Sometimes doctors need more information to put the correct diagnosis or to determine the actual cause of the problem. In this case doctors usually recommend making other tests which specifically help to understand the underlying cause and severity of ED condition. One of these tests may be prostaglandin E1 injection test. It is performed to assess the penile blood flow. Prostaglandin is directly injected into the corpora cavernosa of the penis, this is made to cause the blood vessels wide and provide blood flow into the penile tissues. If erection occurs as a result of this procedure it assures normal blood flow to the organ. In addition the procedure provides information for possible therapeutic possibilities.
The other method or procedure which monitors erections that happen during sleep is called nocturnal penile tumescence. This helps distinguish if erectile dysfunction is a result of psychological or physical disorders. During two or three night a man has to sleep with a band around his penis to determine intensity and duration of erections if they occur. If nocturnal erections do not happen, erectile dysfunction affliction is of physical rather than psychological character. Still this procedure is not absolutely reliable and should be accompanied by other tests and methods.
One of the methods to estimate the penile nerve function is direct vibrational stimulation which is known as biothesiometry. Vibration amplitude is adjusted with the help of electromagnetic electrodes which are put on the shaft of the penis. The patient is tested to notice the sensation of the penis to this vibration. The procedure is used as a screening method to discover any sensory nerve loss caused by impotence.