Dr. McCreery is an associate director of audiology and staff scientist at Boys Town National Research Hospital in Omaha, NE.
It's Monday morning. Your first patient of the day is a 3-year-old with bilateral moderate hearing loss who wears hearing aids in both ears. Your mission, should you choose to accept it, is to assess speech recognition with those hearing aids that you painstakingly matched to Desired Sensation Level targets. The child will probably self-destruct in 30 seconds if you can't decide which test materials and under what conditions you will do the assessment.
Figure. The Phrases ...Image Tools
Although many children who are deaf and hard of hearing are identified and fit with amplification before 6 months of age or around 12 months for a cochlear implant, speech-recognition assessment is often difficult to perform or not done at all until the child is close to 3 years old because of normal developmental factors, such as speech production, language skills, or limited attention. While measuring speech recognition in young children is challenging, it is important for documenting the progression of auditory skills, particularly in those who use hearing aids, cochlear implants, or a combination of auditory devices.
Figure. Ryan McCreer...Image Tools
To examine current practices in speech-recognition testing among pediatric audiologists in the United States, Karen Muñoz, EdD, and colleagues surveyed these practitioners, finding that about two-thirds included aided speech-recognition testing as part of their standard audiological test battery for preschool children with hearing loss (J Educ Audiol 2012;18:53-60).
Among those who reported performing speech-recognition testing with their preschool patients, most used the Phonetically Balanced Kindergarten (PBK) monosyllabic word lists, Word Intelligibility by Picture Identification (WIPI) monosyllabic word tests, or Northwestern University–Children's Perception of Speech (NU–CHIPS) test. The PBK lists most often require a verbal response from the child. The WIPI and NU-CHIPS are both point-to-picture tasks, minimizing the influence of speech production on the results.
The results of the investigation by Dr. Muñoz and colleagues are encouraging, as the majority of pediatric audiologists surveyed are documenting the ability of preschool children with hearing loss to understand speech.
MAKE IT A GAME
Speech recognition evaluation is important to accomplish as soon as children are developmentally able. The following practices can help ease the challenge of speech-recognition assessment in our preschool patients and facilitate more meaningful results.
• Use tasks that are more like a game. The Phrases in Noise Test (PINT) uses common commands such as “hold his hand” and “pat his leg” that a child can act out on a doll (J Educ Audiol 2012;18:38-52). The PINT has been validated in children as young as 3 years old and is a much more engaging task for young children than repeating words or pointing at pictures.
• Use recorded materials whenever possible. The survey by Dr. Muñoz and colleagues also revealed that approximately 82% of audiologists routinely used monitored live voice (MLV) presentation instead of recorded materials. Clinicians often use MLV because it is more flexible than recorded materials and allows clinicians to vary the presentation and rate of stimuli. However, studies with adults have documented poor reliability with MLV, making it difficult to interpret changes in speech recognition across time or examiners.
Recordings are available for many clinical speech-recognition tests and will improve the reliability and interpretability of results. Using the pause button to give young children more time to respond to recorded materials can be helpful when the gap between stimuli is too short.
• Choose meaningful presentation levels. A presentation level equivalent to that of average conversational speech at 1 meter from the talker (60 dB SPL) can be important for documenting ability to recognize speech at a level likely to be encountered during a typical listening condition.
Additional presentation levels can help characterize the range of performance across different listening environments. We routinely include a soft-speech presentation level at 50 or 55 dB SPL—10 dB below the level we used for average speech—to measure recognition at a level that may be more indicative of listening at a greater distance.
Using presentation levels that match the input levels employed for hearing-aid verification can allow for comparisons of aided audibility and speech recognition.
• Should testing be conducted in quiet or in noise? Testing in quiet is useful for these comparisons with data obtained from hearing-aid verification and can help familiarize children with the task. On the other hand, children also listen in different types of background noise, so testing with noise can provide data on how speech understanding varies in those conditions. Young children can be tested in noise once they have demonstrated that they can perform a speech recognition task in quiet.
• Share the results with parents and other professionals. Speech recognition provides important information about what the child is able to do with the auditory signal received from a hearing aid or cochlear implant. Results can be used to help parents understand how their child's device is making speech more audible or how speech understanding varies across different presentation levels. Speech–language pathologists may also be interested in the results of speech-recognition testing, particularly in the context of how the child may be using communication skills to support speech understanding.
• Monitor progress over time. Children should show significant progress in their speech-recognition abilities during the preschool period. Speech recognition should be documented at each clinic visit, and a standard protocol developed so that results are obtained at comparable presentation levels and with similar materials across visits.
The protocol should include guidance on when to move on to new test materials and when to incorporate noise. A more standardized approach will allow clinicians to track patient progress consistently over time.
Speech-recognition assessment can be used to guide decisions about intervention and offer evidence that the provided audibility is contributing to perception. Additional tests and materials developed for younger children may help to provide even earlier estimates of speech understanding in our youngest patients.
© 2013 by Lippincott Williams & Wilkins, Inc.