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Exchange and Developmental Therapy

Center of Excellence for autism and neurodevelopmental disorders - Tours (EXAC-T)

Published onApr 15, 2023
Exchange and Developmental Therapy

Brief Historic Overview 

Exchange and Developmental Therapy (EDT) was developed in the late sixties by Prof. G.Lelord and Prof. C.Barthélémy at the Child Psychiatry Department of Tours University Hospital.

This creation was concomitant with the evidence of atypical brain functioning based on electrophysiological studies run by the same team. Abnormal cortical event-related potentials were observed in children with Autism Spectrum Disorder (ASD) and related to atypical sensory processing called “insuffisance modulatrice cérébrale” made on cerebral electrophysiology in the same years which demonstrated a dysfunction of brain modulation and insufficiency of the filter of sensory stimulation (Bruneau et al., 1986 (1) ; lelord, 1966 (2) ; Lelord & Trouche, 1963 (3) ; Martineau et al., 1980 (4)).

EDT was first published by G.Lelord on the 27th of January 1987 in the bulletin of the French National Academy of Medicine. From the beginning of the 70’s, EDT was implemented for young children with ASD at the child psychiatry day-care unit in Tours.

The first publication demonstrating its effectiveness was written in 1991 by Pr C.Barthélémy in the journal Brain Dysfunction. It was followed by the publication of the book Infantile Autism: Exchange and Developmental Therapy in 1995, which now serves as a reference book.

Some great figures of autism such as Sally Rogers went to Tours in the nineties to be introduced to EDT. S. Rogers was then inspired to imagine her own model of the Early Start Denver Model published in 2013 which is now considered a reference in ASD treatment.

Nowadays, several clinical teams in different countries have been trained in EDT and have experienced the effectiveness of EDT in the management of children with ASD.


EDT is an individual developmental therapy that allows a neuro-functional rehabilitation of social communication. Its purpose is to restimulate the developmental trajectory by developing various basic functions: attention, intention, association, imitation, perception, contact, communication, regulation, and cognition. This rehabilitation is done through social games.

The basic principle is free acquisition, in opposition to conditioning and learning. EDT is a developmental therapy, and not behavioral, with several declination principles :

·         Limit sensory stimulations to allow the selection of information or actions.

  • Arrange the sequences and adapt them: it is necessary to provide free acquisition with preselected activities, where it will be needed to encourage oriented gestures and stimulate the demand while inhibiting aimless agitation.

  • Encourage exchanges: through looks, mimics, or imitations to create joint attention. 

Serenity, availability, and reciprocity are the 3 golden rules because they are the vectors of moments of synchronization. It is necessary to know how to adapt to the capacities of the child and his initiatives, one could compare this to a "tennis game": it is necessary to help the child, encourage him, comfort him, to be a receptive and communicative presence.

The therapy is performed after an extensive analysis of the faculties and difficulties of the child with a game adaptation. In practice, this requires 2 co-therapists who will in turn be observers and therapists, there will be 1 to 2 sessions of EDT per week of 10-20 minutes depending on the abilities of the child.  

 A repeated evaluation will be carried out with a follow-up and session tracing, as well as a regular video recording to observe the child’s progression over time. That way a readaptation of the proposed activities is possible by increasing the difficulty over sessions as indicated in the 2012 recommendations of the French High Health Authority (HAS). Questionnaires and tests will also be used for follow-up such as the SCEB profile (Socio-emotional and Cognitive Evaluation Battery, Blanc et al., 2005 (5)), BSE2 scale (=ERCA2, Autistic Behavior Rating Scale, Blanc et al., 2021 (6)), EFC-R test (Revised Functional Behavioral Rating Scale, Adrien et al., 2001 (7)) or GRAM test (Regulation-Adaptation Modulation Grid, Cochin et al., 1998 (8)).

Main uses

Initially reserved for children with ASD, EDT is now available for children with neurodevelopmental disorders more generally. It mainly concerns young children between 12 months and 10 years old since brain plasticity is optimal at this age of development.

The functional analysis of the child and the diagnosis are made using the criteria of the DSM-5 but also by the realization of an ADI-R (Autism Diagnostic Interview-Revised, Lord et al., 1994 (9)), ADOS (Autism Diagnostic Observation Schedule, Lord et al., 1989 (10)) and CARS test (Childhood Autistic Rating Scale, Schopler et al., 1980 (11)), SCEB profile and BSE2 scale.

EDT is carried out in addition to other traditional therapies whether medical, pharmacological, psychological, etc. The involvement of families is also essential to strengthen the child's acquisition at home as well as increase family and social integration. That's why they are also trained in EDT by explaining what we are looking for through interactions.


The effectiveness of EDT has been described for the first time by C.Barthélémy in 1991 in the scientific journal Brain Dysfunction where she spoke of a better and faster evolution for patients subsequently the effectiveness has been observed many times by the teams carrying out the project so much so that EDT is since 2012 in the recommendations of the French HAS with the consensus grade of experts.

It has also been demonstrated in recent articles such as the one published by Blanc et al., 2013 (12). This study of 35 children with autism followed for 9 months shows improvement in the capacity of exchange and communication in children with severe autism associated with a developmental delay.

The latest scientific article published on this subject dates from December 2021, Blanc et al., 2021 (6), statistically significant post-intervention improvements were found in cognitive and social-emotional skills. Autistic symptomatology evaluated in one-to-one settings significantly decreased with therapy, this reduction was observed in more than 85% of children.

Comment from an expert

“EDT is one of the first early intervention programs described in autism, which allows for significant hindsight on its effectiveness.  It allows the child's trajectory to be re-launched while respecting the different stages of development and thus ensuring the foundations for future development. Residents in Psychiatry can be trained to EDT and have a clinical practice in their department. EDT practice helps to better understand the socio-emotional synchronization phenomena while placing the resident in a therapist's position. “

Frédérique BONNET BRILHAULT, child Psychiatrist, University Professor and Hospital Practitioner at the Tours hospitals, Specialist in neurodevelopmental disorders, Coordinator of the EXAC-T (center of excellence for autism and neurodevelopmental disorders), and Head of the Neurofunctional Psychiatry team of the "Imaging and brain" research unit Inserm/University of Tours.

Comment from a trainee with some kind of experience 

”EDT allows the physiological beginnings of socialization development through synchronization moments and shared pleasure between the adult and the child mediated by game”

Oliviana LEFTER and Sophie MAGNE, first-year psychiatric trainees.

Book, manuals, videos, applications, published online courses, or international association

EDT training is open to any professional involved in the care of patients with autism. It includes two days of theoretical initiation and two days of practical training. It is available at the University Center of Child Psychiatry of Tours with Pr. Frédérique BONNET - BRILHAULT as pedagogical manager and Dr. Joëlle MALVY as co-responsible.

EDT reference book: “Infantile Autism: Exchange and Developmental Therapy” by C.Barthélémy et al, published in 1995.

Research possibilities

A scientific study led by M.Latinus is currently underway at EXAC-T and aims to study behavioral and brain synchronizations between the therapist and the child during EDT sessions compared to a control group.


Link for EDT training : Formation Continue - Thérapie d'échange et de développement - TED (Formation courte - 4 jours) ( For more information, please call 02 47 36 81 31 or Catherine PESCHARD at 02 47 36 81 45.

Link for more information about the Excellence Center in Autism of Tours - France (

Link for more information about the University Center of child psychiatry of Tours : Centre universitaire de pédopsychiatrie - CHRU de Tours (



 We really wanted to thank Hugo Simião, Thomas Gargot, and Frédérique Bonnet Brilhault for their help, their kindness, and their participation in this publication.



 (1) Bruneau, N., Barthelemy, C., Jouve, J., & Lelord, G. (1986). Frontal auditory-evoked potential augmenting-reducing and urinary homovanillic acid. Neuropsychobiology, 16(2‑3), 78‑84.

(2) Lelord, G. (1966). Etude EEG chez l’animal et chez l’homme d’un mode d’association specifique, distinct du conditionnement classique, l’acquisition libre. Acta Biologiae Experimentalis, 379.

(3) Lelord, G., & Trouche, E. (1963). Comparison of the responses to auditory stimulation observed in the primary somatic cortex and thalamus following somatic stimulation given in an intermittent or regular fashion. Journal de physiologie, 55, 283‑284.

(4) Martineau, J., Laffont, F., Bruneau, N., Roux, S., & Lelord, G. (1980). Event-related potentials evoked by sensory stimulation in normal, mentally retarded and autistic children. Electroencephalography and Clinical Neurophysiology, 48(2), 140‑153.

(5) Blanc, R., Adrien, J.-L., Roux, S., & Barthélémy, C. (2005). Dysregulation of pretend play and communication development in children with autism. Autism, 9(3), 229‑245.

(6) Blanc, R., Latinus, M., Guidotti, M., Adrien, J.-L., Roux, S., Dansart, P., Barthélémy, C., Rambault, A., Bonnet-Brilhault, F., & Malvy, J. (2021). Early Intervention in Severe Autism : Positive Outcome Using Exchange and Development Therapy. Frontiers in Pediatrics, 9.

(7) Adrien, J.-L., Rossignol‐Deletang, N., Martineau, J., Couturier, G., & Barthelemy, C. (2001). Regulation of cognitive activity and early communication development in young autistic, mentally retarded, and young normal children. Developmental Psychobiology: The Journal of the International Society for Developmental Psychobiology, 39(2), 124‑136.

(8) Cochin, S., Barthelemy, C., Lejeune, B., Roux, S., & Martineau, J. (1998). Perception of motion and qEEG activity in human adults. Electroencephalography and clinical neurophysiology, 107(4), 287‑295.

(9) Lord, C., Rutter, M., & Le Couteur, A. (1994). Autism Diagnostic Interview-Revised : A revised version of a diagnostic interview for caregivers of individuals with possible pervasive developmental disorders. Journal of autism and developmental disorders, 24(5), 659‑685.

(10) Lord, C., Rutter, M., DiLavore, P. C., Risi, S., Gotham, K., & Bishop, S. (1989). Autism diagnostic observation schedule. Western Psychological Services, 12031, 90025‑91251.

(11) Schopler, E., Reichler, R. J., DeVellis, R. F., & Daly, K. (1980). Toward objective classification of childhood autism : Childhood Autism Rating Scale (CARS). Journal of autism and developmental disorders.

(12) Blanc, R., Malvy, J., Dansart, P., Bataille, M., Bonnet-Brilhault, F., & Barthélémy, C. (2013). La thérapie d’échange et de développement, une rééducation neurofonctionnelle de la communication sociale. Neuropsychiatrie de l’Enfance et de l’Adolescence, 61(5), 288‑294.

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