Paul Ayala was charged with operating a vehicle while under the influence of an intoxicating drug in Milwaukee County, Wisconsin. The trial court excluded the testimony of his expert witness and Ayala was convicted. The Wisconsin Court of Appeals affirmed the trial judge’s exclusion of the expert testimony.

Facts of the Case

A police officer observed Ayala’s car facing west in an eastbound traffic lane. The engine was running but the car was not moving.

The officer noted that the car was damaged. Two mirrors were broken, the bumpers were dented, and the car had a flat tire. Ayala seemed confused and his speech was slurred.

Ayala failed field sobriety tests and was arrested. A blood test revealed the presence of Ambien in an amount well in excess of a therapeutic dose. Ayala denied taking Ambien on the night of his arrest.

Expert Evidence

Ayala wanted to raise the defense of involuntary intoxication. To that end, he proffered the testimony of Dr. Esam Dajani, a toxicologist and pharmacologist.

Dr. Dajani’s expert report expressed the opinion that Ayala suffered from a medical condition that inhibited his ability to absorb Ambien, causing it to remain in his stomach for two to three days. Dr. Dajani opined that Ambien built up in Ayala’s system over a period of time and that the cumulative effect of the Ambien, coupled with some antihistamines he took before he started driving, produced his intoxicated state.

The prosecution moved to exclude Dr. Dajani’s testimony on the ground that he was offering a medical opinion that he was not qualified to give. The trial court held a Daubert hearing before granting that motion.

The court based its ruling on Dr. Dajani’s assumption that Ayala suffered from the medical condition that supposedly inhibited his ability to absorb Ambien. Dr. Dajani based that assumption on medication that had been prescribed to Ayala. However, Ayala’s medical records did not include a diagnosis confirming that medical condition.

Appellate Review

While the Wisconsin Supreme Court declined for many years to adopt the Daubert standard, the state legislature amended the Rules of Evidence to require trial courts to subject expert testimony to Daubert scrutiny. Wisconsin appellate courts nevertheless give trial courts “broad latitude” in deciding how to determine the reliability of an expert’s opinion.

The Wisconsin Court of Appeals applied that deferential review to the trial court’s exclusion of Dr. Dajani’s opinion. The appellate court deferred to the trial court’s finding that, as a pharmacologist and toxicologist, Dr. Dajani was not qualified to diagnose a medical condition. Since his expert opinion depended on a diagnosis that Dr. Dajani could not make, his opinion was not reliable.

The outcome may well have been different if Ayala’s medical records had confirmed that he had the medical condition that Dr. Dajani inferred was the basis for the medication that Ayala’s doctor had prescribed. Dr. Dajani’s expertise would likely have permitted him to render an opinion about the absorption of Ambien into the system of a patient who suffers from that condition. But since the condition had never been diagnosed (or at least had never been recorded in the medical records that Dr. Dajani reviewed), Dr. Dajani had no reliable facts upon which to base his expert opinion.

Lesson Learned

It isn’t clear whether Dr. Dajani contacted Ayala’s physician to inquire about the missing diagnosis. Had he done so, and had the diagnosis been consistent with the condition upon which Dr. Dajani based his opinion, Dr. Dajani would presumably have been relying on the kind of facts that experts are permitted to consider in forming an opinion. Since his opinion would then have had a foundation, Dr. Dajani would presumably have been allowed to testify.

Perhaps the defense made a calculated gamble not to contact the physician for fear that the physician had not made a diagnosis that would support Dr. Dajani’s opinion. If so, the gamble did not pay off. Hindsight is always 20-20, but the lesson to be learned is that an expert who is not a physician and whose opinion is conditioned on a medical diagnosis should confirm that a physician actually made that diagnosis rather than inferring that the diagnosis must have been made.