Comparison of methods for measuring longitudinal brain change in cognitive impairment and dementia

PURPOSE: The goal of this project was to compare MRI measures of hippocampal, entorhinal cortex (ERC), and whole brain longitudinal change in cognitively normal elderly controls (C), non-demented subjects with cognitive impairment (CI), and demented (D) subjects. METHODS: 16 C, 6 CI, and 7 D subjects of comparable age were studied with MRI twice, at least 1 year apart. Longitudinal change in total brain size was measured by several methods, including computerized segmentation, non-linear warping, and change in the fluid/tissue boundaries between cerebrospinal fluid (CSF) and brain. Change in hippocampal volume was measured by semi-automated methods, and ERC volumes were manually measured. RESULTS: The annual rate of atrophy was greater in D versus C and D versus CI for cortical gray matter (cGM) (P=0.009 and 0.002), hippocampus (P=0.0001 and 0.002), and for the change in the fluid/tissue boundary (P=0.03 and 0.03). The annual rate of atrophy of ERC was greater in both CI and D versus C (P=0.01 and 0.0002). No significant differences between groups were found using non-linear warping. CONCLUSIONS: In CI, the greatest annual rates of atrophy were in ERC, while in D the greatest annual rates of atrophy were in hippocampus and cortex. Progressive ERC atrophy was observed with a greater degree of cognitive impairment, while hippocampal and cortical atrophy were only observed in demented subjects.     

Participants in phase 1 oncology research trials: are they vulnerable?

Phase 1 oncology trials involve risk and offer a relatively low prospect of benefit to participants. Some claim that participants constitute a vulnerable population requiring special protections. We undertook this study to determine whether phase 1 oncology trial participants have demographic and health status characteristics of a vulnerable population. We reviewed participant demographic and health status data from phase 1 trials sponsored by the Cancer Therapy Evaluation Program at the National Cancer Institute that began between 1991 and 2002 and from 11 previously published studies. Main outcome measures were median age, sex, race/ethnicity, performance status, previous therapy, educational achievement level, and health insurance coverage. Almost 10 000 participants in trials sponsored by the Cancer Therapy Evaluation Program had a median age of 57 years, 90% self-identified as white, 93% had near-normal performance status, 85% had some form of health insurance, and 92% had been previously treated for cancer; 20 000 individuals from published studies had comparable profiles. The demographic and health status characteristics of phase 1 oncology trial participants are not those of a conventional vulnerable population and suggest little reason to assume that, as a group, they have a compromised ability to understand information or to make informed and voluntary decisions.