Document Type


Date of Award

Spring 5-31-1998

Degree Name

Master of Science in Biomedical Engineering - (M.S.)


Biomedical Engineering Committee

First Advisor

Stanley S. Reisman

Second Advisor

David S. Kristol

Third Advisor

Arthur B. Ritter


Clinical evidence exists to suggest that an individual's level of stress contributes to the state of many physiological and psychological disorders, The autonomic nervous system, by adjusting parasympathetic and sympathetic activity, is attributed with the control over an individual's level of neural stress. Therefore, it is desired to develop a better and quantitative understanding of the stress! autonomic system mechanism.

Previous work has been done to gain a partial understanding of such activity. The primary objective for this study is to complement and advance the previous work by determining whether there is other physiological data which could reveal more about the correlation between autonomic neurological activity and illness or disease.

The work in this study was designed to identify a valid procedure for quantifying relative stress levels. Furthermore, it includes the objective to be useful for clinical and commercial application. This requires that the equipment be inexpensive, and the method simple to implement, non-invasive, straightforward to interpret, and yield accurate results.

A method which uses a Photoplethysmograph to measure blood volume in the fingertip was selected. A lap-top computer with Lab VIEW software was used to acquire, display, store and process that data. An experimental protocol which was designed to change the stress level in test subjects was executed.

The method devised effectively met the objectives for clinical! commercial development. Preliminary results indicate that the acquired data is useful and may be processed to readily quantify relative changes in blood volume.

This technique effectively complements other methods which provide information about parasympathetic activity. With some enhancement, this technique may be developed to obtain information about both sympathetic and parasympathetic activity, all at the same time.



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