Poster Session P2 - Diagnosis and Disease Progression - Neuroimaging

Monday, July 19, 2004

Abstract: P2-208

Citation: NeuroBiology of Aging, Volume 25, Number S2 , July 2004, Page 289


Corpus Callosum Atrophy in a Mixed Elderly Population

Charlotte Ryberg1, Egill Rostrup1, Ellen Garde1, Anne Mette Hejl2, Anne Mette Leffers1, Gunhild Waldemar2

On behalf of the LADIS group, University of Florence, Florence, Italy; 1 Danish Research Center for Magnetic Resonance, Copenhagen University Hospital, Hvidovre, Denmark; 2 Memory Disorders Research Unit, Dept. of Neurology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark. Contact e-mail: ryberg@magnet.drcmr.dk

Background: Corpus Callosum (CC) pathways communicates cognitive and learned information between the two hemispheres. Effects on regional callosal structure has been reported in Alzheimer's Disease and multiple sclerosis and suggest that CC tissue loss may be a marker for early phase degenerative disease. To evaluate this hypothesis we investigated the relationship between CC size and the severity of white matter hyperintensities (WMH) and degree of cognitive impairment, in a mixed population of non-demented elderly subjects with WMH. Methods: Sixty-two subjects (34/32 F/M, mean age = 74.7 years, range 65-84 years) participated in the Danish cohort of a European longitudinal study on ``Leukoaraiosis And DISability'' (LADIS). Subjects were recruited from an outpatient memory clinic and from a population of healthy elderly and had no or minor disability (ADL). For all subjects high-resolution 3D sagittal MPRAGE of the whole head was acquired on a 1,5 T Vision Siemens scanner. CC cross-sectional area was manually delineated on the midsagittal slice. Subsequently, the CC cross-section was automatically subdivided into 5 regions (rostrum and genu, rostral body, midbody, isthmus and splenium) in an antero-posterior direction. The severity of WMH were categorized according to Fazekas scale in mild, moderate or severe WMH. Cognitive impairment was assessed with the Mini-Mental State Examination (MMSE). Results: Mean MMSE was 28.2 (range 22-30). The mean total CC area was 518.6 mm2 (range 293.8-779.5; ICV-normalized values). Smaller CC area correlated significantly (Spearman) with lower MMSE (CCtotal p < 0.039; Rostral body p < 0.001; Midbody p < 0.006; Isthmus p < 0.041) and increased WMH load (Rostral body p < 0.006; Midbody p < 0.032). We also found a significantly higher WMH load (p < 0.002) and lower MMSE score (p < 0.045) with increasing age. However when we corrected for age the only significant correlations were those between MMSE and Rostral body (F 5.447; p = 0.023), and between MMSE and Midbody (F 2.034; p = 0.047). Conclusion: Loss of CC tissue correlates significantly with impaired cognitive function and with increased WMH load as well as age.