Human biosignals analyzed in realtime are at the basis of synthetisation, modulation and control of sound, images, and light. The Realtime Biosignal Workstation is the technical center-piece, a computer system conceived for experimental research and clinical use by the Institute for Biosignal-Engineering.
Aiming at an unambiguous illustration of each biosignal, we are trying to achieve a maximum of transparency in our transformation of each physiological activity, thus creating a new human sound image using only electronic sound devices.
Breathing - as a basis so to speak - is represented in different dimensions at each moment of the performance: in-/exhalation, abdominal/thoracic breathing, respiration depth and frequency as well as pausing between the ex- and inhalation phases.
Heart activity is acquired by means of the electrocardiogram and peripheral blood flow - measured on fingertips and earlobes. Heartbeat, heartrate and pulse volume amplitude form the source of individually programmed sounds, which allow the rhythmical heart activity to be heard and felt, e.g. "Heartpump" in phase 0.
The muscle tone of various surface muscles is measured by the electromyogram. In phase 5 both trapeziuses modulate the overtone structure of a sound played on a keyboard.
The electrooculogram conveys information about horizontal and vertical eye movements as well as blinks. In phases 4 and 6 the panorama position of a sound is controlled by horizontal eye movements. (The video PTT167 should be listened to in stereo.)
The brain activity is acquired by means of a multichannel electroencephalogram. Power spectrum density, coherence of a pair of EEG-waves as well as slow cortical potentials are analyzed. Amplitude spectra divided into frequency bands form the basis of the increasingly harmonious sounds in phase 1. Its graphical representation is a colour coded chronological view of the same spectra.
The skin - first and foremost the activity of the sweat glands - is represented by electrical skin resistance. In the last phase the skin resistance response controls the pitch of a sirene, whose panorama position is controlled by the eye movements of a different person.
The peripheral body temperature is also taken from two fingers. This slowly changing signal is suitable for controlling the tempo of a musical piece or for the modulation of light.