Speech understanding and cognitive capacity
Depending on its volume, frequency, content, duration and predictability, ambient noise can adversely affect our ability to listen to and understand speech. My doctoral research indicates that individual differences in cognitive capacity largely explain how well normal hearing people cope in noisy listening environments.
In my most recent study1, adolescents’ ability to understand speech in different kinds of background noise was examined. The study compared two groups: adolescents (11-18 years) with ADHD diagnosis and a control group in which the occurrence of ADHD symptoms was negligible. All adolescents included in the study had normal hearing and could perceive speech in silence at a normal level of conversation at close distance.
We saw that in all noise conditions, the ADHD group needed much lower noise levels than the control group before they could understand the speaker and the differences between the groups increased significantly when the quality of the voice signal deteriorated. This indicates that the ADHD cognitive system was less able to compensate under the most difficult listening conditions. When we examined what factors could explain the participants' general speech-in-noise performance, we saw that differences in hearing ability contributed to a significant part of the result. However, cognitive capacity played an even more important role in how well an individual performed on the speech-in-noise task. The higher the result an individual ranked on our cognitive tests, the better they performed on the speech-in-noise test. Overall, our results show that adverse listening situations that arise due to degraded signal quality or background noise, is significantly more demanding for people with impaired cognitive capacity than people with typical capacity levels.
Interactions between degraded auditory signals and cognitive processes
Alongside my doctoral research, I assist in the data collection and participant recruitment of a large longitudinal study, "Ear, memory and dementia", which investigates alternative hypotheses about the human signal-cognition interface.2 Participants undergo a thorough evaluation of their hearing abilities and are also tested for their cognitive abilities using tests of working memory, executive function, attention and semantic inference. The project involves approximately 10 senior researchers with different disciplinary backgrounds and is sponsored by the Swedish Research Council through the Linnaeus HEAD centre for excellence and a grant from the Swedish council for working life and social research.
Perceptual clarity of speech in noise
The perceptual clarity of speech in noise (PCSN) is enhanced by cognitive abilities such as: semantic coherence; prior knowledge and contextual experience (long term memory based predictions); the suppression of irrelevant information; and working memory capacity.3 Although we understand the contribution of these systems is vital to PCSN, precisely when and how the brain solves these tasks is not well understood. It has been a privilege for me to assist in the data collection and analysis of a postdoctoral research team investigating the neural correlates of PCSN. The project used MEG (magnetoencephalogram) to record the neural processes of test-participants performing a speech-in-noise listening task. From this data we hope to develop a better understanding of the role anticipatory mechanisms and working memory capacity play across different temporal stages of speech processing and how these two functions interact.
1 Blomberg, R., Danielsson, H., Rudner, M., Söderlund, G. B. W., and Rönnberg, J. (2019). Speech Processing Difficulties in Attention Deficit Hyperactivity Disorder. Front. Psychol. 10. doi:10.3389/fpsyg.2019.01536.
2 Stenfelt, S., Rönnberg, J., 2009. The signal-cognition interface: Interactions between degraded auditory signals and cognitive processes, Scand. J. Psychol. 50, 385
3 Rönnberg, J. A., Rudner, M. A., Lunner, T. A., Zekveld, A. A., 2010. When cognition kicks in: Working memory and speech understanding in noise. Noise & Health, 263.
Blomberg, R., Danielsson, H., Rudner, M., Söderlund, G. B. W., and Rönnberg, J. (2019). Speech Processing Difficulties in Attention Deficit Hyperactivity Disorder. Front. Psychol. 10. doi:10.3389/fpsyg.2019.01536.
Blomberg, R. (2013). Evoked Multisensory Cortical Representations During Unisensory Stimulation. Linköping University, Department of Computer and Information Science (Bachelor Thesis).
Blomberg, R. (2015). Cortical Phase Synchronisation Mediates Natural Face-Speech Perception. Linköping University, Department of Computer and Information Science (Master Thesis).
Bachelor of Science, 2013
Master of Science, 2015