Central and peripheral neural responses in males with idiopathic hypogonadotropic hypogonadism.

It has previously been shown that abnormal neurophysiologic responses are associated with Kallmann's syndrome. However, little is known about neurophysiologic responses in idiopathic hypogonadotropic hypogonadism (IHH). Fifty-six untreated male patients with IHH (mean age: 20 +/- 0.7 years) were compared with a control group of 20 age-matched male subjects to determine whether IHH can lead to alterations in somatosensory evoked potentials (SSEPs) and brainstem auditory evoked potentials (BAEPs). We have also investigated the effect of gonadotropin replacement (hCG/hMG) therapy on these tests in 20 randomly selected patients. Significant cervical 7 (N13), Erb (N9) and thoracic 12 (N22) latency prolongation was observed in median and tibial nerve SSEPs in patients with IHH as compared with a matched control group. Other components of SSEPs and interpeak latencies of BAEPs yielded no significant difference between untreated patients and control group. Abnormal components of SSEPs did not correlate with basal hormone levels and did not improve with gonadotropin therapy. We conclude that IHH results abnormalities in peripheral but not central nervous system components of SSEPs and that short term gonadotropin treatment cannot correct these abnormalities.