EEG rhythms lateralization patterns in children with unilateral hearing loss are different from the patterns of normal hearing controls during speech-in-noise listening

Abstract

a b s t r a c tUnilateral hearing loss constitutes a field of growing interest in the scientific community. In fact, this kind of patients represent a unique and physiological way to investigate how neuroplasticity overcame unilateral deafferentation by implementing particular strategies that produce apparently next-to-normal hearing behavioural performances. This explains why such patients have been underinvestigated for a long time. Thanks to the availability of techniques able to study the cerebral activity underlying the mentioned behavioural outcomes, the aim of the present research was to elucidate whether different electroencephalographic (EEG) patterns occurred in unilateral hearing loss (UHL) children in comparison to normal hearing (NH) controls during speech-in-noise listening. Given the intrinsic lateralized nature of such patients, due to the unilateral side of hearing impairment, the experimental question was to assess whether this would reflect a different EEG pattern while performing a word in noise recognition task varying the direction of the noise source. Results showed a correlation between the period of deafness and the cortical activity asymmetry toward the hearing ear side in the frontal, parietal and occipital areas in all the experimental conditions. Concerning alpha and beta activity in the frontal and central areas highlighted that in the NH group, the lateralization was always left-sided during the Quiet condition, while it was right-sided in noise conditions; this evidence was not, however, detected also in the UHL group. In addition, focusing on the theta and alpha activity in the frontal areas (Broca area) during noise conditions, while the activity was always left-lateralized in the NH group, it was ipsilateral to the direction of the background noise in the UHL group, and of a weaker extent than in NH controls. Furthermore, in noise conditions, only the UHL group showed a higher theta activity in the temporal areas ipsilateral to the side where the background noise was directed to. Finally, in the case of bilateral noise (background noise and word signal both coming from the same two sources), the theta and alpha activity in the frontal areas (Broca area) was left-lateralized in the case of the NH group and lateralized towards the side of the better hearing ear in the case of the UHL group.

Higher Right Hemisphere Gamma Band Lateralization and Suggestion of a Sensitive Period for Vocal Auditory Emotional Stimuli Recognition in Unilateral Cochlear Implant Children: An EEG Study

“…It was averaged from the following ones: F3, F7, T7, P3, P7, O1. The LI was already employed on hearing-impaired children, in particular, SSD children, finding an asymmetry in cortical activity during the execution of a word in noise recognition task influenced by the direction of the background noise in SSD but not in NH children (Cartocci et al, 2019).…”

Cortical Reorganization in Unilateral Deafness Revealed by Auditory Evoked Response

“…In fact, the relationship between N1/P2 responses and deafness duration is somehow predictable because a large number of auditory-evoked potential studies examining the cortical plasticity have demonstrated that the N1/P2 components are highly responsive to neural changes caused by hearing deprivation and restoration with hearing devices such as cochlear implants [52][53][54] . For example, in adult unilaterally deaf persons, a decrease in N1 response is associated with reduced ability in speech-in-noise perception, and contralateral activity to the side of simulation weakens as the duration of deafness becomes longer 12,19 . Taken together, the ndings of studies on unilaterally deafness suggest that people who have experienced a shorter duration of deafness exhibit relatively robust cortical activity due to smaller plastic changes compared to those who have experienced a longer period of hearing loss, indicating a clear need for the early treatment of people with asymmetrical hearing loss.…”

“…Contrary to this nding, a signi cant inverse relationship of cortical N1 responses with behavioral speech perception ability and the duration of deafness was observed only in right-sided deaf persons, indicating greater neurophysiological changes due to right-side deafness over the left-side deafness 19 . In children, the alpha and theta activities during speech-in-noise listening reveal leftward asymmetries for normal hearing, while more lateralized activation on the side of the stimulation was found in unilaterally deaf children, irrespective of the deafness side 12 . Meanwhile, a study on applied N1 source waveform analysis led the authors to conclude that long-term unilateral deafness did not alter hemispheric asymmetry 20 .…”

“…The plasticity of central auditory processing induces functional and/or structural changes in the brain to reorganize neural network following auditory deprivation [9][10][11][12][13] . People with unilateral hearing loss develop a distinct pattern of brain reorganization that is related to poor peripheral representation of the spatial features of sound (e.g., ITD, ILD, and interaural phase difference).…”

How Neurophysiological Measures Can be Used to Enhance the Evaluation of Remote Tower Solutions

“…Although many works have demonstrated the possibility to measure user’s mental states in laboratory settings by using neurophysiological measures, just few works demonstrated the applicability of neurophysiological measures out of the labs i.e., real/realistic settings (Aloise et al, 2013; Cartocci et al, 2015; Aricò et al, 2016a, 2017a, 2018b; Blankertz et al, 2016; Vecchiato et al, 2016; Borghini et al, 2017a, b; Cartocci et al, 2018a,b, 2019a,b; Di Flumeri et al, 2018; Modica et al, 2017, 2018). Even less, the studies demonstrating the effectiveness of such measures in comparing different solutions in operational environments.…”