Erection: The Sleep Laboratory

The sleep laboratory is popular in some countries. In others, it is not, partly due to the high expense. A healthy sexually-active man may have five separate erections during the night. The average number is three to five, depending upon how often the sleeper enters dream sleep.

In a sleep laboratory, sleep cycles and NPT (nocturnal penile tumescence) are monitored on a device called a Rigiscan. Two silicone rings filled with mercury act as “strain gauges.” They are put around the corona and the shaft base. Each takes a separate recording calibrated to measure width increase in millimeters. This is called penile plethysmography.

Normal erectile capacity as girth increase is in the range of 10 to 15 mm at the corona, and 12 to 20 mm at the base.

Rigidity is tested in the same way. The readings are recorded as millimeters of deflection. These are converted by calibration to the grams force needed to buckle an erect shaft. A force in excess of 1500 must never be applied. Normal tonicity challenge is in excess of 500 grams force. (Penile plethysmography is also used for sex criminals who deny their desires. Pictures of a woman being attacked and of naked children of both genders are shown when he is awake. If the plethysmograph records tumescence, he is shown the print-out and can accept his deviancy. And the psychologist learns in which area to apply aversion therapy techniques.)

Other measurements include: two leads on the outer area of the eyelids to record separate eye movements; two EEG leads on the head to record brain activity on the electro-encephalograph; and various other leads to record involuntary muscle movement, heart and respiratory rate, and skin activity. There should be at least one full erection lasting at least five minutes without any fluctuation in width increase and rigidity.

It may be necessary to spend three nights in the laboratory. Night 1 is for getting used to strange surroundings, and learning to sleep while wired up (painlessly) to machines. On Night 2, sleep is usually better quality, allowing more REM sleep and more NPT. Recordings of these two nights are collated and become data base for assessing maximum NPT rigidity, number, endurance time.

On Night 3, the man is awakened during REM sleep and asked to observe his erection, and comment on rigidity, width and angle. A polaroid photograph is taken so he can rate the quality with those before trouble started. If the problem is psychogenic, they are much the same.

If the problem is physical, other factors to note are:
1. Partial engorgement only.
2. Frequent short-endurance erections.
3. Very few short-endurance erections.
4. Uneven ratio of width increase between the corona and base.

While expensive, the sleep lab provides measurable answers to questions on health and erection. But knowing what the problem is can be a cost-saver in the end, both in terms of money and setting the right expectations.

Tags: erectile dysfunction, erection, erection dysfunction, erection problems, impotency, maintaining erection, painful erection, sleep disorder