ABSTRACT
Simultaneous monitoring of penile photoelectric plethysmography, penile tumescences, penile rigidity, bulbocavernosus-ischiocavernosus EMG and EKG was attempted to investigate the age-related erectile response to short period erotic film in 50 normal males and to elucidate the range of its characteristics for the diagnosis of impotence. The results obtained were summarized as follows ; l. Variability was observed in temporal relationship between penile pulse amplitude and penile erection. Of the 45 subjects who showed erection and/or increase in penile pulse amplitude 4 categories of response could be defined : Type I was observed in 13 subjects (28.9%)-erection and increased penile pulse amplitude occurring in parallel ; Type II, in 26 subjects(57.8%)_erection with increased penile pulse amplitude during the development or decline of erection but not during maximum erection ; Type III, in 4 subjects(8. 8%)_erection with no change in penile pulse amplitude ; and Type IV, in 2 subjects (4.4 %)_increased penile pulse amplitude without any erection. These results suggest that penile erection does not exclusively depend increased penile arterial blood flow but upon the cooperative mechanisms with the action of venous blockade which corresponds flexibly to the degree of arterial blood flow. 2. Following erotic stimulation, there was tendency to delay in latency to erection with aging. However, no difference in penile tumescence and rigidity among age groups was observed. This indicates that if the subject is affected by libido owing to strong erotic stimulation, maximum erection ensues regardless of aging. 3. The fact that subjects with good erection shows enough libido and that maximum erection ensues if erection develop under strong erotic stimulation suggests visual sexual stimulation method would be useful in differentiatial diagnosis of erectile dysfunction.