Temperament and sensory features of children with autism.

This study sought to characterize temperament traits in a sample of children with autism spectrum disorder (ASD), ages 3-7 years old, and to determine the potential association between temperament and sensory features in ASD. Individual differences in sensory processing may form the basis for aspects of temperament and personality, and aberrations in sensory processing may inform why some temperamental traits are characteristic of specific clinical populations. Nine dimensions of temperament from the Behavioral Style Questionnaire (McDevitt and Carey in Manual for the behavioral style questionnaire, Behavioral-Developmental Initiatives, Scottsdale, AZ, 1996) were compared among groups of children with ASD (n = 54), developmentally delayed (DD; n = 33), and the original normative sample of typically developing children (McDevitt and Carey in J Child Psychol Psychiatr 19(3):245-253, 1978; n = 350) using an ANOVA to determine the extent to which groups differed in their temperament profiles. The hypothesized overlap between three sensory constructs (hyperresponsiveness, hyporesponsiveness, and seeking) and the nine dimensions of temperament was analyzed in children with ASD using regression analyses. The ASD group displayed temperament scores distinct from norms for typically developing children on most dimensions of temperament (activity, rhythmicity, adaptability, approach, distractibility, intensity, persistence, and threshold) but differed from the DD group on only two dimensions (approach and distractibility). Analyses of associations between sensory constructs and temperament dimensions found that sensory hyporesponsiveness was associated with slowness to adapt, low reactivity, and low distractibility; a combination of increased sensory features (across all three patterns) was associated with increased withdrawal and more negative mood. Although most dimensions of temperament distinguished children with ASD as a group, not all dimensions appear equally associated with sensory response patterns. Shared mechanisms underlying sensory responsiveness, temperament, and social withdrawal may be fruitful to explore in future studies.

Vibrotactile adaptation fails to enhance spatial localization in adults with autism.

A recent study [Tannan, V., Tommerdahl, M., Whitsel, B.L., 2006. Vibrotactile adaptation enhances spatial localization. Brain Res. 1102(1), 109-116 (Aug 2)] showed that pre-exposure of a skin region to a 5 s 25 Hz flutter stimulus ("adaptation") results in an approximately 2-fold improvement in the ability of neurologically healthy human adults to localize mechanical stimulation delivered to the same skin region that received the adapting stimulation. Tannan et al. [Tannan, V., Tommerdahl, M., Whitsel, B.L., 2006. Vibrotactile adaptation enhances spatial localization. Brain Res. 1102(1), 109-116 (Aug 2)] proposed that tactile spatial discriminative performance is improved following adaptation because adaptation is accompanied by an increase in the spatial contrast in the response of contralateral primary somatosensory cortex (SI) to mechanical skin stimulation--an effect identified in previous imaging studies of SI cortex in anesthetized non-human primates [e.g., Simons, S.B., Tannan, V., Chiu, J., Favorov, O.V., Whitsel, B.L., Tommerdahl, M, 2005. Amplitude-dependency of response of SI cortex to flutter stimulation. BMC Neurosci. 6(1), 43 (Jun 21) ; Tommerdahl, M., Favorov, O.V., Whitsel, B.L., 2002. Optical imaging of intrinsic signals in somatosensory cortex. Behav. Brain Res. 135, 83-91; Whitsel, B.L., Favorov, O.V., Tommerdahl, M., Diamond, M., Juliano, S., Kelly, D., 1989. Dynamic processes govern the somatosensory cortical response to natural stimulation. In: Lund, J.S., (Ed.), Sensory Processing in the Mammalian Brain. Oxford Univ. Press, New York, 79-107]. In the experiments described in this report, a paradigm identical to that employed previously by Tannan et al. [Tannan, V., Tommerdahl, M., Whitsel, B.L., 2006. Vibrotactile adaptation enhances spatial localization. Brain Res. 1102(1), 109-116 (Aug 2)] was used to study adults with autism. The results demonstrate that although cutaneous localization performance of adults with autism is significantly better than the performance of control subjects when the period of adapting stimulation is short (i.e., 0.5 s), tactile spatial discriminative capacity remained unaltered in the same subjects when the duration of adapting stimulation was increased (to 5 s). Both the failure of prior history of tactile stimulation to alter tactile spatial localization in adults with autism, and the better-than-normal tactile localization performance of adults with autism when the period of adaptation is short are concluded to be attributable to the deficient cerebral cortical GABAergic inhibitory neurotransmission characteristic of this disorder.

Practice parameter: screening and diagnosis of autism: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Child Neurology Society.

Autism is a common disorder of childhood, affecting 1 in 500 children. Yet, it often remains unrecognized and undiagnosed until or after late preschool age because appropriate tools for routine developmental screening and screening specifically for autism have not been available. Early identification of children with autism and intensive, early intervention during the toddler and preschool years improves outcome for most young children with autism. This practice parameter reviews the available empirical evidence and gives specific recommendations for the identification of children with autism. This approach requires a dual process: 1) routine developmental surveillance and screening specifically for autism to be performed on all children to first identify those at risk for any type of atypical development, and to identify those specifically at risk for autism; and 2) to diagnose and evaluate autism, to differentiate autism from other developmental disorders.

Autism during infancy: a retrospective video analysis of sensory-motor and social behaviors at 9-12 months of age.

This retrospective video study explored the usefulness of sensory-motor measures in addition to social behaviors as early predictors of autism during infancy. Three groups included 11 children with autism, 10 with developmental disabilities, and 11 typically developing children. Home videos were edited to obtain a 10-minute cross-section of situations at 9-12 months for each subjects. Using interval scoring, raters coded several behavioral categories (i.e., Looking, Affect, Response to Name, Anticipatory Postures, Motor/Object Stereotypies, Social Touch, Sensory Modulation). Nine items, in combination, were found to discriminate the three groups with a correct classification rate of 93.75%. These findings indicate that subtle symptoms of autism are present at 9-12 months, and suggest that early assessment procedures need to consider sensory processing/sensory-motor functions in addition to social responses during infancy. Furthermore, prior to a time that they reported autistic symptoms, caregivers used compensatory strategies to increase the saliency of stimuli in order to engage their children more successfully; these strategies may provide a window for earlier diagnosis.

The screening and diagnosis of autistic spectrum disorders.

The Child Neurology Society and American Academy of Neurology recently proposed to formulate Practice Parameters for the Diagnosis and Evaluation of Autism for their memberships. This endeavor was expanded to include representatives from nine professional organizations and four parent organizations, with liaisons from the National Institutes of Health. This document was written by this multidisciplinary Consensus Panel after systematic analysis of over 2,500 relevant scientific articles in the literature. The Panel concluded that appropriate diagnosis of autism requires a dual-level approach: (a) routine developmental surveillance, and (b) diagnosis and evaluation of autism. Specific detailed recommendations for each level have been established in this document, which are intended to improve the rate of early suspicion and diagnosis of, and therefore early intervention for, autism.

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.

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.