Research relating increased academic achievement with the use of sound field amplification in the classroom.

Millett, P. PhD, “Sound Field Amplification: Research Summary”, York University, September, 2008.
Abstract: This paper identifies research studies focused upon the efficacy of sound field amplification as it pertains to children and adults. Topics covered include: sound field amplification in regular classrooms, special education referral rates, studies of aboriginal students, ESL, students with learning challenges, adults and children in post-secondary settings, and teacher vocal problems. A fairly extensive list of references is included.

Massie, R. and Dillon, H., “The Impact of Sound Field Amplification in Mainstream Cross-Cultural Classrooms: Parts 1 (outcomes) and 2 (participant opinions), Australian Journal of Education, April 2006.
Abstract: Investigation of the effects of Sound Field Amplification (SFA) intervention on achievement of educational goals for elementary school students. The study premise is that speech quality is directly related to phonemic discrimination and, ultimately, comprehension. This 1 year study involved 242 students across 12 classrooms. Students comprised a variety of ethnic backgrounds. The research evaluated achievement in reading, writing, and math as a result of amplification being ON and OFF. Audiological assessments were made on each student at the beginning of the study; a subset was evaluated at the midpoint of the study. The acoustics of each classroom was assessed in terms of ambient noise levels, speech-plus-noise levels, and reverberation time. Improvement in test scores was significant when amplification was used. The reasons cited include the increase in the teacher's voice above the background noise (an average increase of 6 dB) along with speaker placement ensuring students were predominantly in the direct path of the transmitted audio. Increase in achievement with SFA was apparently irrespective of ethnic or language background. Part 2 provides considerable details on the questionnaires used along with comments by both students and teachers.

Darai, B., “Using Sound Field FM Systems to Improve Literacy Scores”, ADVANCE for Speech-Language Pathologists and Audiologists, 2002.
Abstract: Roughly 44 million Americans cannot read. Nearly 50 million read at or below the 5th grade level. The research herein investigates the influence of increased speech-to-noise levels on hearing and learning. This 5 month study involved 166 1st grade students across 4 schools and 8 classrooms. The literacy measure used was “Informal Reading Inventory”. The researchers reported a significant increase in literacy for those receiving amplified instruction as compared to the unamplified control group. In addition, there was marked increase in the number of students able to read up to seven reading levels above their initial level. Teachers reported increased student attention, reduction in requests to repeat material, and overall student acceptance of amplification.

Flexer, C. and Long, S., “Sound Field Amplification: preliminary information regarding special education referrals, Communication Disorders Quarterly, 2003,
Abstract: Research was predicated on the assumption that an improvement in teacher speech-to-noise levels can have a positive impact on special education referrals. This hypothesis relies on the fact that a young child’s auditory neurological network is too immature to allow use of an extensive word “data bank” or contextual clues to accurately discriminate speech and comprehend instructional material (Berlin & Weyand, 2003; Boothroyd, 1997; Musiek & Berge, 1998). This 8 month study involved kindergarten through 5th grade students with fluctuating hearing loss, cognitive disorders, attention problems, behavior problems, etc. Overall, as a result of increasing acoustic accessibility through use of SFA systems, there was marked decrease in % referrals across the grades studied (nearly 50%) compared to previous years. While only a preliminary investigation, the expectation is that the trend showing a significant reduction of referral case loads will be observed in those classrooms that maintain positive speech-to-noise levels. This paper also provides considerable detail regarding critical hearing and listening skills, methods for creating a quiet classroom, and a general discussion of SFA equipment.