Associations of Central Auditory Processing With Brain Volumes

We investigated the cross-sectional associations of speech-in-noise performance with magnetic resonance imaging brain volumes among 588 cognitively normal participants (77±4 years, 56% female) from the Aging and Cognitive Health Evaluation in Elders Study (randomized trial embedded in the Atherosclerosis Risk in Communities (ARIC) Study) baseline in 2018-19 (N=427, with hearing loss) and ARIC (N=161, normal hearing) Visit 6/7 in 2016-17/2018-19. Central auditory processing was measured by Quick Speech-in-Noise (QuickSIN) test; range: 0 to 30, lower scores=worse performance. In models adjusted for demographic and disease covariates, every 5-point decrease in QuickSIN score was associated with smaller volumes of the temporal lobe overall (-0.07SD, 95% CI:-0.13,-0.01) as well as subregions including but not limited to those important for auditory processing (amygdala:-0.13SD, 95% CI:-0.21,-0.04; middle temporal gyrus:-0.08SD, 95% CI:-0.15,-0.00; superior temporal gyrus:-0.08SD, 95% CI:-0.15,-0.01). Further research is needed to understand the mechanisms underlying these observed associations.

An auditory-visual tradeoff in susceptibility to clutter

Sensory cortical mechanisms combine auditory or visual features into perceived objects. This is difficult in noisy or cluttered environments. Knowing that individuals vary greatly in their susceptibility to clutter, we wondered whether there might be a relation between an individual’s auditory and visual susceptibilities to clutter. In auditory masking, background sound makes spoken words unrecognizable. When masking arises due to interference at central auditory processing stages, beyond the cochlea, it is called informational masking. A strikingly similar phenomenon in vision, called visual crowding, occurs when nearby clutter makes a target object unrecognizable, despite being resolved at the retina. We here compare susceptibilities to auditory informational masking and visual crowding in the same participants. Surprisingly, across participants, we find a negative correlation (R = –0.7) between susceptibility to informational masking and crowding: Participants who have low susceptibility to auditory clutter tend to have high susceptibility to visual clutter, and vice versa. This reveals a tradeoff in the brain between auditory and visual processing.

Evaluation of temporal processing skills in individuals with normal hearing

Objective: In a cumulative perspective, the aim of this study is to perform Frequency Pattern Test (FPT), Duration Pattern Test (DPT) and Gap In Noise (GIN) Test in order to determine descriptive values of these tests to evaluate central auditory processing on the individuals’ with normal hearing. Material and Methods: A total of 52 participants, as of 28 women and 24 men, with normal hearing, within the age range of 20 to 55 were included in the study. Otoscopic examination, pure tone audiometry and FPT, DPT GIN Test which are central auditory processing tests, were performed on the participants who meet the criteria of the study and voluntarily agreed to participate in the study. Results: Descriptive values were obtained as an average of 78% in FPT, 92.11% in DPT, an average of 61.22% in GIN Test and an average of 6.34 ms in Gap Detection Threshold Conclusions: It is thought that the obtained descriptive values will contribute to the clinics and the literature. Keywords: Auditory temporal tests, central auditory processing, duration pattern test, frequency pattern test, gap in noise test

Deficits in central auditory processing among migraine patients

Background Migraine is a neurological disease associated with abnormal excitability in visual, somatosensory, and motor cortex. This study aimed to verify and compare auditory processing performance in migraine patients with and without dizziness and healthy controls. Results Sixty subjects were divided into 3 groups: control group, twenty normal healthy subjects, and study group I (twenty subjects diagnosed with migraine) and study group II (twenty subjects diagnosed with vestibular migraine). They were evaluated using the Central Auditory Processing Questionnaire for adults, tympanometry, pure tone audiometry, Psychophysical Central Auditory Tests, including Arabic Speech Intelligibility in Noise Test for adults, Arabic Dichotic Digit Test [version II], Gap in Noise Test, Duration Pattern Test, and Arabic Memory Tests. No significant difference was found between the two study groups I and II, but the significant difference was found between the study groups and the control group in all central auditory test results. Statistically significant difference was found between the control group and study groups I and II regarding all memory tests. The highest percentage of abnormality was present in temporal resolution and selective auditory attention in both study groups. There was no significant statistical correlation between the number of attacks/month and central auditory test results. There was no significant statistical correlation between the frequency of attacks in VM patients and central auditory test results. Conclusions Patients with migraine and vestibular migraine had an inferior performance in all psychophysical central auditory tests when compared with control. Also, there was no significant difference between the 2 study groups regarding central auditory test results which may support that both migraine with and without dizziness have the same pathophysiology.

Dysconnectivity between auditory-cognitive network associated with auditory GABA and glutamate levels in presbycusis patients

Accumulating studies suggest an interaction between presbycusis (PC) and cognitive impairment, which may be explained by the cognitive-ear link to a large extent. However, the neurophysiological mechanisms underlying this link are largely unknown. Here, 51 PC patients and 51 well-matched healthy controls were recruited. We combined resting-state functional MRI and edited magnetic resonance spectroscopy to investigate changes of intra- and inter-network functional connectivity and their relationships with auditory gamma-aminobutyric acid (GABA) and glutamate (Glu) levels and cognitive impairment in PC. Our study confirmed the plastic model of cognitive-ear link at the level of the large-scale brain network, including the dysconnectivity within high-order cognitive networks and between the auditory-cognitive network and overactivation between cognitive networks dependent on hearing loss, which was closely related to the cognitive impairment of PC patients. Moreover, GABA and Glu levels in the central auditory processing were abnormal in patients with PC. Importantly, reduction of GABA-mediated inhibition plays a crucial role in a dysconnectivity between the auditory-cognitive network, which may be neurochemical underpinnings of functional remodeling of cognitive-ear link in PC. Modulation of GABA neurotransmission may enable the development of new therapeutic strategies for the cognitive impairment of PC patients. Keywords: presbycusis, cognitive impairment, cognitive-ear link, GABA, resting-state networks.

Relationship Between Peripheral and Central Auditory Abilities and Iron Deficiency Anemia in Adolescent Girls

Purpose This study evaluated the peripheral hearing and central auditory processing abilities in Indian adolescent girls with iron deficiency anemia (IDA). Method The participants consisted of 75 adolescent girls with IDA, 50 adolescent girls without IDA, and 50 adolescent boys without IDA. Participants underwent a test battery to evaluate auditory processing and peripheral hearing assessment. In this study, central auditory processing abilities were assessed using Speech Perception in Noise test in Kannada (SPIN-K) and quick speech perception in noise tests in Kannada, dichotic consonant–vowel test, gap detection threshold (GDT), and auditory digit sequencing and auditory digit span tests. Results Results showed that the hearing thresholds at extremely low and high frequencies (250 and 8000 Hz), although within clinically normal limits, were poorer in girls with IDA than in the control groups. Also, girls with IDA performed poorly in SPIN-K of the right ear, GDT, and auditory backward digit span tests. Conclusion These subtle auditory deficiencies may be attributed to the compromised blood supply to the central auditory nervous system, as observed in the current study.

Effect of tinnitus on the performance of central auditory system: a review

Background and Aim: Tinnitus is one of the most difficult challenges in audiology and oto­logy. Previous studies have been shown that tinn­itus may interfere with the function of central auditory system (CAS). Involvement of CAS abilities including speech perception and audi­tory processing has led to serious problems in people with tinnitus. Due to the lack of enough information about the impact of tinnitus on CAS and its function, and given that there is no standardized protocol for assessment and mana­gement of tinnitus, this study aimed to review the studies on the effect of tinnitus on the CAS function. Recent Findings: Sixteen eligible articles were reviewed. Temporal and spectral resolution, fre­quency differentiation and speech perception deficits were reported in patients with tinnitus, especially in background noise. This was repor­ted even in tinnitus patients with normal hearing. Conclusion: Assessment of central auditory pro­cessing and speech perception in noise seems to be useful for proper management of tinnitus in clinical practice. Keywords: Tinnitus; auditory system; central auditory processing; speech in noise performance