Verbal memory deficits associated with fornix atrophy in carbon monoxide poisoning.

Magnetic resonance (MR) images and neuropsychological testing data of 69 carbon monoxide (CO) poisoned patients were prospectively obtained within 1 day of CO poisoning, two weeks and six months. CO patients' Day 1 cross-sectional fornix surface area measurements, corrected for head size by using a fornix-to-brain ratio (FBR), were compared to normal age and gender-matched controls. Additionally, a within-subjects analysis was performed comparing the mean areas between CO patients' Day 1, 2 weeks and 6-month FBR. The FBR was correlated with patients' neuropsychological data. There were no significant differences between CO patients' Day 1 fornix measurements compared to normal control subjects. However, significant atrophic changes in the fornix of CO poisoned patients occurred at two weeks with no progressive atrophy at 6 months. By 6 months, CO patients showed significant decline on tests of verbal memory (when practice effects were taken into account), whereas visual memory, processing speed and attention/concentration did not decline. This study indicates that CO results in brain damage and cognitive impairments in the absence of lesions and other neuroanatomic markers.

SPECT, MR and quantitative MR imaging: correlates with neuropsychological and psychological outcome in traumatic brain injury.

This study examined the relative effectiveness of magnetic resonance (MR) imaging, single photon emission tomography (SPECT) and quantitative magnetic resonance (QMR) imaging in detecting brain abnormalities in 52 traumatically brain injured patients. The relationship between brain abnormalities and neuropsychological and psychological testing results was also investigated. Sixty-two per cent of patients had abnormal clinical MR findings, 57% had abnormal SPECT and 51% had abnormal QMR. Each neuroimaging modality detected brain abnormalities that the other two did not. Neuropsychological and psychological testing indicated significant memory impairments and subjective emotional distress even several years post-injury. Memory and intellectual impairments modestly but significantly correlated with the number of brain abnormalities indicated by all three imaging studies combined, as well as those detected individually by QMR and MR. SPECT abnormalities alone were not correlated with intellectual and memory outcome. Psychological distress was also related to the number of MR abnormalities, with most brain abnormalities being in the frontal areas.