Taser Takes Down Expert in Patent Infringement Action Where Electrical Engineer Was Not Qualified to Offer Expert Opinions on Electrophysiology

Taser International, Inc. ("Taser') proceeded to trial on its patent infringement action against Karbon Arms, LLC ("Karbon Arms"). After expert reports and with the trial approaching, Taser filed a motion to exclude the expert testimony Val DiEuliis, one of Karbon Arms' experts, regarding electrophysiology.

As explained by Taser, Dr. DiEuliis offered opinions on certain limitations of the patent-in-suit (United States Patent 7,800,885), including: "compliance signals of the group differ in intensity of pain compliance," "compliance signals of the group differ in intensity of skeletal muscle contraction," and "effective duration."

Dr. DiEuliis had disclaimed any expertise in electrophysiology and, because these terms related to the physiological effects of electricity, TASER moved to exclude his testimony on these limitations under Fed. R. Evid. 702 and Daubert.

In opposing the motion, Karbon did not dispute that Dr. DiEuliis is not an expert in electrophysiology. Instead, Karbon argued that Dr. DiEuliis need not be an expert in electrophysiology for his testimony to be admissible because he is a person of ordinary skill in the art. As explained by the district court, "[e]ssentially, Karbon argues that Dr. DiEuliis' testimony does not concern electrophysiology, but electrical engineering, something about which he is qualified to testify."

The district court disagreed. "Karbon's argument misses the mark. As Dr. DiEuliis has admitted, he is not an expert in electrophysiology. Therefore, Dr. DiEuliis cannot testify concerning electrophysiology. While Karbon argues that his testimony only concerns electrical engineering, TASER has pointed to numerous instances where Dr. DiEuliis attempts to rebut TASER's electrophysiology expert, opines on the stimulation of nerves, muscular response to electricity, and muscle contractions, and offers an electrophysiological definition of the term 'effective duration.' This testimony is improper."

Finally, the district court concluded that Dr. DiEuliis could not testify concerning electrophysiology. However, the district court found that he may testify to those things within his expertise. The district court then concluded that "[i]t is difficult to tell beforehand where that line is drawn, but I expect it will be clear during trial."

Taser International, Inc. v. Karbon Arms, LLC, Case No. 1:11-cv-00426 (D. Del. Dec. 18, 2013)