Jill M Goldstein — Page 2

PubMed2002

Left hippocampal volume as a vulnerability indicator for schizophrenia: a magnetic resonance imaging morphometric study of nonpsychotic first-degree relatives.

BACKGROUND: Clues to the causes of schizophrenia can be derived from studying first-degree relatives because they are genetically related to an ill family member. Abnormalities observed in nonpsychotic relatives are indicators of possible genetic vulnerability to illness, independent of psychosis. We tested 4 hypotheses: (1) that hippocampal volume is smaller in nonpsychotic relatives than in controls, particularly in the left hemisphere; (2) that hippocampi will be smaller in multiplex relatives as compared with simplex relatives, and both will be smaller than in controls; (3) that hippocampal volumes and verbal declarative memory function will be positively correlated; and (4) that hippocampi will be smaller in patients with schizophrenia than in their nonpsychotic relatives or in controls. METHODS: Subjects were 45 nonpsychotic adult first-degree relatives from families with either 2 people ("multiplex," n = 17) or 1 person ("simplex," n = 28) diagnosed with schizophrenia, 18 schizophrenic relatives, and 48 normal controls. Sixty contiguous 3-mm coronal, T1-weighted 3-dimensional magnetic resonance images of the brain were acquired on a 1.5-T magnet. Volumes of the total cerebrum and the hippocampus were measured. RESULTS: Compared with controls, relatives, particularly from multiplex families, had significantly smaller left hippocampi. Verbal memory and left hippocampal volumes were significantly and positively correlated. Within families, hippocampal volumes did not differ between schizophrenic patients and their nonpsychotic relatives. CONCLUSIONS: Results support the hypothesis that the vulnerability to schizophrenia includes smaller left hippocampi and verbal memory deficits. Findings suggest that smaller left hippocampi and verbal memory deficits are an expression of early neurodevelopmental compromise, reflecting the degree of genetic liability to schizophrenia.

Adult↗

PubMedDate not supplied

Adjustment for whole brain and cranial size in volumetric brain studies: a review of common adjustment factors and statistical methods.

In this article we address analytic challenges inherent in brain volumetrics (i.e., the study of volumes of brains and brain regions). It has sometimes been assumed in the literature that deviations in regional brain size in clinical samples are directly related to maldevelopment or pathogenesis. However, this assumption may be incorrect; such volume differences may, instead, be wholly or partly attributable to individual differences in overall dimension (e.g., for head, brain, or body size). What quantitative approaches can be used to take these factors into account? Here, we provide a review of volumetric and nonvolumetric adjustment factors. We consider three examples of common statistical methods by which one can adjust for the effects of body, head, or brain size on regional volumetric measures: the analysis of covariance, the proportion, and the residual approaches. While the nature of the adjustment will help dictate which method is most appropriate, the choice is context sensitive, guided by numerous considerations-chiefly the experimental hypotheses, but other factors as well (including characteristic features of the disorder and sample size). These issues come into play in logically framing the assessment of putative abnormalities in regional brain volumes.

Analysis of Variance↗