What is it?
The CST comprises speech materials that can be used to quantify the intelligibility of connected speech. There is no standardized method for administering these materials, nor for interpreting the results of the CST. Rather, these materials can be applied according to the user’s objective. The user is encouraged to consult the reference given about the development and administration of the test and reliability of data from normal-hearing and hearing-impaired listeners.
Briefly, the talker is a female who produces speech of average intelligibility. The multi-talker babble can be adjusted to simulate the signal to babble ratio (SBR) encountered in everyday listening situations. Each test item is a passage of speech, 9 or 10 sentences in length, about a familiar topic. The listener should be informed of the passage topic. Each passage is presented one sentence at a time. The passage score is based on the proportion of 25 scoring words correctly repeated. Scores typically are averaged across several test passages to produce a measure of intelligibility for a particular listening situation.
How do I get it?
Obtaining the CST
These materials are available for free download. The audio files can be downloaded through the link at right. These zipped .mp3 files include only the audio part of the CST. Software is available for purchase that can assist with administration and scoring. The CST videos contain both the Audio and Visual parts of the CST. These can be accessed through the HARL YouTube account here. There is no available software to assist with administration and scoring of the CST videos.
The downloadable ZipFile contains each audio track of the CST, along with the Speech Intelligibility Rating Test (SIR Test) that can be downloaded to your computer. The audio part of the CST contains no video signal. The CSTs may be administered manually by pausing the track between sentences using the space bar or pause button. To facilitate manual presentation of the test, brief pauses have been inserted between the sentences. Scoring is accomplished manually as described in the documents below. Materials in the ZipFile include a calibration noise for setting levels, a set of practice passages, a set of test passages, and some additional passages. All speech passages are recorded with the talker on the left channel and the competing babble on the right channel.
Speech Intelligibility Tests
Test Passages Manuals
Documents for Automatic Scoring
Software to administer and score the audio CD:
The software administers and scores the audio-only version of the CST. In order to use the software for scoring/administration of the CST you must have the CST audio files and a CD drive on your computer. It will not work with the audiovisual version.
The CST administration program can be purchased from the AUSP Software Group at the School of Communication Sciences and Disorders at the University of Memphis for $50.
Once the software has been installed, remove the setup disk from the CD drive and use the audio tracks from the ZipFile during testing.
YouTube Videos
The original audiovisual recordings of the Connected Speech Test passages have been uploaded to YouTube. The outputs and frequency responses of these recordings are equivalent when presented from the DVD and through YouTube. The CST test passages are organized into six-passage audio-visually equivalent sets as discussed in Cox, et al, (1989). These tracks can be accessed through the HARL YouTube Account. The test passages can be administered manually by selecting each set in sequential order, and by pausing between each video. A set of learning passages and practice passages are available in addition to the test passages. Scoring is accomplished manually as described in the accompanying handbook.
These tests were developed at the Hearing Aid Research Laboratory at The University of Memphis with primary support from the Department of Veterans Affairs Rehabilitation: Research and Development Service. Support was also provided by the Center for Research Initiatives and Strategies for the Communicatively Impaired (CRISCI), The University of Memphis.
References
Cox, R.M., Alexander, G.C., Gilmore, C. and Pusakulich, K.M. “The Connected Speech Test Version 3: Audiovisual Administration”. Ear and Hearing, 10(1), 29-32 (1989).
Cox, R.M., Alexander, G.C., Gilmore, C. and Pusakulich, K.M. “Use of the Connected Speech Test (CST) with Hearing-Impaired Listeners”. Ear and Hearing, 9(4), 198-207 (1988).
Cox, R.M., Alexander, G.C., and Gilmore, C.A. “Development of the connected speech test (CST).” Ear and Hearing, 8 (supplement): 119S-126S (1987).