BATOD
The British Association of Teachers of the Deaf
Promoting Excellence in Deaf Education

Peter Preston Audiology Award 2012

This annual award is given for the best article on audiology written by a practitioner in the previous year’s Magazine. The nominated eligible articles from those published in 2011 BATOD Magazines were:

Magazine page title author
January 2011 42 Useful  Kit  Mary Gordon
May 2011 20 FM Chip Kathy Owston
September 2011 4 Managing noise Stuart Whyte
September 2011 8 Listening lessons Jacqui Gardner
September 2011 13 Scottish Accounts Elaine Harris
September 2011 18 Soundfield for all Julie Carter and Liz Reed-Beadle
September 2011 22 My Amigo Lois Couch

Managing noise by Stuart Whyte was nominated to receive the award at the BATOD AGM on 10th March 2012 in London

Managing noise

Stuart Whyte is a qualified Teacher of the Deaf and educational audiologist who currently works for West Sussex County Council as an advisory teacher for hearing impairment. He considers the nature of reverberation and noise in learning settings and provides some practical suggestions for improving conditions for children and staff affected by noise

Reverberation and noise combine to make it difficult for children to understand speech. Deaf children, or children with language difficulties or other special needs such as auditory neuropathy or autism, may find speech discrimination particularly challenging. There are many children whose needs can be met with a little adaptation by mainstream staff. However, there are others whose needs are highly complex and their learning settings may require advice from a Teacher of the Deaf or an educational audiologist.

The challenge of listening

Hearing is a complex process that involves the functions of the ear and the brain. The brain interprets what we hear – we call this listening, or auditory processing. Listening skills develop with time and experience; sound associations are built up and our brain learns to use different levels of attention. Active listening uses the ability to focus on one sound to the exclusion of others. This ‘tuned in’ analytical listening may be associated with the left brain, the side used in language processing. We also use an intermediate or background kind of listening – the brain is ready to receive information and evaluate its significance, but our attention is probably directed elsewhere. Background listening is an important part of the listening process, but noise levels compete against this skill.

The nature of noise

Sound waves travel through the air until they meet a surface; the sound is then partly absorbed by the surface and partly reflected back into the room (reverberation). When we listen to sound we hear not only an original direct sound source, but also its many complex reflections. Reverberation time (RT) is an important way to describe the acoustic character of a space. Early reflections support speech intelligibility but late reflections (long RT) increase the reverberant noise levels and degrade speech. The level of the desired speech signal compared to everything else (noise) is described as the signal-to-noise ratio (SNR). The brain is adept at sound pattern detection, but a minimum SNR is required so that speech can be separated from competing noise. (See the Acoustics and Soundfield section of the Audiology Refresher publication on the BATOD website for further information on RT and SNR.)

The effects of noise

The quality and intelligibility of speech depends on the acoustic conditions of the room, ie the amount of reflected sound and the level of noise. Listening in conditions of competing noise is challenging because of the greater information load on the brain. Noise can come from a variety of external and internal sources; for example, from weather, transportation or industrial noise, the playground, stairs, corridors or other classrooms, heating, lighting, ventilation and plumbing systems and the people and equipment present in the room itself.

A poor acoustic environment makes it difficult to communicate and can lead to staff suffering voice problems because of the increased vocal effort. Research studies have also looked at children’s views of their acoustic environment and the effects of noise and reverberation within the classroom. The London South Bank University and the Institute of Education considered the effects of school classroom design on learning so as to develop better acoustic guidelines and teaching strategies. Their studies in primary schools have shown the negative relationship between Key Stage 2 test performance and noise levels.

Improving conditions

Since 2003 new school buildings and refurbished rooms in schools have to comply with Approved Document E, Section 4 of the Building Regulations, revised in 2004. This document, known as BB93, defines performance standards for various teaching spaces in terms of the ambient noise level, the reverberation time and the noise transfer from other spaces into the room. BB93 allows for alternative performance standards, provided these derogations can be justified for educational, environmental or health and safety reasons.

My initial experience of providing acoustical advice on refurbishment was for a large mainstream secondary school with a special support centre for deaf children. Using a Norsonic 118 sound level meter supplied by the local authority, I was able to provide information on ambient noise and reverberation time across a representative sample of classrooms. This highlighted the need for some treatment to a drama studio. Using I was able to model different interventions and provide a cost-effective solution using a sound absorbing wall treatment.

Appendices to BB93 and the NDCS Acoustic Toolkit provide helpful guidance on calculating, modelling, and reducing RT with sound-absorbing materials. Noise treatments vary and information about a wealth of materials (for example, spray on, stick on, screw on) can be found with the Royal Institute of British Architects’ search facility. Consideration should be given to practical requirements and ‘wear and tear’ factors such as ease of cleaning, dirt repellence and impact resistance.

For some teaching spaces, acoustic intervention is highly specialised. For example, an initial acoustic survey of a primary school with a resource base for children with a hearing impairment was passed to the Local Authority Capital Planning Team. Architects and acousticians were then employed to specify remedial work. ‘Before’ and ‘after’ pictures (on page 6) show the lowered ceiling and wall panels with the original aesthetic wall tiles still in place. Significant changes in reverberation times were effected in these classrooms, improving accessibility for all children and especially those with hearing aids and cochlear implants.

In March 2010 BATOD published David Canning’s interim report on a study into the process of classroom refurbishment for Essex County Council. The study considered an evidence-based approach to changing the acoustic environment to provide short reverberation times. It found the costs of refurbishing rooms to be small in comparison to the benefits, such as reduced out-of-county placements. Acoustic intervention helps reduce stress, reduces the risk of hearing damage and benefits communication and learning. Noise treatments take into consideration the users of a learning space, its shape and size and the activities that will take place there. Reverberation times of 0.4 seconds are possible in pre-school settings too, and support communication and language development.

Help with existing classrooms

No funds for refurbishment? Improving the acoustic environment can be achieved with reasonable adjustments. Different age groups and activities generate different levels of noise, but children are aware of and annoyed by noise that distracts them. Age-appropriate strategies should be employed to support children in being more self-aware of noise.
  • Pupil talk is important but teach children and young people the meaning of different working noise levels. Use recorded sound samples or role-play to model what you mean – for younger children discuss stories such as The Quiet Woman and the Noisy Dog by Sue Eves (Andersen, 2009) or Hannibal’s Noisy Day by Anne Adeney (Sea to Sea Publications, 2008).
  • Define acceptable limits; for example, use ‘mute’, ‘whisper voices’, ‘partner voices’ and ‘group voices’ for working noise ranging from no talking through to conversational level; use ‘playground/breaktime voices’ for levels unacceptable in the classroom.
  • Use visual indicators of noise levels such as a ‘noiseometer’ to represent the range. These can be paper, card or whiteboard versions of ‘classroom management aids’ (see www.primaryresources.co.uk), or there is even an ‘AudioTools’ sound-level meter traffic light app for the iPod Touch and the iPhone. Support your spoken instructions with accessible visual cues so that pupils can see the steps to completing tasks within the lesson. Have clear systems for pupils to show their understanding and ask for help.
  • Distance is critical; deliver spoken instructions near to a deaf child. Provide good access to lip patterns and facial expressions; don’t ‘walk and talk’!
  • Co-ordinate your learning activities if teaching in open-plan areas – don’t start your music lesson if the neighbouring class is reading!
  • Turn off the digital projector or computer(s) when not in use to avoid fan noise and to save energy.
  • Close doors or windows as far as possible. Carpets, curtains, soft furnishing, soft covers on tables, fabric on walls, soft-fibre display boards, and mobiles or materials hung from the ceiling can help. However, if suspending items, ensure that materials are not a fire hazard and are not likely to activate the motion sensor of the school alarm system at night!
  • Interference by noise affects working memory. A poor acoustic environment affects pupils in different ways; be aware that verbal tasks like reading and spelling are affected by speech noise (classroom babble), while non-verbal tasks may be more affected by environmental noise.
  • Share good practice with colleagues and talk about noise awareness across the school. Consider establishing ‘Quiet Zones’ in the building. The NDCS DVD Here to Learn includes a section that shows how some simple steps can reduce noise in a classroom.
  • Some children will benefit from personal FM radio aid systems or Soundfield amplification within the classroom. Personal FM systems will provide the best signal-to-noise ratio. However, careful thought should be given to the provision and maintenance of such systems. They need to be set up for the amplification needs of individual deaf children and access to a qualified Teacher of the Deaf or educational audiologist is essential.

Worried about your voice?

Teachers make up a disproportionate part of the case list of voice clinics. Surveys by the unions serving school staff and the RNID have shown the impact on health. Some sound advice is available from your union’s health and safety representative and some top tips for vocal health can be found at www.voicecare.org.uk/vcn/voice-tips/
  • Avoid shouting over background noise – gain attention with a visual signal like a hand in the air for pupils to copy, or use a sound signal like a clapping rhythm.
  • If voice hoarseness persists for longer than three weeks, consult your GP.

Standards and services under threat?

Children do not have the same auditory perception abilities as adults. Children develop their sensitivity to the small differences in speech sounds (acoustic cues) as their attending and listening skills mature. Speech perception abilities within conditions of noise and reverberation may not reach adult-like levels of performance until the mid-to-late teenage years.

Along with the rise of academies and free schools, the Coalition Government is considering further review of BB93. Following the James Review into school capital spending there is a concern that the regulations that govern acoustic standards in schools could be weakened. Classroom acoustics should be considered a critical variable in the educational achievement of children. We know that staff and children experience difficulties in learning settings with excessive noise and reverberation levels, so essential services for deaf children and measures to reduce the risks to health and achievement should be maintained.

Download Managing noise Stuart Whyte.pdf