Effects of haloperidol and atypical neuroleptics on psychomotor performance and driving ability in schizophrenic patients - Results from an experimental study

The influence of antipsychotic treatment on the neuropsychological and psychomotor performance of schizophrenic patients is still a subject of investigation. The present study was designed to evaluate the effects of atypical neuroleptics in comparison with a conventional dopamine antagonist neuroleptic (haloperidol) on several dimensions of psychomotor performance (visual perception, attention, reaction time, and sensorimotor performance) considered to be of relevance in evaluating driving fitness. Psychomotor performance was assessed by means of the ART 90, a computerized Act and React Test which is generally used in diagnosis of psychomotor performance. The 49 participating patients were examined at discharge following psychopathological stabilisation; 20 received haloperidol, 29 received an atypical neuroleptic. Our findings demonstrate a remarkably reduced psychomotor performance in the haloperidol-treated group of schizophrenic patients compared with patients treated with atypical neuroleptics. Only 1 (5%) subject passed all subtests without major failures and could be regarded as competent to drive. Among patients with atypical neuroleptics, 7 patients (24%) passed all test parameters without major failures. Copyright (C) 2003 S. Karger AG, Basel

Magnetic relaxation measurements of exchange biased (Pt/Co) multilayers with perpendicular anisotropy

Magnetic relaxation measurements were carried out by magneto-optical Kerr effect on exchange biased (Pt/Co)5/Pt/FeMn multilayers with perpendicular anisotropy. In these films the coercivity and the exchange bias field vary with Pt spacer thickness, and have a maximum for 0.2 nm. Hysteresis loops do not reveal important differences between the reversal for ascending and descending fields. Relaxation measurements were fitted using Fatuzzo's model, which assumes that reversal occurs by domain nucleation and domain wall propagation. For 2 nm thick Pt spacer (no exchange bias) the reversal is dominated by domain wall propagation starting from a few nucleation centers. For 0.2 nm Pt spacer (maximum exchange bias) the reversal is strongly dominated by nucleation, and no differences between the behaviour of the ascending and descending branches can be observed. For 0.4 nm Pt spacer (weaker exchange bias) the nucleation density becomes less important, and the measurements reveal a much stronger density of nucleation centers in the descending branch.Comment: Europhysical Journal B, in print DOI: 10.1140/epjb/e2005-00053-

Effects of haloperidol and atypical neuroleptics on psychomotor performance and driving ability in schizophrenic patients - Results from an experimental study

The influence of antipsychotic treatment on the neuropsychological and psychomotor performance of schizophrenic patients is still a subject of investigation. The present study was designed to evaluate the effects of atypical neuroleptics in comparison with a conventional dopamine antagonist neuroleptic (haloperidol) on several dimensions of psychomotor performance (visual perception, attention, reaction time, and sensorimotor performance) considered to be of relevance in evaluating driving fitness. Psychomotor performance was assessed by means of the ART 90, a computerized Act and React Test which is generally used in diagnosis of psychomotor performance. The 49 participating patients were examined at discharge following psychopathological stabilisation; 20 received haloperidol, 29 received an atypical neuroleptic. Our findings demonstrate a remarkably reduced psychomotor performance in the haloperidol-treated group of schizophrenic patients compared with patients treated with atypical neuroleptics. Only 1 (5%) subject passed all subtests without major failures and could be regarded as competent to drive. Among patients with atypical neuroleptics, 7 patients (24%) passed all test parameters without major failures. Copyright (C) 2003 S. Karger AG, Basel

Optimal use of visual information in adolescents and young adults with developmental coordination disorder

Recent reports offer contrasting views on whether or not the use of online visual control is impaired in individuals with developmental coordination disorder (DCD). This study explored the optimal temporal basis for processing and using visual information in adolescents and young adults with DCD. Participants were 22 adolescents and young adults (12 males and 10 females; M = 19 years, SD = 3). Half had been diagnosed with DCD as children and still performed poorly on the movement assessment battery for children (DCD group; n = 11), and half reported typical development (TD group; n = 11) and were age- and gender-matched with the DCD group. We used performance on a steering task as a measure of information processing and examined the use of advance visual information. The conditions varied the duration of advance visual information: 125, 250, 500, 750, and 1,000 ms. With increased duration of advance visual information, the TD group showed a pattern of linear improvement. For the DCD group, however, the pattern was best described by a U-curve where optimal performance occurred with about 750 ms of advance information. The results suggest that the DCD group has an underlying preference for immediate online processing of visual information. The exact timing for optimal online control may depend crucially on the task, but too much advance information is detrimental to performance

Intact procedural motor sequence learning in developmental coordination disorder

The purpose of the present study was to explore the possibility of a procedural learning deficit among children with developmental coordination disorder (DCD). We tested 34 children aged 6–12 years with and without DCD using the serial reaction time task, in which the standard keyboard was replaced by a touch screen in order to minimize the impact of perceptuomotor coordination difficulties that characterize this disorder. The results showed that children with DCD succeed as well as control children at the procedural sequence learning task. These findings challenge the hypothesis that a procedural learning impairment underlies the difficulties of DCD children in acquiring and automatizing daily activities. We suggest that the previously reported impairment of children with DCD on the serial reaction time task is not due to a sequence learning deficit per se, but rather due to methodological factors such as the response mode used in these studies.Peer reviewe

Functional network centrality indicates interactions between APOE4 and age across the clinical spectrum of Alzheimer's Disease

Advanced age is the most important risk factor for Alzheimer's disease (AD), and carrier-status of the Apolipoprotein E4 (APOE4) allele is the strongest known genetic risk factor. Many studies have consistently shown a link between APOE4 and synaptic dysfunction, possibly reflecting pathologically accelerated biological aging in persons at risk for AD. To test the hypothesis that distinct functional connectivity patterns characterize APOE4 carriers across the clinical spectrum of AD, we investigated 128 resting state functional Magnetic Resonance Imaging (fMRI) datasets from the Alzheimer's Disease Neuroimaging Initiative database (ADNI), representing all disease stages from cognitive normal to clinical dementia. Brain region centralities within functional networks, computed as eigenvector centrality, were tested for multivariate associations with chronological age, APOE4 carrier status and clinical stage (as well as their interactions) by partial least square analysis (PLSC). By PLSC analysis two distinct brain activity patterns could be identified, which reflected interactive effects of age, APOE4 and clinical disease stage. A first component including sensorimotor regions and parietal regions correlated with age and AD clinical stage (p < 0.001). A second component focused on medial-frontal regions and was specifically related to the interaction between age and APOE4 (p = 0.032). Our findings are consistent with earlier reports on altered network connectivity in APOE4 carriers. Results of our study highlight promise of graph-theory based network centrality to identify brain connectivity linked to genetic risk, clinical stage and age. Our data suggest the existence of brain network activity patterns that characterize APOE4 carriers across clinical stages of AD