Referential communication in Fragile-X syndrome

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The fragile-X syndrome:

What about the deficit in the pragmatic component of language?

Elbouz M. & Comblain A.

Faculty of Psychology and Educational Sciences, Department of Cognitive Sciences

University of Liège, Belgium

Abstract

Language profile of fragile-X syndrome (FXS) individuals looks like the one of Down syndrome individuals, except for phonological and pragmatics abilities. If the pragmatic aspect of language is relatively preserve in Down syndrome, it is one of the most impaired language component in FXS. One aspect of the pragmatic component of language remains almost unexplored in this pathology: the common ground management and the organization of the old and the new information in conversation. We would explore this domain with 4 FXS boys and 4 typically developing (TD) children matched. Different referential communication tasks were used in two conditions: speaker condition and listener condition. The results shows FXS boys can be efficient speakers and listeners as TD children in simple situations. Difficulties

appear when FXS boys have to deal with spatial and ordinate attributes.

The X fragile syndrome and language

Introduction Introduction

- Most common inherited cause of mental retardation. - 1 male per 2000 life birth / 1 female per 4000 life birth. - Mutation on the X chromosome (premutation or full mutation). - Characteristic physical features and behavioral features.

- Mental retardation in 85% of males with full mutation (mean QI: 41 for males with methylated full mutation, 60 for males with mosaic pattern, 88 for males with unmethylated or partially unmethylated full mutation).

Speech production Speech production

- Omission, distorsion and substitution of consonants and vowels in the conversational speech. - Variability in speaking rate.

- Dysfluency and dysprosody. Lexical development Lexical development

- Below chronological age expectations on both receptive and expressive measures of vocabulary. - No litterature about strategies used in new words learning and semantic categories and the

lexico-grammatical categories acquisition. Morphosyntactic development Morphosyntactic development

- Below chronological age expectations on both receptive and expressive measures of morphosyntax.

- Receptive morphosyntax is mental-age appropriate. - Results are less clear for expressive morphosyntax. Communication and pragmatic development Communication and pragmatic development - Below chronological age expectations. - Problems become more severe in adolescence.

- Performance on communication tasks < those of developmental level matched mental retarded individuals (autism and Down syndrome).

- Perseverations and excessive self-repetitions of words, sentences or topics. - Limitations of the recent researches on communication and pragmatic in FXS:

 Few researches

 Assessment of FXS males almost exclusively within the conversation

context and with a limited tange of partners.

 No serious description of the ability of FXS to fulfill the requirements

of the listener’s role.

 Few studies on the emergence of the communicative problems of FXS

individuals over the course of development.

Study

Tasks Tasks

- Tasks were distributed in 2 groups: building tasks and combination tasks. - Groups of 2 boys work together on referential communication tasks.

- 6 referential communication tasks are proposed to children in speaker condition and in listener condition:

1) Preliminary task: build / describe a tower with colored pearls

2) Task 1: find / describe a particular combination of pictures (form+color, form+size, size+color, form+color+size)

3) Task 2: build / describe a tower of « legos » 4) Task 3: build / describe a puppet with elementary forms 5) Task 4: place a puppet in a village

6) Task 5: find / describe a picture Subjects

Subjects

4 FXS males aged 10;6 to 12;7 years-old and 4 TD children matched on lexical age (Peabody Picture Vocabulary Test).

Experimental situations Experimental situations Analysis Analysis 1. FXS child as a speaker 1. FXS child as a speaker -Facing another mental retarded child. -Comparatively to typically developing children. -Analysis of 4 kinds of messages:

Spontaneous sufficient message (SSM): containing all the informations needed and generally leading to a correct response of the interlocutor.

Spontaneous insufficient message (SIM): containing not enough information: the listener must question the speaker to find the correct response.

Spontaneous non-informative message (SNIM): no pertinent information is given concerning the item to describe.

Spontaneous incorrect message (INCM): information is incorrect (e.g. may concern a distractor). Results

FXS children are poor communicators.

Task 1 – Combination: Compare to TD children who produce only SSM, FXS children produce mainly SIM and less MSS.

Task 2 – Legos: Compare to TD children who produce only SSM, FXS children produce a lot of SIM and INCM.

Task 3 – Puppet: For description task, compare to TD children who produce only SSM, FXS children produce a lot of SNIM and clearly less SSM. For buiding task, compare to TD children who produce a majority of SSM, FXS children produce only SIM.

Task 4 – Village: Compare to TD children who produce mainly SSM and a little of SIM, FXS children produce mainly INCM and SIM.

Task 5 – Picture: Compare to TD children who produce only SSM, FXS children produce mainly SSM and SIM, and a little of SNIM and INCM.

Generally, TD children are complete in produced message. FXS children produce a lotf of insufficient message and clearly less of sufficient message.

2. FXS child as a listener 2. FXS child as a listener

-Facing another mental retarded child, an complete adult and an incomplete adult. -Comparatively to typically developing children.

-Analysis in terms of success rate (percentage) in the different tasks. Results

FXS children are poor listeners.

Facing an other child Facing an complete adult Facing an incomplete adult

TD children have maximum scores for all listener’s situations. They have some difficulties for « incomplete adult » situation.

In all situations, compare to TD children, FXS children show lower success rate. This is true particularly for « incomplete adult » situation.

Generally, FXS children are poor listener with better score for « complete adult » situation and lower score when they are faced another child.

Conclusion

Speaker Listener

Situation 1 FXS child

TD child 1

Other etiology child TD child 2

Situation 2 Other etiology child

TD child 2

FXS child TD child 1

Situation 3 Adult (complete) FXS child

TD child

Situation 4 Adult (incomplete) FXS child

TD child 0 10 20 30 40 50 60 70 80 90

SSM SIM SNIM INCM FXS TD child 0 10 20 30 40 50 60 70 80 90 100 P ea rls F +C S+F S + C F +S + C L eg os P up p et 1 P u pp et 2 V il la g e P ic tu re Adult C Adult Ic Child 0 10 20 30 40 50 60 70 80 90 100 Pea rl s F+ C S + F S + C F +S + C Leg o s P u pp et 1 P up pe t2 V illa ge Pic tu re 0 10 20 30 40 50 60 70 80 90 100 P ea rls F+C S+F S+ C F+ S +C Lego s P upp et1 P u pp et2 V ill age P ic tu re 0 10 20 30 40 50 60 70 80 90 100 P ea rl s F + C S + F S + C F + S + C Le g o s P u p pet 1 P u p p et 2 V il la ge P ic tu re FXS Normal Speaker Listener

-FXS children give more spontaneous insufficient messages than TD children. -Messages are rarely totally inappropriate or incorrect.

-Difficulties appears with spatial information -FXS children have difficulties to find the righ word and the pertinent features.

-FXS children perform as well as TD children with a « complete adult », except for the task containing spatial information or for building tasks.

-FXS children are less performant with a child or an « incomplete adult ». -FXS children engage more easily in a verbal interaction with a child than with an adult.