Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 1960283

Counterintuitive reversals in lateralization using rectangularly modulated noise.

E R Hafter·B R Shelton
View original source ↗Export metadata ↓

Abstract

Listeners were required to detect an interaural delay of 37.5 microseconds in the modulation envelope of a pulse-modulated noise. The noise carrier had a bandwidth of 1000 Hz and a center frequency (fc) that varied from 550-9600 Hz. The modulation frequency was either 250, 500, or 1000 Hz and the pulse widths were either 100, 200, or 400 microseconds. For certain combinations of fc and pulse widths, unexpected results occurred when the side of the perceived image did not agree with the side stimulated first. Lateralizations of these stimuli were found to oscillate from the leading side to the lagging depending on the number of cycles of the carrier falling within a single pulse, seemingly indicating the importance of the stimulus' fine structure. Furthermore, conditions that either limited the bandwidth of the stimuli or masked portions of its spectrum show that the oscillations depended on information in the low-frequency regions. A cross-correlation model that emphasizes both the positive and negative peaks in the cross-correlations functions is shown to describe the basic phenomena.

Explore related subjects

AttentionDichotic Listening TestsDominance, CerebralHumansPerceptual MaskingPitch PerceptionPsychoacousticsJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

E R Hafter, B R Shelton. 1991. Counterintuitive reversals in lateralization using rectangularly modulated noise.. https://doi.org/10.1121/1.401669

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

A low glycaemic index breakfast cereal preferentially prevents children's cognitive performance from declining throughout the morning.

This study investigated whether the glycaemic index (GI) of breakfast cereal differentially affects children's attention and memory. Using a balanced cross-over design, on two consecutive mornings 64 children aged 6-11 years were given a high GI cereal and a low GI cereal in a counterbalanced order. They performed a series of computerised tests of attention and memory, once prior to breakfast and three times following breakfast at hourly intervals. The results indicate that children's performance declines throughout the morning and that this decline can be significantly reduced following the intake of a low GI cereal as compared with a high GI cereal on measures of accuracy of attention (M=-6.742 and -13.510, respectively, p<0.05) and secondary memory (M=-30.675 and -47.183, respectively, p<0.05).

Attention↗
PubMed2007

Inhibitory control test is a simple method to diagnose minimal hepatic encephalopathy and predict development of overt hepatic encephalopathy.

OBJECTIVES: To compare inhibitory control test (ICT), a simple/rapid test of attention, to a standard psychometric battery (SPT) to diagnose minimal hepatic encephalopathy (MHE) and predict development of overt hepatic encephalopathy (OHE) in cirrhotic patients. METHODS: Fifty nonalcoholic cirrhotics and 50 age/educational-status-matched controls were given ICT and SPT in the same sitting. Performance impaired beyond two standard deviations of controls was considered MHE in cirrhotics. ICT results (lure/target response and lures/person) were compared between controls and cirrhotics and within cirrhotics with/without MHE. Receiver-operating characteristic analysis was used to study ICT for MHE diagnosis. Twenty subjects were administered SPT and ICT twice to assess test-retest reliability. All cirrhotics were followed routinely for the development of OHE. RESULTS: Cirrhotics performed worse than controls on SPT and ICT. Using SPT, 39 cirrhotics had MHE. ICT was administered faster than SPT (15 vs 37 min). Cirrhotics with MHE had significantly higher lure (28%vs 3%) and lower target response (91%vs 96%) compared with those without MHE. Lure/person >5 had 90% sensitivity/specificity for MHE diagnosis. AUC for receiver-operating characteristic for lures alone was 95.8%. Lure and target responses were highly correlated (r= 0.9) between sessions showing high test-retest reliability. Five (10%) patients developed OHE on f/u of 26 +/- 10 months; all five had been diagnosed with MHE using ICT and SPT. None of the five patients with discordant results on SPT and ICT developed OHE. CONCLUSIONS: ICT has good sensitivity/specificity for MHE diagnosis, is reliable and is equivalent to SPT for predicting OHE development.

Attention↗