cst_c.png Connected Speech Test (CST)



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 references 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.



Obtaining the CST

Note: The CST is available in 2 formats: on the HARL Speech Intelligibility Tests Audio CD and on a DVD. The Audio CD incudes only the audio part of the CST. Software is available for purchase that can assist with administration and scoring of the Audio CD. The DVD contains both the Audio and Visual parts of the CST. There is no available software to assist with administration and scoring of the DVD.

Format: Audio Compact Disc
The CST is included on the HARL Speech Intelligibility Tests audio compact disc along with the Speech Intelligibility Rating Test (SIR Test). The audio CD contains only the audio part of the test (no video signal). It may be used in a regular CD player or in a computer CD drive. The CST may be administered manually (i.e., the tester manually pauses the disc using the space bar or pause button after each sentence is presented), or may be administered using the administration software available for purchase below. To facilitate manual presentation of the test, brief pauses have been inserted between the sentences. Materials 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.

Cost: $50 (US) per CD

Software to administer and score the audio CD:

This software administers and scores the audio CD version of the CST.  In order to use the software for scoring/administration of the CST you must have the CST audio CD and a CD drive on your computer.  It will not work with the DVD 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.

Format: CD

Cost: $30 (US)

Tip: Once the software has been installed, remove the setup disk from the CD drive and insert the HARL Speech Intelligibility Tests audio CD during testing.

Format: DVD
The original video recordings of the Connected Speech Test passages have been transferred onto DVD. The CST test passages are organized into six-passage audio-visually equivalent sets as discussed in Cox, et al, (1989). This disk plays in a computer DVD drive or in a stand-alone DVD player. The test is administered by manually pausing the disk between sentences using the space bar or the pause button. Scoring is accomplished manually as described in the accompanying booklet.

Cost: $50 (US) per DVD

Instructions for Purchasing CST Materials:

All CST CD and DVD purchases must be prepaid.

To order by mail send a written request with payment or purchase order to:
Jani Johnson, Ph.D.
School of Communication Sciences and Disorders
4055 North Park Loop
Memphis, TN 38152

Make check or purchase order payable to "The University of Memphis".

Prices include shipping.

These tests were developed at the Hearing Aid Research Laboratory of 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: Information about the development and research regarding the CST may be found in:

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).

Documents for Automatic Scoring