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Biomedical subjects

James Jerger

Publications and source records attributed to James Jerger.

At least 37 records · Page 2Linked to original sources
PubMed2003

Neuroelectric correlates of hemispheric asymmetry: spectral discrimination and stimulus competition.

In an effort to explore further the role of the right hemisphere in auditory processing, this study utilized brain event-related potentials (ERPs) to investigate hemispheric asymmetry for the processing of complex spectral tones. Subjects participated in two pitch discrimination tasks, one diotic, the other dichotic. ERP components were recorded from 28 electrodes on the scalp and analyzed via individual/group average area measurements. Results showed that ERPs recorded in response to the dichotic target pairs exhibited a larger P3 area when the target tone was presented to the left ear, while the N1 area showed no significant difference. ERPs recorded in the diotic condition showed a larger P3 area and smaller N1 area compared to the dichotic conditions. Finally, all experimental tasks showed that topographic hemispheric activation patterns were asymmetric to the right hemisphere. Findings support the notion that ERP topographic asymmetries may be dependent on specific cognitive task demands (e.g., diotic vs. dichotic modes of presentation). In addition, the data suggest that the P3 component may better reflect interaural advantages for complex tones than the N1 component and may, therefore, be a more sensitive indicator of hemispheric specialization.

Adult↗
PubMed2003

Decisions! Decisions!

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False Negative Reactions↗
PubMed2002

Asymmetry in event-related potentials to simulated auditory motion in children, young adults, and seniors.

We studied auditory evoked responses to the apparent movement of a burst of noise in the horizontal plane. Event-related potentials (ERPs) were measured in three groups of participants: children in the age range from 9 to 12 years, young adults in the age range from 18 to 34 years, and seniors in the age range from 65 to 80 years. The topographic distribution of grand-averaged ERP activity was substantially greater over the right hemisphere in children and seniors but slightly greater over the left hemisphere in young adults. This finding may be related to age-related differences in the extent to which judgments of sound movement are based on displacement versus velocity information.

Adolescent↗
PubMed2002

Quo vadis?

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Audiology↗
PubMed2002

Reversal of hemispheric asymmetry on auditory tasks in children who are poor listeners.

We examined hemispheric activation patterns during auditory and visual processing in two groups of children: 13 boys in the age range from 9 to 12 years rated by their parents and teachers as poor listeners and 11 boys in the same age range rated as normal listeners. Three tasks were employed: auditory gap detection, detection of auditory movement, and a control task involving visuospatial discrimination. Electrical activity was recorded from 30 scalp electrodes as participants responded to target stimuli in an event-related potential paradigm. In the visual task, hemispheric activation was relatively symmetric around the midsagittal plane in both groups. In the two auditory tasks, however, hemispheric activation patterns differed significantly between groups. In the normal-listener group, activation was asymmetric to the right hemisphere. In the poor-listener group, however, activation tended toward asymmetry, favoring the left hemisphere. These results suggest that abnormalities in hemispheric lateralization of function may underlie the auditory processing problems of at least some children described as poor listeners.

Attention↗
PubMed2002

Temporal compounds reveal interaural biases.

A temporal compound is a complex pattern associated with a sequence of brief (30-100 msec) acoustic events whose identity can be distinguished but whose order cannot be reported. In the present study, two frequency glides were concatenated to form a 400-msec temporal compound consisting of 10 40-msec glides. Fourteen young adults were asked to discriminate these temporal compounds in a same-different paradigm employing a dichotic probe technique. Results supported the hypotheses that same judgments of temporal compounds involve global, or right hemisphere, processing and that different judgments of temporal compounds involve analytical, or left hemisphere, processing. Event-related potential (ERP) data revealed an interaction between side attended (right or left) and type of judgment (same or different). Same stimuli presented from the left side elicited greater ERP responses than different stimuli presented from the left side; conversely, different stimuli presented from the right side elicited greater ERP responses than same stimuli presented from the right side. Reaction times showed the "fast-same" effect, consistently observed in this paradigm.

Acoustic Stimulation↗
PubMed2002

Behavioral and electrophysiologic evidence of auditory processing disorder: a twin study.

We administered a battery of both behavioral and electrophysiologic measures to a pair of fraternal twin girls, one of whom exhibited symptoms consistent with an auditory processing disorder. Both twins were within normal limits on standardized tests of cognitive and language skills. Basic audiometric measures, as well as behavioral tests of simultaneous masking, backward masking, gap detection, and frequency-sweep discrimination, showed little difference between the twins. Significant differences, however, were evident on event-related potentials (ERPs) in response to both within-channel and across-channel gap detection tasks. Substantial differences were also noted for ERPs to both linguistic and nonlinguistic targets in dichotic listening paradigms. The pattern of electrophysiologic results was consistent with a deficit in the efficiency of interhemispheric transfer of auditory information. A possible reason for the greater effectiveness of electrophysiologic over behavioral measures is discussed.

Audiometry↗
PubMedDate not supplied

ERP evidence of a dichotic left-ear deficit in some dyslexic children.

Children with and without behavioral dichotic left-ear deficits participated in an event-related potential study with quasidichotic presentations of familiar fairy tale segments. Electrical activity was recorded from the scalp while the children listened for semantically and/or syntactically anomalous words from either the right side or the left side while competing segments of the fairy tale were simultaneously presented from the opposite side. Latencies and amplitudes were averaged for each target condition within the group with dichotic left-ear deficits (LED) and the group with normal dichotic listening performance (WNL). Individual global field power waveforms and topographic brain maps were generated for the average response in each of the two listening conditions, target right and target left. Cross-correlations were performed on the grand averaged global field power waveforms to measure the degree of synchrony between target right and target left responses in both groups. Integration functions were performed to compare the accumulated sum of voltages during target (right and left) and control (right and left) conditions. WNL children produced typical ERP responses to the target words in both target right and target left conditions. Responses from LED children were at delayed latencies in the target left condition and were at reduced amplitudes in both target conditions. Topographic brain maps revealed more lateralized scalp distributions and greater activation of frontal regions in LED children in the target left condition. Cross-correlational and integration function results demonstrated interaural asymmetries in responses from the LED children. Overall results suggest that slowed neural conduction times, poor interhemispheric transfer of neural activity, and a failure to suppress competing information arriving at the right ear may be involved in poor left-sided processing in children with behavioral left-ear dichotic deficits.

Analysis of Variance↗