Periodic Reporting for period 1 - SensationaHL (Sensitive periods for audition: Teenagers with Normal Hearing & Hearing Loss)
Période du rapport: 2023-06-01 au 2025-11-30
Understanding the teacher’s explanation despite the surrounding chatter, lip-reading to support auditory perception in noisy backgrounds: these are complex but essential skills for navigating lively schools. In children with normal hearing, complex auditory processing remains immature until mid to late adolescence. Strikingly, adolescence is characterized by the onset of puberty, which triggers a cascade of hormonal changes that drive neural plasticity, and vice-versa. The overarching hypothesis of SensationaHL is that adolescence might present a second sensitive period for complex auditory processing.
If so, we expect (i) brain changes illustrating changes in plasticity, specifically in brain areas that support complex auditory processing; in turn these changes likely (ii) drive the maturation of behavioural abilities associated with complex auditory processing.
First, we will zoom in on the onset of puberty as a potential trigger for heightened plasticity associated with sensitive periods. We predict an increase in sex-steroid levels, which would lead to changes in neurotransmitters, which would ultimately drive the development of cognitive networks. With respect to behavioural performance, we expect a rapid increase in performance, but not full maturity immediately after puberty onset. Indeed, a hiatus remains between the timing of puberty onset (around 11 years in girls and 12 years in boys) and that of auditory processing maturity (between 12 and 16 years, depending on the task). However beneficial for developing systems, plasticity must decrease to allow the definitive (adult) function to appear. A second goal is thus to investigate the braking factors that concur to close sensitive periods in adolescents.
Should adolescence present a sensitive period for auditory processing, sensory experience is expected to affect its outcome. Changes in the neural processing of sounds only emerge in late childhood/adolescence following congenital hearing loss. Puberty might thus trigger reorganization in brains that receive degraded auditory input. We hypothesise that a lifelong experience of degraded auditory input interacts with pubertal hormonal changes to affect the development of neural circuitry at adolescence, which may in turn impact behavioural performance. Two other auditory contexts might lead to “altered auditory inputs”, respectively presenting the worst or best scenarios for complex auditory processing at adolescence: noise exposure and auditory training. It may thus be possible that the effects of auditory exposure (deleterious noise exposure or beneficial training) will be magnified if it happens during puberty.
If so, we expect (i) brain changes illustrating changes in plasticity, specifically in brain areas that support complex auditory processing; in turn these changes likely (ii) drive the maturation of behavioural abilities associated with complex auditory processing.
First, we will zoom in on the onset of puberty as a potential trigger for heightened plasticity associated with sensitive periods. We predict an increase in sex-steroid levels, which would lead to changes in neurotransmitters, which would ultimately drive the development of cognitive networks. With respect to behavioural performance, we expect a rapid increase in performance, but not full maturity immediately after puberty onset. Indeed, a hiatus remains between the timing of puberty onset (around 11 years in girls and 12 years in boys) and that of auditory processing maturity (between 12 and 16 years, depending on the task). However beneficial for developing systems, plasticity must decrease to allow the definitive (adult) function to appear. A second goal is thus to investigate the braking factors that concur to close sensitive periods in adolescents.
Should adolescence present a sensitive period for auditory processing, sensory experience is expected to affect its outcome. Changes in the neural processing of sounds only emerge in late childhood/adolescence following congenital hearing loss. Puberty might thus trigger reorganization in brains that receive degraded auditory input. We hypothesise that a lifelong experience of degraded auditory input interacts with pubertal hormonal changes to affect the development of neural circuitry at adolescence, which may in turn impact behavioural performance. Two other auditory contexts might lead to “altered auditory inputs”, respectively presenting the worst or best scenarios for complex auditory processing at adolescence: noise exposure and auditory training. It may thus be possible that the effects of auditory exposure (deleterious noise exposure or beneficial training) will be magnified if it happens during puberty.
WP1 – First, the team members of WP1 conducted a collective literature review on the topic of brain networks that support maturation of speech perception at adolescence. Simultaneously, the PI wrote a mini-review on the development of auditory scene analysis, an ability that is thought to underlie complex auditory processes. It led to the analysis of electroencephalographic data collected while children, adolescents and adults with typical hearing performed auditory scene analysis. Results indicate a protracted development of the neural signatures of auditory scene analysis until (late) adolescence, which could in fact constitute a bottleneck to speech perception in noise abilities.
The second activity undertaken within WP1 is neuroimaging project that focuses on the neurobiological changes in the structure and function of the auditory pathways, that are thought to be affected by puberty and/or adolescent brain development. As part of this study, we are recruiting a cohort of adolescents who are invited to go into an MRI scanner, undergo an electroencephalography, and take part in cognitive and psychoacoustic tasks evaluating complex auditory processing. Data collection is ongoing, and will be part of a longitudinal follow-up.
WP2a – If adolescence really offers a second sensitive period for auditory processing, its outcome likely varies according to sensory input received during childhood. Therefore, we are currently recruiting children/adolescents with a mild to moderate sensorineural hearing loss to take part in a study that uses the same protocol as in WP1. Their functional and structural neural responses will be compared to those of puberty-, age- and gender-matched participants with typical hearing (selected from the WP1 cohort).
WP2b: Noise exposure could be especially deleterious to adolescents – as hinted by animal work and some epidemiological data. Here, a study was conducted to evaluate the prevalence of noise-induced acquired hearing loss at adolescence. ~5% of our adolescent sample (n = 200) showed signs of acquired hearing loss due to noise-exposure. Neither puberty nor age appeared to be significant predictors of acquired hearing loss in our sample. Future work related to this work package will explore the possibility that noise exposure varies with socioeconomical status of adolescents.
WP2c will be dedicated to potentially larger effects of auditory training during (than before/after) adolescence. Experimental work for this work package will start in 2026.
WP3 – This work package was built as a mirror to WP1, with an important difference: it focuses on puberty offset (instead of puberty onset in WP1). Therefore, the protocol is exactly the same as in WP1, but applied to adolescents who are at mid- to late-pubertal stages. Data collection is ongoing.
Following the collective literature review on the brain networks supporting speech perception at adolescence (WP1), it became obvious that some changes in real-life speech processing might be triggered by puberty, especially around its offset. This led to the analysis of a neurophysiological dataset, taking into account pubertal stage and sex-steroid changes around puberty offset. So far, these are our most promising results: in a cohort of n = 150 participants (9 to 22 years of age), pubertal stage seems to drive changes in the neurophysiological response to natural speech, with marked changes between mid- and late pubertal stages.
The second activity undertaken within WP1 is neuroimaging project that focuses on the neurobiological changes in the structure and function of the auditory pathways, that are thought to be affected by puberty and/or adolescent brain development. As part of this study, we are recruiting a cohort of adolescents who are invited to go into an MRI scanner, undergo an electroencephalography, and take part in cognitive and psychoacoustic tasks evaluating complex auditory processing. Data collection is ongoing, and will be part of a longitudinal follow-up.
WP2a – If adolescence really offers a second sensitive period for auditory processing, its outcome likely varies according to sensory input received during childhood. Therefore, we are currently recruiting children/adolescents with a mild to moderate sensorineural hearing loss to take part in a study that uses the same protocol as in WP1. Their functional and structural neural responses will be compared to those of puberty-, age- and gender-matched participants with typical hearing (selected from the WP1 cohort).
WP2b: Noise exposure could be especially deleterious to adolescents – as hinted by animal work and some epidemiological data. Here, a study was conducted to evaluate the prevalence of noise-induced acquired hearing loss at adolescence. ~5% of our adolescent sample (n = 200) showed signs of acquired hearing loss due to noise-exposure. Neither puberty nor age appeared to be significant predictors of acquired hearing loss in our sample. Future work related to this work package will explore the possibility that noise exposure varies with socioeconomical status of adolescents.
WP2c will be dedicated to potentially larger effects of auditory training during (than before/after) adolescence. Experimental work for this work package will start in 2026.
WP3 – This work package was built as a mirror to WP1, with an important difference: it focuses on puberty offset (instead of puberty onset in WP1). Therefore, the protocol is exactly the same as in WP1, but applied to adolescents who are at mid- to late-pubertal stages. Data collection is ongoing.
Following the collective literature review on the brain networks supporting speech perception at adolescence (WP1), it became obvious that some changes in real-life speech processing might be triggered by puberty, especially around its offset. This led to the analysis of a neurophysiological dataset, taking into account pubertal stage and sex-steroid changes around puberty offset. So far, these are our most promising results: in a cohort of n = 150 participants (9 to 22 years of age), pubertal stage seems to drive changes in the neurophysiological response to natural speech, with marked changes between mid- and late pubertal stages.
As part of WP1, we had the opportunity to analyse neurophysiological data collected while children, adolescents and adults with typical hearing performed auditory scene analysis. Results indicate a protracted development of the neural signatures of auditory scene analysis until (late) adolescence, which appears to constitute a bottleneck to speech perception in noise abilities. This could have major clinical implications for both (i) children with listening difficulties and (i) those with a hearing loss faced with noisy environments.
As part of WP3, we had the opportunity to analyse neurophysiological data evoked in response to natural speech in a cohort of (n = 150) children, adolescents and young adults. Results highlight a role of puberty on the maturation of these neurophysiological responses, and thus on the central auditory pathways. In fact, an inflection point appears between mid and late pubertal stages, which could stem from the second wave of hormonal changes triggered by puberty onset. We are currently investigating this possibility by analysing saliva samples - looking for changes in concentration of testosterone, oestrogen and DHEA.
As part of WP3, we had the opportunity to analyse neurophysiological data evoked in response to natural speech in a cohort of (n = 150) children, adolescents and young adults. Results highlight a role of puberty on the maturation of these neurophysiological responses, and thus on the central auditory pathways. In fact, an inflection point appears between mid and late pubertal stages, which could stem from the second wave of hormonal changes triggered by puberty onset. We are currently investigating this possibility by analysing saliva samples - looking for changes in concentration of testosterone, oestrogen and DHEA.