I sit on the scientific and medical advisory board for TASER International and wish to comment on the column "Police search for a defense in death" by Rebecca Walsh ( Tribune, June 21).

Commenting on the tragic death of Brian Cardall, Walsh states that the TASER Electronic Control Device was "zapping Cardall full of 50,000 volts" and implies that it contributed to his death.

The actual pulse voltage delivered by the TASER X26 is 600 volts and that is in very short pulses.

This 100-fold exaggeration is provided by Amnesty International material. This anti-police activist group has long used exaggeration and innuendo against TASER ECDs as a significant fundraising tool.

It is helpful to discuss the most common electronic control devices -- electric fences. The TASER X26 ECD satisfies the Underwriters Laboratory electric fence standards and puts out only 40 percent of the output allowed. If the TASER ECD were actually dangerous, the ranchers in your readership would have to remove their electric fences lest they risk electrocuting the next person that walks into one.

Walsh scoffs at the deadly condition known as "excited delirium" syndrome. She states, "Promoted by a retired Texas medical examiner, excited delirium is not accepted by either the American Medical Association or the American Psychological Association." This represents another of the statements of Amnesty International.

Your readers can see what the AMA actually says about excited delirium by going to their website.

"Excited delirium" is a widely accepted entity in forensic pathology and is cited by medical examiners to explain the sudden in-custody deaths of individuals who are combative and in a highly agitated state.

Excited delirium is broadly defined as a state of agitation, excitability, paranoia, aggression and apparent immunity to pain, often associated with stimulant use and certain psychiatric disorders.

The signs and symptoms typically ascribed to "excited delirium" include bizarre or violent behavior, hyperactivity, hyperthermia, confusion, great strength, sweating and removal of clothing, and imperviousness to pain.

Excited delirium deaths have been reported in the medical literature for over 150 years. The exact term is found in medical textbooks beginning in the 1800s.

The fundamentals of an excited delirium death are not that difficult to understand. Our bodies have limits to exertion. If we were to run rapidly we would eventually tire and slow down or stop because our brain recognizes signals of overexertion such as acid in our blood. If we were to continue -- because our brain ignored such signals -- we would exert ourselves until we died. The body has limits for a reason. If these limits are sufficiently exceeded we will die.

Walsh adds, "Brian Cardall is missing key symptoms of excited delirium: He had no cocaine in his system. He was not massive or obese."

If your readers read the AMA statement on excited delirium, they'll see that these criteria are actually not required.

Our thoughts and prayers should be with the Cardall family that is suffering from their sudden loss. It does them a great disservice to repeat exaggerations and innuendo from the fundraising material of an activist anti-police group to incorrectly imply that police officers killed their son.

Mark Kroll teaches in the biomedical engineering department at the University of Minnesota.