White matter lesions on magnetic resonance imaging and their relationship with vascular risk factors in memory clinic attenders.

BACKGROUND: The association between white matter lesions on magnetic resonance imaging (MRI) and the presence of vascular risk factors has been investigated in different populations, and results have varied widely. However, this relationship has not been adequately addressed in memory clinic attenders who have relatively early cognitive impairment.

OBJECTIVES: This study was undertaken to determine the relationship between the severity of white matter lesions and vascular risk factors in elderly subjects referred to a Memory Clinic, irrespective of their diagnoses. Patients attending the Memory Clinic had relatively early, mild cognitive impairment and differed, in this respect, from typical unselected community-based samples and from patients with established dementia. The study also investigated whether periventricular and deep white matter lesions differed in their relationship with vascular risk factors.

METHODS: All patients assessed in the Memory Clinic at Leicester General Hospital between April 1998 and October 2000 who had undergone an MRI scan were included in the study. They received a comprehensive clinical and cognitive assessment, a standard dementia laboratory screen and evaluation of vascular risk factors. MRI scans were reviewed by two independent raters and semi-quantitative ratings of the severity of white matter lesions were made using standardised protocols. The relationship between cerebral white matter lesions and vascular risk factor variables was examined by multiple linear regression.

RESULTS: One hundred and seventy-seven subjects were included in the study. The mean age was 69.8 and the mean MMSE score was 23.2. Of the risk factors investigated, only age and prior cerebrovascular disease were significantly associated with severe periventricular white matter lesions; age, hypertension and diabetes were significantly associated with severe deep white matter lesions.

CONCLUSIONS: Periventricular and deep white matter lesions are differentially influenced by vascular risk factors.