Sound-Field Amplification: Preliminary Information regarding Special Education Referrals

Article excerpt

In this clinical exchange, the authors discuss acoustic accessibility and sound-field amplification in general education classrooms. They bridge theory to practice by presenting preliminary information from two different school systems demonstrating how an improved signal-to-noise ratio can have a positive impact on special education referrals.


General education classrooms are auditory-verbal environments; listening is the primary modality for learning (Berg, 1993; Chermak & Musiek, 1997). Instruction is presented through the speech of the teacher, with the underlying assumption that pupils can hear clearly and attend to spoken communication. To the extent that students cannot consistently and clearly hear the teacher, the entire premise of the educational system is undermined. Ironically, the acoustic environment rarely is considered when designing a school (Boothroyd, 2002; Crandell, Smaldino, & Flexer, 1995).

Our purposes in this clinical exchange are threefold. First, we discuss acoustic accessibility. Second, we describe sound-field amplification systems. Finally, we present information from two different school systems where a reduction in special education referrals occurred in buildings that have sound-field amplification systems in their general education classrooms (kindergarten through fifth grade). These two school systems offer examples of how sound-field technology can be beneficial.


In order to learn, children require a quieter environment and a louder signal than do adults. The quieter the room and the more distinctive the auditory signal, the better opportunity the child will have to process the signal and accomplish the desired cognitive integration (Anderson, 2001; Leavitt & Flexer, 1991). Sadly, most classrooms are "acoustically hostile" (Boothroyd, 2002; Crandell & Smaldino, 1996).

Children require a more favorable acoustic environment than adults for two main reasons:

1. Children cannot listen like adults because the auditory neurological network is not fully developed until about 15 years of age (Berlin & Weyand, 2003; Boothroyd, 1997; Musiek & Berge, 1998).

2. Children do not bring 30-plus years of listening and life experience to a learning situation; hence, they cannot perform the automatic "auditory-cognitive closure" of missed information (Flexer, 1999). To fill in the blanks of missed information, that information already has to be in the brain's "data banks" for retrieval. Children thus need a sharper auditory signal than that required by adults (Anderson, 2001). A classroom that sounds acceptable to an adult could be woefully inadequate for typical children who (a) have not reached their full neurological capacity and (b) have not had decades of language and life experience.

Because hearing is a first-order event in a general education classroom, if children do not hear clearly and consistently, their academic potential is compromised.

The main difficulty with trying to learn in a poor acoustic environment is that the child cannot distinguish specific speech sounds. Consequently, speech might be very audible but not consistently intelligible, causing children to hear, for example, words such as walked, walking, walker all as "-- -ah." (Leavitt & Flexer, 1991; Ling, 2002; Robertson, 2000).

A great deal is involved in "hearing" the teacher. Erber (1982) was one of the first to identify the levels of auditory skill development associated with hearing and listening, and Ling (2002) expanded on levels:

* Detection: This is the lowest, least sophisticated level of auditory skill development. Detection refers to the presence and absence of sound. Obtaining pure tone thresholds is a detection task.

* Discrimination: This involves distinguishing between two speech sounds. An example of a discrimination task would be noting if "da" and "tha" are the same or different. …