January 16, 2005, Updated September 13, 2012

Prof. Yoram Vardi: We can use the test to verify the effectiveness of hormones and drugs that are meant to increase or decrease libido.Millions of Americans suffer from lack of sexual desire – or at least think they do. Now, for the first time, an Israeli-developed test can scientifically determine the level of a person’s libido. The method – developed by a team led by Prof. Yoram Vardi of Rambam Hospital in Haifa – can enable medical professionals to determine the root cause of diminished sexual desire, and whether medication or treatment is being effective.

“What we’ve developed is a test that objectively measures the subject’s amount of interest in sex – it rates their libido,” Vardi told ISRAEL21c. “Until now, through all the years of research in this subject, we’ve only have had subjective ideas on this matter – mainly what the patient would tell us. There isn’t even an evaluated standardized questionnaire on libido. What we set out to do is to devise something objective – that can measure and quantify a person’s sexual desire.”

The chief of the neurological unit at Rambam, and a professor of urology at the Technion Israel Institute of Science, Vardi is also the head of the Armon Center for Sexual Dysfunction, a joint project of Rambam and the Clalit Health Fund.

“I’m a urologist and deal with mostly neurological problems like incontinence. However I also deal with the subject of sexual dysfunction,” he said.

His study was designed to provide preliminary data on the use of brain waves for objectively quantifying the level of interest in sexual content. Twenty two healthy volunteer subjects with normal sexual function participated in this study (11 females and 11 males, with a mean age of 26.8 years).

“Our methodology is not a new one. We produced brain waves by giving auditory stimuli and measure them through electrodes placed on the head. We then examine the p300 waves – these are brain waves that are delayed by 300 milliseconds.”

Vardi explained that a baseline is established – the norm of the p300 waves for someone listening to music. Based on an accepted methodology that people cannot concentrate equally on two different stimuli, a visual element is then added to the mix.

“Once you add the visual element, the p300 waves are going to be diminished, depending on how much the subject is paying attention to the new stimuli,” said Vardi. “What we did – after establishing the baseline of the brain wave, was to present other types of stimuli – video clips of erotic, sexual content, but also clips of sports, nature, and romance, as means of providing contrasting results. We then compared the baseline p300 brain waves with those obtained during the viewing of the video clips.”

A higher reduction in p300 amplitude meant more attention to the visual stimuli, explained Vardi, adding that for validation, these results were compared to the scores obtained through a questionnaire that evaluated the subject’s reaction to the different clips.

“What we found was that, in all subjects, the most significant reduction in p300 amplitudes was found when viewing sexual clips. At the end of the testing session, we also asked the subjects via the questionaire how much they were attracted to the sexual content. We found a very significant statistical correlation between what the subject told us and the amount the brain waves were diminished.”

For all subjects, a lesser degree of reduction, but still statistically significant from baseline, was found when viewing sports and romantic clips. According to Vardi, what the study shows – and the questionnaire verifies – is that the p300 testing accurately reveals if and how much a person’s brain waves react to the film clips of sexual content.

“The p300 testing could provide us with important data regarding the subject’s sexual interest and we believe that in the future this method will probably be applied for the evaluation of sexual desire or libido.”

“This has great implications from a clinical point of view in the very near future. If for example, someone is in a car accident, and comes in later saying that due to the trauma after the accident, they’ve lost their sexual desire, we now have a tool to measure if that is indeed true,” said Vardi.

“Not only that, but it can also be used to measure the effect of treatment and medication on the libido. It can help doctors diagnose and provide the right treatment for patients. We can use it to test hormones and drugs that are meant to increase or decrease libido.”

Vardi said that the test can also help determine if a patient is suffering from a physical or emotional problem which is affecting his libido.

“In sexual dysfunction, there are two types of problems – organic and psychogenic. The organic include medical problems like diabetes or cardio-vascular disease which can affect the libido, while the psychogenic involve an emotional problem. Our test will be able to help determine whether the organic problem prompts the decline in sexual interest or whether it’s a psychogenic problem.”

Vardi presented the results to the International Society of Sexual Dysfunction which was held in Buenos Aries, and at a conference of the European division of the Society which was held in December in London.

“It was received very well and prompted lots of talk and interest. First of all it’s a simple test, not too sophisticated, it’s not molecular biology. Secondly, it’s about sex, so it’s a novelty, and people get excited about it.”

None more so than Vardi himself.

“We’re beginning to use the test on actual patients, not just volunteers. I’m thinking of calling it the Libido-meter. That’s a good name, isn’t it?”

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