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Methods for estimating infant thresholds
1University of Washington, Seattle 98195.
Insights
Auditory detection thresholds for tone bursts were measured in infants and adults using psychoacoustic procedures. Results show reliable auditory sensitivity in 6-month-olds, but less consistency in 3-month-olds.
Area of Science:
- Auditory perception
- Psychoacoustics
- Infant hearing
Background:
- Accurate measurement of auditory detection thresholds is crucial for understanding auditory development.
- Previous research has established hearing abilities in adults, but infant hearing thresholds are less understood.
Purpose of the Study:
- To estimate auditory detection thresholds for tone bursts in 3- and 6-month-old infants and young adults.
- To compare the reliability and validity of different psychoacoustic procedures for threshold estimation in infants.
Main Methods:
- Utilized an observer-based psychoacoustic procedure to estimate detection thresholds for 1000-Hz, 16-ms tone bursts.
- Employed two adaptive procedures and the method of constant stimuli.
- Assessed response bias using receiver operating characteristic (ROC) plots.
Main Results:
- Little difference was found among average thresholds determined by the different techniques.
- The method of constant stimuli yielded the least variable thresholds.
- No significant change in average thresholds was observed across blocks for 3-month-olds, 6-month-olds, or adults.
- Individual 6-month-olds' thresholds were consistent across blocks, while 3-month-olds' thresholds showed more variability.
- Infant/observer teams generally responded in an unbiased manner.
Conclusions:
- Auditory detection thresholds can be reliably estimated in 6-month-old infants using psychoacoustic methods.
- While 3-month-olds demonstrate auditory sensitivity, threshold measurements show greater variability compared to older infants and adults.
- The method of constant stimuli appears most suitable for minimizing threshold variability in infant hearing studies.
Abstract:
Detection thresholds for 1000-Hz, 16-ms tone bursts were estimated for 3- and 6-month-old infants and for young adults. The test procedure used was the observer-based psychoacoustic procedure. Thresholds were estimated using two different adaptive procedures and the method of constant stimuli. There was little difference among the average thresholds determined by any of these techniques. The least variable thresholds were obtained in the method of constant stimuli. In addition, 10 infants at each age completed two 30-trial blocks of trials in the method of constant stimuli; 22 adults completed 8 blocks of 30 trials. For 3- and 6-month-olds and for adults, there was no significant change in average threshold between blocks. Individual 6-month-olds' thresholds rarely changed by more than 5 dB between blocks, and the correlation between the thresholds obtained in the two blocks was significant. Individual 3-month-olds' thresholds, however, sometimes changed by as much as 10 dB between blocks, and the correlation between first and second block threshold was not significant. The effects of response bias on threshold were assessed by examining receiver operating characteristic plots of hit and false alarm rates at threshold and the correlation between false alarm rate and threshold. Although there was some variability in response bias, infant/observer teams tended to respond in an unbiased fashion. In one of the adaptive procedures only, false alarm rate was significantly correlated with threshold. In all procedures, the exclusion of infants with high false alarm rates changed the average thresholds obtained by less than 5 dB.(ABSTRACT TRUNCATED AT 250 WORDS)