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Saturday, May 9, 2009
Northwest Hall (Chicago Hilton)
10:00 AM
Background: Early signs of autism spectrum disorder (ASD) are usually studied using retrospective designs. However, these designs are susceptible to several biases, such as selectivity (e.g., in home video fragments) or recall. Therefore, we conducted a large, prospective screening study in Flemish day-care centres.
Objectives: To identify which early signs of ASD are the most common in one- and two-year-olds, and to determine which signs are the most useful in discriminating between infants with and without ASD.
Methods: Personnel of day-care centres received a 3-hour training in recognizing early signs of ASD. Afterwards, child care workers filled out the Checklist for Early Signs of Developmental Disorders (CESDD) for all children. This checklist consists of 25 signs of ASD and was based on a literature review and home video analysis. Children with at least 4 signals were invited for further assessment, including confirming a possible diagnosis of ASD.
Results: The CESDD was filled out for 4036 children between 12 and 36 months of age (mean age = 21.92 months; 51.9% male). Of these children, 85.7% showed no signs of ASD. For 5.8% 1 sign was recognized, for 2.5 % 2 signs were ticked, for 1.4% 3 signs were ticked and for 4.7% 4 or more signs were recognized.
For the one-year-olds (12-24 months), the most commonly indicated signals were: being easily frustrated (4.7%), limited showing (4.3%), and limited declarative pointing (3.5%). A discriminant function analysis revealed that limited declarative pointing, a dislike of being touched or held, and an unusual posture were the items that discriminated the best between children with and without ASD (standardized canonical discriminant function coefficients were .45, .42, and .37, respectively).
For the two-year-olds, the most commonly indicated signals were identical to those of the one-year-olds (6.2%, 4.0% and 3.0%, respectively). The most discriminating items however were different: limited showing, limited response to joint attention, and limited symbolic play (standardized canonical discriminant function coefficients were .51, .45, and .43, respectively).
Conclusions: Although being easily frustrated was the most commonly identified signal in both age groups, its discriminative value for ASD was not very high. This indicated that some items on the checklist may be quite common in typically developing children as well. In one-year-olds, limited declarative pointing is the most predictive of a diagnosis of ASD. However, sensorimotor abnormalities (oversensitivity to touch and abnormal postures) also play an important role at this age. In two-year-olds, the most predictive signals are related to joint attention and symbolic play. These results confirm the importance of assessing joint attention and play in young children, but also stress the importance of evaluating non-social factors such as sensorimotor behaviour.
Objectives: To identify which early signs of ASD are the most common in one- and two-year-olds, and to determine which signs are the most useful in discriminating between infants with and without ASD.
Methods: Personnel of day-care centres received a 3-hour training in recognizing early signs of ASD. Afterwards, child care workers filled out the Checklist for Early Signs of Developmental Disorders (CESDD) for all children. This checklist consists of 25 signs of ASD and was based on a literature review and home video analysis. Children with at least 4 signals were invited for further assessment, including confirming a possible diagnosis of ASD.
Results: The CESDD was filled out for 4036 children between 12 and 36 months of age (mean age = 21.92 months; 51.9% male). Of these children, 85.7% showed no signs of ASD. For 5.8% 1 sign was recognized, for 2.5 % 2 signs were ticked, for 1.4% 3 signs were ticked and for 4.7% 4 or more signs were recognized.
For the one-year-olds (12-24 months), the most commonly indicated signals were: being easily frustrated (4.7%), limited showing (4.3%), and limited declarative pointing (3.5%). A discriminant function analysis revealed that limited declarative pointing, a dislike of being touched or held, and an unusual posture were the items that discriminated the best between children with and without ASD (standardized canonical discriminant function coefficients were .45, .42, and .37, respectively).
For the two-year-olds, the most commonly indicated signals were identical to those of the one-year-olds (6.2%, 4.0% and 3.0%, respectively). The most discriminating items however were different: limited showing, limited response to joint attention, and limited symbolic play (standardized canonical discriminant function coefficients were .51, .45, and .43, respectively).
Conclusions: Although being easily frustrated was the most commonly identified signal in both age groups, its discriminative value for ASD was not very high. This indicated that some items on the checklist may be quite common in typically developing children as well. In one-year-olds, limited declarative pointing is the most predictive of a diagnosis of ASD. However, sensorimotor abnormalities (oversensitivity to touch and abnormal postures) also play an important role at this age. In two-year-olds, the most predictive signals are related to joint attention and symbolic play. These results confirm the importance of assessing joint attention and play in young children, but also stress the importance of evaluating non-social factors such as sensorimotor behaviour.