ABSTRACT
Following our previous cross-sectional analysis, indicating age-related improvements of response inhibition in a random-motor-generation task (MPT) in adolescents with Asperger syndrome (AS), the present study reports data from a 2.5-year follow-up examination in the original sample. We found more marked improvements within the follow-up interval in younger AS children, while older AS boys as well as typically developing (TD) boys remained at a relatively constant level throughout. The current longitudinal study further substantiates the notion that AS children (on average) catch up with TD children when they grow older as regards the basic inhibition of developing routine response patterns.
Subject(s)
Adolescent Development/physiology , Asperger Syndrome/physiopathology , Child Development/physiology , Inhibition, Psychological , Psychomotor Performance/physiology , Adolescent , Age Factors , Child , Humans , Longitudinal Studies , MaleABSTRACT
Deficits in specific executive domains are highly prevalent in autism spectrum disorder; however, age-related improvements in executive functions (reflecting prefrontal maturational changes) have been reported even in individuals diagnosed with autism. The current study examined two components of cognitive flexibility (inhibition of prepotent responses and memory monitoring/updating) by using a random-motor-generation task (MPT) in a group of 23 boys with Asperger syndrome (AS) and 23 matched healthy controls. We found poorer inhibition and more repetitive responses in younger AS children solely, but comparable memory monitoring/updating skills across groups. Overall, our findings correspond well with previous studies and reveal that even in AS specific EFs may improve with age and, thus, call for a more differentiated view of executive (dys) function profiles in children diagnosed with AS. Tests such as the random-motor-generation task may help to disentangle more specific processes of executive deficits in autism spectrum disorder as compared to the more classical tests.
Subject(s)
Aging , Asperger Syndrome/complications , Asperger Syndrome/psychology , Inhibition, Psychological , Memory Disorders/etiology , Adolescent , Age Factors , Attention/physiology , Child , Humans , Male , Neuropsychological TestsABSTRACT
Understanding genetic factors that affect monoamine neurotransmitters flux in prefrontal cortex may help to further specify the complex neurobiological processes that underlie cognitive function and dysfunction in health and illness. The current study examined the associations between the polymorphisms of dopaminergic (COMT Met158Val) and serotoninergic (5-HTTLPR) genes and the sequential pattern of responses in a motor random generation task providing well-established indexes for executive functioning in a large sample of 255 healthy women. Participants homozygous for the Met allele of the COMT polymorphism showed impaired inhibition of prepotent responses, whereas individuals homozygous for the s-allele of the 5-HTTLPR showed a restricted ability to update information in working memory. Taken together the results indicate differentiated influences of dopaminergic and serotonergic genes on important and definite executive sub-processes related to cognitive flexibility.
Subject(s)
Catechol O-Methyltransferase/genetics , Cognition/physiology , Memory/physiology , Polymorphism, Genetic , Serotonin Plasma Membrane Transport Proteins/genetics , Adolescent , Adult , Alleles , Executive Function/physiology , Female , Genotype , Humans , Inhibition, Psychological , Middle Aged , Neuropsychological Tests , Young AdultABSTRACT
Random sequence generation tests have proved to be a useful diagnostic tool for the identification of clinically relevant impairments of executive functions and for the study of cognitive functioning in healthy individuals. The most prevalent variety, random number generation, involves several limitations, however. In the original Mittenecker Pointing Test (MPT; Mittenecker, 1958), subjects were instructed to point successively and as randomly as possible at nine unlabeled circles irregularly arranged on a cardboard. With the computer program presented here, Mittenecker's classical test has been transferred to a contemporary format. The MPT can be applied using a standard PC keyboard and computes a series of sophisticated measures of deviations from randomness on the basis of information theory analysis. Because of its easy and well-controlled administration and reduced demands on memory and attention, the automatized MPT offers a wide range of application possibilities in normal but also in severely impaired clinical samples.
