White matter abnormalities in mobility-impaired older persons

Objective: To investigate the relationship between white matter abnormaliti es and impairment of gait and balance in older persons. Methods: Quantitati ve MRI was used to evaluate the brain tissue compartments of 28 older indiv iduals separated into normal and impaired groups on the basis of mobility p erformance testing using the Short Physical Performance Battery. In additio n, individuals were tested on six indices of gait and balance. For imaging data, segmentation of intracranial volume into four tissue classes was perf ormed using template-driven segmentation, in which signal-intensity-based s tatistical tissue classification is refined using a digital brain atlas as anatomic template. Results: Both decreased white matter volume, which was a ge-related, and increased white matter signal abnormalities, which were not age-related, were observed in the mobility-impaired group compared with th e control subjects. The average volume of white matter signal abnormalities for impaired individuals was nearly double that of control subjects. Concl usions: This cross-sectional study suggests that decreased white matter vol ume is age-related, whereas increased white matter signal abnormalities are most likely to occur as a result of disease. Both of these changes are ind ependently associated with impaired mobility in older persons and therefore likely to be additive factors of motor disability.