Masters Theses

Date of Award

6-1983

Degree Type

Thesis

Degree Name

Master of Arts

Major

Audiology

Major Professor

Allan O. Diefendorf

Committee Members

Charles J. Ferrell, Samuel B. Burchfield

Abstract

The purpose of this study was to investigate the use of six complex stimuli (complex noise, filtered complex noise, white noise, filtered white noise, speech, filtered speech) in the following conditions: (1) to determine if one or more of the stimuli could reduce the reported normal range of responding in behavioral observation audiometry (BOA) and make it a valid test for improving the accuracy of early identification of hearing loss in infants; (2) to compare two methods (BOA and visual reinforcement audiometry: (VRA)) when using the same subjects; and (3) to determine how the six stimuli breakdown in terms of mean intensity levels when reinforcement was added to the assessment procedures.

Ten infants were divided into two groups: Group 1 (2 to 4 month olds) was tested in the BOA condition with the six stimuli; and Group 2 (6 to 8 month olds) was tested in the BOA condition and the VRA condition with the six stimuli.

Results indicated that the BOA ranges cannot be further reduced because infants below 5 months of age cannot be conditioned to respond systematically. Visual reinforcement reduced the response thresholds but was not appropriate for infants below 5 months of age. Therefore, it was concluded that the wide response ranges obtained in BOA were typical and it would remain a screening procedure.

Visual reinforcement reduced the response thresholds for infants Comparison of the BOA and VRA mean thresholds supported the use of visual reinforcement with the appropriate age 5 months and older. range.

Stimulus type was an important factor in BOA. The type of stimulus utilized effected the infant's response. Complex noise appeared to be the optimal stimulus to use in the BOA condition. However, a high frequency hearing loss may not be detected by complex noise alone. Therefore, high pass filtered white noise appeared to be an optimal stimulus to use in the high frequency assessment of an infant's hearing abilities based on the results of this study.

Visual reinforcement was the primary factor influencing results in VRA, followed by stimulus type which showed a minor effect. With all stimulus types the infant's hearing sensitivity was considered within normal limits.

It was concluded that early assessment of an infant should include BOA and VRA at the appropriate ages.

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