Abstract
Background:
Children with hearing loss often experience difficulty understanding speech in noisy
and reverberant classrooms. Traditional remote microphone use, in which the teacher
wears a remote microphone that captures her speech and wirelessly delivers it to radio
receivers coupled to a child’s hearing aids, is often ineffective for small-group
listening and learning activities. A potential solution is to place a remote microphone
in the middle of the desk used for small-group learning situations to capture the
speech of the peers around the desk and wirelessly deliver the speech to the child’s
hearing aids.
Purpose:
The objective of this study was to compare speech recognition of children using hearing
aids across three conditions: (1) hearing aid in an omnidirectional microphone mode
(HA-O), (2) hearing aid with automatic activation of a directional microphone (HA-ADM)
(i.e., the hearing aid automatically switches in noisy environments from omnidirectional
mode to a directional mode with a cardioid polar plot pattern), and (3) HA-ADM with
simultaneous use of a remote microphone (RM) in a “Small Group” mode (HA-ADM-RM).
The Small Group mode is designed to pick up multiple near-field talkers. An additional
objective of this study was to compare the subjective listening preferences of children
between the HA-ADM and HA-ADM-RM conditions.
Research Design:
A single-group, repeated measures design was used to evaluate performance differences
obtained in the three technology conditions. Sentence recognition in noise was assessed
in a classroom setting with each technology, while sentences were presented at a fixed
level from three different loudspeakers surrounding a desk (0, 90, and 270° azimuth)
at which the participant was seated. This arrangement was intended to simulate a small-group
classroom learning activity.
Study Sample:
Fifteen children with moderate to moderately severe hearing loss.
Data Collection and Analysis:
Speech recognition was evaluated in the three hearing technology conditions, and subjective
auditory preference was evaluated in the HA-ADM and HA-ADM-RM conditions.
Results:
The use of the remote microphone system in the Small Group mode resulted in a statistically
significant improvement in sentence recognition in noise of 24 and 21 percentage points
compared with the HA-O and HA-ADM conditions, respectively (individual benefit ranged
from −8.6 to 61.1 and 3.4 to 44 percentage points, respectively). There was not a
significant difference in sentence recognition in noise between the HA-O and HA-ADM
conditions when the remote microphone system was not in use. Eleven of the 14 participants
who completed the subjective rating scale reported at least a slight preference for
the use of the remote microphone system in the Small Group mode.
Conclusions:
Objective and subjective measures of sentence recognition indicated that use of remote
microphone technology with the Small Group mode may improve hearing performance in
small-group learning activities. Sentence recognition in noise improved by 24 percentage
points compared to the HA-O condition, and children expressed a preference for the
use of the remote microphone Small Group technology regarding listening comfort, sound
quality, speech intelligibility, background noise reduction, and overall listening
experience.
Key Words
adaptive directional microphone - pediatric audiology - remote microphone system -
small group - speech perception
