The role of stereotypies in overselectivity process in Rett syndrome

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1 Available online at Research in Developmental Disabilities xxx (2008) xxx xxx The role of stereotypies in overselectivity process in Rett syndrome Rosa Angela Fabio a, Samantha Giannatiempo a, *, Alessandro Antonietti a, Sarojini Budden b a Department of Psychology, Catholic University of the Sacred Heart, Milano, Italy b Health Sciences University Portland, OR, USA Received 4 November 2007; received in revised form 18 January 2008; accepted 19 January 2008 Abstract Ten Rett syndrome (RS) girls and 10 control girls executed an attentional task in which a complex stimulus was shown followed by individual stimuli presented with distractors. Participants had to discriminate previously presented stimuli from distractors. RS girls carried out thetaskbothinacondition with the containment of stereotypies and in a no-containment condition. Overselectivity occurred in RS since patients failed to discriminate about 1/3 of the individual stimuli. There were no statistical differences with respect to the number of correct responses in the two conditions; RS girls learned quickly when their stereotypies were contained as opposed to when the containment of stereotypies was lacking. # 2008 Elsevier Ltd. All rights reserved. Keywords: Rett syndrome; Stereotypies; Learning; Overselectivity; Attention Rett syndrome (RS) is a developmental disorder, predominantly affecting females (incidence 1/20,000 1/15,000), resulting in severe mental retardation and neuro-behavioral disability. In late infancy, after a period of apparent normal development (Nomura & Segawa, 1990), RS patients undergo striking developmental regression (Hagberg, 1993; Moeschler, Charman, Berg, & Graham, 1991) characterised by the loss of pre-existing hand use (such as object reach, grasp, and manipulation) and by the appearance of distinctive hand stereotypies (hand wringing, tapping, and mouthing). In spite of severe disabilities in the post-regression phase, often * Corresponding author. Rosa Angela Fabio, Department of Psychology, Largo Gemelli, 1, Milano, Italy. Tel.: address: rosaangela.fabio@unicatt.it (S. Giannatiempo) /$ see front matter # 2008 Elsevier Ltd. All rights reserved. doi: /j.ridd

2 2 R.A. Fabio et al. / Research in Developmental Disabilities xxx (2008) xxx xxx individuals regain social interest and are relatively stable for an extended period before they manifest progressive motor deterioration as a result of weakness, wasting, and dystonia (Hagberg, 1993, 2002). During this period, crude self-feeding capabilities may be retained, but voluntary hand use is generally exceedingly limited and hand stereotypies are pervasive (Fontanesi & Haas, 1988; Keer, Montagne, Mus, & Stephenson, 1987). Some studies (Perry, Sarlo-McGravy, & Haddad, 1991; Witt-Engerström, 1990) have reported that patients often remain visually attentive to objects and people, tracking their movements and even showing preferences by means of eye pointing (Baptista, Mercadante, Macedo, & Schwartzman, 2006). This may reflect their cognitive abilities however stereotypic behaviors could interfere with their learning process. Recent research has suggested that this conceptualization of stereotypy is accurate but incomplete (Guess & Carr, 1991; Kennedy, Meyer, Knowels, & Shukla, 2000), for example, Kennedy et al. (2000) analyzed the stereotypy of autistic students and found several patterns. For some students, stereotypy was a function of sensory and social reinforcement, while for others an undifferentiated patter of behavior occurred across conditions. These findings suggest that the causes of stereotypy can be a function of (a) positive sensory reinforcement, (b) negative sensory reinforcement, (c) positive social reinforcement, and/or (d) negative social reinforcement. As Berkson and Tupa (2002) showed, there is an increased probability of stereotypy inversely related to a person s intellectual functioning level. This impairment may occur because the resources of attention can be allocated to the involuntary movement (stereotypic) so the residual resources are very few for the codification process. The purpose of this study is to analyse how stereotypies influence attention processes in RS girls and to test whether stereotypy containment improves the attention. One of the paradigms to study selective attention is overselectivity. This refers to atypically limited learning with respect to the range or to the number of stimulus features (Lovaas, Koegel, & Shreibman, 1979). Overselectivity is a widely acknowledged problem in the education of individuals with developmental disabilities like mental retardation and autism (Allen & Fuqua, 1985). Although the problem is widespread, literature about its remediation is remarkably limited (Schreibman, 1997). Lovaas et al. (1979) reported restricted stimulus control in mentally retarded and autistic people. Their study involved initial discrimination training with complex stimuli followed by testing with individual stimuli, which were included in the complex ones, to determine how many individual stimuli had been previously coded. For example, if initial training used the complex ABC stimulus (that is, a stimulus constituted by the individual stimuli A, B, and C) presented as correct and the XYZ stimulus as incorrect (see Fig. 1), then, in the test phase, pairs of individual stimuli were presented in combination (A versus Y, B versus X, and so forth: Fig. 2) with the request to recognise which stimulus was the correct one. When given such tests, individuals with development disabilities may respond appropriately only to a lower number of individual stimuli as compared to non-disabled individuals. Wilhelm and Lovaas (1976) reported reliable stimulus encoding by all three correct stimuli in typically developing children, two correct stimuli in children with moderate mental retardation, and only one or two correct stimuli in children with severe retardation. Restricted stimulus encoding has been documented with multiple stimuli differentiated along the same dimension (Koegel & Wilhelm, 1973; Wilhelm & Lovaas, 1976) as well as along different dimensions (differences in colour, form, and so on: Kovattana & Kraemer, 1974). The finding has been replicated by controlling the discrimination of stimuli presented individually (Dube, Kledaras, Iennaco, Stoddard, & McIlvane, 1993) and the discrimination of stimuli presented in multiple arrays (Stromer, McIlvane, Dube, & Mackay, 1993).

3 R.A. Fabio et al. / Research in Developmental Disabilities xxx (2008) xxx xxx 3 Fig. 1. Complex stimuli. Overselectivity has never been analyzed in RS, even though the assessment of specific attention abilities in this syndrome has been wished for in order to depict a precise outline of the cognitive profile of the patients, an outline that as yet research has failed to provide (Baptista et al., 2006; Nomura, 2005). The first aim of the present study was to assess to what extent overselectivity occurs in RS by presenting complex stimuli formed by three different pictures and then by asking to recognize the same pictures presented separately. The second aim was to assess if RS girls learning is influenced by their stereotypies. To do this, the same task was presented with containment of stereotypies and without containment. 1. Methods 1.1. Participants Ten girls with a diagnosis of RS, matching DSM IV criteria, took part in the experiment. Their families had been contacted by the Italian Rett Association which asked them to participate in the Fig. 2. Examples of individual stimuli.

4 4 R.A. Fabio et al. / Research in Developmental Disabilities xxx (2008) xxx xxx study. The 10 girls whose families agreed to collaborate lived in Northern Italy. They ranged in age between 5 and 26 years. A general assessment was carried out by a psychologist through the Vineland Adaptive Behavior Scale (VABS) (Sparrow, Balla, & Cicchetti, 1984) and the Portage Scale (Bluma, Shearer, Frohman, & Hilliard, 1976). The analyses of MCP2 mutation was conducted in the laboratories of the Istituto Auxiologico Italiano in Milan, MCP2 specific mutations of RS are presented in Table 1. Nine girls attended schools or socio-educational centres; one girl was assisted by an educator at home. All the girls were in the post-regression phase of the disorder. They were severely mentally retarded and were not able to use verbal speech. All showed little or no purposeful hand use and pervasive hand stereotypies were striking. Ambulation was preserved in eight girls. Table 1 shows the chronological age of the girls, their mental age assessed through the Portage Scale, the scores in the Portage subscales, as well as the total and subtotal VABS Scores. Since in this study it was important to examine the type and duration of stereotypies, these data were recorded in a free and unstructured examination during a preliminary observation session lasting 5 min (see Table 2) which was video recorded through a video camera. Two-independent observer, a psychologist and a caregive, coded data about the presence of stereotypies. Particularly, they were asked to count the numbers of stereotypies for each second. The interobserver agreement was 94%. The medium value regarding the presence of stereotypies is presented in Table 2. Ten normally achieving girls attending a public nursery school in a town of the Northern Italy constituted the control group. They were matched for mental age with RS girls. They ranged in age between 18 and 28 months. The same assessment procedure based on the VABS and the Portage Scale was carried out by the same psychologist. Scores proved that the developmental level reached by the control girls was similar to that of the matched RS patients. Table 1 Characteristics of the RS participants RS participants A B C D E F G H I L Age (years) Mental age (months) VABS a (total score) VABS subscales Communication Daily ability Socialization Motor ability Portage subscales Language Socialization Autonomy Cognitive level Motor level Type of mutation T158M P152R R168X R294X R133C R306C P152R R294X T158M R168X a Vineland Adaptive Behavior Scales.

5 R.A. Fabio et al. / Research in Developmental Disabilities xxx (2008) xxx xxx 5 Table 2 Type and frequency of stereotypies in RS participants Patients Hand stereotypies Hand and mouth stereotypies Duration in a 5 min period A Fist-shaking Joins hands at or in mouth Hand tapping Bruxism B Hand wringing Hand tapping C Hand tapping on the legs Hand mouthing with right hand; hand tapping with the left hand on the right one D Manipulation Hand wringing E Manipulation Hand mouthing F Swinging body Moving tongue in mouth G Fist shaking Hand mouthing 83 0 Hand wringing Bruxism H Hand mouthing 206 I Hand mouthing 244 L Manipulation Material For the first phase of the experiment 10 cards of 10 cm 30 cm each reporting a different complex stimulus formed by three familiar objects depicted in black and white (Fig. 1) were used. In the second phase individual stimuli, consisting of cards of about 10 cm 10 cm, were employed. Each card represented a familiar object included in the complex stimuli (Fig. 2). The cards have been calibrated by presenting them to an independent sample of 10 girls aged 4 years. They were asked by the examiners to evaluate the clarity of the pictures on each card on a scale of 1 10 in which 1 means the absence of clarity and the impossibility to say what the picture is; 10 means that the picture was very clear and the child can easily say what it is. The four cards reporting the complex stimuli which obtained the highest rates were selected (they had mean values ranging from 8 to 9) Procedure The experiment was carried out at the RS girls homes and in the nursery (for the control group). The examiner administered the VABS and the Portage Scale through an interview with

6 6 R.A. Fabio et al. / Research in Developmental Disabilities xxx (2008) xxx xxx the parents of the RS girls and the educators who assisted them at school or at the socioeducational centre. Next the examiner presented the overselectivity test. For each participant a session of 20-min duration was conducted. The whole session was video recorded. The examiner placed a pair of cards in every girl s lap or on a table in front of her, placed to the right and left of her. Location of the cards on the right or on the left took place in a random order. The cards were placed 40 cm from each other. In this way both cards were observable and within an easy reach and grasp of the girls. The task was carried out in two phases. During the first phase two cards reporting complex stimuli (ABC, correct stimulus; XYZ, incorrect stimulus: Fig. 1) were presented. The examiner presented every girl with the correct card described as the correct one ; both the correct and incorrect cards were then placed on the table in front of every girl who was asked: Which is the correct one? The 45 s to answer the question started. The girls could answer by grasping a card or by looking at it. The answer was considered as correct if the RS girls looked at it and/or grasped it for almost 3 s. If RS girls looked alternatively at both stimuli, the behavior was coded no answer. If the girl chose the correct card (ABC) during the 45 s, the examiner gave her a verbal reinforcement ( Great! Very good! ). The card selected and the manner in which it was chosen (by pointing, by touching or by looking at) were recorded. If the girl chose the incorrect card (XYZ) or did not choose any cards during 45 s or looked at both cards alternatively, both cards were removed and the no answer was coded and a new possibility of choice started after 10 s. The examiner counted how many attempts every girl made to learn the criterion of five correct consecutive answers. The criterion of five correct consecutive answers was requested in order to measure the consistency of learning and to reduce chance effects. In a second phase the examiner used the cards reporting individual objects (Fig. 2) extracted both by correct and incorrect complex stimuli by devising nine different pairs of individual cards from the combination of A with Y, B with X, etc. The examiner asked every girl to choose the correct stimulus. For RS girls both phases were repeated in a second session with other two complex stimuli (a correct and an incorrect one). For RS girls this procedure occurred under two conditions: with and without containment of stereotypies. In the first condition the girls were free, without any physical containment. In the second condition, girls performed the test with physical containment. Physical containment took place in a friendly way through an embrace or by putting a hand on the girl s hand, the goal being to increase their attention to external stimuli and to decentralise them from their body. The first session was executed in a condition and the second session in the other condition. The order of the with- and without-containment conditions was set randomly. 2. Results Two independent observers coded the variables from the videos. Interobserver agreement was 93%. When the value agreement was not the same, the medium value was coded. Table 3 shows how the girls gave their responses, the number of attempts needed to reach the criterion in the first phase of the experiment, and the number of correct answers in the second phases in the two conditions (with and without containment of stereotypies). Analyses were conducted assuming group (RS vs. control group) and presence of containment as independent variables. The first variable was between-subject and the second one was within-subject (it concerned only RS patients).

7 R.A. Fabio et al. / Research in Developmental Disabilities xxx (2008) xxx xxx 7 Table 3 Ways of answering, number of attempts to reach the criterion and number of correct answers in the two conditions of RS participants RS patients Way of answering Number of attempts With containment of stereotypies Without containment of stereotypies Number of correct answers With containment of stereotypies A Grasping B Looking C Looking D Looking E Grasping F Looking G Grasping H Grasping I Looking L Looking Without containment of stereotypies There were two dependent variables, the total number of trials to reach five consecutive identifications of the correct stimuli and, the number of correct selections of the individual stimuli. Table 4 reports means and standard deviation of the number of attempts which control and RS girls made to reach the criterion of five correct consecutive answers. There were no relevant differences between control and the RS girls under the condition with containment of stereotypies (t(18) = 0.95, p = 0.35), but there were significant differences between this group and the RS group in the condition without containment of stereotypies (t(18) = 5.92, p < 0.01). By analysing only the performance of RS participants, significant effects due to the variable presence of containment emerged (t(18) = 3.92, p < 0.01). RS girls learned more quickly when their stereotypies were kept in check than when the containment of stereotypies was lacking. Table 4 also reports the mean number of correct answers which both control and RS girls gave when asked to recognise the correct individual stimulus (A or B or C), previously presented in the complex one (ABC), paired to an incorrect one. There were relevant statistical differences between the control group and the RS girls group for both conditions (with and without the containment of stereotypies) (respectively: t(18) = 3.75, p < 0.01; t(18) = 4.78, p < 0.01). By considering only the RS subsample, no significant difference in the number of correct responses between the containment and the Table 4 Number of attempts to reach the criterion and number of correct answers Response RS girls Normally developing girls Number of attempts to reach the criterion with the complex stimuli Number of correct answers to the individual stimuli With containment Without containment M S.D. M S.D. M S.D

8 8 R.A. Fabio et al. / Research in Developmental Disabilities xxx (2008) xxx xxx Table 5 Number of correct answers based on the contents: means and standard deviations Individual stimuli M S.D. First series Banana Ball Cup Second series Pot Strawberries Chair Table 6 Number of correct answers of the stimulus position: means and standard deviations Stimulus position M S.D. First position Second position Third position no-containment conditions was found (t(9) = 1.08, p = 0.35). This means that, when learning is established, outcomes are independent of how (with or without containment of stereotypies) learning occurs. RS girls seem to have forgotten about 1/3 of the nine stimuli, as if they had only partially elaborated the information coming in. We conducted two analyses just with data of the RS girls to verify two hypotheses about the overselectivity process: the first pertained to the content of the stimuli and the second concerned the position of the stimuli. As far as the first hypothesis was concerned, we tried to assess if the content could justify the overselectivity process. As far as the second hypothesis is concerned, we analyzed if the position (independent of the content) that each of the three individual stimuli occupied in the complex stimulus could influence the overselectivity process. It was important to underline that three individual stimuli were collocated in the first position, three in the second position (in the centre), and three in the third position within the complex stimulus. Table 5 reports the means and standard deviation of the number of correct answers related to the content of each card. No significant differences among the six objects emerged (F(5,45) = 0.97, p = 0.44). The content did not influence the information that the girl had missed. Table 6 shows the means and standard deviation of the number of correct answers related to each position. The variable position produced statistical significant effects (F(2,18) = 3.46, p < 0.05). RS girls were unlikely to give the correct responses when the stimulus occupied the central position: it was as if the girls focused their attention on the first object of the complex stimulus and on the last object, by failing to elaborate the central object. No significant effect was found in the two depended variables limited to normal age and mental age. 3. Discussion RS girls were able to learn to discriminate complex stimuli in this study. Thus confirms Perry et al. (1991) that reported a good level of visual attention. It has been shown that RS patients

9 acquired the criterion of five consecutive correct answers in the identification of a complex stimulus both with or without containment of stereotypies and gave the same rate of correct answers in both conditions. However, they learned more quickly with containment of stereotypies than without containment. Even if the role and the conceptualization of stereotypy is not yet clear, some studies showed decreased levels of stereotypy when sensory stimulation was presented (Tang, Patterson, & Kennedy, 2003). This study, for some aspects, confirms the work of Tang et al. (2003): while in the work of Tang et al. (2003) sensory stimulations decreased level of stereotypy, here the containment of stereotypy improved the codification of sensory stimulations. The analyses also showed that RS girls partially selected information, by omitting to code 1/3 of the stimuli. Wilhelm and Lovaas (1976) reported similar results infact children with severe retardation omitted 2/3 of the stimuli. This omission was not related to the content of the complex stimuli but to the position of the individual objects within such stimuli. Girls seemed to encounter difficulties in elaborating the objects that occupied the central position within the complex stimulus. This experiment has implications for methodologies that can help educators to interact in effective ways with RS girls. Since RS patients have a deficit in selective attention, it is useful and effective to control posture and physical containment in order to decrease their stereotypies and to remove all external stimuli that make it difficult to work on the target stimulus. As far as the omission of the central position is concerned, it is very important to put on the bench the material that is strictly necessary for the activity, to sit in a proper way and hold the girls hands gently, so that all their attention is concentrated on the stimuli. It is also opportune to present the materials in a well-organised manner with time and task provisions being well clarified. References R.A. Fabio et al. / Research in Developmental Disabilities xxx (2008) xxx xxx 9 Allen, K. D., & Fuqua, R. W. (1985). Eliminating selective stimulus control: A comparison of two procedures for teaching mentally retarded children to respond to compound stimuli. Journal of Experimental Child Psychology, 39, Baptista, P. M., Mercadante, M. T., Macedo, E. C., & Schwartzman, J. S. (2006). Cognitive performance in Rett syndrome girls: A pilot study using eyeracking technology. Journal of Intellectual Disabi1ity Research, 50, Berkson, G., & Tupa, M. (2002). Studies of the development of stereotyped and self-injurious behaviors in young children. In S. Schroeder & M. L. Oster-Granite (Eds.), Self-injurious behavior: Gene-brain-behavior relationships (pp ). Washington, DC: American Psychological Association. Bluma, S., Shearer, M., Frohman, A., & Hilliard, J. (1976). Portage guide to early education. Portage, MI: Portage Printers. Dube, C., Kledaras, J. B., Iennaco, F. M., Stoddard, L. T., & McIlvane, W. J. (1993). Observing complex visual stimuli: Effects of component protraing pretraining. Experimental Analysis of Human Behavior Bulletin, 8, Fontanesi, J., & Haas, R. H. (1988). Cognitive profile of Rett syndrome. Journal of Child Neurology, 3, S20 S24. Guess, D., & Carr, E. G. (1991). Emergence and maintenance of stereotypy and self-injury. American Journal on Mental Retardation, 96, Hagberg, B. (1993). Clinical criteria, stage and natural history. In B. Hagberg (Ed.), Rett syndrome clinical and biological aspects (pp. 4 21). London: Mackeith Press. Hagberg, B. (2002). Clinical manifestations and stages of Rett syndrome. Mental Retardation and Developmental Disabilities Research Reviews, 8, Keer, A. M., Montagne, J., Mus, B., & Stephenson, J. B. P. (1987). The hands and the mind, pre-and post-regression in Rett syndrome. Brain Development, 9, Kennedy, C. H., Meyer, K. A., Knowels, T., & Shukla, S. (2000). Analyzing the multiple functions of stereotypical behavior for students with autism: Implications for assessment and treatment. Journal of Applied Behavior Analysis, 33, Koegel, R. L., & Wilhelm, H. (1973). selective responding to the components of multiple visual cues by autistics children. Journal of Experimental Child Psychology, 15,

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