the data.
The development of the quantitative PPG technique based on computer-aided
data processing has removed this obstacle. In cooperation between the Indian
Institute of Technology at Chennai and RWTH Aachen University, an
Indo-German Project was initiated in 1996 for advanced studies in this research
area. Measuring system designs, experimental details and some preliminary results
obtained within the framework of this project are presented in this book. From the
investigations carried out so far using the PPG sensors in conjunction with
breathing sensors, it has been possible to monitor the 0.1–0.15 Hz rhythms in the
arterial blood volumetric changes and to study the influence of breathing on them.
These rhythms, which according to medical experts have relevance to psychosomatic conditions like stress or relaxation, can also be addressed to quantify the
benefits or lack of ancient Indian practices like yoga and meditation. Using the PPG
ix