10.3 Augmentative & Alternative Communication (AAC) & PECS Protocols

Augmentative & Alternative Communication (AAC) & PECS Protocols

Exam Tip: PECS questions on the QASP-S examination heavily emphasize Phase 1 procedural fidelity and Skinnerian verbal operant classifications. In Phase 1, there must be TWO adults present: the Communicative Partner (who sits in front of the learner, holds the reinforcer, holds out an open hand upon reach, and remains completely silent) and the Physical Prompter (who sits behind the learner, provides physical guidance, and never speaks). Any question where the communicative partner speaks (e.g., saying "What do you want?" or "Give me the card") describes a protocol violation that destroys the mand operant. Furthermore, be prepared to categorize communicative acts as mands (controlled by Motivating Operations, reinforced by specific access) or tacts (controlled by non-verbal sensory stimuli, reinforced by generalized social praise).

Communication is the core deficit targeted in autism intervention. When an individual lacks a functional, fluent vocal verbal repertoire, behavioral frustration, aggressive outbursts, and severe self-injurious behavior frequently emerge as maladaptive functional equivalents. Augmentative and Alternative Communication (AAC) provides learners with immediate, functional communication modalities, reducing challenging behavior while fostering autonomy and language development.

AAC modalities are broadly bifurcated into:

1. Unaided Communication Systems: Rely entirely on the user's own body without external tools or equipment. Examples include manual sign language (e.g., ASL), finger spelling, natural gestures, and body language.
2. Aided Communication Systems: Require external materials or technological equipment. These range from low-tech aided systems (communication boards, Picture Exchange Communication System binders) to high-tech aided systems (dynamic display speech-generating devices [SGDs], dedicated tablets running apps like Proloquo2Go, TouchChat, or LAMP Words for Life).

---

The Picture Exchange Communication System (PECS; Frost & Bondy)

Developed in 1985 by Lori Frost and Andy Bondy, the Picture Exchange Communication System (PECS) is an evidence-based, low-tech aided AAC intervention designed specifically for individuals with autism and related developmental disabilities who display minimal to no functional speech. Unlike traditional language training that requires pre-existing eye contact, vocal imitation, or seated compliance, PECS immediately teaches the learner to be an active, self-initiated communicative agent.

                             PECS SIX-PHASE ARCHITECTURE
  ┌─────────────────────────────────────────────────────────────────────────────┐
  │ Phase 1: Physical Exchange (Pick up, Reach, Release to open hand; 2 adults) │
  │   │                                                                         │
  │   ▼                                                                         │
  │ Phase 2: Distance & Persistence (Travel to book, travel to partner)         │
  │   │                                                                         │
  │   ▼                                                                         │
  │ Phase 3: Picture Discrimination (3A: Preferred vs Non-preferred; 3B: Choice)│
  │   │                                                                         │
  │   ▼                                                                         │
  │ Phase 4: Sentence Structure (Sentence strip: "I want" + item icon)          │
  │   │                                                                         │
  │   ▼                                                                         │
  │ Phase 5: Answering "What do you want?" (Responding to verbal inquiry)       │
  │   │                                                                         │
  │   ▼                                                                         │
  │ Phase 6: Commenting (Tacting: "I see", "I hear", "It is"; Social praise)    │
  └─────────────────────────────────────────────────────────────────────────────┘

Phase 1: The Physical Exchange

• Target Objective: Upon observing a highly preferred item, the learner independently picks up the picture icon, reaches toward the communicative partner, and releases the icon into the partner's open hand.
• The Two-Person Prompter Model (Critical Fidelity Rule):
  1. Communicative Partner (CP): Sits facing the learner. Holds the desired reinforcer in view. The moment the child reaches toward the reinforcer or icon, the CP extends an open hand with palm facing up. The CP never uses verbal prompts (does not say "Give me the card", "What do you want?", or "Show me").
  2. Physical Prompter (PP): Sits directly behind the learner. The PP provides hand-over-hand physical assistance to guide the child through: (a) picking up the icon, (b) reaching toward the CP, and (c) releasing the icon into the CP's open hand. The PP provides zero vocal interaction and systematically fades physical pressure from full hand-over-hand to wrist guidance, elbow nudge, and then complete withdrawal (shadowing).
• Reinforcement: Within 0.5 seconds of icon release, the CP names the item ("Cookie!") and delivers the item to the learner.

Phase 2: Expanding Distance and Persistence

• Target Objective: The learner navigates environmental obstacles, travels across physical space to retrieve the icon from the communication book cover, and travels across the room to locate the communicative partner.
• Key Procedural Elements:
  • Introduces a portable communication binder with a Velcro strip on the exterior.
  • The distance between learner and communication book is systematically expanded (from inches to across the room).
  • The distance between learner and communicative partner is systematically expanded (from across the table to across the room, into hallways, and around corners).
  • Teaches persistence: if the partner turns their back or walks away, the learner must tap the partner's shoulder or move into their visual field to complete the exchange.

Phase 3: Picture Discrimination

• Phase 3A (Preferred vs. Non-Preferred Discrimination):
  • The binder cover presents two icons: one highly preferred item (e.g., chocolate) and one non-preferred/distractor item (e.g., paperclip, sock, broken pencil).
  • If the learner selects the preferred item, they receive it immediately.
  • If the learner selects the non-preferred item, the CP hands them the non-preferred item neutrally without correcting vocally. When the child reacts with distaste or non-acceptance, the CP implements the 4-Step Error Correction Procedure:
    1. Model / Show: Tap or point to the correct icon.
    2. Prompt: Guide child physically to take the correct icon.
    3. Switch: Flip the book over, have child touch their nose, or perform a brief distractor task to clear short-term memory.
    4. Repeat / Test: Re-present the original two-icon array and allow the child an independent opportunity to select the correct icon.
• Phase 3B (Discrimination Between Multiple Preferred Items):
  • The binder presents two highly motivating items (e.g., bubbles vs. pretzel).
  • Correspondence Check: After the learner exchanges an icon (e.g., pretzel), the CP presents both items on a tray and says, "Take it." If the child reaches for the pretzel (matching the exchanged icon), the trial is scored correct. If the child reaches for the bubbles (mismatch), the CP blocks the reach and implements the error correction sequence.

Phase 4: Sentence Structure

• Target Objective: The learner constructs multi-word sentences using a detachable Sentence Strip.
• The binder provides a stationary "I want" icon alongside vocabulary pictures.
• The learner removes the "I want" icon, places it on the left side of the sentence strip, selects the desired item icon, places it to the right, detaches the entire sentence strip, and exchanges it with the CP.
• Once basic sentence exchange is established, Attributes are introduced (e.g., "I want" + "big" + "red" + "ball").

Phase 5: Answering "What do you want?"

• Target Objective: The learner responds to the vocal inquiry "What do you want?" while maintaining spontaneous manding.
• The CP points to the "I want" icon while simultaneously asking "What do you want?". Using Progressive Time Delay, the pointing prompt is systematically delayed (0s $\rightarrow$ 1s $\rightarrow$ 2s $\rightarrow$ 3s $\rightarrow$ 5s) until the child initiates sentence formulation immediately upon hearing the question.

Phase 6: Responsive & Spontaneous Commenting

• Target Objective: The learner expands beyond requesting (manding) to labeling and commenting on their environment (tacting).
• Icons for "I see", "I hear", "I feel", and "It is" are introduced.
• The CP asks "What do you see?" while pointing to an interesting stimulus (e.g., an airplane). The learner builds the strip: "I see" + "airplane" and exchanges it.
• Consequence shifts from item delivery to generalized social reinforcement (e.g., "Wow, you see an airplane flying high!").

---

High-Tech AAC: Speech-Generating Devices (SGDs)

High-tech AAC devices utilize digital speech synthesis software to emit vocal output when the learner activates graphic icons, symbols, or text. Selecting between low-tech (PECS) and high-tech (SGD) depends on motor access, cognitive profile, portability, and communicative environment.

                           AAC VOCABULARY TAXONOMY
 ┌──────────────────────────────────────────────┬──────────────────────────────────────────────┐
 │               CORE VOCABULARY                │              FRINGE VOCABULARY               │
 ├──────────────────────────────────────────────┼──────────────────────────────────────────────┤
 │ • Represents ~80% of words used in daily     │ • Represents ~20% of words used in daily     │
 │   human discourse across all age groups.     │   discourse.                                 │
 │ • Highly flexible, cross-contextual words    │ • Highly specific, context-dependent nouns   │
 │   consisting of verbs, pronouns, prepositions│   and specialized terms.                     │
 │   and adjectives.                            │ • Examples: "Dinosaur", "iPad", "Pepperoni", │
 │ • Examples: "Go", "Stop", "More", "Want",    │   "Trampoline", "Waterpark", "Stethoscope".  │
 │   "Help", "Look", "Open", "Mine", "Not".     │ • Limited generative value across diverse    │
 │ • Fosters generative, spontaneous language   │   social settings (e.g., "Dinosaur" is       │
 │   across home, school, and community.        │   useless during a meal or math routine).    │
 └──────────────────────────────────────────────┴──────────────────────────────────────────────┘

A common clinical trap in AAC programming is constructing pages composed exclusively of fringe vocabulary nouns (e.g., 50 pictures of favorite snacks). A robust AAC system must feature a persistent, accessible Core Vocabulary layout that empowers the learner to direct actions, protest, combine descriptors, and navigate diverse social interactions.

---

B.F. Skinner's Verbal Operants (1957)

In his seminal 1957 treatise Verbal Behavior, B.F. Skinner revolutionized the analysis of language by categorizing verbal responses not by their grammatical form or syntax, but by their functional relations to antecedent conditions and consequences:

                        SKINNER'S PRIMARY VERBAL OPERANTS
 ┌───────────────┬───────────────────────────────┬─────────────────────────────────────────────┐
 │ VERBAL OPERANT│ CONTROLLING ANTECEDENT        │ CONTROLLING CONSEQUENCE / FUNCTION          │
 ├───────────────┼───────────────────────────────┼─────────────────────────────────────────────┤
 │ MAND          │ Motivating Operation (MO)     │ Specific Reinforcement                      │
 │               │ (State of deprivation/aversion│ (Access to the exact item, action, or state │
 │               │ e.g., hunger, thirst, pain)   │ specified by the mand; benefits speaker)    │
 ├───────────────┼───────────────────────────────┼─────────────────────────────────────────────┤
 │ TACT          │ Non-Verbal Discriminative     │ Generalized Conditioned Reinforcer ($S^{r+})│
 │               │ Stimulus (Sensory object,     │ (Social attention, praise, head nod, verbal │
 │               │ event, sound, odor in sight)  │ confirmation; benefits listener)            │
 ├───────────────┼───────────────────────────────┼─────────────────────────────────────────────┤
 │ ECHOIC        │ Vocal Verbal Discriminative   │ Generalized Conditioned Reinforcer ($S^{r+})│
 │               │ Stimulus with Point-to-Point  │ (Social praise, tokens; reinforces vocal    │
 │               │ Correspondence & Formal Sim.  │ imitation accuracy)                         │
 ├───────────────┼───────────────────────────────┼─────────────────────────────────────────────┤
 │ INTRAVERBAL   │ Verbal Discriminative Stimulus│ Generalized Conditioned Reinforcer ($S^{r+})│
 │               │ WITHOUT Point-to-Point        │ (Conversational responsiveness, social      │
 │               │ Correspondence                │ validation; e.g., answering questions)      │
 └───────────────┴───────────────────────────────┴─────────────────────────────────────────────┘

Key Conceptual Distinctions for the Exam

• Point-to-Point Correspondence: Occurs when the beginning, middle, and end of the antecedent verbal stimulus matches the beginning, middle, and end of the verbal response. (Present in Echoic; absent in Intraverbal).
• Formal Similarity: Occurs when the controlling antecedent stimulus and the response share the same physical modality (e.g., both are vocal, or both are written, or both are manual signs). (Present in Echoic; absent in Tact and Mand).
• Pure vs. Impure Operants:
  • A pure mand is controlled strictly by an MO (e.g., child is thirsty, says "Water" without any adult prompt).
  • An impure mand is evoked by an MO combined with an adult verbal $S^D$ (e.g., therapist asks "What do you want?" while child is thirsty).