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Frank Rattay and his work group say their farewells

Frank Rattay 2025: 15 years of retirement, a milestone birthday, and the conclusion of a research project on the simulation of cochlear implants

Portraits of Andreas Fellner, Prof. Rattay and Cornelia Wenger

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The world’s first simulations of electrically generated nerve signals in the auditory nerve by implanted electrodes were carried out by Frank RATTAY more than 40 years ago. The occasion was provided by the very first microelectronic multichannel cochlear implants developed at TU Wien by the pioneers Ingeborg HOCHMAIR-DESOYER and Erwin HOCHMAIR.

At that time, rapid solutions to the nonlinear differential equations were only possible with the help of analog circuits, the basic elements of TU Wien’s hybrid computer. However, the principle of electrical nerve stimulation has many other applications in medical technology, from pacemakers to deep brain stimulation for Parkinson’s, and retinal implants for the blind. Through the analysis of electrical relationships, Frank Rattay succeeded in providing a simple explanation of the mechanism of extracellular electrical and magnetic nerve stimulation with the introduction of the activation function (see Wikipedia, opens an external URL in a new window) There is an article, opens an external URL in a new window in Artificial Organs about Frank Rattay as a pioneer of electrostimulation.

In a discussion with Nobel laureate Andrew Fielding HUXLEY about Rattay’s simulations, it became apparent how limited the theoretical knowledge of extracellular electrostimulation was in the 80s. This lack of basic knowledge between electrophysiology and the application of electrical nerve stimulation encouraged Frank Rattay in 1986 to develop the concept of the activation function for nerve fibers, to write the first monograph "Electrical Nerve Stimulation" in 1990, and in 1999 to generalize the activation function from the classic cylindrical form for nerve fibers to arbitrary surfaces of nerve cells.

Throughout his academic life at TU Wien, Frank Rattay supervised 170 diploma theses and 76 dissertations. Furthermore, as chair of the study commission, he led the transition to the Bachelor-Master system in mathematics. Since 1994, Frank Rattay has coordinated the biomedical engineering research area at TU across faculties and, together with Philippe ZYSSET, established the Master’s program in "Biomedical Engineering".

Frank Rattay was leader of numerous research projects, most of them funded by the Austrian Science Fund, the city of Vienna, EU and USA. The last project, entitled "Scala vestibuli prostheses," ended in April 2025 and was carried out with Andreas FELLNER and Cornelia WENGER who have found new positions in Portugal and Upper Austria. Thematically, the project dealt with an alternative positioning of the electrode carrier in the upper duct system of the cochlea. Although this strategy has been clinically tested for years in cases of heavily ossified cochleae, this situation was investigated by computer modelling and simulation for the first time as part of the project. This made it possible to compare the resulting excitability of the auditory nerve with the standard case of a Scala tympani implant. Some of these initial research results were summarized and featured in Advances in Engineering, opens an external URL in a new window

Apart from his academic commitments, Frank Rattay led an artists’ group for many years, exhibiting their works in public spaces (Kunstmeile Liesing, among others sculptures from rounded steel, see the news report, opens an external URL in a new window), and remains very active in craftsmanship, working on house construction and re-roofing.

We wish all the best to Frank Rattay, Andreas Fellner and Cornelia Wenger for their futures.