Ear Advantage Research Articles

What happens when we get angry? Hormonal, cardiovascular and asymmetrical brain responses

This study aimed to evaluate neuroendocrine and cardiovascular responses together with changes in brain asymmetry following an anger mood induction laboratory task. Previous research has shown an increase in heart rate and blood pressure when anger is experienced. Increased testosterone and decreased cortisol in response to anger and aggressive behavior have also been reported. With regard to asymmetrical frontal brain activity and emotion, the valence model links negative affect (as anger) to the right hemisphere while the motivational direction model links approach-related emotions (as anger) to the left hemisphere. From the subjective perception and from the neuroendocrine and cardiovascular response of the subjects, we can conclude that the self-referent statement anger induction method by Engebretson et al. (1999) was able to generate an experience of an anger affect in 30 healthy men. Another question was to analyze the consequences of that experience upon perceptual asymmetry when measured with a non-emotional laterality task. Regarding dichotic listening, an enhanced REA (right ear advantage) was observed after anger which indicates greater left hemisphere activity, supporting the motivational direction model.

Hemispheric laterality assessment with dichotic digits testing in dyslexia and auditory processing disorder

One of the widely used tests to evaluate functional asymmetry of cerebral hemispheres is the dichotic listening test with the usually prevailing right ear advantage. The current study aims at assessing hemispheric laterality in an adult sample of individuals with dyslexia, with auditory processing disorder (APD), and adults experiencing comorbidity of the two mentioned disorders against a control group with normal hearing and absence of learning disabilities. Results exhibit a right hemispheric dominance for the control and APD group, a left hemispheric dominance for the group diagnosed with both dyslexia and APD, and absence of dominance for the dyslexia group. Assessment of laterality was repeatable and produced stable results, indicating a true deficit. A component of auditory processing, specifically the auditory performance in competing acoustic signals, seems to be deficient in all three groups, and laterality of hemispheric functions influenced at least for auditory-language stimuli in the two of the three groups, one being adults with dyslexia and the other being adults with comorbidity of dyslexia and APD.SumarioUna de las pruebas más ampliamente utilizadas para evaluar la asimetría funcional de los hemisferios cerebrales es la prueba de escucha dicótica, generalmente con la resultante ventaja del oído derecho. El presente estudio tiene como objetivo evaluar la lateralidad hemisférica en una muestra de adultos con dislexia, con desórdenes del procesamiento auditivo (APD) y adultos con ambos problemas vs un grupo control de normoyentes sin alteraciones del aprendizaje. Los resultados muestran una dominancia del hemisferio derecho para el grupo control y el grupo con APD y una dominancia del hemisferio izquierdo para el grupo diagnosticado con ambas condiciones, y ninguna dominancia del grupo de dislexia. La evaluación de la lateralidad fue repetible y produjo resultados estables, indicando un déficit verdadero. Un componente del procesamiento auditivo, específicamente el desempeño auditivo bajo señales acústicas competitivas, parece ser deficiente en los tres grupos y las funciones de lateralidad hemisférica se vieron influidas al menos por los estímulos auditivos lingüísticos en dos de los tres grupos; el de adultos con dislexia y el de adultos con ambas condiciones, dislexia y APD.

Right-hemispheric brain activation correlates to language performance

Language function in the right-hemispheric homologues of Broca's and Wernicke's areas does not only correlate with left-handedness or pathology, but occurs naturally in right-handed healthy subjects as well. In the current study, two non-invasive methods of assessing language lateralization are correlated with behavioral results in order to link hemispheric dominance to language ability in healthy subjects.Functional magnetic resonance imaging (fMRI) together with a sentence-completion paradigm was used to determine region-specific lateralization indices in the left- and right-sided Broca's and Wernicke's areas, the frontal temporal lobe, the anterior cingulate cortex and the parietal lobe. In addition, dichotic listening results were used to determine overall language lateralization and to strengthen conclusions by correlating with fMRI indices. Results showed that fMRI lateralization in the superior parietal, the posterior temporal, and the anterior cingulate cortices correlated to dichotic listening. A decreased right ear advantage (REA), which indicates less left-hemispheric dominance in language, correlated with higher performance in most administered language tasks, including reading, language ability, fluency, and non-word discrimination. Furthermore, right hemispheric involvement in the posterior temporal lobe and the homologue of Broca's area suggests better performance in behavioral language tasks. This strongly indicates a supportive role of the right-hemispheric counterparts of Broca's and Wernicke's areas in language performance.

Atypical functional lateralization in children with fetal alcohol syndrome

In order to explore effects of prenatal alcohol exposure on functional lateralization, item tasks measuring preferences of hand, foot, eye, and ear were administered to a sample of 23 children diagnosed with fetal alcohol syndrome (FAS) compared with typically developing (TD) children. In addition, a dichotic listening task was administered to a subsample of 11 children with FAS and a TD group of comparable age, sex and handedness. The children with FAS were characterized by increased nonright-handedness compared with TD children. No differences were evident for preferential use of foot, eye, or ear. Moreover, children with FAS displayed more right ear extinctions during dichotic listening relative to TD children, indicating a lack of right ear advantage. The results add to findings of decreased manual asymmetry and less left-lateralized speech perception in children with developmental disorders, and are further discussed in relation to the high incidence of callosal abnormalities in alcohol-exposed children.

The effects of background noise on dichotic listening to consonant-vowel syllables: An fMRI study

The present fMRI study attempts to identify brain areas that may underlie the effect of different background noises on functional brain asymmetry in a dichotic listening task. Previous studies have shown that the prominent right ear advantage in dichotic listening to consonant-vowel syllables is affected by background noise. To explore the underlying neuronal processes, haemodynamic brain responses using fMRI were recorded while participants performed the dichotic listening task in two different noisy backgrounds (conversational “babble” and traffic noise). The behavioural results showed a reduction of the right ear advantage in the background noise conditions, especially in the traffic noise condition. The behavioural results are discussed in terms of alertness-attentional mechanisms. The effects of background noise on brain activation involved significant activations in a speech-processing network. Specifically the changes in activations in the peri-Sylvian region of the superior temporal gyrus and in the temporo-parietal junction part in the left hemisphere, as well as in the superior temporal gyrus/sulcus area in the right hemisphere may mirror the effects of noise on behavioural performance. The effects of noise on brain activation are discussed with regard to pre-activation mechanisms.

Tone burst evoked otoacoustic emissions in neonates

A potential research project in otoacoustic emissions is the use tone bursts - frequency-specific stimulus. AIM:to study otoacoustic emission responses evoked by tone bursts in neonates with hearing loss risk factors. MATERIALS AND METHODS: 21 neonates with risk factors for hearing loss (study group) and 30 neonates without these risk factors (control group) were evaluated by otoacoustic emissions at the frequency range of 2,000 and 4,000 hertz. STUDY: Clinical and experimental. RESULTS: There was a right ear advantage in female individuals and in the control group, although without statistical significance. Mean "Response" values at 2,000 hertz were 17.73 dB in the control group and 16.55 dB in the study group for female subjects; and 16.63 dB in the control group and 16.12 dB in the study group for male subjects. At 4,000 hertz, the values were 14.63 dB in the control group and 15.09 dB in the study group for female subjects; and 18.57 dB in the control group and 15.06 dB in the study group for male subjects. CONCLUSION: Tone bursts may help evaluate cochlear function in neonates.

Dichotic listening in schizotypal personality disorder: Evidence for gender and laterality effects

Verbal dichotic listening performance was examined in 42 right-handed men and women with DSM-IV-defined schizotypal personality disorder (SPD) and 68 right-handed controls. As expected, both male and female control groups showed a right ear advantage on a verbal dichotic listening task. Although SPD subjects in general had lower accuracy scores than comparison subjects, only male SPD subjects showed an abnormal left ear advantage that was specifically due to deficient right ear performance. The results suggest that left hemisphere temporal lobe structures may be particularly involved in male, but not female, SPD.

Dichotic listening impairments in early onset schizophrenia are associated with reduced left temporal lobe volume

Dichotic listening (DL) impairments, in particular the loss or reduction of right ear advantage (REA) in people with schizophrenia have been variously interpreted as both a state and trait marker for schizophrenia. To date, there has been no comprehensive investigation of dichotic language impairments in relation to the structural integrity of the temporal cortex - the likely neural substrate for such impairments. In this study of 39 early onset patients and matched controls we used a dichotic listening procedure and examined the findings in relation to MRI measurements of gross and regional cerebral volumes. No overall group difference in ear advantage was found between patients and controls but patients who showed absence of REA also demonstrated an accompanying reduction of left temporal lobe volume compared with patients who showed normal ear advantage and controls. The findings suggest that impaired DL performance is a correlate of structural change in the temporal lobe and that this is apparent in early onset cases.

Corpus callosum function in verbal dichotic listening: Inferences from a longitudinal follow-up of Relapsing-Remitting Multiple Sclerosis patients

This study conducted a follow-up of 13 early-onset slightly disabled Relapsing-Remitting Multiple Sclerosis (RRMS) patients within an year, evaluating both CC area measurements in a midsagittal Magnetic Resonance (MR) image, and Dichotic Listening (DL) testing with stop consonant vowel (C-V) syllables. Patients showed a significant progressive loss of posterior CC areas (isthmus and splenium) related to increasing EDSS scores and an enhancing right ear advantage (REA) over time. A significant correlation between posterior CC areas and DL scores emerged in both evaluations, being negative for the right and positive for the left ear. The pattern of correlations suggests that the CC can serve an inhibitory and also excitatory influence on the contralateral hemisphere when studying the phonological processing of language. Statement of significance to the neuroscience of languageThe scope of the manuscript is language lateralization. The task used in the experiment is a verbal dichotic listening task, tapping the most basic phonological aspects of language. Finally, the available research is scarce when focusing on the interhemispheric excitation or inhibition of the corpus callosum in linguistic functioning.

Tone burst evoked otoacoustic emissions in neonates

SummaryA potential research project in otoacoustic emissions is the use tone bursts - frequency-specific stimulus.Aimto study otoacoustic emission responses evoked by tone bursts in neonates with hearing loss risk factors.Materials and Methods21 neonates with risk factors for hearing loss (study group) and 30 neonates without these risk factors (control group) were evaluated by otoacoustic emissions at the frequency range of 2,000 and 4,000 hertz.StudyClinical and experimental.ResultsThere was a right ear advantage in female individuals and in the control group, although without statistical significance. Mean “Response” values at 2,000 hertz were 17.73 dB in the control group and 16.55 dB in the study group for female subjects; and 16.63 dB in the control group and 16.12 dB in the study group for male subjects. At 4,000 hertz, the values were 14.63 dB in the control group and 15.09 dB in the study group for female subjects; and 18.57 dB in the control group and 15.06 dB in the study group for male subjects.ConclusionTone bursts may help evaluate cochlear function in neonates.

Auditory discrimination of voice-onset time and its relationship with reading ability

The perception of voice-onset time (VOT) during dichotic listening provides unique insight regarding auditory discrimination processes and, as such, an opportunity to learn more about individual differences in reading ability. We analysed the responses elicited by four VOT conditions: short–long pairs (SL), where a syllable with a short VOT was presented to the left ear and a syllable with a long VOT was presented to the right ear, as well as long–short (LS), short–short (SS), and long–long (LL) pairs. Stimuli were presented in three attention conditions, where participants were instructed to attend to either the left or right ear, or received no instruction. By around 9.5 years of age children perform similarly to adults in terms of the size and relative magnitude of the right ear advantage (REA) elicited by each of the four VOT conditions. Overall, SL pairs elicited the largest REA and LS pairs elicited a left ear advantage (LEA), reflecting stimulus-driven bottom-up processes. However, children were less able to modulate their responses according to attention condition, reflecting a lack of top-down control. Effective direction of attention to one ear or the other was related to measures of reading accuracy and comprehension, indicating that reading skill is associated with top-down control of bottom-up perceptual processes.

The role of linguistic experience in the hemispheric perception of Mandarin tone.

The current study investigated whether and to what extent lexical tone is processed as linguistic information by native Mandarin listeners, early Mandarin‐Dutch bilinguals, second year Dutch students of Chinese, and monolingual Dutch students. Dichotic listening task was conducted in each of the four groups in order to determine to what extent the processing of lexical tones in Mandarin was lateralized to the left hemisphere. The majority of native Mandarin listeners revealed a right‐ear advantage (REA) corresponding to a left‐hemisphere lateralization in the perception of Mandarin tones. Similar to the native Chinese listeners, the Dutch‐Mandarin bilinguals also exhibited an REA. Moreover, the left‐hemisphere dominance was even more evident for these proficient bilinguals than for the native listeners. However, the Dutch listeners without any experience with Mandarin or other tonal languages showed no ear advantage. For the second year Chinese major listeners, five listeners revealed an REA, while others exhibited a bilateral pattern. The results suggested that there is a tendency for a right‐ear advantage corresponding to left‐hemisphere superiority for listeners with at least some basic experience of Mandarin tones.

Between- and within-ear congruency and laterality effects in an auditory semantic/emotional prosody conflict task

The present study investigated the influence of within- and between-ear congruency on interference and laterality effects in an auditory semantic/prosodic conflict task. Participants were presented dichotically with words (e.g., mad, sad, glad) pronounced in either congruent or incongruent emotional tones (e.g., angry, happy, or sad) and identified a target word or emotion under one of two conditions. In the within-ear condition, the congruent or incongruent dimensions were bound within a single stimulus and therefore, presented to the same ear. In the between-ear condition, the two dimensions were split between two stimuli and, therefore, presented in separate ears. Findings indicated interference in both conditions. However, the expected right ear advantage (EA) for words and left EA for emotions were obtained only in the between-ear condition. Factors involved in producing interference and laterality effects in dichotic listening tasks are discussed.

Dichotic listening with consonant–vowel pairs: The role of place of articulation and stimulus dominance

The present study investigated the possibility that the place of articulation in stop-consonant–vowel syllable pairs would affect the magnitude and direction of perceptual asymmetries in a dichotic listening task. Forty-one participants were presented dichotically with stop-consonant–vowel syllable pairs and asked to detect a specific target syllable. Stimulus pairs were analyzed in terms of the combination of place of articulation presented to each ear for the stop consonant. The expected right ear advantage (REA) was obtained. However, the ear advantage varied in such a way that location of the velar syllable typically produced better performance for the relevant ear. The effect of place of articulation on the ear advantage became non-significant when stimulus dominance was controlled. The results are interpreted in terms of the role of sub-phonemic components of speech and stimulus dominance in the measurement of auditory asymmetries. Their implications for models of dichotic listening are also discussed.

A comparison of the effects for sustained versus shifted attention on dichotic listening performance

We measured the effect of two types of directed attention instructions, sustained by a verbal cue or shifted by a tone cue with different time intervals (150, 450, and 750 ms), on a consonant-vowel dichotic listening (C-V DL) test for a large group of right- and left-handed participants of both sexes. An increasing of the hits and a decreasing of the intrusions from the baseline DL test scores was evident for both types of attentional manipulations, with no differences regarding sex or handedness. Increasing the time from 150 to 450 ms benefited the focusing of attention but this advantage was markedly attenuated at the longer 750-ms interval. The improving effect was seen for the hits of both the left and right ears and so a right ear advantage was evident for the three time intervals.

Correlations between measures of executive attention and cortical thickness of left posterior middle frontal gyrus - a dichotic listening study.

BackgroundThe frontal lobe has been associated to a wide range of cognitive control functions and is also vulnerable to degeneration in old age. A recent study by Thomsen and colleagues showed a difference between a young and old sample in grey matter density and activation in the left middle frontal cortex (MFC) and performance on a dichotic listening task. The present study investigated this brain behaviour association within a sample of healthy older individuals, and predicted a positive correlation between performance in a condition requiring executive attention and measures of grey matter structure of the posterior left MFC.MethodsA dichotic listening forced attention paradigm was used to measure attention control functions. Subjects were instructed to report only the left or the right ear syllable of a dichotically presented consonant-vowel syllable pair. A conflict situation appears when subjects are instructed to report the left ear stimulus, caused by the conflict with the bottom-up, stimulus-driven right ear advantage. Overcoming this processing conflict was used as a measure of executive attention. Thickness and volumes of frontal lobe regions were derived from automated segmentation of 3D magnetic resonance image acquisitions.ResultsThe results revealed a statistically significant positive correlation between the thickness measure of the left posterior MFC and performance on the dichotic listening measures of executive attention. Follow-up analyses showed that this correlation was only statistically significant in the subgroup that showed the typical bottom-up, stimulus-driven right ear advantage.ConclusionThe results suggest that the left MFC is a part of an executive attention network, and that the dichotic listening forced attention paradigm may be a feasible tool for assessing subtle attentional dysfunctions in older adults.

Patterns of language and auditory dysfunction in 6-year-old children with epilepsy

In a previous study we reported difficulty with expressive language and visuoperceptual ability in preschool children with epilepsy and otherwise normal development. The present study analysed speech and language dysfunction for each individual in relation to epilepsy variables, ear preference, and intelligence in these children and described their auditory function. Twenty 6-year-old children with epilepsy (14 females, 6 males; mean age 6:5 y, range 6 y–6 y 11 mo) and 30 reference children without epilepsy (18 females, 12 males; mean age 6:5 y, range 6 y–6 y 11 mo) were assessed for language and auditory ability. Low scores for the children with epilepsy were analysed with respect to speech-language domains, type of epilepsy, site of epileptiform activity, intelligence, and language laterality. Auditory attention, perception, discrimination, and ear preference were measured with a dichotic listening test, and group comparisons were performed. Children with left-sided partial epilepsy had extensive language dysfunction. Most children with partial epilepsy had phonological dysfunction. Language dysfunction was also found in children with generalized and unclassified epilepsies. The children with epilepsy performed significantly worse than the reference children in auditory attention, perception of vowels and discrimination of consonants for the right ear and had more left ear advantage for vowels, indicating undeveloped language laterality.

Hearing Loss in Middle-aged Subjects with Type 2 Diabetes Mellitus

Complications of type 2 diabetes mellitus (T2DM) can result in hearing loss, which is characterized by high-frequency sensorineural hearing impairment and accelerated age-related decline of the right ear advantage. This investigation aimed to determine which auditory functions are affected in middle-aged subjects with T2DM and the change of the right ear advantage. We assessed the auditory function of 50 diabetic and 50 healthy subjects using pure-tone audiometry, auditory brainstem response and otoacoustic emissions. Diabetic subjects showed elevated thresholds at 4000 Hz and 8000 Hz (p <0.01) and increased wave V and interwave I-V latencies (p <0.01) when compared to healthy subjects. Consistently, subjects with diabetes also had smaller distortion product otoacoustic emission amplitudes at 2.0, 3.0 and 4.0 kHz (p <0.01) and smaller transient otoacoustic emission amplitude in the right ear when compared to healthy controls (p <0.05). Meanwhile, the right ear transient otoacoustic emission amplitude of subjects with T2DM was smaller than the left ear at 4.0 kHz (p <0.05). Our data suggest that middle-aged subjects with T2DM have subclinical hearing loss, impaired auditory brainstem response and diminished otoacoustic emissions, and the peripheral right ear advantage is being lost in middle-aged subjects with T2DM.

Gap Detection and Ear of Presentation: Examination of Disparate Findings

Objectives The purpose of this Letter is to address incongruent findings reported in two current papers concerning an ear advantage for gap detection. The methodology of one of the studies was closely replicated in order to determine whether those data were confounded by a floor effect. A novel methodology not prone to a floor effect was also implemented to test for an ear advantage.

Once more with feeling: The effects of emotional prosody on hemispheric specialisation for linguistic processing

Speech perception requires a bilateral network of neural systems, with the left hemisphere specialised for linguistic processes including phonology, and the right hemisphere specialised for paralinguistic processes including emotional prosody. The present study used dichotic listening to determine how these two processing systems interact. Experiment 1 confirmed that the left hemisphere was specialised for the linguistic task, and the right hemisphere was specialised for the prosodic task. In Experiment 2, participants performed the linguistic task, but the words were spoken in prosodies that were neutral, happy, angry, or sad. Although the emotional prosody was irrelevant for the task, there was an attenuation of the typical right ear advantage when words were spoken with sad prosody, suggesting greater right hemisphere contributions to linguistic processing for sad speech. Similar effects were not observed with angry or happy prosody, suggesting that emotional prosody per se does not facilitate right hemisphere linguistic processing. Results are interpreted in terms of both psychoacoustic and emotion-specific theories of hemispheric specialisation.