Frequency Modulation System Research Articles

Coexistence of OFDM-Based IMT-Advanced and FM Broadcasting Systems

Coexistence analysis is extremely important in examining the possibility for spectrum sharing between orthogonal frequency-division multiplexing (OFDM)-based international mobile telecommunications (IMT)-Advanced and other wireless services. In this letter, a new closed form method is derived based on power spectral density analysis in order to analyze the coexistence of OFDM-based IMT-Advanced systems and broadcasting frequency modulation (FM) systems. The proposed method evaluates more exact interference power of IMT-Advanced systems in FM broadcasting systems than the advanced minimum coupling loss (A-MCL) method. Numerical results show that the interference power is 1.3 dB and 3 dB less than that obtained using the A-MCL method at cochannel and adjacent channel, respectively. This reduces the minimum separation distance between the two systems, which eventually saves spectrum resources.

Factors Contributing to Speech Perception Scores in Long-Term Pediatric Cochlear Implant Users

The objectives of this report are to (1) describe the speech perception abilities of long-term pediatric cochlear implant (CI) recipients by comparing scores obtained at elementary school (CI-E, 8 to 9 yrs) with scores obtained at high school (CI-HS, 15 to 18 yrs); (2) evaluate speech perception abilities in demanding listening conditions (i.e., noise and lower intensity levels) at adolescence; and (3) examine the relation of speech perception scores to speech and language development over this longitudinal timeframe. All 112 teenagers were part of a previous nationwide study of 8- and 9-yr-olds (N = 181) who received a CI between 2 and 5 yrs of age. The test battery included (1) the Lexical Neighborhood Test (LNT; hard and easy word lists); (2) the Bamford Kowal Bench sentence test; (3) the Children's Auditory-Visual Enhancement Test; (4) the Test of Auditory Comprehension of Language at CI-E; (5) the Peabody Picture Vocabulary Test at CI-HS; and (6) the McGarr sentences (consonants correct) at CI-E and CI-HS. CI-HS speech perception was measured in both optimal and demanding listening conditions (i.e., background noise and low-intensity level). Speech perception scores were compared based on age at test, lexical difficulty of stimuli, listening environment (optimal and demanding), input mode (visual and auditory-visual), and language age. All group mean scores significantly increased with age across the two test sessions. Scores of adolescents significantly decreased in demanding listening conditions. The effect of lexical difficulty on the LNT scores, as evidenced by the difference in performance between easy versus hard lists, increased with age and decreased for adolescents in challenging listening conditions. Calculated curves for percent correct speech perception scores (LNT and Bamford Kowal Bench) and consonants correct on the McGarr sentences plotted against age-equivalent language scores on the Test of Auditory Comprehension of Language and Peabody Picture Vocabulary Test achieved asymptote at similar ages, around 10 to 11 yrs. On average, children receiving CIs between 2 and 5 yrs of age exhibited significant improvement on tests of speech perception, lipreading, speech production, and language skills measured between primary grades and adolescence. Evidence suggests that improvement in speech perception scores with age reflects increased spoken language level up to a language age of about 10 yrs. Speech perception performance significantly decreased with softer stimulus intensity level and with introduction of background noise. Upgrades to newer speech processing strategies and greater use of frequency-modulated systems may be beneficial for ameliorating performance under these demanding listening conditions.

A Low-cost Ultrasonic 3D Measurement Device for Calibration for Cartesian and Non-Cartesian Machines

The major obstacles to the widespread adoption of 3D measurement systems are accuracy, speed of process and the cost. At present, high accuracy for measuring 3D position has been achieved, and there have been real advances in reducing measurement time, but the cost of such systems remains high. A high-accuracy and high-resolution ultrasonic distance measurement system has been achieved in this project by creating multi-frequency continuous wave frequency modulation (MFCWFM) system. The low-cost system measures dynamic distance (displacements of an ultrasound transmitter) and fixed distance (distances between receivers). The instantaneous distance between the transmitter and each receiver can be precisely determined. New geometric algorithms for transmitter 3D position and receiver positing have also been developed in the current research to improve the measurement system‟s practicability. These algorithms allow the ultrasound receivers to be arbitrarily placed and located by self-calibration following a simple procedure. After the development and testing of the new 3D measurement system, further studies have also been carried out on the system, considering the two major external disturbances: air temperature drifting and ultrasound echo interference. Novel methods have been successfully developed and tested to minimize measurement errors and evaluation of speed of sound. All the enabling research described in the thesis means that it is now possible to build and implement a measurement system at reasonable cost for industrial exploitation. This will have the necessary performance to provide ultrasonic 3D position measurements in real time for monitoring position.

Temporal AM–FM combination for robust speech recognition

A novel method for feature extraction from the frequency modulation (FM) in speech signals is proposed for robust speech recognition. To exploit of the multistream speech recognizers, each stream should compensate for the shortcomings of the other streams. In this light, FM features are promising as complemental features of amplitude modulation (AM). In order to extract effective features from FM patterns, we applied the proposed feature extraction method by the data-driven modulation analysis of instantaneous frequency. By evaluating the frequency responses of the temporal filters obtained by the proposed method, we confirmed that the modulation observed around 4 Hz is important for the discrimination of FM patterns, as in the case of AM features. We evaluated the robustness of our method by performing noisy speech recognition experiments. We confirmed that our FM features can improve the noise robustness of speech recognizers even when the FM features are not combined with conventional AM and/or spectral envelope features. We also performed multistream speech recognition experiments. The experimental results show that combination of the conventional AM system and proposed FM system reduced word error by 43.6% at 10 dB SNR as compared to the baseline MFCC system and by 20.2% as compared to the conventional AM system. We investigated the complementarity of the AM and FM features by performing speech recognition experiments in artificial noisy environments. We found the FM features to be robust to wide-band noise, which certainly degrades the performance of AM features. Further, we evaluated the efficiency of multiconditional training. Although the performance of the proposed combination method was degraded by multiconditional training, we confirmed that the performance of the proposed FM method improved. Through a series of experiments, we confirmed that our FM features can be used as independent features as well as complemental features.

Verifying Frequency-Modulated System Performance: It's The Right Thing to Do

Frequency-modulated (FM) systems provide a means of overcoming negative effects of noise, distance, and reverberation, improving communication access for children with hearing loss and/or special listening needs. These systems may be worn alone at the ear or coupled to hearing aids or cochlear implants. Technology in all these devices continues to advance at an astonishing rate. With these advances, there continues to be a need for careful verification of the entire amplification system's performance. The overall goal of verification is to confirm that the entire amplification system is set and functioning as intended. This article addresses current recommended practices for FM system verification for a variety of FM coupling options.

Low-cost resolution improvement technique for short distance measurement systems

In this work, a new scheme for short-range distance measurement is presented. It reduces significantly the amount of signal processing needed for frequency-modulated continuous-wave radar or Lidar systems to obtain a good resolution in beat frequency measurement. In this article, a low cost and easy to implement technique is proposed. This resolution improvement is achieved by simple previous processing of the beat signal. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1496–1498, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25243

Interfacing FM Systems with Implantable Hearing Devices

Cochlear implant recipients can reduce the challenges they encounter in noisy environments through the use of a remote microphone. Although there are numerous options for delivering the signal from the frequency modulated (FM) transmitter worn by the speaker to the FM receiver coupled to the implant, several have now been verified through research as viable, beneficial arrangements. Recommendations for the settings on the implant include mixing ratio and settings on the FM receivers (i.e., FM advantage). Because coupling of the FM system with the implant cannot be tested with traditional electroacoustic methods, behavioral verification using speech recognition in noise with the implant alone and with the implant plus the FM system is necessary. A variety of resources are available for the audiologist to consult for the specific components, start sequence of switches, and verification protocols. Resources can be found through manufacturer and professional association Web sites.

The national protocol for paediatric amplification in Australia

This document describes the national protocol for the selection, fitting, verification, and evaluation of amplification for hearing-impaired children in Australia. It also outlines the approach to management of children who have auditory neuropathy spectrum disorder, children who have mild and unilateral hearing loss, and children who require cochlear implantation. Audiological management of all Australian citizens and permanent residents under twenty-one years of age who have a hearing loss is carried out by the national hearing service provider, Australian Hearing. It is funded by the Australian Government's Hearing Services Program to provide fully subsidised hearing aids, frequency modulated (FM) systems and ongoing audiological management. All hearing aids for children are multi-channel devices that offer wide dynamic range compression, directional microphone technology and feedback cancellation as well as access to multiple listening programs, telecoil and audio-input facilities. Hearing aid gain, frequency response and maximum power output are derived according to the NAL-NL1 prescription procedure and verified using real ear measurements. Amplification benefit is evaluated using a range of speech perception tests and functional assessment questionnaires.SumarioEste documento describe el protocolo nacional para la selección, la adaptación, la verificación y la evaluación de la amplificación en niños hipoacúsicos en Australia. También esboza el acercamiento para el tratamiento de niños con el espectro de desórdenes de neuropatía auditiva, niños con hipoacusia moderada y unilateral y niños que requieren implante coclear. El tratamiento audiológico de todos los ciudadanos australianos y residentes permanentes menores de veintiún años de edad con hipoacusia se lleva a cabo por el proveedor nacional de servicios auditivos: Australian Hearing. Es financiado por el Programa del Gobierno Australiano de Servicios Auditivos para otorgar auxiliares auditivos, sistemas de frecuencia modulada (FM) y tratamiento audiológico subsidiados. Todos los auxiliares auditivos para niños son de tipo multicanal que ofrecen un amplio rango de compresión, tecnología de micrófono direccional y de cancelación de la retroalimentación, así como acceso a múltiples programas, telecoil y múltiples propiedades de ingreso de la señal. La ganancia del auxiliar auditivo, la frecuencia de respuesta y la máxima salida derivan de acuerdo a los procedimientos de las prescripciones NAL-NL1 y se verifican utilizando las mediciones de oído real. El beneficio de la amplificación se evalúa utilizando un rango de pruebas de habla y cuestionarios prescripción de la prueba de rango de habla y cuestionarios de desempeño funcional.

Origin and Control of Sinusoidal Nonlinearities in Wavelength-Tuned Littman External Cavity Laser Diodes

In a recent paper, we presented the influence of sinusoidal nonlinearities in the wavelength sweeping speed on the performance of an absolute distance interferometry setup. Nonlinearities in an optical frequency modulation system are generally the source of degradation in performance. The interest of this study comes from the experimental observation of the good behavior of an absolute distance measurement system with the presence of sinusoidal nonlinearities in the wavelength sweeping speed obtained from an external cavity laser diode (ECLD). This paper presents experimental results obtained with a custom ECLD based on a Littman-Metcalf setup. We link the sinusoidal nonlinear sweep to some mechanical properties of the cavity. The main source of these nonlinearities comes from the digitization of the piezoelectric transducer excitation. Different types of excitation like super-Gaussian and ramp, including or not sinusoidal modulations, were implemented and analyzed. By this way, we are able to reduce the spectral width by a factor 3 without adding linearization electronics such as a servo-loop control on injection current or nonuniform samplers, and our system achieves a 3 times 10- 6 relative uncertainty on distance measurement with a number of samples reduced by a factor 8.

The Benefits of Remote Microphone Technology for Adults with Cochlear Implants

Cochlear implantation has become a standard practice for adults with severe to profound hearing loss who demonstrate limited benefit from hearing aids. Despite the substantial auditory benefits provided by cochlear implants, many adults experience difficulty understanding speech in noisy environments and in other challenging listening conditions such as television. Remote microphone technology may provide some benefit in these situations; however, little is known about whether these systems are effective in improving speech understanding in difficult acoustic environments for this population. This study was undertaken with adult cochlear implant recipients to assess the potential benefits of remote microphone technology. The objectives were to examine the measurable and perceived benefit of remote microphone devices during television viewing and to assess the benefits of a frequency-modulated system for speech understanding in noise. Fifteen adult unilateral cochlear implant users were fit with remote microphone devices in a clinical environment. The study used a combination of direct measurements and patient perceptions to assess speech understanding with and without remote microphone technology. The direct measures involved a within-subject repeated-measures design. Direct measures of patients' speech understanding during television viewing were collected using their cochlear implant alone and with their implant device coupled to an assistive listening device. Questionnaires were administered to document patients' perceptions of benefits during the television-listening tasks. Speech recognition tests of open-set sentences in noise with and without remote microphone technology were also administered. Participants showed improved speech understanding for television listening when using remote microphone devices coupled to their cochlear implant compared with a cochlear implant alone. This benefit was documented both when listening to news and talk show recordings. Questionnaire results also showed statistically significant differences between listening with a cochlear implant alone and listening with a remote microphone device. Participants judged that remote microphone technology provided them with better comprehension, more confidence, and greater ease of listening. Use of a frequency-modulated system coupled to a cochlear implant also showed significant improvement over a cochlear implant alone for open-set sentence recognition in +10 and +5 dB signal to noise ratios. Benefits were measured during remote microphone use in focused-listening situations in a clinical setting, for both television viewing and speech understanding in noise in the audiometric sound suite. The results suggest that adult cochlear implant users should be counseled regarding the potential for enhanced speech understanding in difficult listening environments through the use of remote microphone technology.

Sistema de freqüência modulada no transtorno do processamento auditivo: prática baseada em evidências?

use of frequency modulation (FM) system in auditory processing disorder. to verify the existence of scientific evidence confirming the effectiveness of personal FM systems in the treatment of central auditory processing disorders (APD). For this purpose a systematic review of the literature was made, using data found in electronic databases (Medline, Lilacs and Cochrane library) as well as on the internet. The articles retrieved were analyzed according to the CONSORT statement and then classified by their evidence level. the search resulted in 1,589 references out of which only 19 met the inclusion criteria. All of the analyzed articles were classified as having low level of evidence (expert opinion or case studies). Strong scientific evidence supporting the use of personal FM systems for APD intervention was not found. Since such device is frequently recommended for the treatment of APD, it becomes essential to carry out studies with high scientific evidence that could safely guide clinical decision making on this subject.

Noise immunity of synchrosignal reception in a start-stop communications system

An option of start-stop communications frequency-modulation system with orthogonal signals and the separate transfer of the synchrosignal and message has been considered. It was shown that optimal results during the synchrosignal reception could be achieved at the quadrature detection of its elements in channels of the frequency detector.

Evaluation of Speech Recognition in Noise with Cochlear Implants and Dynamic FM

Use of personal frequency-modulated (FM) systems significantly improves speech recognition in noise for users of cochlear implants (CIs). Previous studies have shown that the most appropriate gain setting on the FM receiver may vary based on the listening situation and the manufacturer of the CI system. Unlike traditional FM systems with fixed-gain settings, Dynamic FM automatically varies the gain of the FM receiver with changes in the ambient noise level. There are no published reports describing the benefits of Dynamic FM use for CI recipients or how Dynamic FM performance varies as a function of CI manufacturer. To evaluate speech recognition of Advanced Bionics Corporation or Cochlear Corporation CI recipients using Dynamic FM vs. a traditional FM system and to examine the effects of Autosensitivity on the FM performance of Cochlear Corporation recipients. A two-group repeated-measures design. Participants were assigned to a group according to their type of CI. Twenty-five subjects, ranging in age from 8 to 82 years, met the inclusion criteria for one or more of the experiments. Thirteen subjects used Advanced Bionics Corporation, and 12 used Cochlear Corporation implants. Speech recognition was assessed while subjects used traditional, fixed-gain FM systems and Dynamic FM systems. In Experiments 1 and 2, speech recognition was evaluated with a traditional, fixed-gain FM system and a Dynamic FM system using the Hearing in Noise Test sentences in quiet and in classroom noise. A repeated-measures analysis of variance (ANOVA) was used to evaluate effects of CI manufacturer (Advanced Bionics and Cochlear Corporation), type of FM system (traditional and dynamic), noise level, and use of Autosensitivity for users of Cochlear Corporation implants. Experiment 3 determined the effects of Autosensitivity on speech recognition of Cochlear Corporation implant recipients when listening through the speech processor microphone with the FM system muted. A repeated-measures ANOVA was used to examine the effects of signal-to-noise ratio and Autosensitivity. In Experiment 1, use of Dynamic FM resulted in better speech recognition in noise for Advanced Bionics recipients relative to traditional FM at noise levels of 65, 70, and 75 dB SPL. Advanced Bionics recipients obtained better speech recognition in noise with FM use when compared to Cochlear Corporation recipients. When Autosensitivity was enabled in Experiment 2, the performance of Cochlear Corporation recipients was equivalent to that of Advanced Bionics recipients, and Dynamic FM was significantly better than traditional FM. Results of Experiment 3 indicate that use of Autosensitivity improves speech recognition in noise of signals directed to the speech processor relative to no Autosensitivity. Dynamic FM should be considered for use with persons with CIs to improve speech recognition in noise. At default CI settings, FM performance is better for Advanced Bionics recipients when compared to Cochlear Corporation recipients, but use of Autosensitivity by Cochlear Corporation users results in equivalent group performance.

Effects of FM-receiver gain on speech-recognition performance of adults with cochlear implants

The primary aim of this study was to examine the effects of frequency-modulated (FM) settings on speech-recognition performance in noise of listeners using two different cochlear implant speech processors. Participants included eight users of ESPrit 3G speech processors and nine users of Auria speech processors. A modified adaptive-testing paradigm was used to assess speech recognition in noise with the cochlear implant and FM system at four receiver-gain settings: +6, +10, +14, or +20. In the no-FM condition, performance differences were not detected between the two processor groups. In the FM conditions, significantly better performance was found for participants with the Auria processor compared to those using the ESPrit 3G processor. Increases in receiver gain did not significantly improve speech recognition of participants using ESPrit 3G processors, but did significantly influence performance for those using Auria processors. For Auria users, the +6 setting resulted in significantly poorer performance than all other conditions, and optimal FM performance was found in the +14 and +20 gain settings. Clinical recommendations will be provided according to results of the study.

Trends in Classroom Amplification

Advances in hearing instrument and fre- quency-modulated (FM) technology provide audiologists and families with many choices when selecting class- room amplification. An understanding of the benefits and limitations of amplification options, as well as an understanding of current fitting and verification proce- dures, is important for audiologists who recommend and fit these devices. This article will address two of the most commonly used options in classroom amplification: individual FM systems and sound-field systems (FM and infrared). Device options and procedures for fitting and follow-up will be discussed.

Optimizing The Benefit of Sound Processors Coupled to Personal FM Systems

Use of personal frequency modulated (FM) systems significantly improves speech recognition in noise for users of cochlear implants (CI). There are, however, a number of adjustable parameters of the cochlear implant and FM receiver that may affect performance and benefit, and there is limited evidence to guide audiologists in optimizing these parameters. This study examined the effect of two sound processor audio-mixing ratios (30/70 and 50/50) on speech recognition and functional benefit for adults with CIs using the Advanced Bionics Auria sound processors. Fully-repeated repeated measures experimental design. Each subject participated in every speech-recognition condition in the study, and qualitative data was collected with subject questionnaires. Twelve adults using Advanced Bionics Auria sound processors. Participants had greater than 20% correct speech recognition on consonant-nucleus-consonant (CNC) monosyllabic words in quiet and had used their CIs for at least six months. Performance was assessed at two audio-mixing ratios (30/70 and 50/50). For the 50/50 mixing ratio, equal emphasis is placed on the signals from the sound processor and the FM system. For the 30/70 mixing ratio, the signal from the microphone of the sound processor is attenuated by 10 dB. Speech recognition was assessed at two audio-mixing ratios (30/70 and 50/50) in quiet (35 and 50 dB HL) and in noise (+5 signal-to-noise ratio) with and without the personal FM system. After two weeks of using each audio-mixing ratio, the participants completed subjective questionnaires. Study results suggested that use of a personal FM system resulted in significant improvements in speech recognition in quiet at low-presentation levels, speech recognition in noise, and perceived benefit in noise. Use of the 30/70 mixing ratio resulted in significantly poorer speech recognition for low-level speech that was not directed to the FM transmitter. There was no significant difference in speech recognition in noise or functional benefit between the two audio-mixing ratios. Use of a 50/50 audio-mixing ratio is recommended for optimal performance with an FM system in quiet and noisy listening situations.

Personal Amplification for School-Age Children with Auditory Processing Disorders

Children with auditory processing disorders (APD) are described to have a signal-to-noise ratio (SNR) difficulty. Frequency-modulated (FM) systems have been reported to improve this situation. Yet the use of personal amplification that may be more portable has not been attempted. To determine whether personal amplification would result in improvement in speech-in-noise performances (attentiveness and speech recognition) and daily functioning in children with diagnosed APD. In addition, the desired hearing aid features (such as required gain, directional microphone and noise reduction, and open-ear fitting) are examined. A single-blind, longitudinal descriptive study in which subjects served as their own control in various hearing aid conditions. Fourteen normal hearing children who had a diagnosis of APD and who were between the ages of 7 and 11 participated. All subjects wore bilateral, mild-gain, behind-the-ear, wide dynamic range compression hearing aids fitted in an open-ear mode. Gain on the hearing aids was adjusted to provide approximately 10 dB of insertion gain for conversational input. Directional microphone and noise reduction were used on the hearing aids. Subjects wore the hearing aids home and were encouraged to use them as much as possible in their daily environments (school, home, and social activities). Subjects were seen four times: an initial visit where hearing aids were fitted, then visits at 2 weeks, 3 months, and 6 months after the initial fitting. The majority of the testing was completed during these final three visits. The children were evaluated on the Northwestern University word-list (NU-6) and the Auditory Continuous Performance Test (ACPT) in noise at most visits. The hearing aids were evaluated in the omnidirectional microphone mode only, omnidirectional microphone with noise reduction (NR) mode, and directional microphone with NR mode. The children's parents and teachers were asked to complete the Children's Auditory Processing Performance Scale (CHAPS) questionnaire both before and at the end of the study. The results showed that the use of hearing aids in the omnidirectional microphone mode alone did not improve speech identification in noise over the unaided condition. However, the inclusion of the NR algorithm and directional microphones improved speech understanding in noise. Amplification reduced the number of errors on the ACPT and improved several areas on the CHAPS; however, the results were not statistically significant. The use of mild-gain, open-ear fitting hearing aids with a directional microphone and noise reduction algorithm may be attempted on some children with APD on a trial basis.

Assessment of ability to discriminate frequency of bone-conducted ultrasound by mismatch fields

According to previous studies, ultrasound can be perceived through bone conduction and ultrasound amplitude modulated by different speech sounds can be discriminated by some profoundly deaf subjects as well as the normal-hearing. These findings suggest the usefulness of development of a bone-conducted ultrasonic hearing aid (BCUHA) for profoundly deaf subjects. In this study, with a view to developing a frequency modulation system in a BCUHA, the capability to discriminate the frequency of sinusoidal bone-conducted ultrasound (BCU) was evaluated by measuring mismatch fields (MMF). We compared MMFs between BCU (standard stimuli were 30 kHz, and deviant stimuli were 27 and 33 kHz) and air-conducted audible sound (ACAS; standard stimuli were 1 kHz, and deviant stimuli were 900 and 1100 Hz). MMFs were observed in all subjects for ACAS, however, not observed in a few subjects for BCU. Further, the mean peak amplitudes of MMF for BCU were significantly less than those for ACAS. These findings indicate that the discrimination capability of frequency of sinusoidal BCU is inferior to that of ACAS. It was also demonstrated that normal hearing could to some extent discriminate differences in frequency in sinusoidal BCU. The results indicate a possibility of transmission system for language information making use of frequency discrimination.

Selecting the Optimal FM System for Children With Cochlear Implants

Children who use cochlear implants experience significant difficulty hearing speech in the presence of background noise, such as in the classroom. To address these difficulties, audiologists often recommend frequency-modulated (FM) systems for children with cochlear implants. The purpose of this article is to examine current empirical research in the area of FM systems and cochlear implants. Discussion topics will include selecting the optimal type of FM receiver, benefits of binaural FM-system input, importance of DAI receiver-gain settings, and effects of speech-processor programming on speech recognition. FM systems significantly improve the signal-to-noise ratio at the child's ear through the use of three types of FM receivers: mounted speakers, desktop speakers, or direct-audio input (DAI). This discussion will aid audiologists in making evidence-based recommendations for children using cochlear implants and FM systems.

Meeting the Listening Needs of Adolescents: FM and Other Technologies

The benefits of frequency-modulated (FM) systems have been well established. An FM system provides a favorable signal-to-noise (S/N) ratio even in the most difficult listening situations. With today's technology, FM systems are smaller and easier to use; however, many older school-aged children and adolescents choose to not use them, due to a variety of reasons. This manuscript provides suggestions for creative ways for audiologists to meet the needs of adolescents. Audiologists who work with school-aged children and adolescents can be creative in regards to FM technology and encourage FM use beyond the traditional classroom. Audiologists also can provide information on assistive devices and alternative technology such as the use of direct audio input (DAI), vibrating alarm clocks, and Bluetooth® technology. These options may address the unique listening needs of adolescents and allow them to interact and participate in the same activities as their normal-hearing peers.