Congenital Anosmia: Detection Thresholds for Seven Odorant Classes in Hypogonadal and Eugonadal Patients

Abstract

Detection thresholds for a representative from each of seven odorant classes (putrid, pepperminty, ethereal, camphoraceous, pungent, musky, floral) were determined by double-blind smell testing of seven normal males, six normal females, 6 patients with uncomplicated congenital anosmia and 13 patients with the syndrome of congenital anosmia and hypogonadotropic hypogonadism (the Kallmann syndrome, olfactogenital dysplasia). The median detection thresholds did not differ significantly between hypogonadal and eugonadal anosmics for any of the odorants, suggesting that the endocrine deficit does not result from inadequate rhinencephalic input to brain centers controlling gonadotropin release. Phenylethylmethylethylcarbinol (PEMEC), a stable chemical of the floral class, was detected at very low concentrations (10⁻⁶ to 10⁻⁸ M in water) by all normals tested. Since no patient with congenital anosmia was able to distinguish even undiluted PEMEC from water, we suggest that this compound is the material of choice for convenient, rapid and objective testing of the sense of smell (cranial nerve I).