Alzheimer's disease (AD) is a representative neurodegenerative disorder associated with memory disturbance. Recent research has shown that risk factors for cerebrovascular disorders are also causes of dementia. Of these risk factors, hyperhomocysteinemia is well known to be positively correlated with all types of dementias including AD. But it is not clear if there is a difference in the concentration of homocysteine according to subtypes of memory impairment of AD. We performed this study to explore the relationship between homocysteine and memory.

A total of 54 patients (male: 15 patients) to the dementia clinic at our hospital were recruited for this study. All subjects underwent neuropsychological tests including detailed memory function tests and brain magnetic resonance images. The plasma homocysteine level was measured routinely in all patients.

Verbal and visual memories in AD were significantly associated with the concentration of plasma homocysteine. The plasma homocysteine level was significantly correlated with delayed recalls of verbal and visual memories and recognition of visual memory. However, there was no relationship between plasma homocysteine and working memory.

This study showed that plasma homocysteine level was related to the consolidation and retrieval stage of memory in AD. Therefore, we cautiously assumed that control of plasma homocysteine level could contribute to management for the prevention of cognitive impairment.