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Friday, May 8, 2009
Northwest Hall (Chicago Hilton)
11:00 AM
Background:
The results of several previous studies of memory in individuals with Autism Spectrum Disorder (ASD) indicate deficits in relational semantic processing and decreased spontaneous use of mnemonic strategies (Gaigg et al., 2008) relative to individuals without ASD. However, when additional external supports are provided at test, individuals with ASD perform more similarly to their typically developing peers, a finding that led Bowler et al. (1997) to develop the Task Support Hypothesis of memory in ASD. The California Verbal Learning Test (CVLT) is a widely used neuropsychological measure of verbal learning and memory that also evaluates the use of strategies, which are thought to reflect executive functioning. To date, there have been no reported studies using the children's version of the CVLT to examine learning and memory in youth with ASD.
Objectives:
We examined learning and memory, as measured by the California Verbal Learning Test, Children's Edition (CVLT-C), in children and adolescents with high-functioning ASD. We were particularly interested in variables pertaining to learning strategies.
Methods:
Participants included 14 children and adolescents with ASD and 14 controls, matched for age, IQ and gender. Estimated IQ was measured using the Wechsler Abbreviated Scale of Intelligence. The CVLT-C is a list-learning task that involves five repetitions of a list of 15 words that includes 3 categories of items (clothes, toys and fruits). Immediate recall, delayed recall, and recognition of the words are assessed. We compared overall recall (List A Trials 1-5 Total, max score = 75), semantic and serial cluster ratios, recall consistency, total perseverations and total intrusions between ASD and control groups. We also examined relationships between CVLT-C performance and estimated IQ and age.
Results:
The ASD and control groups did not significantly differ on measures of semantic and serial cluster ratios, recall consistency, total perseverations, or total intrusions. There was a near significant difference (p = .07) for overall recall, with the ASD group recalling fewer items in total (mean = 47.2, SD = 10.8) than controls (mean = 55.3, SD = 11.6). In the ASD group, there was a significant positive correlation between estimated IQ and percent recall consistency (r = .79, p < .01) and a significant negative correlation between estimated IQ and total intrusions (r = -.54, p < .05). There were no relationships between IQ and CVLT-C performance for the control group or between age and CVLT-C performance for the ASD group. However, there was a significant negative correlation between age and serial cluster ratio scores for the control group (r = -.64, p < .05).
Conclusions:
Although these results suggest that individuals with ASD experience some overall deficits in learning and memory, there was no evidence of differences in strategy use. Interestingly, within the ASD group, individuals with a higher IQ showed higher recall consistency and fewer intrusions, suggesting a more systematic approach to the task. Findings will be discussed within the context of current theories of memory dysfunction in ASD, including the Task Support Hypothesis.
The results of several previous studies of memory in individuals with Autism Spectrum Disorder (ASD) indicate deficits in relational semantic processing and decreased spontaneous use of mnemonic strategies (Gaigg et al., 2008) relative to individuals without ASD. However, when additional external supports are provided at test, individuals with ASD perform more similarly to their typically developing peers, a finding that led Bowler et al. (1997) to develop the Task Support Hypothesis of memory in ASD. The California Verbal Learning Test (CVLT) is a widely used neuropsychological measure of verbal learning and memory that also evaluates the use of strategies, which are thought to reflect executive functioning. To date, there have been no reported studies using the children's version of the CVLT to examine learning and memory in youth with ASD.
Objectives:
We examined learning and memory, as measured by the California Verbal Learning Test, Children's Edition (CVLT-C), in children and adolescents with high-functioning ASD. We were particularly interested in variables pertaining to learning strategies.
Methods:
Participants included 14 children and adolescents with ASD and 14 controls, matched for age, IQ and gender. Estimated IQ was measured using the Wechsler Abbreviated Scale of Intelligence. The CVLT-C is a list-learning task that involves five repetitions of a list of 15 words that includes 3 categories of items (clothes, toys and fruits). Immediate recall, delayed recall, and recognition of the words are assessed. We compared overall recall (List A Trials 1-5 Total, max score = 75), semantic and serial cluster ratios, recall consistency, total perseverations and total intrusions between ASD and control groups. We also examined relationships between CVLT-C performance and estimated IQ and age.
Results:
The ASD and control groups did not significantly differ on measures of semantic and serial cluster ratios, recall consistency, total perseverations, or total intrusions. There was a near significant difference (p = .07) for overall recall, with the ASD group recalling fewer items in total (mean = 47.2, SD = 10.8) than controls (mean = 55.3, SD = 11.6). In the ASD group, there was a significant positive correlation between estimated IQ and percent recall consistency (r = .79, p < .01) and a significant negative correlation between estimated IQ and total intrusions (r = -.54, p < .05). There were no relationships between IQ and CVLT-C performance for the control group or between age and CVLT-C performance for the ASD group. However, there was a significant negative correlation between age and serial cluster ratio scores for the control group (r = -.64, p < .05).
Conclusions:
Although these results suggest that individuals with ASD experience some overall deficits in learning and memory, there was no evidence of differences in strategy use. Interestingly, within the ASD group, individuals with a higher IQ showed higher recall consistency and fewer intrusions, suggesting a more systematic approach to the task. Findings will be discussed within the context of current theories of memory dysfunction in ASD, including the Task Support Hypothesis.