Flavor perception test: evaluation in patients with Kallmann syndrome

In Kallmann syndrome (KS), congenital hypogonadism is associated with olfactory impairment. To evaluate flavor perception-related disability in KS patients, 30 patients with KS, 12 with normosmic hypogonadism (nIHH), 24 with acquired anosmia (AA), and 58 healthy controls entered the study. All participants completed questionnaires concerning dietary habits, olfaction-related quality of life (QoL), and self-determined olfactory, flavor, and taste abilities prior to undergoing standardized olfactometry and gustometry. Each subject underwent flavor testing, using orally administered aqueous aromatic solutions, identifying 21 different compounds by choosing each out of 5 alternative items. Flavor score (FS) was calculated as the sum of correct answers (range 0-21). Flavor perception by self-assessment was similar between KS, nIHH, and controls, and was mostly reduced only in AA. FS was similar between KS (5.4 ± 1.4) and AA (6.4 ± 1.9), and lower than in nIHH (16.2 ± 2.4, p < 0.001) and controls (16.8 ± 1.7, p < 0.0001). FS showed strong reproducibility, and correlated with olfactory scores in the overall population. KS and AA patients identified aromatics eliciting trigeminal stimulation better than pure odorants. Olfaction-related QoL was more impaired in AA than in KS. We report significant flavor impairment in KS. This contrasts with routine clinic evidence; KS patients, in contrast with AA, do not complain of flavor perception impairment, perhaps owing to the congenital nature of the dysfunction. Flavor perception impairment should be considered a specific KS disability, because of important detrimental effects on physical and mental health and on QoL. KS patients should also be advised of this impairment in order to prevent accidental and life-threatening events.