Relation of cerebral infarctions to dementia and cognitive function in older persons.

BACKGROUND: Cerebral infarctions are common in older persons but their relationship with dementia and cognitive function remains controversial.
METHODS: Participants were 164 older Catholic nuns, priests, and brothers who underwent annual clinical evaluation and brain autopsy at death. The authors quantified number and volume of old cerebral infarctions on postmortem examination and determined the association with dementia and cognitive function proximate to death. Analyses controlled for age, sex, and education.
RESULTS: A total of 58 (35.4%) subjects had cerebral infarctions: 29 had one infarction and 29 had multiple infarctions. In logistic regression analyses, infarctions increased the odds of dementia twofold (OR 2.12; 95% CI 1.06 to 4.25). The odds of dementia increased by 2.67-fold for multiple infarctions (95% CI 1.08 to 6.61), whereas the odds of dementia with single infarctions increased by 69% (95% CI 0.70 to 4.09). In linear regression analyses, there was a trend for multiple infarctions to be associated with lower global cognitive scores (-0.44 standard units, p = 0.057). Multiple infarctions were related to perceptual speed, visuospatial skills, and working memory, but not to episodic or semantic memory. The authors found similar results with infarction volume. In secondary analyses, only infarctions that were clinically evident during life were associated with dementia and cognitive function.
CONCLUSION: Cerebral infarctions are associated with a twofold increase in odds of dementia. Odds are higher in persons with multiple, large, or clinically evident infarctions. In addition, cerebral infarctions do not affect all cognitive systems equally, showing the strongest association with perceptual speed and the weakest with episodic memory.