a synthesis of research findings on speech supplementation strategies for dysarthric speakers

A Synthesis of Research Findings on Speech

Supplementation Strategies for Dysarthric

Speakers

Marcie L. McNeill, M.A., CCC-SLPJanice Light, PhD.

The Pennsylvania State University

The Problem

Many individuals with moderate to severe dysarthria choose to utilize speech as primary mode of communication

Because it is most natural & most efficientHowever it is often very difficult to understand

So, alternative strategies for enhancing intelligibility need to be considered

Speech supplementation strategies provide a solution to this problem(e.g.,

Beliveau, Hodge, & Hagler, 1995; Beukelman

& Yorkston, 1977; Carter, Yorkston, Strand, & Hammen, 1996; Crow & Enderby, 1989; Dongilli, 1994; Garcia & Cannito, 1996a; Hustad, Auker, Natale, & Carlson, 2003; Hustad

& Beukelman, 2000, 2002)

Speech Supplementation Strategies

Cueing strategies that are intended to facilitate a speaker’s intelligibility through providing additional information regarding the spoken message include:

Alphabet CuesTopic and Semantic CuesSyntactic CuesGesturesCombined Cues

Alphabet Cues

• The speaker uses an AAC device such as an alphabet board and points to the first letter of each word as they speak• Example: Where is the dog?Why they work:

Enhances the listener’s knowledge of the phonetic content of the message through:

Reduction in ratePlaces constraints on word possibilitiesProvides clearer word boundariesIncreases processing time for listenersReduces lexical ambiguity

Topic and Semantic Cues

The speaker uses some type of AAC device to communicate information about the intended meaning of the utterance.

Example: Pointing to the word DogWhy they work:

Provides listeners with information that is broader in nature than alphabet cues

Serve as a frame of reference, preparing the listener for the future messageAllows listener to make predictions

Syntactic Cues

The grammatical structure (e.g. noun, verb) of the words within a message is communicated to the listener using some type of AAC device.

Example: (Adverb) Where (verb) is the (noun) dog?

Why they work:Specifies the number of words, the placement of words, and the role of each word without providing information about the meaning or intent of the utterance.

Gestures

The speaker uses body movements that are in direct relation to what is being said.

Synchronized with linguistic unitsParallel in semantic and pragmatic functionsPerform text functions like speech

Examples: Where (Hands out with palms up) is thecar? (hands moving a steering wheel)

Why they work:Very closely connected to speechAdditional channel of observation along with the speech signal, visually illustrating an aspect of the message

Combined Cues

Usually a combination of both alphabet and topic cues, intending to provide additional information to the listeners.

Example: Point to a the word “dog” and then the first letters of the sentence, “Where is the dog?”

Why they work:Listeners receive both broad contextual information and narrow word-specific information pertaining to the message.

Theoretical SupportMutual intelligibility between speakers and listeners occurs through two means:

(a) information exclusively from the speech signal (i.e. signal-dependent, bottom-up acoustic phonetic information). (b) contextual information other than, or in addition to, the speech signal (i.e. signal-independent, top-down linguistic contextual information).

The underlying premise is that speech intelligibility is not exclusively determined by the quality of the speech signal and that listeners play a very important role. Linguistic and contextual knowledge, and language redundancy allow listeners to discriminate incomplete or distorted messages.(Lindblom, 1990)

Theoretical Support

Top-down, signal independent informationAlphabet CuesTopic CuesSyntactic CuesGestural CuesCombined Cues

Bottom-up, signal dependent informationAlphabet Cues Gestural CuesCombined Cues

When a speaker uses the various supplementation strategies they change the acoustic signal and provide additional information to the listener.

Goals of the research

Given the importance of increasing the intelligibility of dysarthric speakers, a review of the research was completed with the following goals:

Review studies in which speech supplementation strategies were used as a method of improving intelligibility with dysarthric speakers Provide a description of supplemental speech strategies;Analyze the results of the studies Review of the quality of researchDiscuss directions for future research in the utilization of speech supplementation strategies to enhance communication.

Search Methods

Initial searches began with reviews of abstracts on the electronic databases using the key word terminology of “speech”, “dysarthria”, and “intelligibility”.

PsycINFOProQUEST (ProQUEST Psychology Journals), ERIC (Education Resources Information Center, U.S. Department of Education) MEDLINE (PubMED)EBSCO Host Research Databases (Loyola College Database)

Studies were chosen based upon evidence of focus on the intelligibility of speech of dysarthric speakers and one or more speech supplementation strategies.

Synthesized Studies

Empirical studies included were those that:Were published in journals and edited books related to the field of speech and language pathology.Had specific focus on improving intelligibility of dysarthric speakers through use of speech supplementation strategies.

The search procedures yielded a total of 24 studies that were appropriate for review.

Synthesized StudiesStudy Speakers Severity / %

Intelligibility Listeners Formats/

Strategies Utilized

Used by speakers

Group Changes in Intelligibility &/or Rate

Beukelman & Yorkston (1977)

2 BS CVA =1 BS injury = 1 Ages 61 & 17

Nearly 0% to 10-15% for conversation

30 Ages NR Randomly divided into 6 groups

Words / sentences AV format, not enhanced Unaided, Aided/AC , Aided/AC (concealed)

Yes Aided/Concealed AC: ↑ intelligibility at the word and sentence levels. Rate ↓ of 21 & 58 wpm

Crow & Enderby (1989)

6 MN disease = 1 De. Disease = 1 Ages NR

1 Mild 2 Moderate 1 Moderate- severe 2 Severe

26 Ages 18-20 Divided into 2 groups

Words/ Sentences AO, with and without alphabet chart Word, Picture Description, Conversation

Yes Alphabet chart: ↑ in intelligibility at all levels There was an average ↓ of 66.5 wpm with the use of an alphabet chart

Hammen, Yorkston, & Dowden (1991)

21 CP = 13 TBI = 4 ALS = 2 CVA = 1 My. Gravis = 1 Ages 20-73

14 Profound 2 Severe 4 Moderate

3 Ages NR

Words AO, cues on answer sheets No Context Context cues

No Context cues: Profound= ↑ by 18% Severe = ↑ by 40% Moderate = ↑ by 29%


IntelligibilityListeners Formats/

Strategies Utilized

Used by speakers

Group Changes in Intelligibility &/or Rate

Hunter, Pring, & Martin (1991)

8 Ages 13-17

4 Moderate 4 Severe

32 Ages 18 +

Sentences AO & AV formats, cues on answer sheets. High and Low redundancy in sentences AC, Repetition

No

Moderate = word identification in all conditions ↑ over AO format Severe = word identification better in AC, than with AO, AV, or repetitions

Dongilli (1994)

8 Ages 23-87

2 Mild 2 Moderate 2 Severe 2 Profound

96 Ages 19-50 Randomly divided into 8 groups

Words/Sentences AO, cues prior to stimuli Word-NC Word-Semantic Context Sentence-NC Sentence-Semantic Context

No

Semantic context cues: Word level Profound = ↑ 26%- 26% Moderate = ↑ 28%- 39% Severe = ↑ 31%- 48% Mild = ↑ 3%& 24% Sentence level Profound = ↑ 1%-7% Moderate = ↑ 16%-17% Severe = ↑ 7% Mild = no increase

Synthesized StudiesStudy Speakers Severity/ %


Strategies Utilized Used by speakers

Group Change in Intelligibility &/or Rate

Beliveau, Hodge, & Hagler (1995)

3 CP = 2 TBI = 1 Ages 25-33

1 Moderately severe 1 Severe 1 Profound

40 Ages NR Randomly divided into 4 groups

Words AO format, cues via video monitor NC, FL, WC, Combined

No

AC: ↑ 10% WC: ↑ 10% Combined: ↑ 18%

Carter, Yorkston, Strand, & Hammen (1996)

6 CVA = 1 Park. = 3 TBI = 1 Tumor = 1 Ages 32-73

3 Moderate 3 Severe

36 Ages 18-40 Divided into 3 groups

Sentences AO format cues on answer forms NC, Semantic Context Cues, Syntactic Context Cues

No Semantic Context Cues: Moderate = ↑ 3% Severe =↑ 8% Syntactic Context Cues: Moderate = ↑ 3% Severe = ↑ 11%

Garcia & Cannito (1996a)

1 CVA=1 Age 62

1 Severe

32 Ages 18–30 Randomly divided into 2 conditions, AO & AV

Sentences AO & AV formats, Sentences were Random (R) and in Context (C) with both HP & LP NC, Gestures

Yes Gestures: LPR sentences ↑ 28% LPC sentences ↑ 25% HPR sentences ↑ 22% HPC sentences ↑ 25% Concealed gestures did not appear to influence overall intelligibility.

Synthesized StudiesStudy Speakers Severity/ %


Strategies Utilized Used by speakers


Garcia & Cannito (1996b)

1 CVA = 1 Age 62

1 Severe 96 Ages 18-30 Randomly divided into 3 conditions, AO, AV, & VO

Sentences AO, AV, and VO formats, LP & HP sentences with no context and context NC, Gestures

Yes .

Predictiveness: ↑ 30% Gestures: ↑ 21%

Garcia, Dagenais, & Cannito (1998)

1 CVA = 1 Age 62

17% at sentence level

N/A Acoustic analysis

Sentences HP & LP Gestures

Yes Interword interval (IWI), sentence duration, and speaking time ↓ when sentences were produced with gestures Sentence intelligibility ↓ as IWI time ↑

Garcia & Dagenais (1998)

4 Subarachnoid Hemorrhage = 1 Multiple CVAs = 1 ALS = 1 BS stroke = 1 Ages 37-76

10%-79% at sentence level

96 Ages 18-35

Sentences AO, AV, and VO formats, HP & LP sentences NC, Gestures

Yes

Iconic gestural cues: ↑ of 4% - 38% ↓ for speaker with ALS by 9%


Intelligibility Listeners Format/ Strategies

Utilized Used by Speakers


Garcia & Cobb (2000)

1 ALS=1 Age 76

28% at sentence level

N/A Acoustic analysis

Sentences HP & LP Gestures

Yes Speaking time, intelligibility, and IWI ↓ with gestures, rate ↑ by 26 wpm

Hustad & Beukelman (2001)

4 CP = 4 Ages 19- 46

4 Severe 72 Ages 18-31

Sentences AO format, cues via video screen, related and unrelated sentences NC, TC, AC, Combined

No Unrelated sentences: TC = ↑ 20% AC = ↑ 18% Combined = ↑ of 33% Related sentences: TC = ↑ 11% AC = ↑ 24% Combined cues = ↑ of 35%

Hustad (2001)

4 CP = 4 Ages 19-46

4 Severe 68 Ages 18–31

Sentences AV format, cues on video screens NC, TC, AC, Combined

No

Ratings of effectiveness: -Better for combined cues -Worse for NC -AC better than TC Ratings of willingness to interact: -Better for combined cues -Worse for NC Listener ratings of persistence: - Better for combined cues


Intelligibility Listeners Format/ Strategies

Utilized Used by Speakers

Change in Intelligibility &/or Rate

Hustad & Beukelman (2002)

4 CP = 4 Ages 19-46


Sentences AO format, cues via video screen, related and unrelated sentences NC, TC, AC, Combined

No Comprehension of Unrelated sentences: TC = ↑ ~ 10% AC = ↑ ~ 9% Combined cues = ↑ ~ 30% Comprehension of Related sentences: TC = ↑ ~ 10% AC = ↑ ~ 23% Combined cues = ↑ ~ 38%

Beukelman, Fager, Ullman, Hanson, & Logeman (2002)

8 TBI = 8 Ages 19-44

1.5% to 87.1% at sentence level Mean 39.5%

8 Ages 19-45

Sentences AV format, cues on video screen NC, AC, TC, Clear Speech

Yes AC: ↑ of 33%, rate ↓ of 49 wpm TC: ↑ of 15%, rate ↓ of 9 wpm Clear Speech: ↑of 8%, rate ↓ of 7 wpm

Hustad & Garcia (2002)

1 CP = 1 Age 42


Sentences AV format, Alphabet cues on video monitor NC, AC, Gestures High- and low-predictive sentences for each condition

Yes HP sentences: AC =↑ 15% Gestures =↑ 15% LP sentences: AC = ↑ 27% Gestures =↑ 19%


Intelligibility Listeners Formats/ Strategies

Utilized Used by speakers


Hustad, Jones & Dailey (2003)

5 CP = 4 TBI = 1 Ages 33-58

5 Severe 120 Ages 18- 35 Randomly divided into 5 groups

Sentences Enhanced AV format, cues shown to the side of the speaker, prior to and during speech. NC, TC, AC, Combined

Yes TC: ↑ 2%, rate ↑ of .02 wpm AC: ↑ 32%, rate ↓ of 49 wpm Combined cues: ↑ of 36%, rate ↓ of 45 wpm

Hustad, Auker, Natale, & Carlson (2003)

3 CP = 3 Ages 24-37

3 Profound

72 Ages 18-45

Sentences AV format, cues on video screen NC, TC, AC, Combined

Yes TC: ↑ 3% - 4% AC: ↑ 16%- 37% Combined cues: ↑ of 29% - 49%

Jones, Mathy, Azuma & Liss (2004)

1 ALS = 1 Age 75

1 Severe 30 2 groups Ages 19 – 29 Ages 55-74

Sentences AO format Each sentence had 3 open-class (noun, verb, adjective, adverb) and 2 closed class (prepositions, articles, pronouns, conjunctions, and auxiliaries) words, cues heard prior to stimuli using synthesized speech General cues, TC

No

TC: ↑ in transcription accuracy of 8 words compared to general cues


Intelligibility Listeners Formats/ Strategies Utilized Used by

speakers Change in Intelligibility &/or Rate

Jones, Mathy, Azuma & Liss (2004)

1 ALS = 1 Age 75

1 Severe 30 2 groups Ages 19 – 29 Ages 55-74

Sentences AO format Each sentence had 3 open-class and 2 closed class words, cues heard prior to stimuli using synthesized speech General cues, TC

No

TC: ↑ in transcription accuracy of 8 words compared to general cues

Hustad & Gearhart (2004)

7 CP = 7 Ages 24-58

4 Severe 3 Profound

168 Ages 18-35 Randomly divided into 7 groups

Sentences Enhanced AV format, cues shown to the side of the speaker, prior to and during speech. NC, TC, AC, Combined

Yes 7 Point Attitude Scale: TC: ↑ 0.4 AC: ↑ 1.7 Combined cues: ↑ of 2.3

Hanson, Beukelman, Fager, & Ullman (2004)

9 TBI = 9 Ages 19-44

1.5% to 86.7% at sentence level

60 Ages 27-84 4 groups by label: 1) General Public 2) SLPs 3) Allied Health 4) Family Members

Sentences AV format NC, AC, TC, Clear Speech

Yes AC viewed as most effective and acceptable, followed by TC and clear speech

Synthesized Studies

Note: AC =Alphabet Cues, ALS= Amyotrophic Lateral Sclerosis, AO= Audio Only, AV= Audio Video, BS= Brain Stem, CP= Cerebral Palsy, CVA= Cerebral Vascular Accident, De. =

Degenerative. HP= High Predictability, HR= High Redundancy, IWI = interword

intelligibility, LP= Low Predictability, LR= Low Predictability, MN = Motor Neuron, NC= No Cues, NR= Not

Reported, Park. = Parkinson’s, TBI= Traumatic Brain Injury, TC= Topic Cues, WC= Word Class, ↑

= Increase, ↓= Decrease

Study Speakers Severity / % Intelligibility

Listeners Formats/ Strategies Utilized

Used by speakers


Hustad & Garcia (2005)

3 CP = 3 Ages 33-42

7%-27% at sentence level

144 Mean age 21 Divided into 3 groups

Sentences Half of group = AO format. Half of group = AV format NC, AC, Gestures

Yes AC provided higher intelligibility scores and helpfulness ratings in both AV and AO formats. Gestures scored higher than no cues in AV format. No significant difference between AC and gestures for intelligibility in AO format

Hustad (2005)

1 CP=1 Age 52

Mild 75% at sentence level

24 Mean age 20 Listeners randomly assigned to stimuli

Narrative Passages Enhanced AV format, cues on video screen NC, AC, TC, Combined

Yes AC provided highest intelligibility scores and attitude ratings. No significant difference between intelligibility scores for topic cues, habitual speech, and combined cues. No significant difference between attitude ratings between topic cues and habitual speech.

Common Factors

Each study involved the use of key supplemental speech strategies with dysarthric speakers and non-disabled listeners. All listeners transcribed what they heard at the word and/or sentence levels through the use of audio or audiovisual formats. 15 had the speakers implementing the strategies.5 specifically addressed the impact the strategies had on a speaker’s rate.

Positive Findings

Alphabet cues Consistently improved speech intelligibilityImprovements varied depending upon severity levels of the speakers and length and predictability of utterances. Attitudes of listeners towards speakers improved Significant reduction in rate of speaker

Topic & Semantic CuesConsistently improved speech intelligibilityConsistently improved listeners’ comprehension

Positive Findings

Syntactic CuesKnowledge of a grammatical label increased intelligibility 5-17%Given contextual cues, improvements of 3%-48% across profound to moderately impaired speakers

Gesture CuesSignificantly improved the intelligibility levels 6/7 speakers. (the 7th speaker had ALS)

Positive Findings

Combined CuesConsistently improved intelligibility in all of the studies when comparing the scores to a no cue conditionCombining topic and alphabet cues together proved most effective

•

Profoundly and Severely impaired speakers improved intelligibility at the word level by 25.96%-83.6% (Hustad, Auker

et al., 2003; Hustad

& Beukelman, 2002; Hustad, Jones, & Dailey, 2003)

Positive Findings

Increase in intelligibility due to a reduction in rate of speech

When utilizing alphabet cues, 90% of the speakers reduced their speaking rate by 20-90 words per minute

The use of speech supplementation strategies in combination with natural speech does improve overall intelligibility!

Clinical Decision Making

Who do the strategies work for?We know that a speaker needs to be 70% intelligible in order to be considered functional (Ball, Beukelman, & Patee, 2004).

When intelligibility levels are below 81% at the sentence level, listeners have significant difficulty comprehending the content of messages (Beukelman and Yokston,1989).

These strategies appear to be most appropriate for mild-moderately impaired dysarthricspeakers.

Challenges in the Research

Only 62% of the studies had the participants actually implementing the strategies addressed.58% of the studies provided cues via answer sheets and video screens.No “real life” communication interactionsLittle is known about the preferences of the stakeholders.

Future Directions

Areas to Explore:Use with young and old speakers and listenersUse with family members Use in interactive settings with speakers implementing the strategiesUse in conversation

Both quantitative and qualitative information could be gathered regarding speakers’ and listeners’ perceptions of the effectiveness of different strategies in different communication settings.

References

Beliveau, C., Hodge, M. M., & Hagler, P. (1995). Effects of supplemental linguistic cues on the intelligibility of severely dysarthric speakers. AAC Augmentative and Alternative Communication, 11, 176-186.

Beukelman, D., Fager, S., Ullman, C., Hanson, E., & Logemann, J. (2002). The impact of speech supplementation and clear speech on the intelligibility and speaking rate of people with traumatic brain injury. Journal of Medical Speech-Language Pathology, 10 (4), 237-242

Beukelman, D. R., & Yorkston, K. (1977). A communication system for the severely dysarthricspeaker with an intact language system. The Journal of Speech and Hearing Disorders, 42 (2), 265-270.

Beukelman, D. R., & Yorkston, K. (1989). Augmentative and alternative communication application for persons with severe acquired communication disorders: An introduction. Augmentative and Alternative Communication, 5, 42-48.

Carter, C.R., Yorkston, K.M., Strand, E. A., & Hammen, V. L. (1996). Effects of semantic and syntactic context on actual and estimated sentence intelligibility of dysarthric speakers. In D. Robin, K. Yorkston, & D. Beukelman (Eds.), Disorders of motor speech: Assessment treatment, and clinical characterization (pp. 67- 87). Baltimore: Paul H. Brookes.

Crow, E. & Enderby, P. (1989). The effects of an alphabet chart on the speaking rate and intelligibility of speakers with dysarthria. In K. Yorkston, & D. Beukelman (Eds.), Recent advances in clinical dysarthria (pp. 99-107). Boston: College Hill.

Dagenais, P. A., Garcia, J. M., & Watts, C. R. (1998). Acceptability and intelligibility of mildly dysarthric speakers by different listeners. In M. P. Cannito, K. M. Yorkston, & D. R. Beukelman (Eds.), Neuromotor speech disorders: Advances in assessment and treatment (pp. 175-191). Baltimore: Paul H. Brookes.

ReferencesDollaghan, C. A. (2004). Evidence-based practice in communication disorders: What do we

know, and when do we know it? Journal of Communication Disorders, 37, 391-400.Dongilli, P. A. Jr. (1994). Semantic context and speech intelligibility. In J. Till, K. M. Yorkston, &

D. R. Beukelman (Eds.), Motor speech disorders: Advances in assessment and treatment (pp. 175-191). Baltimore: Paul H. Brookes.

Garcia, J. M., & Cannito, M. P. (1996a). Top-down influences on the intelligibility of a dysarthricspeaker: Addition of natural gestures and situational context. In D. Robin, K. Yorkston, & D. Beukelman (Eds.), Disorders of motor speech: Assessment treatment, and clinical characterization (pp. 67- 87). Baltimore: Paul H. Brookes.

Garcia, J. M., & Cannito, M. P. (1996b). Influence of verbal and nonverbal contexts on the sentence intelligibility of a speaker with dysarthria. Journal of Speech & Hearing Research, 39 (4), 750-761.

Garcia, J. M. & Cobb, D. S. (2000). The effects of gesturing on speech intelligibility and rate in ALS dysarthria: A case study. Journal of Medical Speech-Language Pathology, 8, 353-357.

Garcia, J. M., & Dagenais, P. A. (1998). Dysarthric sentence intelligibility: Contribution of iconic gestures and message predictiveness. Journal of Speech, Language, and Hearing Research, 41, 1282-1293.

Garcia, J. M., & Dagenais, P. A., & Cannito, M. P. (1998). Intelligibility and acoustic differences in dysarthric speech related to use of natural gestures. In M. P. Cannito, K. M. Yorkston, & D. R. Beukelman (Eds.), Neuromotor speech disorders: Nature, assessment, and management (pp. 213-227). Baltimore: Paul H. Brookes.

References

Hammen, V. L., Yorkston, K. M., & Dowden, P. (1991). Index of contextual intelligibility: Impact of semantic context in dysarthria. In C. A. Moore, K. M. Yorkston, & D. R. Beukelman(Eds.), Dysarthria and apraxia of speech; Perspectives on management (pp. 43-54). Baltimore: Paul H. Brooks.

Hanson, E. K., Beukelman, D. R., Fager, S., & Ullman, C. (2004). Listener attitudes toward speech supplementation strategies used by speakers with dysarthria. Journal of Medical Speech-Language Pathology, 12, 161-166.

Hanson, E. K., Yorkston, K. M., & Beukelman, D. R. (2004). Speech supplementation techniques for dysarthria: A systematic review. Journal of Medical Speech-Language Pathology. 12, IX-XXIX.

Hunter, L., Pring, T., & Martin, S. (1991). The use of strategies to increase speech intelligibility in cerebral palsy: An experimental evaluation. British Journal of Disorders of Communication, 26, 163-174.

Hustad, K. C. (2001). Unfamiliar listeners’ evaluation of speech supplementation strategies for improving the effectiveness of severely dysarthric speech. AAC Augmentative and Alternative Communication, 17, 213-220.

Hustad, K. C. (2005). Effects of speech supplementation strategies on intelligibility and listener attitudes for a speaker with mild dysarthria. Augmentative and Alternative Communication, 21, 256-263.

Hustad, K. C., Auker, J., Natale, N., & Carlson, R., (2003). Improving intelligibility of speakers with profound dysarthria and cerebral palsy. Augmentative and Alternative Communication, 19 (3), 187-198.

References

Hustad, K. C., & Beukelman, D. R. (2000). Integrating AAC strategies with natural speech in adults. In Beukelman, D. R., Yorkston, K. M. & Reichle, J. (Eds). Augmentative and Alternative Communication for Adults with Acquired Neurologic Disorders. (pp. 83-106). Baltimore: Paul H. Brookes•

Hustad, K. C., & Beukelman, D. R. (2001). Effects of linguistic cues and stimulus cohesion on

intelligibility of severely dysarthric

speech. Journal of Speech, Language, and Hearing Research, 44, 497-510.

Hustad, K. C., & Beukelman, D. R. (2002). Listener comprehension of severely dysarthric speech: Effects of linguistic cues and stimulus cohesion. Journal of Speech, Language, and Hearing research, 45, 545-558.

Hustad, K. C. & Garcia, J. M. (2002). The influences of alphabet supplementation, iconic gestures, and predictive messages on intelligibility of a speaker with cerebral palsy. Journal of Medical Speech-Language Pathology, 10, 279-285.

Hustad, K. C. & Garcia, J. M. (2005). Aided and unaided speech supplementation strategies: Effect of alphabet cues and iconic hand gestures on dysarthric speech. Journal of Speech, Language, and Hearing Research, 48, 996-1012.

Hustad, K. C., & Gearhart, K. J., (2004). Listener attitudes toward individuals with cerebral palsy who use speech supplementation strategies. American Journal of Speech-Language Pathology, 13, 168-181.

Hustad, K. C., Jones, T., & Dailey, S. (2003). Implementing speech supplementation strategies: Effects on intelligibility and speech rate of individuals with chronic severe dysarthria. Journal of Speech, Language, and Hearing Research, 46, 462-474.

References

Jones, W., Mathy, P., Azuma, T., & Liss, J. (2004). The effect of aging and synthetic topic cues on the intelligibility of dysarthric speech. Augmentative and Alternative Communication, 20 (1), 22-29.

Lindblom, B. (1990). On the communication process: Speaker-listener interaction and the development of speech. AAC Augmentative and Alternative Communication, 6, 220-230.

Schlosser, R. W. (1999). Social validation of interventions in augmentative and alternative communication. AAC Augmentative and Alternative Communication, 15, 234-247.

Vogel, D. & Miller, L. (1991). A top-down approach to treatment of dysarthric speech. In D. Vogel & M. P. Cannito (Eds.) Treating disordered speech motor control: For clinicians by clinicians (pp. 87-109). Austin, TX: Pro-Ed.

Yorkston, K. M., & Beukelman, D. R. (1978). A comparison of techniques for measuring intelligibility of dysarthric speech. Journal of Communication Disorders, 11, 499-512.

Yorkston, K. M., & Beukelman, D. R. (1981). Communication efficiency of dysarthric speakers as measured by sentence intelligibility and speaking rate. Journal of Speech and Hearing Disorders, 46, 296-301.

Yorkston, K. M., Dowden, P. A., & Beukelman, D. R. (1992). Intelligibility measurement as a tool in the clinical management of dysarthric speakers. In Kent, R. D. (Ed.), Intelligibility in Speech Disorders (265-285). Philadelphia: John Benjamins.

Yorkston, K. M., Strand, E.A., & Kennedy, M. R. T. (1996). Comprehensability of dysarthric speech: Implications for assessment and treatment planning. American Journal of Speech-Language Pathology, 5, 55-66.

a synthesis of research findings on speech supplementation strategies for dysarthric speakers

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