Association between cognitive performance and striatal dopamine binding is higher in timing and motor tasks in patients with schizophrenia.

The basal ganglia have received increasing attention with regard to their role in time pacing, motor function and other components of cognition. The aim of this study was to test whether the finer the motor activity and/or time perception performance were, the higher the striatal dopamine D(2) binding would be. Single photon emission computed tomography (SPECT) with [(123)I]iodobenzamide (IBZM) was performed to measure striatal D(2) receptor densities. A battery of neuropsychological tests, including the Wisconsin Card Sorting Test (WCST), the finger tapping test (FTT), and an attention test, was performed by patients with schizophrenia. Results indicated a strong correlation between the FTT score and striatal D(2) receptor binding. Neuroleptic dosage plays an important role in the relationship between cognitive tasks and striatal dopamine receptor densities. In addition, the striatal D(2) receptor density is more significantly correlated with attentional tests that consider the time effect than those that do not. Among the three tests performed, the WCST was least significantly correlated with striatal D(2) receptor densities. A decrease in striatal dopamine D(2) receptor density seems to be associated with impaired performance on optimal timing tasks and motor processing in patients with schizophrenia.

Eye-hand preference in schizophrenia: sex differences and significance for hand function.

Hand preference and eye dominance were investigated in 73 (30 women, 43 men) schizophrenic patients and 71 (30 women, 41 men) healthy controls. There were significantly more schizophrenic patients and normal controls who were significantly right-hand dominant. However, schizophrenic patients showed a significant excess of left-eye dominance relative to controls (65.8% vs 29.6%; Odds Ratio= 4.75, p< .001). In addition, female schizophrenic patients showed a higher rate of nonright (either left or inconsistent) eye dominance (80%) than male schizophrenic patients (55.8%) and controls (33.3%). Analysis of hand performance on the Purdue Pegboard Test indicated that schizophrenic patients who showed crossed eye-hand dominance scored higher than did patients without crossed eye-hand dominance.

Common features of fluency-evoking conditions studied in stuttering subjects and controls: an H(2)15O PET study.

UNLABELLED: We used H(2)15O PET to characterize the common features of two successful but markedly different fluency-evoking conditions -- paced speech and singing -- in order to identify brain mechanisms that enable fluent speech in people who stutter. To do so, we compared responses under fluency-evoking conditions with responses elicited by tasks that typically elicit dysfluent speech (quantifying the degree of stuttering and using this measure as a confounding covariate in our analyses). We evaluated task-related activations in both stuttering subjects and age- and gender-matched controls. Areas that were either uniquely activated during fluency-evoking conditions, or in which the magnitude of activation was significantly greater during fluency-evoking than dysfluency-evoking tasks included auditory association areas that process speech and voice and motor regions related to control of the larynx and oral articulators. This suggests that a common fluency-evoking mechanism might relate to more effective coupling of auditory and motor systems -- that is, more efficient self-monitoring, allowing motor areas to more effectively modify speech. These effects were seen in both PWS and controls, suggesting that they are due to the sensorimotor or cognitive demands of the fluency-evoking tasks themselves. While responses seen in both groups were bilateral, however, the fluency-evoking tasks elicited more robust activation of auditory and motor regions within the left hemisphere of stuttering subjects, suggesting a role for the left hemisphere in compensatory processes that enable fluency. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to: (1) compare brain activation patterns under fluency- and dysfluency-evoking conditions in stuttering and control subjects; (2) appraise the common features, both central and peripheral, of fluency-evoking conditions; and (3) discuss ways in which neuroimaging methods can be used to understand the pathophysiology of stuttering.

Psychiatric morbidity and posttraumatic symptoms among earthquake victims in primary care clinics.

Three months after the devastating Chi-Chi earthquake (magnitude of 7.3 on the Richter scale) struck the central area of Taiwan, 663 victims were screened for psychiatric morbidity at a local general hospital in a community mental health program. The rate of psychiatric morbidity as defined by the 12-item Chinese Health Questionnaire as greater than 4, was 24.5%. Posttraumatic symptoms were still prevalent. The rate of posttraumatic stress disorder was 11.3%, and the rate of partial PTSD was 32.0%. Variables associated with the presence of psychiatric morbidity and posttraumatic symptoms included female gender, old age, financial loss, obsessive trait, and nervous trait. A disproportionate use of mental health services (18%) was found, suggesting an urgent need to deliver mental health care to disaster victims at local medical settings. In addition, health care professionals who work with the earthquake victims need to be promptly and efficiently trained in mental health crisis intervention.

Association between regional cerebral blood flow and eye-tracking performance and the Wisconsin Card Sorting Test in schizophrenics: a single photon emission computed tomography study.

The objectives of this study were (1). to examine the changes in regional cerebral blood flow (rCBF) during Wisconsin Card Sorting Test (WCST) performance in two different eye-tracking groups; (2). to explore the relationship between eye-tracking movement and rCBF at rest; and (3). to estimate the association between WCST performance and rCBF in patients with schizophrenia. A total of 17 patients with schizophrenia were recruited. SPECT with Tc-99m HMPAO (Tc-99m hexamethylpropyleneamine oxime) was carried out while patients were performing the WCST and resting. Brodmann area 9 of the prefrontal cortex, a part of the dorsal lateral prefrontal cortex (DLPFC), was less activated during performance of the WCST in poor trackers (relative to good trackers). The eye pursuit tracking error measure in schizophrenic patients was negatively associated with decreases in rCBF in the middle temporal area, superior parietal lobule, thalami, and caudate nuclei. The rCBF increased significantly in the superior temporal gyri, inferior parietal lobe, and some frontal regions during WCST performance; however, this was not the case in the DLPFC. Additionally, significant correlations were found between WCST scores and rCBF during WCST performance in the prefrontal lobes, and in thalamic and cerebellar regions. Our findings suggest that the rCBF changes during WCST performance may be distinctive in different eye-tracking groups. Our results confirm the hypothesis that the middle temporal area, superior parietal lobule, thalami, and caudate nuclei-mainly parts of the oculomotor circuit-are involved in eye pursuit tracking. Surprisingly, no significant association was found in the frontal eye field. Although the frontal lobe plays a significant role in WCST performance, our findings demonstrate that WCST performance is widely involved with other regions in patients with schizophrenia.