Early development of stereotyped and self-injurious behaviors: I. Incidence.

From five programs with 457 eligible children, 39 children younger than 40 months who had developmental disabilities were studied. Video sampling, observation notes, parent reports, staff reports, and clinical records were the data sources. Twenty-one children, or 4.6% of the total number in the program, exhibited SIBs. Virtually all children in the sample who were motorically capable of it showed body-rocking in at least one position. The SIBs were directed mainly toward the head, and body-rocking occurred mainly in four-point and seated position.

More information on the nature of stereotyped body-rocking.

Body-rocking was exposed to kinematic analysis in two studies. In the first study, amplitude was larger in the natural body-rocking of individuals with mental retardation than in the natural body-rocking of college students. Variability did not differ. In the second study, natural body-rocking of people with mental retardation was compared with their artificial body-rocking. Amplitude and variability were larger in the artificial condition. However, this result was not clear. We suggest that group and condition differences might have been a function of practice.

Self-injurious behavior: gene-brain-behavior relationships.

This paper summarizes a conference held at the National Institute of Child Health and Human Development on December 6-7, 1999, on self-injurious behavior [SIB] in developmental disabilities. Twenty-six of the top researchers in the U.S. from this field representing 13 different disciplines discussed environmental mechanisms, epidemiology, behavioral and pharmacological intervention strategies, neurochemical substrates, genetic syndromes in which SIB is a prominent behavioral phenotype, neurobiological and neurodevelopmental factors affecting SIB in humans as well as a variety of animal models of SIB. Findings over the last decade, especially new discoveries since 1995, were emphasized. SIB is a rapidly growing area of scientific interest to both basic and applied researchers. In many respects it is a model for the study of gene-brain-behavior relationships in developmental disabilities.

Body-rocking in college students and persons with mental retardation: characteristics, stability, and collateral behaviors.

Body-rocking was analyzed in four studies. The first showed that rocking chairs are not necessarily preferred by people with mental retardation, and that a rocking chair produces a higher amplitude of body-rocking. A second study demonstrated the stability of various measures of body-rocking over a 21-month period. Stable idiosyncratic behaviors accompanying body-rocking also were described. The third study showed that, when compared with college students who engage in habitual body-rocking, persons with mental retardation engage in more body-rocking than college students on various dimensions, and that they also show different collateral behaviors. Finally, in the fourth study, a reanalysis of the data from Study I showed that collateral behaviors do not necessarily occur as part of a body-rocking complex.

Body-rocking and other habits of college students and persons with mental retardation.

Prevalence of body-rocking in college students was assessed, and the characteristics of body-rocking of college students were compared to those of individuals with mental retardation. For college students, the prevalence depended on the restrictiveness of the method used and varied between 3% and 25%. Video samples showed that when compared with college students, a greater proportion of people with mental retardation engage in body-rocking, seem less sensitive to situational factors, demonstrate atypical collateral behaviors, engage in less leg-kicking, and execute their body-rocking with larger amplitudes. There were no differences in duration or number of individual rocks or bouts of body-rocking. We conclude that body-rocking is a "normal" behavior whose form of expression may become atypical.

Self-reported body-rocking and other habits in college students.

A brief survey of eight motor habits, including body-rocking, was administered to two large samples of college undergraduates. A subsample was retested to establish survey reliability and validity. Those indicating engagement in body-rocking were interviewed about their body-rocking. Two psychopathology instruments were administered. The general prevalence of self-described body-rocking was higher than expected, and there were positive correlations among the eight habits. Body-rocking was usually related to negative affect and usually reported to begin during the school years and later. Many individuals said other family members engaged in body-rocking. Psychopathology assessments indicated higher levels of general distress and higher prevalence of Generalized Anxiety Disorder in this subsample compared with a group not reporting body-rocking.

Tactile defensiveness and stereotyped behaviors.

OBJECTIVES: This study explores the constructs of stereotyped behaviors (e.g., repetitive motor patterns, object manipulations, behavioral rigidities) and tactile defensiveness as relevant to occupational therapy theory and practice and attempts to test their purported relationships in children with developmental disabilities. METHOD: Twenty-eight children with developmental disabilities and autism were assessed on eight factors of stereotyped behavior via a questionnaire and by four measures of tactile defensiveness. The subjects' scores from the questionnaire were correlated with their scores on the tactile defensiveness measures to see what, if any, relationship among these behaviors exists. RESULTS: Significant relationships emerged from the data, indicating that subjects with higher levels of tactile defensiveness were also more likely to evidence rigid or inflexible behaviors, repetitive verbalizations, visual stereotypes, and abnormal focused affections that are often associated with autism. No significant association was found between motor and object stereotypes and tactile defensiveness. These relationships could not be explained solely by maturational factors. CONCLUSION: The results suggest that clinicians should include observations of stereotyped behaviors, particularly behavioral rigidities, in conjunction with assessments of sensory defensiveness because these are related phenomena that may pose unique challenges for children with developmental disabilities and autism. Further study is needed to determine the causal mechanisms responsible for these relationships.

Relative prevalence and relations among stereotyped and similar behaviors.

Relative prevalence and relations among stereotyped and similar behaviors were studied in 246 children and adults with developmental disabilities. For each subject, two staff members who knew the participant at least moderately well filled out a checklist of 54 items that sampled various forms of stereotyped behaviors, abnormal focused affections, compulsions, rigidity, savant skills, and defensiveness. Agreements between raters for individual participants were low to moderate. However, the item prevalence scores for the two groups of observers were stable. Correlations between several items were significant. Factor analyses produced weak evidence for a general Stereotypy factor and further evidence for 6 to 8 subfactors, some of which are generally consistent with accepted classification of the types of behaviors studied here.

Definition of abnormal focused affections and exploration of their relation to abnormal stereotyped behaviors.

The relation between abnormal stereotyped behaviors and abnormal focused affections (i.e., abnormally consistent preferences for specific objects, symbols, and/or physical locations) was examined in 20 children with developmental disabilities. Results indicated that (a) all children who exhibited abnormal focused affections exhibited stereotypies; (b) abnormal focused affections could be studied reliably in individuals with developmental disabilities through the use of direct time-sampling observations, naturalistic observations, and informant reports; and (c) developmental age was significantly related to the frequency of (and the number of different) stereotyped behaviors and the frequency of nonstereotyped (i.e., developmentally appropriate) behaviors exhibited across the sample. Results also provide preliminary support for the notion of a general stereotyped behavioral repertoire in individuals with developmental disabilities.

Tactile defensiveness in children with developmental disabilities: responsiveness and habituation.

Tactile defensiveness (TD) is characterized by behaviors such as rubbing, scratching, negative expressions, withdrawal, or avoidance in response to tactile stimulation. An inhibition deficit has been implied in the literature and is the focus of this study. School-aged children with developmental disabilities were first assessed for level of TD using three measures. Later, the children were presented with a repeated tactile stimulus while engaged in a computer game. Intensity, duration, and latency of the responses were recorded on each trial. It was hypothesized that higher levels of TD would be associated with (a) greater responsiveness and (b) slower habituation rates to the tactile stimulus. Correlations of three separate TD measures and a series of 3 x 10 (Level of TD by Responsiveness across trials) repeated measures ANOVAs were used to test the two hypotheses. Children who demonstrated higher levels of TD on some of the preliminary measures also showed higher responsiveness in the experimental situation. There was no general habituation effect, and the limited group by trials interactions were not interpretable. We conclude that there is evidence for a differential sensitivity in TD, but not an inhibition deficit. Another significant finding included a negative correlation between TD and developmental age.

Stimulation and control as components of stereotyped body rocking.

Severely and profoundly mentally retarded children who engaged in stereotyped body rocking were presented with all possible pairs of three conditions and made a choice as to which they preferred: a rocking chair that rocked freely under the child's control (active stimulation), a rocking chair that provided the same stimulation but was under the experimenter's control (passive stimulation), and a rocking chair that had been immobilized (stationary). Children significantly chose the active stimulation condition over the passive and the passive over the stationary; however, the degree of the effect was associated with developmental level. Results were interpreted as showing that self-stimulation involves at least two independent processes, control and stimulation.

Analyzing the stimulus properties of objects used in stereotyped behavior.

Ten severely retarded children who engaged in object stereotypies were observed during 10, 1-hour sessions in various contexts of their living and school environments. The percentage of object stereotypies performed and the nature of the objects manipulated were described. For the children as a group, context did not affect the level of object stereotypies, but other stereotypies were performed most often during music sessions. In Study 2 the objects manipulated in a stereotyped manner were presented to six people who were asked to describe the physical dimensions of the object when it was moved. Judges found that most children appeared to respond to flexibility, whereas some children appeared to respond to other feedback. Study 3 was designed to validate the dimensions selected by the judges. Each dimension agreed on by five of the judges in Study 2 was used to construct sets of five objects that varied with respect to that dimension. The children were presented with the set of objects and differential manipulation along the dimension was assessed. The judges' selections were partially validated.

Effect of intervention techniques in reducing stereotypic hand gazing in young severely disabled children.

Stereotypic hand gazing by very young severely disabled children was investigated. In Study 1 a dramatically increased therapy program substantially reduced a child's hand gazing and augmented his toy manipulation skills. In Study 2 specific interventions were prescribed for two children who were hand gazers and had significant yet correctable visual impairment. Both glasses and toys effectively reduced each child's hand-gazing. Results suggest that stereotypic hand gazing may be eliminated by intervention with very young children.

Normal repetitive and abnormal stereotyped behavior of nonretarded infants and young mentally retarded children.

The topographical similarities and differences between repetitive behaviors exhibited by 12 nonretarded infants and 11 severely mentally retarded children were examined. An analysis of stereotyped body-rocking and hand-gazing behavior exhibited by both groups demonstrated topographical differences. The results and methodology of this study may be of value to future investigators examining the ontogenesis of stereotyped behavior and may assist in the early identification and amelioration of these pathological behaviors.

Stereotyped behavior of severely disabled children in classroom and free-play settings.

The relationships between stereotyped behavior, object manipulation, self-manipulation, teacher attention, and various developmental measures were examined in 101 severely developmentally disabled children in their classrooms and a free-play setting. Stereotyped behavior without objects was positively correlated with self-manipulation and CA and was negatively correlated with complex object manipulation, developmental age, developmental quotient, and teacher attention. Stereotyped behavior with objects was negatively correlated with complex object manipulation. Partial correlations showed that age, self-manipulation, and developmental age shared unique variance with stereotyped behavior without objects.

Repetitive stereotyped behaviors.

This paper points to factors that determine whether repetitive stereotyped behavior occur in the behavior repertoire. The analysis pits an "intrinsic oscillator" mechanism against a "self-stimulation" theory and chooses to emphasize the latter. The paper accounts for the repetitive and rhythmic nature of stereotypy by suggesting that repetition in a rhythmic way is the most efficient way of self-stimulation. It proposes that rhythm may be a reinforcement in at least some cases. It raises the question of whether control of stimulation by the person is a necessary condition for maintaining stereotypy. The paper recognizes the possibility that stereotyped behaviors may have their origin in the common repetitive behaviors of infancy but emphasizes that pathological stereotypy may involve more than immature repetition. It suggests that there is reason to believe that early intervention to prevent pathological stereotyped behavior might be effective but that we do not know much about how stereotypies get started.