Differences Between Young and Older Adults in Working Memory and Performance on the Test of Basic Auditory Capabilities†

The Test of Basic Auditory Capabilities (TBAC) is a battery of auditory-discrimination tasks and speech-identification tasks that has been normed on several hundred young normal-hearing adults. Previous research with the TBAC suggested that cognitive function may impact the performance of older adults. Here, we examined differences in performance on several TBAC tasks between a group of 34 young adults with a mean age of 22.5 years (SD = 3.1 years) and a group of 115 older adults with a mean age of 69.2 years (SD = 6.2 years) recruited from the local community. Performance of the young adults was consistent with prior norms for this age group. Not surprisingly, the two groups differed significantly in hearing loss and working memory with the older adults having more hearing loss and poorer working memory than the young adults. The two age groups also differed significantly in performance on six of the nine measures extracted from the TBAC (eight test scores and one average test score) with the older adults consistently performing worse than the young adults. However, when these age-group comparisons were repeated with working memory and hearing loss as covariates, the groups differed in performance on only one of the nine auditory measures from the TBAC. For eight of the nine TBAC measures, working memory was a significant covariate and hearing loss never emerged as a significant factor. Thus, the age-group deficits observed initially on the TBAC most often appeared to be mediated by age-related differences in working memory rather than deficits in auditory processing. The results of these analyses of age-group differences were supported further by linear-regression analyses with each of the 9 TBAC scores serving as the dependent measure and age, hearing loss, and working memory as the predictors. Regression analyses were conducted for the full set of 149 adults and for just the 115 older adults. Working memory again emerged as the predominant factor impacting TBAC performance. It is concluded that working memory should be considered when comparing the performance of young and older adults on auditory tasks, including the TBAC.

Disturbed Balance of Inhibitory Signaling Links Hearing Loss and Cognition

Neuronal hyperexcitability in the central auditory pathway linked to reduced inhibitory activity is associated with numerous forms of hearing loss, including noise damage, age-dependent hearing loss, and deafness, as well as tinnitus or auditory processing deficits in autism spectrum disorder (ASD). In most cases, the reduced central inhibitory activity and the accompanying hyperexcitability are interpreted as an active compensatory response to the absence of synaptic activity, linked to increased central neural gain control (increased output activity relative to reduced input). We here suggest that hyperexcitability also could be related to an immaturity or impairment of tonic inhibitory strength that typically develops in an activity-dependent process in the ascending auditory pathway with auditory experience. In these cases, high-SR auditory nerve fibers, which are critical for the shortest latencies and lowest sound thresholds, may have either not matured (possibly in congenital deafness or autism) or are dysfunctional (possibly after sudden, stressful auditory trauma or age-dependent hearing loss linked with cognitive decline). Fast auditory processing deficits can occur despite maintained basal hearing. In that case, tonic inhibitory strength is reduced in ascending auditory nuclei, and fast inhibitory parvalbumin positive interneuron (PV-IN) dendrites are diminished in auditory and frontal brain regions. This leads to deficits in central neural gain control linked to hippocampal LTP/LTD deficiencies, cognitive deficits, and unbalanced extra-hypothalamic stress control. Under these conditions, a diminished inhibitory strength may weaken local neuronal coupling to homeostatic vascular responses required for the metabolic support of auditory adjustment processes. We emphasize the need to distinguish these two states of excitatory/inhibitory imbalance in hearing disorders: (i) Under conditions of preserved fast auditory processing and sustained tonic inhibitory strength, an excitatory/inhibitory imbalance following auditory deprivation can maintain precise hearing through a memory linked, transient disinhibition that leads to enhanced spiking fidelity (central neural gain⇑) (ii) Under conditions of critically diminished fast auditory processing and reduced tonic inhibitory strength, hyperexcitability can be part of an increased synchronization over a broader frequency range, linked to reduced spiking reliability (central neural gain⇓). This latter stage mutually reinforces diminished metabolic support for auditory adjustment processes, increasing the risks for canonical dementia syndromes.

Altered Effective Brain Connectivity During Habituation in First Episode Schizophrenia With Auditory Verbal Hallucinations: A Dichotic Listening EEG Study

Background: Habituation is considered to have protective and filtering mechanisms. The present study is aim to find the casual relationship and mechanisms of excitatory–inhibitory (E/I) dysfunctions in schizophrenia (SCZ) via habituation.Methods: A dichotic listening paradigm was performed with simultaneous EEG recording on 22 schizophrenia patients and 22 gender- and age-matched healthy controls. Source reconstruction and dynamic causal modeling (DCM) analysis were performed to estimate the effective connectivity and casual relationship between frontal and temporal regions before and after habituation.Results: The schizophrenia patients expressed later habituation onset (p < 0.01) and hyper-activity in both lateral frontal–temporal cortices than controls (p = 0.001). The patients also showed decreased top-down and bottom-up connectivity in bilateral frontal–temporal regions (p < 0.01). The contralateral frontal–frontal and temporal–temporal connectivity showed a left to right decreasing (p < 0.01) and right to left strengthening (p < 0.01).Conclusions: The results give causal evidence for E/I imbalance in schizophrenia during dichotic auditory processing. The altered effective connectivity in frontal–temporal circuit could represent the trait bio-marker of schizophrenia with auditory hallucinations.

The value of audio description for the therapy of speech-communicative disorders

The article aims at presenting the potential of audio description (AD) as an efficient tool to support the speech-language and social-communicative skills of children with developmental disorders. It includes information for both speech therapists and parents on what they may expect from AD, and how they can use it in their everyday work with children. It may also serve as a set of guidelines for AD creators for making their products more effective. The considerations assembled in the article are based on a literature review. Remarks on the possible uses of AD are presented in the context of various problems to be remedied during speech therapy of a child; they range from incorrect articulation of sounds, through hearing problems such as auditory processing disorder, to developmental disabilities, such as autism spectrum disorder (ASD) characterized by difficulties with social interaction and repetitive behaviors including pretending play. The existing evidence proves that audiovisual (AV) materials are an attractive starting point for exercises with a child. Video-modeling, in turn, has proven to be one of the best tools for therapy of individuals with ASD, allowing for better understanding of interpersonal interactions. Therefore, AV materials accompanied with an AD track – which itself is perceived as a tool for enhancing information processing by children – need to demonstrate similar value for mastering communicative competences. AD can be an effective tool in speech therapy. However, to meet the needs of practitioners, caregivers and beneficiaries in a useful manner, it must be prepared with care regarding both its content and form.

Screening of Auditory Processing Disorders in School- Aged Children in Tehran, Iran Using the Auditory Processing Domain Questionnaire

Background and Aim: Early detection of auditory processing disorders (APD) is essential for preventing learning and educational problems in school-aged children. It is crucial to take into account the comorbidity with APD, as well. The goal of APD screening is to obtain the basic information about those with auditory disorders to be referred for further evaluation. This study aimed to identify the elementary school students at risk of APD in Tehran, Iran. Methods: Participants were the parents of 536 children selected from 11 elementary schools in four districts of Tehran city. The schools in each district were selected by a random clustering method. The auditory system of students was first evaluated. The parents were then asked to complete the Persian version of the auditory processing domain questionnaire (APDQ). Results: The prevalence of APD was 3.3% in girls and 8.3% in boys and the difference between them was statistically significant (p=0.021). The overall prevalence of APD was 4.6% based on the cut-off points of four APDQ domains, with a male-to-female ratio of 2.6. Conclusion: It is necessary to screen APD in school-aged children to minimize learning and educational problems in them. Moreover, there is a need for developing screening methods to provide timely detection and appropriate intervention for those at risk of APD.

Going Beyond Rote Auditory Learning: Neural Patterns of Generalized Auditory Learning

The ability to generalize across specific experiences is vital for the recognition of new patterns, especially in speech perception considering acoustic–phonetic pattern variability. Indeed, behavioral research has demonstrated that listeners are able via a process of generalized learning to leverage their experiences of past words said by difficult-to-understand talker to improve their understanding for new words said by that talker. Here, we examine differences in neural responses to generalized versus rote learning in auditory cortical processing by training listeners to understand a novel synthetic talker. Using a pretest–posttest design with EEG, participants were trained using either (1) a large inventory of words where no words were repeated across the experiment (generalized learning) or (2) a small inventory of words where words were repeated (rote learning). Analysis of long-latency auditory evoked potentials at pretest and posttest revealed that rote and generalized learning both produced rapid changes in auditory processing, yet the nature of these changes differed. Generalized learning was marked by an amplitude reduction in the N1–P2 complex and by the presence of a late negativity wave in the auditory evoked potential following training; rote learning was marked only by temporally later scalp topography differences. The early N1–P2 change, found only for generalized learning, is consistent with an active processing account of speech perception, which proposes that the ability to rapidly adjust to the specific vocal characteristics of a new talker (for which rote learning is rare) relies on attentional mechanisms to selectively modify early auditory processing sensitivity.