The meaning of sound environment for children with special needs: Action research on room acoustics in child development support center Saki Noguchi 1 Acoustic Design for Children / Meiji University Hamamatsu City, Shizuoka, Japan Minami Arai 2 Kanako Ueno 3 Meiji University 1-1-1, Higashimita, Kawasaki City, Kanagawa, Japan Hisao Funaba 4 Acoustic Design for Children / Yokohama National University Ota-ku, Tokyo, Japan Tomoko Matsumoto 5 Nearai Gakuen 667-1, Nearaicho, Kita-ku, Hamamatsu City, Shizuoka, Japan Ryoko Watanabe 6 Nearai Gakuen / Hamamatsu Gakuin University 667-1, Nearaicho, Kita-ku, Hamamatsu City, Shizuoka, Japan

ABSTRACT This study aimed to investigate the meaning of a sound environment for children with special needs through conducting action research on room acoustics in a child development support center. First, the actual conditions were investigated through acoustic measurement, behavioral observation, and interviews with teachers. Results revealed that daily sounds comprised of loud voices, crying, and screaming voices. The teachers were aware of the problems with the sound environment. Second, an experiment to improve the sound absorption performance in the classroom was conducted. The effects of the alleviation of noisiness and enhancement of calmness were confirmed in the sound environment. This change had supported a child with hyperacusis for decreasing to blocking his ears or speaking actively. In addition, the interviews found that experiencing an environment with different reverberations presented an opportunity for teachers to become aware of their own voices.

1 noguchi.saki@kodomo-oto.org 2 uenoken@meiji.ac.jp 3 uenok@meiji.ac.jp 4 funaba.hisao@kodomo-oto.org 5 nearai@ruby.ocn.ne.jp 6 ryoko.onodera@gmail.com

Sia inter noine 21-24 AUGUST SCOTTISH EVENT CAMPUS GLASGOW

1. INTRODUCTION

At the child development support center, teachers with various specialities help children with special needs to work on various skills namely, communication, social, and language skills. Children and parents can use these facilities from any stage they become concerned about the children’s development. Among them, some children with special needs such as the autism spectrum have been either hypersensitive or insensitive to sensory stimulation [1,2]. In the context of the sound environment, children with hyperacusis experience intolerable pain in various aspects of their daily lives as a result of the sounds in their surroundings [3]. Thus, it is pertinent to secure a sound environment that is calm in which children with these characteristics can spend their time and have a stable relationship with people around. In collaboration with the child development support center, researchers in this study worked to create a sound environment for children with special needs. This paper reports the results of experiments focusing on the sound absorption performance of the classroom. In 2020, the Japanese architectural standard for sound absorption in the facilities of day-care center or kindergarten was established [4]. Many facilities still lack sound absorption. Adequate sound absorption is crucial from an educational point of view for children with significant development of language or communication, as underscored by the standards outlined by other countries [5, 6]. This is increasingly important for children with special needs, which is the focus of this study. According to the Japanese standard [4] mentioned above, the recommended value of sound absorption performance is underscored in three major stages: school classroom, nursery room, and hearing-impaired classroom. Previous studies in day-care center or kindergarten have shown that sound absorption has a positive effect on children and teachers [7-9]. Thus, the effect of sound absorption was verified, and the meaning of the sound environment for children with special needs was examined in this study. 2. METHOD

2.1. Images of the child development support center

Table 1 outlines the details of the child development support center and Figure 1 shows the facility environment. The center offers day care programs for 0 to 12-year-old children, namely, a day-care program for children aged 2 to 6-years old on weekdays, a dual enrolment program combined with day care or kindergarten for children 3 to 6 years, a family support program, and afterschool activities for elementary school children. Various professional services are provided to support children’s development as well as their families.

Table 1: Details of the child development support center

Social welfare corporation, Public-build and private operate, established in 1974 Location : Shizuoka prefecture, Japan / Suburban residential area Architecture: Reinforced concrete construction, Single-story building, Lot area: 6,381 ㎡ , Total floor area: 1,257 ㎡

Number of staff (Teachers): 69 (45) Qualifications: Certified kindergarten teachers, Certified nursery teachers, Certified primary school teachers, Speech therapists, Occupational therapists, Certified public psychologists, Clinical psychologists, Nurses, Public health nurses, Certified social workers, etc. Number of children / Programs: Day care program on weekdays (2-to-6-year-old children): 80 (two or three classes per grade) Dual enrolment program along with a day-care center or kindergarten: 120 (one day a week or two days a month) Others: Family support program, afterschool activities for elementary school children

(c) Sensory integration therapy room

(b) Playroom

(a) Classroom

Figure 1: Facility environment

2.2. Research outline

Since August 2021, this study has been conducting action research to create an environment for children in collaboration with staff from the center. The sound absorption performance improvement experiment was conducted for two classes of 4-year-old children (Table 2 and 3). The teachers requested to install sound-absorbing material in the room because Class A was noisier; hence, this study installed sound-absorbing materials in Class A. Furthermore, the teachers had high awareness of the sound environment and thus provided information about the children's hypersensitivity to sound prior to the experiment. It was found that certain children experienced painful sounds and hypersensitive reactions such as blocking their ears. Table 4 shows the experimental flow of this study, and the experimental environment and the reverberation time before and after the installation of the sound-absorbing material are shown in Figures 2 and 3. To ensure that the difference in sound was felt, we set the target of sound absorption coefficient to 0.3 and installed many sound-absorbing materials on the ceiling and walls as possible. As a result, the sound absorption coefficient was improved almost achieving the target in the 500 Hz to 2 kHz octave band. Before and after the installation, a survey was conducted on the sound environment, behavior, and the teachers' thoughts.

Table 2: Detail of the classroom

Floor area 32.7 ㎡ Ceiling height 2.7 m Room volume 88.3 ㎥ Ceiling material Perforated panel absorber (A part: Gypsum board) Floor material Flooring

Lol =e ie, |

Table 3: Number of people in the 4-year-classes

Class Number of children Number of teachers

Class A 11 8 Class B 11

Table 4: Experiment flow

Date Contents 21’11.11-11.24 Survey before installation

11.25 Installation of the sound-absorbing material Average sound absorption coefficient ( α" ) from 0.18 t o 0.30 11.26-22’ 1.13 Survey after the installation

. Se ~~ ax 4 pa y a SI | biog c rest ee) 8 | Baa oll =_

Before After Target (α=0.30)

1.0

Reverberation time [s]

0.8

0.6

0.4

0.2

0.0

Sound absorbing material

Microphone

125 250 500 1k 2k 4k

Frequency [Hz]

Figure 2: Installation of sound-absorbing material Figure 3: Reverberation time 3. RESULTS

3.1. Changes in the sound environment

The timer of the recorder was set to 10: 15-14: 30, and the activity sound was recorded daily using the microphone of the sound level meter. The A-weighted sound pressure level per minute ( L Aeq, 1min ) and maximum sound pressure level per minute ( L Amax, 1min ) were calculated, and the characteristics of the sound environment were analysed. In this section, the changes in the daily core time of 30 minutes (10: 30-11: 00) that children performed activities such as changing clothes, playing, and tidying up are considered. Time when there are no children such as playing outside were excluded from the analysis. The characteristics of the generated sound were investigated by observing and listening to the sound. Both Class A and Class B were analysed to examine the effects of sound absorption. Figure 4 shows the daily changes associated with the sound pressure level. The sound pressure in Class A tended to decline gradually after installation, while decline change was not observed in Class B. Figure 5 shows the averaged results divided into terms of approximately two weeks (i.e., Term 1: 11.11-11.24, Term 2: 11.26-12.10, Term 3: 12.13-24, Term 4: 1.5-13). In Class A, the sound pressure was approximately 5 dB smaller than before installation. Thus, it was confirmed that the generated sound decreased gradually due to sound absorption.

Class A Class B

[dB]

Installation

80

75

70

Nov. 11 Nov. 26 Dec.13 Jan. 5 Jan.13

Date

*30-minute (AM10:30-11:00) arithmetic mean of L Aeq, 1min

Figure 4: Daily changes in A-weighted sound pressure levels ( L Aeq, 1min )

[dB]

Class A Class B

80

Installation

75

Term 1: 21’ Nov.11- 24 Term 2: Nov. 26 – Dec. 10 Term 3: Dec. 13 - 24 Term 4: 22’ Jan. 5 - 13

70

Term 1 Term 2 Term 3 Term 4

Figure 5: Arithmetic mean for each term ( L Aeq, 1min , AM 10:30-11:00 )

Figure 6 shows the results of L Amax, 1min frequencies for each term. Overall, a loud sound such as over 90 dB was emitted. Responses such as screaming or shrilling were observed among the children when they were excited or emotional, which may have caused this result. In Class A, the frequency of loud sounds reduced significantly after installation. This may be due to the difficulty associated with calming down the children making loud sounds in reverberant environment. Thus, the loud voices and crying sounds made by the children were relieved through sound absorption. In contrast, the frequency of loud sounds in Class B slightly increased probably because the number of loud or crying voices generated by children increased in the latter half. As a result, Class B, which was originally thought to be quiet by the teachers, became noisier. Although children's growth factors such as the development of words and expressions may have an influence, overall, it was found that the generated sound became quiet by sound absorption.

< 80dB 80dB - 85dB 85dB - 90dB 90dB - 95dB 95dB ≦

Term 1

0%

7%

43%

48%

1%

Installation

Term 2

2%

20%

37%

35%

6%

Term 3

2%

20%

42%

30%

6%

Term 4

0%

4%

23%

51%

22%

0% 20% 40% 60% 80% 100%

(a) Class A

< 80dB 80dB - 85dB 85dB - 90dB 90dB - 95dB 95dB ≦

Term 1

1%

16%

33%

48%

1%

Term 2

2%

9%

35%

53%

1%

Term 3

0%

8%

38%

54%

1%

Term 4

2%

1%

10%

28%

59%

0% 20% 40% 60% 80% 100%

(b) Class B

Figure 6: Frequency distribution of the maximum sound pressure level for each term

( L AMax, 1min , AM 10:30-11:00 )

3.2. Influence on children and teachers

Observational surveys and interviews were conducted with four teachers to investigate the effects of sound absorption on children and teachers. Observation was conducted once a week by recording with a video camera. Interviews were conducted in groups or individually for 30 minutes to 1 hour before and after installation. The teachers were responsible for Class A and Class B, thus all the teachers used both rooms. The survey before installation found that Child X, who was sensitive to sound, blocked his ears when high-pitched voices became noisy (see Figure 7). In addition, Child X tended to generate small sounds, such as moving to the mat to play with building blocks and speaking soft voice. Child Y uttered a shrill voice when he was both uncomfortable and happy. It was also confirmed that some children spoke a loud voice when such as screaming or speaking a shrill voice while playing. During the interview, the teachers commented that they had an awareness of the problem of the noisy environment.

Figure 7: The scene of group activity: Musical chairs game The survey after installation confirmed that each voice was clear and easy to hear, particularly during free play where it was observed that each playgroup had a gentle conversation, and the children and teachers were calm. Even though screams and shrill voices were generated, the sound absorption effect in the high-frequency range was particularly high, reducing the painful feeling in the ears. The teachers think that these loud voices are important expressions used by the children and they need to receive such sounds calmly. Thus it was thought that sound absorption supported teachers to listen children’s expressions. According to the teachers, Child X, who was sensitive to sound became less prone to blocking his ears. It was also observed that Child X spoke to the teacher in a louder voice as opposed to before the installation. This change in behavior was thought to be a result of the raise motivation to speak, as the sound absorption made it easier for him to hear his own words and to make his words more acceptable to the teachers. This shows one of the meanings of the sound absorption for children with special needs such as supporting the language development. In the interview with the four teachers, it was said that loud noise was reduced, and it became easier to calm down. In addition, a veteran teacher, Teacher Z commented how her voice should be. Parts of the interview are outlined below.

Table 5: Teacher Z ’s comment on teacher’s own voice.

December 2021: "When I entered Class B after Class A, my voice seemed loud. ... I don't know which class is appropriate for the children. " January 2022: "When I entered Class B, I felt that my voice was very loud, so I told children that I would talk in a quiet voice today. And I talked to the children in a small voice to become a “Ninja” (Japanese traditional character who mastered special techniques such as moving quietly to notice nobody) together, then it seemed to be good for the children and the class was very calm. ... I found that a loud voice was not so good for children with special needs. Though sometimes I use a loud voice when I want to convey my feelings, such as happy feelings. I thought that it might be better for these children to stay near them, speak in a calm and small voice."

Teacher Z often had spoken loudly and cheerfully to convey words to the children. From the continuous experience of different reverberation between the two rooms, she was aware of the effect of speaking in a soft voice. This awareness was considered to be due to Teacher Z’s own learning, which emerged from the constant questioning herself to how to convey words to children as a specialist in children's development support.

4. CONCLUSIONS

This study focused on the sound absorption performance of the classroom at the child development support center. It was suggested that the sound environment improved by sound absorption, and this effect supported calmness, ease of participation in activities, and language development among children. Furthermore, the experience of different reverberation in the daily activity would present an opportunity for teachers to become aware of their own voices. It was found that the sound environment had various side meanings for children with special needs. These results are not limited to children with special needs but can be generalized to all children, indicating that proper condition of sound absorption is essential. It was also shown that this is a serious problem, especially for children with hyperacusis, and that further consideration is needed. In the future, appropriate sound absorption performance and introduction methods of sound-absorbing materials should be considered, including viewpoints on teachers' learning and qualitative analysis of the relationship between children, teachers, and the sound environment. 5. ACKNOWLEDGEMENTS

We would like to thank the teachers of the Nearai Gakuen for their cooperation during the experiments. This study was supported by the Research Grant for the Healthy upbringing of children from the Nippon Life Foundation. 6. REFERENCES

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