Diffusion Tensor Imaging, White Matter Lesions, the Corpus Callosum, and Gait in the Elderly

Abstract

Background and Purpose-Gait impairment is common in the elderly, especially those with stroke and white matter hyperintensities on conventional brain MRI. Diffusion tensor imaging (DTI) is more sensitive to white matter damage than conventional MRI. The relationship between DTI measures and gait has not been previously evaluated. Our purpose was to investigate the relationship between the integrity of white matter in the corpus callosum as determined by DTI and quantitative measures of gait in the elderly. Methods-One hundred seventy-three participants of a community-dwelling elderly cohort had neurological and neuropsychological examinations and brain MRI. Gait function was measured by Tinetti gait (0 to 12), balance (0 to 16) and total (0 to 28) scores. DTI assessed fractional anisotropy in the genu and splenium of the corpus callosum. Conventional MRI was used to evaluate for brain infarcts and white matter hyperintensity volume. Results-Participants with abnormal gait had low fractional anisotropy in the genu of the corpus callosum but not the splenium. Multiple regressions analyses showed an independent association between these genu abnormalities and all 3 Tinetti scores (PϽ0.001). This association remained significant after adding MRI infarcts and white matter hyperintensity volume to the analysis. Conclusions-The

Heterogeneity in age-related white matter changes

“…There existed a significant association between white matter lesion load and severity of DTI and MTR measures in the normalappearing white matter with the microstructural changes in normal brain tissue being more closely related to the patients' clinical presentation than the volume of visible white matter abnormalities [9,32,52,61,69,70,74,92,93]. These observations clearly indicate that age-related small vessel disease of the brain is a diffuse process affecting the entire brain and that white matter lesions are probably only the tip of the iceberg.…”

Altered visual–spatial attention to task-irrelevant information is associated with falls risk in older adults

“…The corpus callosum is a dense bundle of neural fibres that connects the two cerebral hemispheres of the brain. Previous studies have reported a critical link between white matter integrity in the corpus callosum and both cognitive and mobility measures (e.g., Bhadelia et al, 2009;Frederiksen et al, 2011;Moscufo et al, 2011;Moscufo et al, 2012;Ryberg et al, 2011;Ryberg et al, 2007). Of particular relevance, atrophy in the splenium -a posterior region of the corpus callosum -appears to be most associated with reduced general mobility (e.g., Frederiksen et al, 2011;Moscufo et al, 2011;Moscufo et al, 2012) as measured by the Short Physical Performance Battery (SPPB) (Guralnik, Ferrucci, Simonsick, Salive, & Wallace, 1995).…”

Lower Magnetization Transfer Ratio in the Forceps Minor Is Associated with Poorer Gait Velocity in Older Adults

“…14,19,24 The only MTR study in healthy, older adults described a relationship between wholebrain MTR and gait velocity. 23 The authors of this investigation quantified MTR changes globally by using histogram-based metrics.…”

“…This hypothesis is supported by 2 DTI studies that reported the higher mean diffusivity and lower fractional anisotropy in the genu of the corpus callosum to be correlated with poorer gait performance independent of visible WMHs. 14,19 Complementary information on microstructural brain tissue alterations may come from magnetization transfer imaging (MTI). Other than DTI, which offers information on brain tissue organization, 20 MTI offers information on tissue composition.…”