Speech Intelligibility Test for Windows

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In no event will Communication Disorders Software be liable for direct, indirect, special, ... Speech (CAIDS) that was developed for the Apple II computer.
Speech Intelligibility Test for Windows

Developed by Communication Disorders Software

Programmed by Matt Dorsey Authored by Kathryn Yorkston, Ph.D. David Beukelman, Ph.D. Mark Hakel, Ph.D. Sentence Intelligibility Test © Copyright Communication Disorders Software 1996

Distributed by Institute for Rehabilitation Science and Engineering at Madonna Rehabilitation Hospital 5401 South Street Lincoln, NE 68506 Phone: (402) 483-9406 – Carrie Stratman Email: [email protected]

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PREFACE The SPEECH INTELLIGIBILITY TEST (SIT) contains updated computerized versions (compatible with Windows 2000, XP, and Vista) of intelligibility measures that were previous distributed separately. These measures are the SENTENCE INTELLIGIBILITY TEST (previously distributed by that name) and the WORD INTELLIGIBILITY TEST (previously distributed as the Phoneme Intelligibility Test). These SPEECH INTELLIGIBILITY TEST is distributed on a CD and can be installed on a number of different computers; however, the SIT CD must be in inserted in the drive or the program will not run.

COPYRIGHT This manual and the software described in it are copyright with all rights reserved. Under copyright laws, this manual or the software may not be copied, in whole or part, without written consent of Communication Disorders Software (Madonna Rehabilitation Hospital), except to make a back up copy of the software. This exception does not allow copies to be made for others, whether or not sold. Opening the diskette envelope constitutes your acceptance of the Software and terms of this agreement. Limited Warranty on Media Communication Disorders Software warrants the disks on which the software is recorded to be free from defects in materials and workmanship under normal use for a period of ninety (90) days from the date of delivery as evidenced by a copy of the sales receipt. Communication Disorders Software will replace the defective diskette at no charge to you, provided you return the faulty diskette with the sales receipt to Communication Disorders Software. Communication Disorders Software shall have no responsibility to replace or refund the purchase price of a diskette damaged by accident, abuse, or misapplication. Any implied warranties on the disks, including implied warranties of merchantability and fitness for a particular purpose, are limited in duration to ninety (90) days from the date of purchase. Disclaimer of warranty and limitation of liability Even though Communication Disorders Software has tested the software and reviewed the documentation, Communication Disorders Software makes no warranty or representation, either express or implied with respect to software, its quality, performance, merchantability, or fitness for a particular purpose. As a result, this software is sold "as is" and you, the purchaser, are assuming the entire risk as to its quality and performance. In no event will Communication Disorders Software be liable for direct, indirect, special, incidental, or consequential damages. In particular, Communication Disorders Software shall have no liability for any programs or data stored in or used with this product including the costs of recovering such programs or data. Some states do not allow the exclusion or limitation of implied warranties or liability for accidental or consequential damages, so the above limitation or exclusion may not apply to you. In any case, Communication Disorders Software liability for damages shall be limited to the product's retail price. The limited warranties provided above are the only warranties of any kind that are made by Communication Disorders Software on this product. No oral or written information or advice given by Communication Disorders Software shall create a warranty or in any way increase the scope of this warranty, and you may not rely on such information or advice.

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TABLE OF CONTENTS 1.0

INSTALLATION

2.0

INTRODUCTION 2.1 Definitions and Populations 2.2 Why Measure Intelligibility 2.3 Why Measure Communication Efficiency 2.4 Reliability

3.0

ADMINISTRATION 3.1 Task Selection 3.2 Recording Techniques 3.3 Examiner and Judge Tasks 3.4 The Computer Program Saving Files Menu Screen 3.5 Sentence Intelligibility Test Print a Test Administer a Test Judge a Test Time a Test Generate a Report Review/Edit a Test 3.6 Word Intelligibility Test Print a Test Administer a Test Judge a Test Generate a Report Quit

4.0

ACKNOWLEDGMENTS

5.0

REFERENCES Intelligibility Assessment Tools Research Articles and Reports

SPEECH INTELLIGIBILITY TEST Welcome to the Speech Intelligibility Test (SIT) for Windows computers. The SIT application is similar to the sentence portion of Assessment of Intelligibility of Dysarthria speech and the Computerized Assessment of Intelligibility of Dysarthric Speech (CAIDS) that was developed for the Apple II computer. 1.0 INSTALLATION INFORMATION SIT has been designed to operate on any computer running Windows 98 or higher (including XP and Vista). 1.1 SIT must be installed onto the hard drive of your computer from the Speech Intelligibility Test CD contained in the packet that you have received. Insert the disk into the CD drive of your computer. 1.2 Open My Computer. Double click on the SIT_2007 icon. When the CD is open, double click on the SIT Setup.exe icon.

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1.3 The setup wizard will open. Select Next to continue.

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1.4 When the following screen appears, specify the name of the directory where you would like the setup program to place a copy of SIT for Windows then click the Install button.

1.5 The following screen will show while installation is occurring. If the installation program finds that your .NET Framework version is not current enough, you will receive directions and a setup wizard to install a newer version of .NET Framework.

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1.6 Once the installation is complete, you can choose to run the test immediately or uncheck the box to run the program later. Click Finish to close the wizard.

1.7 If you choose to run the program at a later time, you will find it on the Start Menu, Programs, Speech Intelligibility Test, SIT (shown below). NOTE: The CD must be in the drive every time you use the program or it will not run.

Please take a moment to review the information contained in the INTRODUCTION section that follows. The ADMINISTRATION section will guide your use of SIT.

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2.0 INTRODUCTION 2.1 Definitions and Populations Speech intelligibility is a measure of the understandability of a speech sample. Intelligibility of speech is an important measure of the functional limitations experienced by speakers with communication disorders (Yorkston, Beukelman, & Bell, 1988). Intelligibility assessment has been commonly used for the assessment of persons with motor speech disorders, laryngeal cancer, oral cancer, foreign dialect, and cleft palate. Most of the supportive research for the SIT was completed with dysarthric speakers; therefore, this population will be referred to frequently in the manual. 2.2 Why Measure Intelligibility? Intelligibility is an overall measure of the understandability of speech and often used clinically as an index of the activity limitation of a speaker or the overall severity of a communication disorder. As such, intelligibility measures are commonly used to document the intervention effectiveness for individuals in intervention programs or groups of speakers in outcome studies. Usually, an overall measure of speech performance, such as intelligibility, is one aspect of a complete clinical speech evaluation, which also includes the physical assessment of speech mechanism structures, the assessment of speech subsystem function during connected speech, and some assessment of the effectiveness of speech performance in important societal contexts. 2.3 Why Measure Communication Efficiency Rate of intelligible speech (IVYTM) is a measure of communication efficiency which takes into account both accuracy (intelligibility) and speaking rate. Rates of intelligible speech can easily be compared to normal adult speakers by means of a communication efficiency ratio. The efficiency ratio is defined as the rate of intelligible speech produced by a dysarthric speaker divided by the normal rate of intelligible speech on SIT tasks (190 WPM).' 2.4 Reliability Reliability was assessed from a variety of perspectives using the data gathered for the Yorkston and Beukelman study (1981). Dispersion of individual judge scores is of particular concern in a clinical setting where many of the samples may be judged by one individual. As a measure of interjudge agreement, dispersion of judges' scores as they performed the same listening task (same speaker and sample) was examined. The percentages of judges' scores that fell within a 20 and a 10% range for intelligibility were 93 and 83%, respectively. The percentages of judges' scores that fell within a 20 and 10 IWPM range for rate of intelligible speech were 100 and 88%, respectively. In order to assess interjudge differences, a judge-by-speaker analysis of variance was performed on both the measures of intelligibility and rate of intelligible speech. No significant differences were found among the four judges for intelligibility (%) and rate of intelligible speech (IWPM)(F =.39 and 2.69, respectively; df 3, 30). Interjudge reliability was assessed by computing Pearson product-moment correlation’s between pairs of judges1 scores as they listened to identical speech samples produced by 13 dysarthric speakers. Table 2. 1 contains a correlation matrix for each of the four judges and the group mean for intelligibility (%) and rate of intelligible speech (IWPM). Examination of the table reveals that interjudge reliability coefficients range from .93 to .99 for intelligibility and are consistently .99 for rate of intelligible speech.

1 2 3 4

1 ---

2 .94(.99) ---

Judges 3 .96 (.99) .96 (.99) ---

4 .93 (.99) .93 (.99) .94 (.99) ---

X .98 (.99) .97 (.99) .99 (.99) .99 (.99)

Table 2.1 A correlation matrix for interjudge comparisons of sentence intelligibility scores (%) and rate of intelligible speech (IWPM in parentheses). 1

In order to determine normal rates of intelligible speech, 20 normal speakers (10 males and 10 females) were recorded as they performed the SIT production task. Analysis of this data revealed that the mean rates of intelligible speech were 197.1 with a standard deviation of 8.5 IWPM for males and 196.8 with a standard deviation of 17.3 for females. For ease of computation and as a conservative estimate of normal speaking rates, 190 IWPM was adopted as the norm for computing the efficiency ration. (1984, Yorkston, Beukelman, & Traynor) 7

Because intersample reliability is also of concern with a technique which will be used to make multiple comparisons over time, a series of Pearson product-moment correlations were computed showing the relationship between judges' scores on different samples produced by the same speaker. Results reveal intersample correlation coefficients ranging from .92 to .99 for intelligibility (%) and from .98 to .99 for rate of intelligible speech (IWPM). These intrajudge correlations range from .96 to .99 for intelligibility (%) and are consistently .99 for rate of intelligible speech (IWPM).

3.0 ADMINISTRATION SIT is a single disk software package that allows the clinician and researcher to administer, score, and store results of a speech intelligibility measurement task. The results for individual speakers can be stored on a hard drive or memory stick. The SIT software operates on any Windows 98 or higher computer. A printer is useful but not required. The SIT contains both sentence (formerly known as Sentence Intelligibility Test) and word (formally known as the Phoneme Intelligibility Test) intelligibility tests. This chapter contains information about test administration. First, the general considerations of audio recording techniques, examiner and judge tasks, and sample selection will be discussed. Then an outline of the computerized administration will be presented. 3.1 Task Selection In the previous SIT version, the clinician was allowed to select either a 22- or 11-sentence test administration. The current software only allows for the administration of the 11-sentence version of the SIT. Research by Olson and Beukelman (1996) documented that the intelligibility scores of 11-sentence and 22- sentence versions of SIT for dysarthric speakers were not significantly different from each other. Some severely involved speakers become so fatigued that they are unable to comfortably complete the longer sentences in the test. For them a sample involving the shorter sentence is necessary. When a shortened sample is used, subsequent testing for that speaker should contain samples of the same length. When a clinician intends to use a sample with shortened sentences, two sentences at each length should be administered. Samples can be shortened either during administration or during judging by simply terminating the test at the desired point. Intelligibility scores will only be computed for those sentences that have been transcribed. Speaking rates will only be computed for those sentences that have been timed. 3.2 Recording Techniques When making audio tape recordings for intelligibility tasks, it is critical that the recordings be of the highest possible quality. Further, because data derived from these tasks will be used to make multiple comparisons over time, it is also critical that quality be maintained consistently. Therefore, a series of consistent recording procedures should be adopted. Recording environments should be as quiet as possible. The distance between the microphone and the mouth should be constant. Head mounted "boom" microphones are particularly effective for this task as they maintain the mouth to microphone distance even in the presence of hearing tremor or postural problems. Recording levels should be adjusted so that the recorder's VU meter operates in the middle of its range as speech is recorded. 3.3 Examiner and Judge Tasks Recording intelligibility samples poses a unique problem in that the individuals, who are judging, must not have precise foreknowledge of what the speaker is saying. An effort has been made to circumvent the problem of judge familiarity with the speech sample in two different ways. First, the speech samples are generated at random by the computer program. Second, persons serving as judges for a specific sample should not be involved in the recording of that sample. All recordings are made by an examiner. The specific roles of the examiner and the judge are quite different. The examiner is responsible for using the computer to generate the sentence samples to be recorded. The examiner tape records the speaker as he or she reads or imitates the sentences either from the computer screen or from a computer-generated printed sheet. The examiner does not judge the samples. The judge does not take part in recording the speech sample but listens to the recorded sample and transcribes the sentences. The computer program scores the sample, computes the intelligibility score and rate of speech and displays or prints a Score Report. Although both examiner and judge may be speech/language pathologists, they need not be. For example, a judge may be any literate adult with normal hearing. The number of judges required depends on the purposes of the intelligibility measurements. If the purpose is to monitor change in an individual speaker over a period of time, a single judge is sufficient, providing that the judge is the same individual each time. However, when measurements of intelligibility are used to establish functional levels or to compare individuals, multiple judges are recommended. 8

3.4 The Computer Program Speech Intelligibility Test (SIT) is contained on a CD. The CD contains the program for administering the sentence and word intelligibility tasks. For sentences, the CD contains the stimuli to generate random sentence samples from a pool of 1,100 sentences (100 sentences ranging from five to 15 words in length). The test files generated by the program are stored on the hard drive or a memory stick. SIT operates with a menu-based system that displays the options that are available to you at each point of the program. The menus allow you to select from a number of options, thus minimizing the need to refer to the printed manual once you are familiar with the program. All pertinent directions will be provided to you on your computer screen. In addition to the menus that guide you through the program, other conventions are used consistently throughout. Illegal codes or entries have been locked out of the keyboard. If you press an illegal character, you will hear an error signal. The computer will ignore all illegal entries. Saving Files The saving feature has changed slightly. By default, the file name will now contain the client’s first and last name, the date, and the time of the test so you can simply click on the Save button. If you wish the change the file name, enter an appropriate name as you would in any other Windows application. This save feature is applicable in both the sentence and word intelligibility sections.

Also, any time you leave a section you will receive a prompt asking if you want to save your changes. Select Yes to save any changes you have made.

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The Menu Screen The following MENU SCREEN appears after the application program is opened. Select either Sentence Intelligibility Test or Word Intelligibility Test.

3.5

Sentence Intelligibility Test

The Sentence Intelligibility Test MENU SCREEN allows you to select each of the following functions of the program:

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Print a Test Use this function to create a printed test sheet for administering the intelligibility task.

The SIT program can generate a test containing an 11-sentence sample (one sentence at each length from 5 to 15 words). Figure 2.1 contains a test sheet for SIT. The SIT program allows you to print a new test or to reprint the test sheets from test files that were developed previously. Figure 2.1 Example of a portion of a test sheet generated by SIT. 5. He has played very well. 6. The typewriter needs to be repaired. 7. This is a good place, though small. 8. She doesn’t like to have it hanging around. 9. He dashed across the parking lot and disappeared inside. The font size of a printed SIT sample can be modified (12, 18 & 24 point) to meet the needs of individual clients.

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Administer a Test Use this function to administer a sentence intelligibility test directly from the computer screen. As with the “Print a Test” function, the program does any of the following functions: (1) present a test that has been created at a previous time and saved, (2) administer a test of 11sentences ranging in length from 5 to 15 words per sentence. The font size of the SIT sample displayed on the monitor can be modified (12, 18 & 24 point) as described above under the “Print a Test” function. You may also choose to load a previously existing test file and display it on the screen. During this operation, you will be able to enter information under Judge’s ID, Date Judged, and Judge’s Comments. If you do not wish to enter that information, simply press RETURN. You may either complete the entire sample or shorten the sample to any length by clicking the “Finish Test” button.

The “Administer a Test” function will present individual sentences on the screen in a window similar to that shown below.

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During the audio tape recording, the examiner introduces each sentence with the appropriate item number (5, 6, 7, etc.). The speaker then reads the sentence after the examiner. The examiner then selects the appropriate options from the lower portion of the screen. When you click Next, the next sentence will appear on the screen. When you click Back, the previous sentence will appear on the screen. When you click First, the first sentence of the test will appear on the screen. When you click the “Finish Test” button, the test will be terminated with the sentence currently appearing on the screen and the test will be shortened.

Judge a Test Use this function to judge a sample that has been tape-recorded. After the judging has been completed, the program will calculate sentence intelligibility scores. When you select the “Judge a test” button, the following window will appear.

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You can judge the sample that is currently open or you can open a new sample file. After having selected the file containing the sample you wish, the following window will appear.

The name of the judge can be typed into this information window along with any comments about the speaker or the judging session that might be useful to store with this judging file. After selecting the OK button the following screen will appear.

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After listening to the sentence, the judge types the words that have been heard. The judge should check for typing and spelling errors at the end of each sentence, before clicking on the Next button to advance the program to the next sentence. Errors can be corrected at this point, using conventional text editing procedures. Because the computer scores the judging, it is very important that there are no misspelled words or typing errors. These will reduce intelligibility scores. You need not capitalize or include commas, periods, or question marks. However, you must include apostrophes in contractions and possessives. Both Back and First and commands can be used to return to previous sentences in order to check for or to correct errors. Errors can be replaced with correct entries before the last response is entered. If some errors are missed during judging of the sample, see the “Review a Test” section for details of how to change a response after the judging has been completed.

Time a Test Use this function to time tape-recorded sentence samples. This timing data will be used to calculate overall speaking rates, rate of intelligible speech measured in words per minute, and communication efficiency ratio. When you select the “Time a Test” button, the following menu will be displayed on the screen.

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When the appropriate file has been opened, the screen will display the following window.

Click on the “Start Timer” button to begin timing at the first word of the sentence and click on the same button, now labeled “Stop Timer” at the completion of the last word of the sentence. The duration of the sentence will be expressed to the nearest tenth of a second. To time the next sentence, select the Next button. Use the Back button to return to a previous sentence. Select the “Finish Timing” button when timing of a test has been completed.

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Generate a Report Use this function from the MENU SCREEN to view the test results on the screen or to print a Score Report from the following screen.

After you open the appropriate test file, the following type of report will appear on the screen and can be printed, if desired.

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Review a Test Use this function from the MENU SCREEN to pull up a judge’s responses to a test that has already been judged in order to review the patterns of errors or to correct spelling and typing errors for recalculation of intelligibility scores. The list of actual or perceived sentences, along with intelligibility data, may be printed.

When the appropriate file has been opened, the following screen will appear.

Compare the perceived sentences to the actual target sentences. If you wish to make changes in the perceived sentences, you can do so using traditional word processing strategies. Note the “score” feature that indicates the number of words correctly transcribed.

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When you click the Next button, the next sentence will then appear on the screen. When you click the Back button, the previous sentence will appear on the screen. When you click the FIRST button, the first sentence of the test will appear on the screen. When you click the “Finish Review” button, the review will be terminated.

3.6

Word Intelligibility Test

The Word Intelligibility Test MENU SCREEN allows you to select each of the following functions of the program.

Print a Test Use this function to create a printed test sheet for administering the word intelligibility task.

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The SIT program can print a test in (1) a new "Word Only" test, (2) a new Word in Phrase test, (3) a Word Only test that already exists and is stored on the hard disk, or (4) a Word in Phase test that already exists and is stored on the hard disk. If you choose to create either form of new test, you will be able to enter Speaker, Examiner, and Agency information as well as Examiner's Comments using the form shown below. If you do not wish to enter that information, simply click the OK button.

If the Word in Phrase option was selected, then the following phrase construction dialog is displayed. You may enter an introduction and a conclusion. When SIT constructs the test, it will place the randomly selected test word between the introduction and the conclusion entered. When you have supplied the desired phrase, press the OK button.

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By clicking the appropriate button the Print Preview screen (shown below), you can examine both the Test Sheet and the Score Sheet before printing out the test. When you have finished printing the test, you click the Menu button to return to Menu Screen. Figure 2.1 contains a Word Only test sheet for SIT. Figure 2.2 contains a Word in Phrase test for SIT. As was mentioned previously, the SIT program allows you to print a new test or to reprint the test sheets from test files that were developed previously.

Figure 2.1. Example of a portion of the Word Only test sheet generated by SIT.

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Figure 2.2. Example of a portion of the Word in Phrase test sheet generated by SIT. When you click the Print button, SIT prints out both the Test Sheet and Score Sheet, regardless of which sheet is being shown on the preview screen.

Administer a Test Use this function to administer a Word Test directly from the computer screen. As with the “Print a Test” function, the program executes the following functions: (1) administer a new “Word Only” test, (2) administer a new Word in Phrase test, (3) administer a Word Only test that already exists and is stored on the hard disk, or (4) administer a Word in Phase test that already exists and is stored on the hard disk.

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As was mentioned previously, you may also choose to load an existing test file and display it on the screen. During this operation, you will be able to enter information under Speaker, Examiner, Agency and Examiner's Comments. SIT automatically supplies the date from the computer's clock. If you do not wish to enter that information, simply press OK.

If the Word in Phrase option was selected, then the following phrase construction dialog is displayed. You may enter an introduction and a conclusion. When SIT constructs the test, it will place the randomly selected test word between the introduction and the conclusion entered. When you have supplied the desired phrase, press the OK button.

The “Administer a Test” function will present individual words in the carrier phrase on the screen in a window similar to that shown below.

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During the audio tape recording, the examiner introduces each word or phrase with the appropriate item number (1, 2, 3, 4, 5, etc.). The speaker then reads the word or phrase after the examiner. The examiner then selects the appropriate options from the lower portion of the screen. When you click the Next button, the next stimulus item will appear on the screen. When you click the Back button, the previous item will appear on the screen. You can restart the test by clicking the First button. When you click the Abort Test button the test will be terminated.

Judge a Test Use this function to judge a sample that has been tape-recorded. After the judging has been completed, the program will calculate sentence intelligibility scores. When you select the Judge a Test button, the following window will appear.

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You can judge the sample that is currently open or you can open a new sample file. After having selected the file containing the sample you wish, the following window will appear.

The name of the judge MUST be typed into this information window along with any comments about the speaker or the judging session that might be useful to store with this judging file. SIT will automatically complete the Date cell, but you are allowed to change it. After selecting the OK button the following screen will appear.

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After listening to the word only or the word in a phrase, the judge double clicks on the words of choice. Double clicking will identify the word of choice and advance to the next item. You can also advance to the next item by clicking on the “next” button. When you have completed judging the test, you should click the Finish Judging button.

Generate Reports Use this function from the Menu Screen to view the test results on the screen or to print the test results.

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After you load the appropriate test file, you can select either a Consonants Matrix, Vowels Matrix or Summary Report by clicking the button that corresponds to the desired report. Regardless of the report requested, the following judge screen will appear. You will need to identify the judge(s) whose results you wish to report. If you wish to display the composite results of several judges, just check the names of the judges who you want included in the report

Examples of the Consonants Matrix, Vowels Matrix, and Summary Report are shown below.

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Quit Select the “Quit” button from the MENU SCREEN to close the SIT program.

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4.0 ACKNOWLEDGMENTS The Speech Intelligibility Test was tested in several different clinical settings. We wish to thank the speechlanguage pathology staffs from the Harborview Medical Center and the University of Washington Medical Center located in Seattle, WA; the Loma Linda Medical Center of LomaLinda, CA; the Madonna Rehabilitation Hospital in Lincoln, NE; and the Meyer Rehabilitation Institute in Omaha, NE. 5.0 REFERENCES Intelligibility Assessment Tools (References) Yorkston, K. M., & Beukelman, D. R. (1981). Assessment of intelligibility of dysarthric speech. Austin, TX. Pro-ed. Yorkston, K. M., Beukelman, D. R., & Traynor, C. (1984). Computerized assessment of intelligibility of dysarthric speech: A computerized assessment tool. Austin, TX. Pro-ed. Yorkston, K., Beukelman, D., & Tice, R. (1996). Sentence Intelligibility Test for Macintosh. Lincoln: Communication Disorders Software. Distributed by the Institute for Rehabilitation Science and Engineering at Madonna Rehabilitation Hospital, Lincoln, NE. Yorkston, K., Beukelman, D., & Tice, R. (1996). Sentence Intelligibility Test for Windows Lincoln: Communication Disorders Software, Distributed by Institute of Rehabilitation Engineering and Science at Madonna Rehabilitation Hospital, Lincoln, NE. Research Articles and Reports Adams, S. (1994). Accelerating speech in a case of hypokinetic dysarthria: Descriptions and treatment. In J. Till, K. Yorkston, & D. Beukelman (Eds.). Motor Speech Disorders: Advances in Assessment and Treatment. (pp. 213228). Baltimore: Paul H. Brookes Publishing Co. Antonius, K., Beukelman, D., & Reid, R. (1996). Communication disability of Parkinson’s disease: Perceptions of dysarthric speakers and their primary communication partners. In D. Robin, K. Yorkston, & D. Beukelman (Eds.). Disorders of motor speech: Assessment, treatment, and clinical characterization. (pp. 275-286). Baltimore: Paul H. Brookes Publishing Co. Bain, C., Ferguson, A., & Mathisen, B. (2005). The effectiveness of the Speech Enhancer on intelligibility: A case study. Journal of Medical Speech-Language Pathology 13(2): 85-96. Ball, L., Beukelman, D., & Pattee, G. (2001). A protocol for identification of early bulbar signs in ALS. Journal of Neurological Sciences, 191: 43-53. Ball, L., Beukelman, D., & Pattee, G. (2002). AAC clinical decision-making in ALS. ASHA Special Interest Division 12 (AAC) Newsletter, 11, 7-12. Ball, L., Beukelman, D., & Pattee, G. Predicting speech performance in persons with amyotrophic lateral sclerosis, Journal of Medical Speech Language Pathology. Barkmeier, J. Jordan, L., Robin, D. & Schum, R. (1991). Inexperienced listener ratings of dysarthric speaker intelligibility and physical appearance. In C. Moore, K. Yorkston & D. Beukelman (Eds.). Dysarthria and Apraxia of Speech: Perspectives on Management. (pp-65-75). Baltimore: Paul H. Brookes Publishing Co. Barlow, S. & Netsell, R. (1989). Clinical neurophysiology for individuals with dysarthria.In K. Yorkston & D. Beukelman (Eds.). Recent Advances in Clinical Dysarthria (pp. 53-82). Boston: College-Hill Press. Beukelman, D. & Yorkston, K. (1977). A communication system for the severely dysarthric speaker with an intact language system. Journal of Speech and Hearing Disorders, 42, 265-270.

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