<prompt> How to differentiate between psychological and organic erectile dysfunction -Nocturnal penile tumescencePIPE therapySildenafil induced erectionSqueeze technique  <response>: Ans. is a i.e.. Nocturnal penile tumescence o One of the important method to distinguish psychogenic impotence from organic impotence is nocturnal penile tumsescence early morning erection which are preserved in psychogenic impotence but not in organic cause of impotence. 