Biomedical subjects
J Jerger
Publications and source records attributed to J Jerger.
Aging affects hemispheric asymmetry on a competing speech task.
This study examined the effects of aging on the hemispheric asymmetry of event-related potentials (ERPs) evoked by morphosyntactic anomalies in a competing speech paradigm. The experimental groups consisted of children, young adults, and elderly persons. The ERPs were recorded from 32 scalp sites while participants listened to a continuous narrative presented quasidichotically via loudspeakers. Participants responded when they heard an anomalous word embedded within a popular fairy tale. Anomalous words evoked a robust positivity in the 700- to 900-msec latency range in all participants. Comparison of area measures from waveforms at the lateral frontal, frontotemporal, temporal, temporoparietal, and parietal electrode sites revealed asymmetry in hemispheric positivity. In children and young adults, asymmetry peaked in the 600- to 800-msec range and favored the left hemisphere in both target-right and target-left conditions. In seniors, however, asymmetry peaked at 1100 msec, favored the left hemisphere in the target-right condition, and favored the right hemisphere in the target-left condition. These results support the concept that aging affects hemispheric asymmetry during linguistic processing.
Are the benefits worth the cost?
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Toward a more ecologically valid measure of speech understanding in background noise.
In an attempt to develop a more ecologically valid measure of speech understanding in a background of competing speech, we constructed a quasidichotic procedure based on the monitoring of continuous speech from loudspeakers placed directly to the listener's right and left sides. The listener responded to the presence of incongruous or anomalous words imbedded within the context of two children's fairy tales. Attention was directed either to the right or to the left side in blocks of 25 utterances. Within each block, there were target (anomalous) and nontarget (nonanomalous) words. Responses to target words were analyzed separately for attend-right and attend-left conditions. Our purpose was twofold: (1) to evaluate the feasibility of such an approach for obtaining electrophysiologic performance measures in the sound field and (2) to gather normative interaural symmetry data for the new technique in young adults with normal hearing. Event-related potentials to target and nontarget words at 30 electrode sites were obtained in 20 right-handed young adults with normal hearing. Waveforms and associated topographic maps were characterized by a slight negativity in the region of 400 msec (N400) and robust positivity in the region of 900 msec (P900). Norms for interaural symmetry of the P900 event-related potential in young adults were derived.
What determines benefit from hearing aids?
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Report of the Consensus Conference on the Diagnosis of Auditory Processing Disorders in School-Aged Children.
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Auditory temporal processing and lexical/nonlexical reading in developmental dyslexics.
Relationships between lexical/nonlexical reading and auditory temporal processing were examined. Poor nonlexical readers (poor nonword readers, phonologic dyslexics) had difficulty across tone tasks irrespective of speed of presentation or mode of recall. Poor lexical readers (poor irregular word readers, surface dyslexics) had difficulty recalling tones in a sequence only when they were presented rapidly. Covariate analysis supported these findings, revealing that nonlexical (nonword) reading performance is associated with general auditory performance, but lexical (irregular word) reading is particularly associated with auditory sequencing. These findings suggest that phonologic and surface dyslexics perform differently on nonspeech auditory tasks. Because the two different types of poor readers did not differ significantly on tests of memory and learning but did differ on auditory tasks, we suggest that their performance on the auditory tasks may reflect auditory processing abnormalities as opposed to more general learning or memory difficulties. In addition to these observed qualitative differences between groups on the tone tasks, collapsing groups (all readers) revealed significant correlations between nonword reading and the Same-Different tone tasks in particular, whereas irregular word reading was not associated with any tone tasks; there also appears to be a quantitative relationship between nonlexical reading and Same-Different tone task performance as better or worse nonword reading predicts better or worse performance on the Same-Different tone tasks. In particular, it is conceivable that an auditory temporal processing deficit might contribute to poor nonword reading.
Consonant enhancement: promising findings.
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Broadening our horizons.
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Comparison of performance with frequency transposition hearing aids and conventional hearing aids.
Four experienced hearing aid users were evaluated using a frequency transposition (TranSonic) hearing system. Following a trial period, the Abbreviated Profile of Hearing Aid Performance (APHAB) and a variety of speech audiometric measures were used to compare the frequency transposition fitting with each subject's conventional hearing aids. A single-subject study design with a series of repeated measures permitted statistical analysis of differences in performance with the various amplification strategies. Two of the four subjects demonstrated statistically significant benefit with the frequency transposition device. Results show the efficacy of frequency transposition in improving speech understanding and quality of life in some individuals with severe-to-profound hearing loss. Overall, results suggest the need for evaluating the benefit of frequency transposition on an individual basis.
The auditory steady-state response.
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Asymmetric suprathreshold speech recognition and the telephone ear phenomenon.
We compared interaural suprathreshold speech recognition scores in 62 adults with sensorineural hearing loss. Subjects were tested at two sites, 25 at the Baylor College of Medicine, Houston, TX and 37 at Brooklyn College, Brooklyn, NY. Ears were categorized according to telephone usage. Results showed, at both sites, a small but significant difference in speech understanding scores between the ear habitually used on the telephone and the opposite, nontelephone ear. The average speech recognition score was approximately 5 percent better on the telephone ear. Results are interpreted in relation to the theories of auditory deprivation and auditory acclimatization.
Unsuccessful use of binaural amplification by an elderly person.
An elderly person who preferred and performed better with monaural than with binaural amplification was extensively studied, both audiologically and neuropsychologically, in search of an explanation for the phenomenon. Particular emphasis was placed on the study of dichotic speech perception, both behaviorally and electrophysiologically. Results suggest that age-related changes in interhemispheric transfer of auditory input via corpus callosum may underlie the preference for monaural amplification. Implications for the evaluation of amplification potential in elderly persons are discussed.
Electrophysiologic indices of Stroop and Garner interference reveal linguistic influences on auditory and visual processing.
The purpose of this study was to examine linguistic influences on the auditory and visual processing of words both behaviorally and electrophysiologically. Our task yielded measures of the effect of irrelevant semantic content (Stroop interference) and of the effect of irrelevant linguistic variability (Garner interference). The behavioral results allow us to assess whether the linguistic and nonlinguistic dimensions of verbal stimuli are processed dependently or independently. The electrophysiologic results allow us to determine where any processing interactions are arising, particularly regarding perceptual versus postperceptual underpinnings, and to evaluate the similarity and dissimilarity between the two interference effects. Results show pronounced Stroop and Garner interference both behaviorally and electrophysiologically, indicating linguistic influences on auditory and visual processing. Subjects could not ignore the irrelevant linguistic dimension and attend selectively to the physical dimension of either spoken or written words. The results indicate that the physical and linguistic dimensions of words are not processed independently. With regard to the stage of processing underlying the interference effects, our results suggest that both Stroop and Garner interference involve multiple stages of processing. The two interference effects are not duplicate measures, however, and different electrophysiologic signatures were observed. Stroop interference is characterized by perceptual and postperceptual components. Similar electrophysiologic patterns within the auditory and visual modalities suggest that each interference effect is tapping similar processes for spoken and written stimuli.
Functional asymmetries in the auditory system.
This paper describes interaural differences in a variety of listening tasks. We summarize both behavioral and electrophysiologic evidence that performance, in persons with both normal and impaired hearing, differs according to which ear is stimulated. The effect extends over the entire age range, but is especially evident in children and elderly persons. Results are presented in three area: 1) cued listening, 2) dichotic words and sentences, and 3) temporal resolution. Some possible clinical implications of functional asymmetries are discussed.