Neural disorganization in the superior cerebellar peduncle and cognitive abnormality in patients with schizophrenia: A diffusion tensor imaging study.

Disconnection in the frontal-thalamic-cerebellar circuit is thought to be associated with cognitive abnormality in patients with schizophrenia. The superior cerebellar peduncle is involved in neural connectivity in the circuit. Because diffusion tensor imaging (DTI) can detect neural disconnection, we investigated whether there was neural disruption in the superior cerebellar peduncle in patients with schizophrenia. DTI was performed in 21 schizophrenic subjects and 21 age- and sex-matched healthy subjects. Cognitive cluster scores were attained by using the Positive and Negative Syndrome Scale (PANSS). Schizophrenic subjects had significantly lower fractional anisotropy (FA) in the right and left superior cerebellar peduncles than healthy subjects. Higher FA in the left superior cerebellar peduncle was associated with worse cognitive function in patients with schizophrenia. These findings suggest that there is neural disruption in the superior cerebellar peduncle in patients with schizophrenia, which may be involved in the cognitive abnormalities found in schizophrenia.

Reduced white matter volume of the caudate nucleus in patients with schizophrenia.

To examine volumetric abnormality, the caudate nucleus was measured in patients with schizophrenia and healthy subjects using magnetic resonance imaging. The absolute and relative volumes of white matter in the caudate nucleus were found to be significantly smaller in patients with schizophrenia compared to those in healthy subjects. There were significant correlations between dosages of neuroleptics during the previous year and absolute gray matter volumes of the caudate nucleus as well as relative white matter volumes in patients with schizophrenia. These findings suggest that reduced white matter volume of the caudate nucleus may be a factor affecting the abnormal connectivity of the corticostriatal loop, and that neuroleptic medication would be related to white matter alteration in patients with schizophrenia. Our result replicates a previous study reporting that there is a lack of negative correlation between age and caudate nucleus volume. We also suggest that the disease process of schizophrenia might interfere with normal aging.

Subtle disruption of the middle cerebellar peduncles in patients with schizophrenia.

Diffusion tensor imaging (DTI) was used to investigate subtle disruption in the middle cerebellar peduncles in patients with schizophrenia. Fractional anisotropy (FA) was measured in 25 patients with schizophrenia and 21 healthy subjects using DTI. The FA of the right and left middle cerebellar peduncles was significantly lower in the schizophrenic patients compared to healthy subjects. FA in the left middle cerebellar peduncles was significantly correlated with the dosage of neuroleptics in patients with schizophrenia. There were no significant differences of mean diffusivity in the right and left middle cerebellar peduncles between patients with schizophrenia and healthy subjects. The findings of the study suggest that antipsychotics may improve the subtle disruption in the middle cerebellar peduncles in patients with schizophrenia.

Global approach to multichannel electroencephalogram analysis for diagnosis and clinical evaluation in mild Alzheimer's disease.

To establish an early diagnosis of Alzheimer's disease (AD), we evaluated brain spatial dynamics and cognitive function in mild AD. Seventeen patients with the diagnosis of mild AD and 17 age-matched controls were examined for Omega (global complexity), Sigma (total power) and Phi (generalized frequency) by 19-channel electroencephalography (EEG). As a result, the mild AD group showed significantly higher Omega values than the control group. The Phi values were highly correlated with the Mini-Mental State Examination scores and the full IQ and performance IQ scores of the Japanese Wechsler Adult Intelligence Scale Revised. These results indicate an increase in spatial complexity of the brain electric field in mild AD, as well as a close relationship between slowing of the global frequency of field changes and the cognitive decline in mild AD.

Inter- and intraoperator reliability of brain tissue measures using magnetic resonance imaging.

Grey matter, white matter and cerebrospinal volume in the human brain were measured using magnetic resonance image analysis software BRAINS. Ten volunteers were scanned in the MR sequence (3D-SPGR; 1.5-mm slice thickness and T2 images; 3mm slice thickness). Two operators obtained ten volume measures of grey matter,white matter and cerebrospinal fluid (CSF) in the intracranial box, frontal box, temporal box, parietal box and occipital box. The same data set of ten scans was segmented and the volumes measured on a second occasion by one operator using the same procedure. The interoperator and intraoperator reliabilities for measures of the three brain tissues were very good, with reliability coefficients (intraclass correlation coefficients) ranging between 0.971 and 0.999. The segmentation and measurement are useful for volumetric studies in the human brain using BRAINS.