Increasing Speech Intelligibility Using the Electronic Speech Enhancer
What is the Speech Enhancer?
The Speech Enhancer is a voice processor that improves intelligibility by rebuilding speech acoustically to create a new prosthetic voice. It is not an amplifier (see Figure 1). It minimizes omissions and distortions, in addition to adjusting vocal intensity higher or lower to the correct functional level. It does not correct for substitutions nor change the rate of speech. However, many individuals have been observed to self-correct their rate and substituted words in as little as 20 minutes after beginning to use the device’s direct Enhanced Auditory Feedback. Several studies have shown that changes may be mediated by self-perception of loudness or intelligibility with use of auditory feedback (Garber, Siegel, & Pick, 1981; Burnett, Senner, & Larson, 1997; Rubow & Swift, 1985). In addition, the Speech Enhancer will in many instances provide dramatic benefits to aeromechanics, motor speech, and social interaction for the eligible client.
What Does the System Look Like and How Does it Work?
The Speech Enhancer is a durable lightweight battery-powered system. It consists of a special microphone, a voice-processor which is worn at the waist or mounted on a wheelchair, direct enhanced auditory feedback to the client’s ear, and several speaker options from which the voice is projected, including optional wireless speakers.
When an eligible candidate speaks into one of the hands-free microphones, their speech is taken into the voice processor where it is analyzed. It is then rebuilt acoustically using a model of hyper-intelligible speech, which results in their speech being clarified, or made more intelligible, electronically. Their voice does not sound robotic, however, but retains their signature voice and dialect.
How is the Speech Enhancer Used?
The device is a prosthetic, diagnostic, and therapeutic tool for children and adults. It is used to clarify speech for moderate to severe dysarthria or imprecise articulation with a soft or loud voice. It is also used to restore volume for voice clients with clear speech and a soft, even aphonic, voice. In addition, for certain individuals it increases the accuracy of speech recognition, enabling many clients with unclear or soft voice to access programs such as Dragon Naturally Speaking.
Which Disorders is the Speech Enhancer Useful For?
The Speech Enhancer has been used with many neurological and vocal disorders. Some are Dysarthria, Parkinson's, Huntington's, Cerebral Palsy, ALS, MS, MD, Myasthenia Gravis, Traumatic Brain Injury, Down Syndrome and Stroke. Some of the vocal disorders are Aphonia, Dysphonia, Ventilator Dependence, Tracheotomy, Laryngectomy, Spasmodic Dysphonia, Vocal Fold Paralysis, and Vocal Nodules. Deaf speech can also be improved with this device.
Who is a Candidate for Testing?
If the client needs clarification, a good candidate for testing is an individual whose speech is more than 30% intelligible to a familiar listener, in context, in a quiet environment. The technology does not create speech. It only uses what the patient has to create the new prosthetic voice. However, this includes the aphonic components that the listener could not otherwise hear. For more severe clients, speech language pathologists have discovered that it can also often be used once any previous unproductive speech strategies are untaught and replaced with newer, appropriate speech and vocal strategies.
If a voice client needs volume restoration, they need have only a minimal level since the device does not require voicing. A small amount of air in the oral cavity, such as "leak" speech is sufficient to allow that person’s voice to fill a room.
What Are the Prosthetic Benefits of the Speech Enhancer?
The Speech Enhancer is a prosthesis for functional communication with unfamiliar listeners, which allows for a more active and fulfilling lifestyle. The freedom and independence that clients experience is important. The interaction with unfamiliar listeners without an interpreter in free flowing conversation is an exciting experience. It is also an essential component to the remarkable Speech Enhancer funding success, as this interaction helps the client meet medical, vocational and educational goals.
Another important benefit of this interaction is the change in the client and the listener’s language. Both talker and listener begin to attempt more complex, abstract interactions, enriching the language experience and creating a most productive feedback cycle.
Severe neuromuscular impairment often results in reduced aeromechanics that are needed to produce and maintain voice and speech. Montgomery (1984) indicates that in the past, when the oral musculature and respiratory system were too weak to produce or sustain phonation, no further treatment was recommended. The Speech Enhancer allows for the voice production envelope to be electronically enhanced, thereby allowing for energy conservation and improved amounts of articulatory agility and time.
The device improves speech aeromechanics by reducing excess musculature posturing typically used to attempt to project voice. Along with respiratory techniques and relaxation strategies, the Speech Enhancer relieves the vocal mechanism from excess effort. And, because it’s the only device that restores volume in noisy environments there’s no need for the client to strain, even in a demanding "real-world" situation with 75 to 85dB of ambient noise.
Removal of excess effort allows the individual’s speech mechanisms to begin to work more naturally, which leads to energy conservation, fatigue reduction, reduction in spasticity, and reduction in hyper-nasality. The client can concentrate on articulation and language instead of worrying about increasing intensity.
A unique feature is Enhanced Auditory Feedback, or EAF, of the client’s processed speech to their ear. The first benefit usually observed is improved pacing and increased self-correction, as the client can now more easily hear their speech production. Secondly, auditory perception is enhanced – especially if there is hearing involvement – because their speech has been shaped to correspond to the device’s hyper-intelligible speech model. Many clients’ articulation improves for as long as a year after they first begin using the device. Clients report using the Speech Enhancer is akin to "wearing an auditory trainer" all day. The effectiveness of EAF is due in part to its having 15 to 20dB greater intelligibility than ordinary auditory feedback.
Another, rather surprising new capability of this EAF is its ability to help the client hear previously aphonic components of their speech. Hearing corrections before they would otherwise be audible leads to quicker success. Increased client motivation with this new auditory information is often the result. Research is underway to further define other auditory feedback benefits.
Unlike typical augmentative communication devices which use digitized voices and need constant evaluation and updating as the client develops (Sheehy, Moore, & Tsamtsouris, 1993), the Speech Enhancer uses the individual’s own voice and does not need to be programmed. Funding sources and families appreciate this feature.
Why Doesn’t Amplification Provide These Benefits?
Decreased intensity is often a primary condition that goes with neuromuscular disorders. In the past, compensation using amplification devices has been attempted for these challenges, but in many cases has not been successful, especially during carryover. There are four primary reasons for this.
1) Amplification, by design, does nothing to improve intelligibility (see Figure 1). It may, in fact, degrade it. In previous research, amplification was said to "exaggerate the dysarthria", causing intelligibility to suffer (Sarno, 1968, p 274).
2) Amplification is successful only with strong voices in a quiet setting. It may appear to give the soft-voiced client sufficient intensity in the therapy room, but it typically overloads and howls when the client attempts to use it in their everyday activities. Amplification is also prone to overload and distortion.
3) Aphonia is an unsolvable challenge for an amplifier. Ordinary amplifiers and microphones require voicing. They cannot reject ambient noise and are therefore incapable of picking up an inaudible voice, or any voice which is weaker than the ambient noise level. Only the Speech Enhancer can do this and work for an aphonic voice, or in realistic ambient noise levels .
4) Finally, amplifiers cannot provide the many perceptual and diagnostic benefits of direct Enhanced Auditory Feedback.
Diagnostic Applications
Therapists and speech scientists have been using electronic spectrographic analysis as an important clinical tool in assessment and treatment of speech, especially in instances which are particularly difficult. (Shuster, Ruscello, & Toth, 1995) However, many labs and clinics are not yet equipped with this electronic analysis nor does the usual demanding therapy schedule permit the luxury of its daily use. Another analytic option is now available. The Speech Enhancer enables the clinician to actually hear the aphonic components of speech in a diagnostic situation. With this valuable tool they can discern when the client is getting closer to the correct target, well before it would be obvious to the unaided ear.
Moreover, the Speech Enhancer can be used in conjunction with spectrographic analysis to obtain a more in-depth evaluation of the client’s speech. This ability may help the clinician develop a more appropriate therapy or treatment plan.
Use of EAF can lead to greater success in a diagnostic evaluation also. Certain clients may be capable of more speech than they realize, which may become apparent in the evaluation. This revelation may also give the client a greater understanding of how using the Speech Enhancer in therapy and as a prosthesis can help them.
Therapeutic Applications
Current funding limits for speech language services create strong pressure to achieve speedy functional results. There are real clinical implications that promote the use of the Speech Enhancer in therapy (Cariski & Rosenbek, 1999). For example, the aeromechanic fatigue-reduction benefits often enable the client to sustain longer therapy sessions and the individual is able to focus on articulation and language strategies, rather than on the effort of being heard. Thus, more productive therapy sessions are often enabled and quicker results may be documented to show continuing progress.
The Speech Enhancer does not have to be preprogrammed or reprogrammed. This makes using it for various clients quick, easy and stress-free because the device automatically adjusts to each client instantly. The individual simply speaks into the microphone. The client or therapist does not have to press any buttons or learn how to program the device.
The locations where therapy is conducted are not always the ideal isolated soundproof places that are recommended. Because the Speech Enhancer blocks all ambient noise and works in a noisy environment, (Cariski & Rosenbek, 1999) it can help compensate for this challenge.
Is Third-Party Funding Available for the Speech Enhancer?
Third party funding is available already. Insurance, vocational programs, schools, Champus, the Veterans Administration and even most state Medicaid programs are paying for it. Surprisingly, funding for the Speech Enhancer has been obtained when other much-needed devices were previously denied. Of course, the correct guidelines must be closely followed. There are funding coaches at Voicewave to assist in getting the devices funded. Call the manufacturer for assistance.
Appropriate Client & Family Expectations
Factors leading to successful outcomes of any augmentative device include: early receipt of the aid, adequate training for use of the aid and speech strategies, and client participation in the evaluation. (Ko, McConachie, & Jolleff, 1998) The Speech Enhancer can be a valuable tool for many clients. However, every family and eligible client needs to be aware that the Speech Enhancer will not cure their speech, but will aid in functional communication with unfamiliar listeners. They should also be informed that this, like other goals, is not an instantaneous process. While there are occasions when a person’s intelligibility improves dramatically at the initial evaluation, most often they improve over time while using the device. Some clients are still gaining improvement a year after they begin using it
It is the speech language pathologist’s responsibility to make sure that the family and client are educated about the Speech Enhancer in order to experience the maximum possible results. According to Rosenbek and Cariski, "superior results may be obtained when a patient receives speech therapy in conjunction with… a device " (p 322).
How Can My Clients Get an Evaluation?
Like all other assistive technologies, the Speech Enhancer does not work for every client... it requires some particular level of intelligibility in order to generate the new synthesized voice. However, since it uses both audible and inaudible components of speech, there is no sure way to pre-determine how it will work by ear alone. The client must be tested using the device. A side benefit is that the client actually gets to see and use the device. Certified trained speech language pathologists conduct these evaluations. To locate an evaluator, call the manufacturer for assistance. It is strongly recommended that the client’s speech language pathologist also attend the evaluation.
Another option is for the trained evaluator to borrow the evaluation equipment from the manufacturer. Speech language pathologists who attend the two-day advanced conference and use the specified evaluation protocol are eligible to borrow the Evaluation Kit for testing. At this training they learn the scientific and acoustic foundation for the Speech Enhancer technology, gain hands-on experience, and learn funding techniques. To find out when and where the conferences are scheduled, see www.SpeechEnhancer.com or call the manufacturer for assistance.
Attachments
References
Burnett, T., Senner, J., & Larson, c. (1997). Voice FO responses to pitch-shifted auditory feedback: a preliminary study. Journal of Voice, 11 (2), 202-211.
Cariski, D., & Rosenbek, J. (1999). The effectiveness of the Speech Enhancer. Journal of Medical Speech-Language Pathology, 7 (4), 315-322.
Garber, S., Siegel, G., & Pick, H. (1981). Regulation of vocal intensity in the presence of feedback filtering and amplifications. Journal of Speech and Hearing Research, 24 (1), 104-108.
Ko, M., McConachie, H., & Jolleff, N. (1998). Outcome of recommendations for augmentative communication in children. Child Care Health Development, 24 (3), 195-205.
Montgomery, JK. (1984). Augmentative communication- an approach for the severely physically handicapped person without oral speech. Int. Rehabilitation Medicine, 6 (3), 135-138.
Rubow, R. & Swift, E. (1985). A microcomputer-based wearable biofeedback device to improve transfer of treatment in parkinsonian dysarthria. Journal of Speech and Hearing Disorders, 50 (2), 178-185.
Sarno, Martha. (1968). Speech impairment in Parkinson’s Disease. Archives of Physical Medicine & Rehabilitation, 269-275.
Sheehy, E., Moore, K., & Tsamsouris, A. (1993). Augmentative communication for the non-speaking child. Journal of Clinical Pediatric Dent, 17 (4), 261-264.
Shuster, L., Ruscello, A., & Toth, A. (1995). The use of visual feedback to elicit correct /r/. American Journal of Speech-Language Pathology, 4, 37-44.
Manufacturer’s Contact Information
Voicewave
Technology Inc.
PO Box 713, Bridgeton, Missouri USA 63044
1 (877) 786-2266,
www.SpeechEnhancer.com
Speech Enhancer is a trademark of
Voicewave
Technology Inc.
PO Box 713
Bridgeton, Missouri 63044
1 (877) 786-2266 voice
1 (888) 463-7353 fax
www.SpeechEnhancer.com
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