Flexibility in children with autism spectrum disorders (ASD): inconsistency between neuropsychological tests and parent-based rating scales.

In this study, we compared neuropsychological tests and parent-based ratings of flexibility in a sample of children with autism spectrum disorders (ASD). We investigated the discriminant validity of the domain-specific flexibility measures by comparison with the domain general measures, general behavioral problems, general ASD-related traits, and general intelligence. Tests and parent-based ratings of flexibility were not significantly correlated. Parent-based ratings were strongly related with the three broadband measures, whereas the discriminant validity indices of the neuropsychological tests were satisfactory. These findings suggest that parent-based ratings do not reflect the specific executive construct of flexibility, but instead reflect a broad spectrum of general child characteristics.

Striatal dopamine and learning strategy-an (123)I-FP-CIT SPECT study.

UNLABELLED: Patients with Parkinson's disease (PD) have difficulty in processing learning tasks that lack external guidelines and, consequently, necessitate the subjects to generate their own problem-solving strategy. While the contribution of striatal dopaminergic deficiency to PD-specific motor symptoms is well established, its role in the PD-characteristic deviant learning style remains unclear. The aim of this study was to assess the relation between striatal dopamine activity as revealed by single photon emission computed tomography (SPECT) with (123)I-FP-CIT, a ligand for the dopamine transporter (DaT), and type of learning strategy, as identified by the California Verbal Learning Task (CVLT) in 19 patients with probable PD. The results showed a robust inverse correlation between striatal dopamine DaT binding and the externally guided, serial learning strategy: the lower the DaT in caudate nucleus as well as in putamen, the more the patient group appeared to rely on externally structured learning. Additionally, a significant positive correlation was found between caudatal DaT activity and the internally generated, semantic learning strategy. Unlike these strategic learning characteristics, IQ equivalent and recall total score appeared to vary independently from striatal DaT availability. CONCLUSION: our findings provide direct evidence that striatal dopaminergic activity is specifically involved in the regulation of strategic learning processes.

Central coherence and cognitive shifting in relation to social improvement in high-functioning young adults with autism.

The objective of this prospective study was to evaluate the possible role of two cognitive styles--weak central coherence and poor cognitive shifting--in predicting social improvement in patients with autistic disorder. Thirty patients, largely similar in age (young adults), intelligence (high-functioning) and living conditions (residential treatment in the same unit) were assessed at two separate time points with a 3-year interval between pretest and posttest. At pretest central coherence, cognitive shifting and several aspects of social functioning--symptom severity, social intelligence and social competence--were measured. At posttest social functioning was reassessed. Unlike central coherence, cognitive shifting was identified as a significant prognostic marker. This differential outcome might be an indication that patients with poor cognitive shifting and patients with weak central coherence have different prognoses with the current, highly structured treatment milieu; it is unknown whether patients with poor cognitive flexibility might benefit more from treatments specifically designed to address this problem.

Perseveration in schizophrenia: failure to generate a plan and relationship with the psychomotor poverty subsyndrome.

Although perseveration in the Wisconsin Card Sorting Test (WCST) has been studied extensively in schizophrenia, the underlying cognitive dysfunctions are not yet clear. In schizophrenia, perseveration has been found to relate to frontal and striatal abnormalities. Therefore, both a failure to generate a plan as seen in patients with frontal abnormalities, or a failure to execute a plan as observed in Parkinson patients, who suffer primarily from striatal abnormalities, could explain perseveration in schizophrenia. The aim of the present study was to distinguish between these two cognitive dysfunctions, which are described by Frith in his routes-to-action model. The main difference between these dysfunctions is the ability to use external guidance. In the present study, 39 schizophrenic patients and 36 healthy controls were assessed with the California Verbal Learning Test (CVLT) and the WCST, in which use of external guidance can be measured, and with the Positive and Negative Syndrome Scale (PANSS) to determine the relationship with symptomatology. The results showed that half of the schizophrenic patients showed perseveration, which could be explained by a failure to generate a plan and was related to the psychomotor poverty subsyndrome. No evidence was found for a failure to execute a plan. Type of antipsychotic medication used (atypical vs. typical) proved not relevant. The results are discussed in the light of evidence for involvement of the dorsolateral prefrontal cortex in perseveration in schizophrenia.