Click-Evoked Otoacoustic Emissions in Children and Adolescents with Gender Identity Disorder

Abstract

Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds that are produced by the inner ear in response to click-stimuli. CEOAEs generally have a higher amplitude in women compared to men and neonates already show a similar sex difference in CEOAEs. Weaker responses in males are proposed to originate from elevated levels of testosterone during perinatal sexual differentiation. Therefore, CEOAEs may be usedas a retrospective indicator of someone's perinatal androgen environment. Individuals diagnosed with Gender Identity Disorder (GID), according to DSM-IV-TR, are characterized by a strong identification with the other gender and discomfort about their natal sex. Although the etiology of GID is far from established, itishypothesizedthat atypicallevels of sexsteroids during a critical period of sexual differentiation of the brain might play a role. In the present study, we compared CEOAEs in treatmentnaïve children and adolescents with early-onset GID (24 natal boys, 23 natal girls) and control subjects (65 boys, 62 girls). We replicated the sex difference in CEOAE response amplitude in the control group. This sex difference, however, was not present in the GID groups. Boys with GID showed stronger, more female-typical CEOAEs whereas girls with GID did not differ in emissionstrengthcomparedtocontrolgirls.Basedontheassumption that CEOAE amplitude can be seen as an index of relative androgen exposure,our results provide some evidence for the idea that boys with GID may have been exposed to lower amounts of androgen during early development in comparison to control boys.

Brain Sex Differences Related to Gender Identity Development: Genes or Hormones?

“…Furthermore, these differences persist throughout the lifespan [69]. Transwomen displayed a more female-typical OAE, confirming the hypothesis that they have been exposed to lower levels of androgens during early development compared to control boys [70]. The role of sex hormone exposure in utero is underlined by the observation that prenatal exposure to anticonvulsant-which may interfere with sex hormones metabolism-was associated with the development of gender dysphoria [71].…”

Postnatal Effects of Sex Hormones on Click-Evoked Otoacoustic Emissions: A Study of Adolescents with Gender Dysphoria

“…The control participants were 65 boys (male sex assigned at birth) and 62 girls (female sex assigned at birth), all of whom had a gender identity congruent with their birth-assigned sex. In this prior study (Burke et al, 2014), it was indeed found that the group of 6-14-yearold (treatment-naïve) trans girls tended to have stronger, more female-typical CEOAEs compared to the male control group, while CEOAEs of trans boys were similar to those of the female controls. Also, in that study we replicated the previously observed sex differences in CEOAE response amplitudes with significantly stronger emissions in control girls than in control boys, but there were no sex differences between boys and girls with GD (Burke et al, 2014).…”

“…In this prior study (Burke et al, 2014), it was indeed found that the group of 6-14-yearold (treatment-naïve) trans girls tended to have stronger, more female-typical CEOAEs compared to the male control group, while CEOAEs of trans boys were similar to those of the female controls. Also, in that study we replicated the previously observed sex differences in CEOAE response amplitudes with significantly stronger emissions in control girls than in control boys, but there were no sex differences between boys and girls with GD (Burke et al, 2014). These results, in line with several neuroimaging studies, suggest a less pronounced sexual differentiation in transgender individuals (Burke, Manzouri, & Savic, 2017, and for reviews, see Guillamon, Junque, & Gómez-Gil, 2016;Kreukels & Guillamon, 2016).…”

“…Due to the putative relationship between prenatal androgen exposure and CEOAE strength, CEOAE measurements have been used as a marker of prenatal androgen exposure. In a previous study, we indirectly investigated the relationship between the (atypical) development of gender identity and prenatal androgen exposure as estimated by CEOAE measurements (Burke, Menks, Cohen-Kettenis, Klink, & Bakker, 2014). Participants were 57 children and adolescents diagnosed with GD (24 had a male sex assigned at birth, self-identifying as female [referred to as "trans girls"], and 33 had a female sex assigned at birth, self-identifying as male [referred to as "trans boys"]).…”

Gender identity, gender assignment and reassignment in individuals with disorders of sex development: a major of dilemma

“…These findings have been further enhanced by the demonstration of gender-atypical brain activation patterns in processing steroid-based odors and erotic stimuli [43,44]. In addition, a recent study found that FtM GD individuals show stronger more female-typical otoacustic emissions compared to control boys, suggesting that boys with GD might have been exposed to relatively lower amounts of androgens during early development [45]. In line with these studies, it has also been reported that MtF individuals have female-typical facial preferences in terms of sexual attraction [46].…”