Blogging about Research: Increasing Social Interaction using PMT with Nonverbal School-age Children with ASD!

Increasing social skills via PMT for school age ASD

Article:  Increasing Social Interaction Using Prelinguistic Milieu Teaching with Nonverbal School-Age Children with Autism

Citation:  Franco, J., Davis, B., & Davis, J. (2013). Increasing social interaction using prelinguistic milieu teaching with nonverbal school-age children with autism. American Journal of Speech Language Pathology22, 489-502. doi: 10.1044/1058-0360(2012/10-0103)

Purpose:  The purpose of this study was to determine the effect the use of PMT (prelinguistic milieu teaching) has on a child’s initiation of intentional communication as well as a child’s development of sustained intentional communication within a play routine for nonverbal school-age children with an outside diagnosis of autism spectrum disorders.

Participants:  six children ages 5-8 with: 1) outside dx of ASD, 2) English identified as dominant language in the home environment, 3) participants lack use of functional communication (i.e. no consistent use of vocalizations, eye gaze, or gestures to communicate), 4) normal levels of vision, hearing, and motor skills, 5) developmental language age-equivalent <18 months for both receptive and expressive language skills.

Methods: Methodological process to this study: Parent interview, Baseline, Treatment Sessions, Follow up

Parent Interview/Evaluation

Parent interview was conducted and at the time the CARS (Childhood Autism Rating Scale) and REEL-3 (Receptive-Expressive Emergent Language Scale-3rd edition) were completed.  Standardized tests were solely used to verify severity of ASD and current receptive and expressive language skills.  All participants received a severity level of moderate-to-severe on the CARS and exhibited receptive language skills between 5-12 months and expressive language skills between 5-9 months.

Baseline Sessions

Each client was randomly assigned a number of baseline sessions ranging from 3-10.  Baseline skills were initially recorded via 25-30 minute sessions by the first author of this article who is a licensed speech-language pathologist and board-certified behavior analyst with experience in PMT intervention.  Evaluation and intervention sessions were conducted by this same professional.

During baseline sessions, the “adult interacted naturally without explicitly using PMT techniques or routines”, “maintained close proximity to the child and maintained nonverbal attention to the child’s activity”.  The adult did not “prompt or cue the child to communicate or attempt to initiate any play routines”.  However the adult did respond to any child initiated communication with a neutral comment (e.g. “Oh, I see.”).


14 intervention sessions were conducted also in each subject’s home environment.  Although parents were not specifically trained on the use of PMT (i.e. that is no responsivity education (RE) was provided), parents were present during every session and questions were answered by the therapist.  Play routines were individualized per each subject’s interest and motivation and were chosen prior to the first intervention session with the assistance of the subjects’ parents.

During the intervention sessions the child was taught to use vocalizations, gestures, and eye gaze using PMT techniques (“previously described in protocols and textbooks”).  To create the appropriate context (i.e. enabling context) the environment is arranged to provide opportunities for child initiated requests (e.g. preferred items placed out of sight/reach of child), and the use of play routines are incorporated to encourage initiation of communication.  The adult “followed the child’s attention and motivation (within the arranged environment) and imitated the child’s vocalizations”.  As the child exhibited a pattern of behavior or play, the adult would interrupt that pattern and attempt to engage the child in turn take (e.g. child bouncing ball, adult interrupts and try to create a turn taking game of “catch”).  “Once a routine was initiated, the adult conducted a series of teaching episodes where a specific child behavior was taught using a sequence of prompts, models, and natural consequences as described in PMT studies”.  Natural consequences were described as the adult responding appropriately to a child’s requests or responding with a smile or nodding when the child communicated. If there was no child initiated communication, a prompt/gestural cue would be given.  If after a few seconds, the child did not respond to the prompt, the appropriate response was modeled by the adult without requiring direct imitation from the child.

Follow up

Two or three follow up sessions were conducted six weeks after the 14 intervention sessions were completed to observe if any skills were maintained.  During the 6-week absence there was no contact with the adult and child and parents were not instructed to use PMT.  However, as parents were present during the intervention sessions and observed the techniques used, it is impossible to determine if parents continued with the use of the observed techniques during this period of time.


It is also important to note that the therapist providing the intervention was also one of the raters of this study along with a group of graduate assistants.  Reliability among raters (interobserver agreement-IOA) was determined to be greater than 75% on all ratings.  Treatment fidelity (i.e. determination of the accuracy of intervention implementation) is a type of reliability rating.  Treatment fidelity ranged between 94%-100%.  A 5-point Likert-type scale was used to determine social validation.  From the results of the 24 graduate students who completed this scale,” the T test for matched pairs revealed statistical significance for each of the seven items” targeting social validity.


Overall baseline results indicated that the subjects’ rate of intentional communication was very low (range averaged=.3-2.5 acts).  Treatment results tripled in the number of communication acts per routine as compared to the baseline (range averaged=7.5-17.3 act).  The maximum rate of initiated communication acts at the baseline was .2.  During intervention, all subjects’ increased their rates of initiated communication acts ranging from 1-2 acts per minute.  All subjects in this study either maintained the current improvements or improved upon their communication skills as noted in follow session data.

Concerns and Limitations of this study:

There appears to be a number of limitations and concerns with this study’s methodology.

Firstly, it concerns me greatly that although the subjects were school-aged there was no information from school staff/personnel regarding the subjects’ communication abilities in the academic environment.  There is no information regarding the type (if any) of functional communication systems that have been implemented or trialed in the academic setting.  Therefore, as a reader, I do not know if the skills observed during the “intervention” and “follow up” stages were truly learned via PMT or if the subjects already possessed theses skills prior to participating in this study.

Secondly, I do question the method of recording baseline data.  The lack of a standard number of baseline sessions for each subject and the procedure that regardless of baseline stability, intervention followed the randomized number of baseline sessions, is questionable.  One could theorize that the greater the number of baseline sessions provided, the better rapport built between the subject and the therapist as well as an increase in the possible number of communication opportunities for the child could result in an inflated baseline.  However, the use of a set number of baseline sessions for all subjects should attempt to control for this phenomena, yet it was not utilized.  No data analysis regarding baseline skills of subjects as compared to the number of baseline sessions implemented was reported, therefore, readers are unable to determine if the number of baseline sessions actually affected baseline scores. Also, if baseline stability was not achieved, how could one report results with confidence?  How do readers know whether results indicate learned skills or were previously obtained?

Thirdly, during baseline sessions it was reported that the adult responded “naturally” however she did not use any PMT techniques.  Nonverbal attention was maintained in close proximity to the child and the adult responded to child initiated communication with a neutral response.  This unfortunately is not reflective of natural communication nor of typical assessment procedures.  Communication is not conducted in a vacuum and we as individuals (whether adults or children) will not maintain interaction or continue to initiate interaction if we are receiving “neutral” responses.  During assessment of a child’s baseline communication skills, it is unrealistic to think we can sit quietly next to a child and have them demonstrate all of their current skills.  This is why for even typically developing children we provide standardized tests and ask questions.  We want to know what the child knows and can do.  With this type of data collection, it is questionable whether we as readers receive a holistic view of any of the subjects’ true communication abilities, which unfortunately result in questioning the results of this study.

Other concerns not previously mentioned:

1)       Choosing Individualized Routines:  Although as a therapist, I understand using routines that are highly motivating and/or individualized to each client as an important tool in facilitating improvements in communication.  However, in a research study, the use of individualized routines that differ among subjects does present a few difficulties in that 1) it is difficult to control for/or compare changes in communication as the same routines were not chosen, and 2) with the use of different routines one cannot account for the role motivation does or does not play in a child’s performance.

2)      Small sample size:  An additional limitation of this study is the use of a very small sample size, which the authors also identify as a limitation to this study and which is a common limitation to many research studies of this nature.  Researchers and readers alike understand the need for more large scale studies in this area.

Implications for further research:

Of course the goal of this article was solely to assess PMTs affect on social skills.  However, the lack of comparison groups to compare effectiveness of other techniques on improvements in communication and social skills could be extremely helpful in our field.  Therefore further research studies that are large scale randomized control trials which compare a number of different evidence-based techniques to each other in order to analyze their effectiveness is implicated and, at least for myself, very much looked forward too hopefully in the near future.