Biomedical subjects

Susan D Scollie

Publications and source records attributed to Susan D Scollie.

6 recordsLinked to original sources

PubMed2006

Effects of applied contact force and volume control setting on output force levels of the BAHA Softband.

The BAHA Softband has been developed to provide a transcutaneous anchor for a BAHA until a child is a surgical candidate for the percutaneous BAHA implant. We tested the objective output force level of the BAHA Classic 300 and Compact connected to a Softband on an artificial mastoid to determine: (1) the effects of direct contact force on output force levels (dB); and (2) the required volume control setting to ensure audibility of speech (assuming an average adult reference equivalent threshold force level). Direct contact force was varied from 2 to 5 N in 1 N steps. Output force level increased with increasing contact force. However, the average increase was 3 dB or lower, suggesting that the contact force is of minor importance. Volume control setting appears to be of much greater importance. It is suggested that the volume setting of either device be set to at least 2.5 to ensure audibility of conversational speech. Data from normal-hearing adults with simulated conductive hearing losses are presented to validate this conclusion.

Adult↗

PubMed2006

Evaluation of a probe-tube insertion technique for measuring the real-ear-to-coupler difference (RECD) in young infants.

A common strategy for measuring the real-ear response of the real-ear-to-coupler difference (RECD) in the pediatric population is to insert a probe-tube separately from the eartip. This strategy is at times difficult to implement while attempting to obtain the measurement from a young infant. An RECD probe-tube insertion technique that involves connecting the probe-tube to an eartip with plastic film for simultaneous insertion was examined on 30 infants. Repeated measurements were completed on each infant to obtain within-session test-retest reliability data. Probe-tube insertion depth was also examined across participants to provide a guideline for the infant population. Findings indicate that reliable RECD values can be obtained in infants when the probe-tube is extended approximately two to four millimeters (mm) beyond the eartip or 11 mm from the entrance to the ear canal. Clinical implications of this work are discussed.

Equipment Design↗

PubMed2003

An approach for ensuring accuracy in pediatric hearing instrument fitting.

Hearing instrument fitting with infants and young children differs in several important ways relative to the fitting process with adults. In developing the Desired Sensation Level method, we have attempted to account for those factors that are uniquely associated with pediatric hearing instrument fitting. Within this article we describe how the external ear acoustics of infants and young children have been systematically accounted for in developing the Desired Sensation Level method. Specific evidence-based procedures that can be applied with infants and young children for the purposes of audiometric assessment, electroacoustic selection, and verification of hearing instrument performance are described.

Journal Article↗

PubMed2002

Evaluation of electroacoustic test signals I: comparison with amplified speech.

OBJECTIVE: To evaluate the ability of clinical test signals to match the aided levels of real speech, across a range of hearing aid circuit types and strengths. DESIGN: Hearing aids (N = 41) were set to DSL targets for moderate, severe, and profound hearing losses. These hearing aids were tested with three test signals (Fonix Pure Tones, Fonix Composite Noise, and Audioscan Swept), as well as with running speech. The difference between the aided test signal and the aided speech was calculated. RESULTS: Accuracy of matches between aided test signals and aided speech levels depended on circuit type, signal type, and test level. CONCLUSIONS: Clinical test signals can more accurately match the aided levels of speech for all types of hearing aids if they are 1) speech-weighted and 2) temporally modulated. Matches were more accurate at low to moderate test levels (i.e., 50 to 70 dB SPL), and less accurate at high test levels (i.e., 85 dB SPL).

Electric Stimulation↗

PubMed2002

Evaluation of electroacoustic test signals II: development and cross-validation of correction factors.

OBJECTIVE: To develop and cross-validate corrections for improving the match between amplified speech levels and frequency response measurements with hearing aids. DESIGN: Previously published correction approaches were reviewed. Two regression-based corrections and two nonregression corrections were developed from an existing database of hearing aid responses measured with clinically available test signals and speech (Scollie & Seewald, 2002). Corrections were evaluated on a second database of digital hearing aid responses for test signals and speech. The second data set was constructed specifically to challenge three hypothesized threats to the robustness of the corrections. RESULTS: The error for each signal (corrected and uncorrected) was calculated. Correction procedures produced a significant improvement in the match between predicted and measured aided levels of speech. Inclusion of compression-related variables provided small but significant improvements. Results generalized to the second data set. CONCLUSIONS: Correction procedures may be applied to improve the match between aided test signal levels and aided levels of speech.

Electric Stimulation↗

PubMed2002

Real-ear-to-coupler difference predictions as a function of age for two coupling procedures.

The predicted real-ear-to-coupler difference (RECD) values currently used in pediatric hearing instrument prescription methods are based on 12-month age range categories and were derived from measures using standard acoustic immittance probe tips. Consequently, the purpose of this study was to develop normative RECD predicted values for foam/acoustic immittance tips and custom earmolds across the age continuum. To this end, RECD data were collected on 392 infants and children (141 with acoustic immittance tips, 251 with earmolds) to develop normative regression equations for use in deriving continuous age predictions of RECDs for foam/acoustic immittance tips and earmolds. Owing to the substantial between-subject variability observed in the data, the predictive equations of RECDs by age (in months) resulted in only gross estimates of RECD values (i.e., within +/- 4.4 dB for 95% of acoustic immittance tip measures; within +/- 5.4 dB in 95% of measures with custom earmolds) across frequency. Thus, it is concluded that the estimates derived from this study should not be used to replace the more precise individual RECD measurements. Relative to previously available normative RECD values for infants and young children, however, the estimates derived through this study provide somewhat more accurate predicted values for use under those circumstances for which individual RECD measurements cannot be made.

Acoustic Impedance Tests↗