Complaint Review: Penile Plethysmograph

From 1982-1988, I was the Director of the Psychophysiological lab at the Sexual Behavior Clinic in New York City. I personally (not through a technician) assessed and treated over 700 adolescent and adult sex offenders. After reading your piece on the plethysmograph, I have a few comments:

1. Plethysmograph data is totally useless for determining guilt or innocence regarding deviant sexual acts. It would be like using a personality test to convict someone of burglary.

2. Plethysmographic data have no diagnostic value of any kind.

3. About one-third of offenders show no arousal in the lab.

4. The proper stimuli to use are not pictures, but taped fantasies. Ideally taped fantasies spoken by the offender themselves, describing the offenders' own fantasies as well as contrived ones.

5. The value in plethysmographic assessment is to aid the offender in learning how to control erection responses during deviant fantasy. that is it. It has no value in "seeing if the treatment worked." Treatment should not be court-ordered. The best outcomes I've seen were post-adjudication, when there was no coercion involving treatment. I had the occasion to do some treatment with post-adjudication offenders at a detention facility in Bucks County, PA.

6. The plethymograph most definitely has value in diagnosing organic versus psychogenic impotence. A study by Dr. Charles Fisher in 1965 determined that 1,000 out of 1,000 healthy men tested had penile erection responses during REM sleep. When there is lack of response, that indicates further evaluation by a urologist. So it is useful as a screening device.

In summary, I agree with many of your concerns regarding the plethysmograph. I may have more direct, hands-on experience with this device than anyone in this country, and I've spoken against its abuses for some time now. But don't throw it away completely. It still has some limited, though functional use.
Robert M. Stein, Ph.D.
Center for Neurobehavioral Health, Ltd.
Lancaster, PA