Small vessel disease and general cognitive function in nondisabled elderly - The LADIS study

Background and Purpose - On cerebral magnetic resonance imaging (MRI), white matter hyperintensities (WMH) and lacunes are generally viewed as evidence of small vessel disease. The clinical significance of small vessel disease in terms of global cognitive function has as yet not been completely clarified. We investigated the independent contribution of WMH and lacunes to general cognitive function in a group of independently living elderly with varying degrees of small vessel disease. Methods - Data were drawn from the multicenter, multinational Leukokraurosis and Disability (LADIS) study. There were 633 independently living participants. General cognitive function was assessed using the Mini Mental State Examination (MMSE) and the modified Alzheimer Disease Assessment Scale (ADAS). On MRI, WMH was rated as mild, moderate, or severe. Lacunes were rated as none, few (1 to 3), or many (4 or more). Results - In the basic analysis, increasing severity of both WMH and lacunes was related to deteriorating score on the MMSE and ADAS. When WMH and lacunes were entered simultaneously, both MRI measures remained significantly associated with MMSE score. Increasing severity of WMH remained associated with ADAS score, whereas the association with lacunes became less prominent. These associations were independent of other risk factors for dementia, like education, depression, vascular risk factors, or stroke. Conclusion - We found WMH and lacunes to be independently associated with general cognitive function in a sample of independently living elderly. These results highlight the fact that WMH and lacunes should both be evaluated when assessing small vessel disease in relation to cognitive function.