This document addresses the use of altered auditory feedback (AAF) devices for the treatment of stuttering.

Investigational and Not Medically Necessary:

Altered auditory feedback (AAF) devices are considered investigational and not medically necessary for the treatment of stuttering.

Traditional treatments for developmental stuttering have involved various speech therapy techniques. In some cases pharmacologic therapy has been used. AAF has been investigated as a potential therapy. The rationale for AAF rests in the observation that individuals who stutter tend to become more fluent when speaking in unison with others – the so-called "choral effect". AAF attempts to emulate the choral effect by allowing the user to hear one's own voice with a slight time delay or a pitch shift which is said to create the illusion of another individual speaking at the same time.

However, the published literature on the clinical use and effectiveness of these devices consists of a few reports with small numbers of individuals in uncontrolled case series. Lincoln et al (2010) reported on 11 adults who used an AAF device to participate in speaking sessions with an investigator. The speaking sessions included conversational speech and reading aloud. Results were highly individualized depending on the condition. All participants responded differently under differing conditions to different AAF settings. The authors of this study concluded that it is not possible to predict who would benefit from AAF devices nor is it possible to predict the extent of any proposed benefit. The results are somewhat mixed and there is minimal data on its effect on everyday social fluency. There is little if any data on the long term use of these devices, and no data to support that fluency would persist following discontinuation of the device. Larger prospective randomized controlled studies are required to demonstrate the effectiveness of AAF for everyday communication and fluency compared both to no treatment and to other forms of established therapy.

Stuttering is a disturbance in the normal fluency and time patterning of speech that is inappropriate for the person's age. Developmental stuttering is the most common form, with an onset prior to the age of 12, and generally between the age of 2 and 5 years. Preschool children normally undergo a transient period of disfluency, and it is estimated that 50%-80% of children with developmental stuttering will recover with or without therapy and generally before puberty. Persistent developmental stuttering is developmental stuttering that has not undergone spontaneous or therapy related remission. Proposed etiologies include abnormal cerebral dominance with differences in regional brain activation patterns in regions of the brain that modulate verbalization. A genetic component has also been observed. Acquired stuttering in a previously fluent individual is much rarer than developmental stuttering, and may be neurogenic resulting from brain damage associated with conditions such as traumatic brain injury, Alzheimer's disease, and Parkinson's disease, among others. Psychogenic stuttering is also recognized following emotional trauma.

Altered auditory feedback (AAF) devices use auditory feedback via an earpiece worn in or behind the ear, and utilize, alone or in combination, the following techniques: Delayed Auditory Feedback (DAF), delaying the user's voice to his ears a fraction of a second (this delay is adjustable) and frequency shifting auditory feedback or Frequency Altered Feedback (FAF) which shifts the pitch of the user's voice in his ears.

Stuttering: A disturbance in the normal fluency and time patterning of speech that is inappropriate for the person's age.

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy.  Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member. 

When Services are Investigational and Not Medically Necessary:
When the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary

Future ICD-10 coding (effective 10/01/2013)
A draft of ICD-10 Coding related to this document, as it might look today, is available for reference and comments at: Appendix 1: Future ICD-10 coding

Peer Reviewed Publications:

1. Armson, J, Stuart A. Effect of extended exposure to frequency altered feedback on stuttering during reading and monologue. Journal of Speech Language Hearing Research 1998; 41(3):479-490.
2. Costa D, Kroll R. Stuttering: An update for physicians. CMAJ. 2000; 162(13):1849-1855.
3. Hargrave S, Kalinowski J, Stuart A, et al. Effect of frequency-altered feedback on stuttering frequency at normal and fast speech rates. J Speech Hear Res. 1994; 37(6):1313-1319.
4. Lincoln M, Packman A, Onslow M, Jones M. An experimental investigation of the effect of altered auditory feedback on the conversational speech of adults who stutter. J Speech Lang Hear Res. 2010; 53(5):1122-1131.
5. Stuart A. Investigations of the impact of altered auditory feedback in-the-ear devices on the speech of people who stutter: initial fitting and four month follow up. Int J Lang Communication Dis. 2004; 39(1):93-113.
6. Van Borsel J. Delayed auditory feedback in the treatment of stuttering: clients as consumers. Int J Lang Communication Dis. 2003; 38(2):119-129.

1. National Library of Medicine. Medical Encyclopedia. Stuttering. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/001427.htm. Accessed on May 5, 2011.

Altered Auditory Feedback
Pocket Speech Lab
SmallTalk
SpeechEasy^®
Stuttering
Telephone Fluency System

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