How Does the ProxTalker Speech- Generating Device Compare ... Boesch - power... · The Picture Exchange Communication System (PECS) • Structured behavioral intervention program

M. Boesch, 4th Annual Adventures in Autism Conference

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College of Education

How Does the ProxTalker Speech-Generating Device Compare to PECS?

Implications for selecting Augmentative & Alternative Communication (AAC) strategies

Miriam C. Boesch, Ph.D.Assistant Professor in Special Education

Department of Educational Psychology


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Today’s Agenda • Brief Overview of PECS and SGDs• Purpose of the Study• Methods• Video Examples• Results• Conclusion• Problem Behaviors Encountered• Study Limitations• Future Research Directions• Q & A

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Autism

• Hallmark characteristics:

– delay in, or total lack of the development of spoken language

– restricted repetitive, & stereotyped patterns of behavior, interests, & activities

– impairments of social interactions (DSM‐IV‐TR, 2000)

• 1 in 88 children are diagnosed with ASD (CDC, 2012)

• Autism prototype – about 50% have limited or no functional speech (Charlop & Haymes, 1994; Peeters & Gillberg, 1999)

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The Picture Exchange Communication System (PECS)

• Structured behavioral intervention program to teach use of visual‐graphic symbols for communication

• 6‐phase exchanged‐based graphic symbol strategy:

– initially teaches to make requests by handing/ exchanging symbols for desired items

– later targets more spontaneous communicative acts(Bondy & Frost, 1994)

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PECS (cont.)

• Primarily for learners with autism who have little or nor functional speech

• It requires very few prerequisites

– only prerequisite is that the individual can clearly indicate what he or she wants

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Speech‐Generating Devices (SGDs)

• Portable, computerized devices producing synthetic/digitized speech output when activated

• Graphic symbols are used to represent messages, activated by selecting a symbol from the display via:

– Finger

– Switch

– headstick, etc.

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SGDs (cont.)

• Advantages over non‐electronic systems due to providing additional auditory stimuli for the learner via speech output:

– SGD may allow more independent form of communication (voice output understood by variety of familiar and unfamiliar comm. partners)

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Research Questions

• Can you start directly teaching the ProxTalker (or similar SGD) within a modified PECS protocol?

• What is the relative effectiveness of PECS vs. ProxTalker in increasing:

– requesting (primary measure)

– social‐communicative behavior

– natural speech production

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Participant Characteristics

Participant Age Gender DX Communication Skills

Christian 6 malesevere autism

very limited speech (less than 5 word approximations); some picture symbol

exposure; few gestures

Nadia 7 femalesevere autism

nonverbal; some picture symbol exposure; some gestures

Zeth 10 malesevere autism

nonverbal; no picture symbol exposure; some gestures; few manual signs

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Methods (cont.)

• Design

– multiple baseline across participants with an embedded alternating treatments design

– Counterbalancing of treatment conditions

– Treatment order was randomly selected

• Setting

– university‐based therapy room (Nadia & Zeth)

– home (Christian)

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Methods (cont.)

• Materials

– PECS book with PCS (picture cards)

– ProxTalker SGD with same picture cards as PECS

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Methods (cont.)

• Dependent Variables

– Requesting:

• picture exchange (PECS)

• button activation (SGD)

– Social‐communicative behavior:

• eye contact

• physical orientation

• positive affect (smiling)

– Speech:

• verbalizations/speech approximations

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Methods (cont.)

• Preference Assessment

1. Parent interview• Identify potential reinforcers (foods only)

2. Trial‐based assessment• Single‐item presentation; 80% consumed = selected as a reinforcer

3. Forced‐choice assessment• Paired presentation

• 2 lists of similarly motivating reinforcers were created

(Pace et al., 1985)

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Intervention Protocol

• Baseline:

– Both modalities were available

• Phase 1:

– Child picks up picture card & gives to trainer 1 (or activates card on SGD)

• Phase 2:

– Child picks up card/SGD, walks to trainer, & exchanges for reinforcer

(Frost & Bondy, 2002)

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Intervention Protocol (cont.)

• Phase 3:

– Child discriminates between pictures then request items

• distracter

• non‐preferred

• 2 preferred

• 3+ preferred

• Phase 3‐modified:

– Child discriminates between 2 picture cards(Frost & Bondy, 2002)

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Intervention Protocol (cont.)

• Follow up:

– Continuation of phase & treatment with best results

• Maintenance:

– Skill reassessed following 8‐wk treatment break

• Each Session:

– 20 trials per session

• Overall phase criterion:

– 80% (16/20 trials) correct for 2 consecutive sessions across 2 communicative partners and 3 reinforcers

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Reliability Analyses

• Inter‐rater reliability

– 2nd, independent observer scoring across all sessions (>33%):

• Requesting: M = 99%

• Social‐Communicative Behavior: M = 95%

• Speech: M = 100%

• Treatment integrity (TI)

– TI conducted on >33% of total treatment sessions

• Trainer 1: M = 98% / Mean agreement = 99%

• Trainer 2: M = 94% / Mean Agreement = 98%

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University Division Here

Phase 1: Physical Exchange

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Phase 2: Expanding Spontaneity

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Phase 3: Picture Discrimination

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Session

Numberof Requests

BL Phase 3

Christian

Nadia

Zeth

Phase 1 Phase 2

PECS

SGD

F3‐mod.

3 sym.

3 sym.

3 sym.

3 sym.

Maintenance

Effects on Requesting Skills*

*No statistically significant differences between AAC strategies in any phase for all participants.

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Effects on Social‐Comm. Behavior*


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Session

Numberof Social‐Communicative Interactions

BL Phase 3

Christian

Nadia

Zeth

Phase 1 Phase 2 F

PECS

SGD

3‐mod.

3 sym.

3 sym.

3 sym.

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Maintenance

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Effects on Emerging Speech*


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Session

Numberof Vocalizations

BL Phase 3

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Phase 1 Phase 2 F

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PECS

3‐mod. Maintenance

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Effect Size

• Non‐overlap of All Pairs (NAP)

– Calculates the # of comparison pairs that do not overlap & divides it by the total # of comparisons

• 0‐65% = weak effects

• 66‐92% = medium effects

• 93‐100% = strong effects

(Parker & Vannest, 2009)

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Effect Size: NAP (cont.)

Phase 1 Phase 2 Phase 3 Follow Maint.

PECS SGD PECS SGD PECS SGD

Request

Chris. 63% 100% 100% 90% 74%100% m

66%80% m

55% S 40% S

Nadia 50% 50% 50% 50% 50% 50% 50% S 50% S

Zeth 50% 50% 50% 54% 50% 50% 50% P 50% P

Soc.‐Comm.

Chris. 63% 100% 100% 90% 74%100% m

66%80% m

55% 100%

Nadia 85% 33% 91% 91% 58% 54% 100% 94%

Zeth 75% 39% 96% 93% 49% 43% 100% 100%

Speech

Chris. 63% 100% 100% 90% 74%100% m

66%80% m

55% 40%

Nadia 50% 50% 50% 50% 50% 50% 50% 50%

Zeth 50% 50% 50% 54% 50% 50% 50% 50%

Note: S = SGD; P = PECS; m = modified protocol

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Number of Sessions to Reach Mastery

Phase 1 Phase 2 Phase 3 Phase 3 (2 sym.)

PECS SGD PECS SGD PECS SGD PECS SGD

Christian 3 3 3 5 --- --- 3 3

Nadia 4 4 12 12 --- --- NA NA

Zeth 6 4 9 12 --- --- NA NA

--- = not mastered NA = not applicable

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Conclusions

• Children can master both AAC strategies

– contribution of modified protocol

• Interest in device features may have contributed to less S‐C behavior (eye contact)

– more S‐C behavior in phase 2 because of demands to locate trainer, thus increasing eye contact & proximity

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Conclusions (cont.)

• Picture Discrimination cumbersome (phase 3)

– may need to remain at 2‐symbols level for some time

• No speech gains

– practitioners need to have realistic expectations of speech development

• Requesting skills maintained at treatment levels

– social‐communicative behavior & speech declined

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AAC Strategy Comparisons

PROS CONS

PECS

+ Affordable

+ Can be used as a backup when SGD fails

+ Lightweight & portable

+ Easy to create

- No voice output ‐ comm. partner needs to be w/in arm’s reach

- May not be as motivating for tech lovers

ProxTalker

+ Voice output – comm. partner can be outside arm’s reach

+ Durable

+ Motivational value

- Cost

- SGD is heavy for younger children

- Cannot be used in some situations (e.g., swimming)

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Problem Behaviors• Escaping

– Minimized open area

– Removed distracter items

– Provided breaks

– Adjusted seating arrangement

• Carrying the SGD– Provided physical assistance

• Transitioning– Gradually moved from large

classroom to therapy room

• Lost interest in previously identified food reinforcers– Reassessed reinforcers

frequently

– Included more reinforcers

– Ensured freshness

– Provided small quantities

• Difficulty pressing SGD buttons– Provided physical assistance

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Problem Behaviors (cont.)

• Meltdowns– Lessened task demands

– Determined root of behavior & addressed

– Provided frequent breaks

– Reassessed reinforcers

• Excessive Stimming– Removed/minimized

distracter items

– Provided redirection

• 3‐Symbol Discrimination– Increased distance b/n

symbol

– Reassessed symbol iconicity

– Checked for symbol similarities

– Revisited the 2‐symbol phase

• Confusion between treatment strategies– Provided physical assistance

– Provided sufficient wait time

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Study Limitations

• Generalization to other settings was not investigated

• Only used food as reinforcers

• Symbol iconicity was not evaluated prior to intervention

• Limited number of participants

• Phases 4‐6 not assessed

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Future Research Directions

• Study replication:

– Various settings; w/ younger participants; CLD learners

• Does symbol iconicity impacts picture discrimination?

• Ongoing transition to PECS phases 4 through 6

• What type of participant is a good candidate for transition, which one is not?

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Future Research Directions• Once a “mid technology” device such as the ProxTalker is mastered, what comes next?

– Potential trajectory of moving along an intervention spectrum:

Low‐tech (PECS)

Mid‐tech (Proxtalker)

High‐tech (iPad)

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Questions / Comments

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Acknowledgements

• This project was supported by:

– A Project Development Team within the ICTSI NIH/NCRR Grant Number RR025761

– Midwest Crossroads Alliance for Graduate Education and the Professoriate

– Purdue Bilsland Dissertation Fellowship

• Thanks to ProxTalker.com, LLC for loaning devices

• Thanks to the families who agreed to participate in our research

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Contact Information

• Miriam Boesch

– [email protected]

– 940‐565‐2293

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References• American Psychiatric Association. (2000). Diagnostic and statistical manual of mental

disorders (4th ed., text revision). Washington, DC: Author.• Bondy, A., & Frost, F. (1994). The Picture Exchange Communication System. Focus on

Autistic Behavior, 9, 1‐19.• Centers for Disease Control and Prevention. (2012). Data and statistics: Prevalence.

Retrieved July 1, 2012 from http://www.cdc.gov/ncbddd/autism/data.html• Charlop, M. H., & Haymes, L. K (1994). Speech and language acquisition and

intervention: Behavioral approaches. In J. L. Matson (Ed.), Autism in children and adults: Etiology, assessment, and intervention (pp. 213‐240). Pacific Grove, CA: Brooks/Cole.

• Frost, L., & Bondy, A. (2002). The Picture Exchange Communication System training manual. Pyramid Educational Products.

• Pace, G.M., Ivancic, M.T., Edwards, G.L., Iwata, B.A., & Page, T.J. (1985). Assessment of stimulus preference and reinforcer value with profoundly retarded individuals. Journal of Applied Behavior Analysis, 18, 249‐255.

• Parker, R. I., & Vannest, K. J. (2009). An improved effect size for single‐case research: Non‐overlap of all pairs (NAP). Behavior Therapy, 40, 357‐367. doi:10.1016/j.beth.2008.10.006

• Peeters, T., & Gillberg, C. (1999). Autism: Medical and educational aspects. London: Whurr.

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How Does the ProxTalker Speech- Generating Device Compare ... Boesch - power... · The Picture Exchange Communication System (PECS) • Structured behavioral intervention program