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Lisa D Newton

Publications and source records attributed to Lisa D Newton.

2 recordsLinked to original sources
PubMed2006

Increased cerebellar vermis white-matter volume in men with schizophrenia.

We aimed to investigate cerebellar structural abnormalities and their functional significance in patients with schizophrenia. Forty right-handed men with schizophrenia and 40 sex, age and handedness matched controls underwent a volumetric magnetic resonance scan with 1 mm3 isotropic spatial resolution. Cerebellar grey- and white-matter volumes were analysed using voxel-based morphometry. Patients with schizophrenia completed a battery of neuropsychological tests assessing sustained attention (continuous performance test), memory (Hopkins memory test) and executive function (verbal fluency and Wisconsin card sorting tests). Patients with schizophrenia exhibited significantly increased cerebellar vermis white-matter volume compared with controls. By contrast, total cerebellar volume, and grey- and white-matter volumes of cerebellar hemispheres were not significantly different between groups. Increased vermis white-matter volume in patients was associated with poor verbal fluency performance. We concluded that increased white-matter in the cerebellar vermis, possibly suggesting anomalous connectivity, may be associated with verbal executive dysfunction in men with chronic schizophrenia.

Adult↗
PubMed2006

A new dissimilarity measure for finding semantic structure in category fluency data with implications for understanding memory organization in schizophrenia.

The ordering of words in category fluency lists is indicative of the semantic distance between items in conceptual memory. Several studies have concluded from structural analyses of such data, using cluster analysis or multidimensional scaling, that the semantic memory of patients with schizophrenia is more disorganized than that of controls. Previous studies have based their analyses on a measure of average interitem dissimilarity devised by A. S. Chan et al. (1993). Here the authors derive a new and improved method of determining dissimilarity and show that when this measure is applied to the fluency lists of patients with schizophrenia, the average pattern of organization for the animal category has similar structure to that of controls, but with greater variability between individuals.

Adult↗