Auditory-cognitive interactions underlying interaural asymmetry in an adult listener: A case study

Abstract

Results are discussed in relation to auditory-specific outcomes on clinical tests for APD.

Age-Related Effects of Dichotic Attentional Mode on Interaural Asymmetry: An AERP Study with Independent Component Analysis

“…Given the limitations of group-averaged AERPs to separate the underlying neural processes that are involved in linguistic processing, we turned to ICA to further illuminate differences among these groups in the processing of left and right dichotic stimuli. The two ICs described in this study are consistent with two temporally overlapping ICs of semantic processing and attention described by three previous studies (Mehta et al, 2009;Davis et al, 2012;Jerger et al, 2014). Both semantic and attentional ICs revealed an age effect of reduced amplitude in the MA group as compared to YAs.…”

“…The word stimuli used in the AERP task have been used in several previous AERP studies (Martin et al, 2007;Davis et al, 2012Davis et al, , 2013Davis and Jerger, 2014). Words were digitally recorded in an audiometric sound-treated room by an adult male who was a monolingual speaker of English.…”

“…Previous ICA research has suggested that during the processing of words, the language-related N400 component overlaps with a sustained attention PN (Mehta et al, 2009;Davis et al, 2012;Jerger et al, 2014). Accordingly, the second purpose of the study was to determine the effectiveness of ICA in isolating overlapping neural sources that contribute to the negativity in the 350-650 msec latency range.…”

The Effect of Middle Age on the Late Positive Component of the Auditory Event-Related Potential

“…We asserted that the middle-aged group was more affected by task difficulty than young adults, which resulted in greater resource allocation at a lower level of perceptual processing and less cognitive resources available for higher-order linguistic processing in the most difficult condition, that is, Different judgments. The fact that no significant interaural asymmetry was evident in the LPC is interesting in light of a recent case study in which we described prominent interaural asymmetry differences in the LPC amplitude in a middle-aged female with a behavioral left-ear deficit and suspected auditory processing disorder (APD) (Davis et al, 2012). Moreover, the interaural asymmetry was only present in the LPC, not in the earlier components of the AERP.…”

“…Therefore, the reduction in the LPC positivity in the frontal electrodes in the young group was, at least partly, related to increased negativity in the N400 component for the more difficult semantic judgment task. It is also noted that overlapping negative AERP components have been found in the 300-600 msec latency range, which have been thought to reflect both semantic analysis and sustained attentional processes (Mehta et al, 2009;Davis et al, 2012). Therefore, an alternative hypothesis is that the increased negativity in the young females was associated with an increase in sustained attention, which was overall less in the middle-aged females.…”