Comparing Head Rotation Angle, Visual Localization, and Recall-proficiency of School-aged Children (8-12) While Listening to a Story by Multiple Discreet Talkers in a Virtual Classroom

 

Daniel L. Valente - daniel.valente@boystown.org

Dawna Lewis

John Franco

Elizabeth Heinrichs

Hearing Research

Boys Town National Research Hospital

Omaha, NE 68106, USA

Popular version of paper 2pAAa9
Presented Tuesday Afternoon, Apr 20, 2010
159^th ASA Meeting, Baltimore, MD

 

 

Its well known that children perform more poorly than adults when listening to speech in noisy environments such as classrooms. This can be made worse when the talker is located to the side or behind the student. While previous research has been conducted in acoustic envirommnents that mimic real classrooms, the tasks used to test listeners often have been limited to a single talker located in front of the subject,which is not typical of many classroom interactions. In this investigation, both elementary-aged (8-12) and adult normal-hearing listeners were presented with a classroom learning task with a more realistic arrangement of talkers (located around the listener, as in a typical classroom).

 

Differences in comprehension performance were seen between children and adults in both multiple and single talker classroom learning tasks that were not found in a simple speech intelligibility test. It was also found that children exhibited poorer comprehension performance in the multiple vs. single talker classroom learning tasks whereas adults exhibited similar performance regardless of the task. The plausible classroom environment illuminates differences in performance between children and adults as well as type of learning task that are not seen in a standard test of the intelligibility of speech.

 

The experiment featured several novel set-up attributes. First, a virtual classroom was created in a lab at the Boys Town Research Hospital. A 3-D rendering of the classroom setup can be seen in Figure 1. By using a combination of acoustic treatment and virtual room-model techniques, a classroom was created that had the same levels of background noise and sound decay (reverberation) as an ideal classroom. This yielded an environment in which both children and adults were able to score over 95% on a sentence perception task.

 

 

Figure 1. Virtual classroom environment.

 

An array of five LCD monitors and loudspeakers reproduced the audio-visual information to a subject that sat in the middle of the classroom. Finally, since it was of interest to monitor the subjects looking behavior throughout the task, a gyroscopic head-tracker was used to record head movements.

 

Classroom learning task:

 

Forty children and 40 adults with normal hearing participated in the study. Half of the subjects in each group listened to an 11-minute elementary-age appropriate readers-theater play read by a teacher and four students reproduced over the LCD monitors (multi-talker). For the other half of the subjects, the play was read by the teacher (single talker). At the end of the play, subjects were asked a series of 18 questions to assess their comprehension of the play. In general, children performed more poorly than adults in both listening conditions. In addition, a significant effect of age was seen for both the multi-talker and single-talker tasks.

 

 

Figure 2. Comprehension scores for the multi- and single-talker conditions of the classroom listening task.

 

To examine looking behavior when there are multiple talkers, results of gyroscopic measurements were analyzed. In general, both age groups localized the individual talkers less than 50% of the time, with children looking directly at the talkers as they spoke significantly more often than adults (Figure 3). However, when general looking behavior was analyzed, children were much more likely to try to look in the direction of individual talkers than adults.

 

 

Figure 3. Proportion of talkers localized for child and adult listeners in the multi-talker condition of the classroom listening task.

 

In this experiment we found that children differed from adults in both the multi- and single-talker conditions. Children performed more poorly in conditions where there were multiple talkers, while adults had similar performance in both conditions. It was found that despite the fact that children looked toward the individual talkers more often than adults, their comprehension scores were still poorer.

 

Ongoing studies are being conducted using the virtual classroom and experimental technique to examine other populations, such as children with hearing loss. Conditions that include a higher level of noise or longer reverberation are also being studied as well as using hearing assistance technologies in the environment.