Association of Cerebral Emboli With Accelerated Cognitive Deterioration in Alzheimer's Disease and Vascular Dementia

Spontaneous cerebral emboli occur frequently in patients with Alzheimer's disease and vascular dementia. The authors investigated the effect of cerebral emboli on cognitive and functional decline in both Alzheimer's disease and vascular dementia patients over a 2-year period.

Cerebral emboli entering the middle cerebral arteries were counted at baseline and every 6 months over the following 18 months using transcranial Doppler ultrasonography in 144 patients with dementia (Alzheimer's disease, N=84; vascular dementia, N=60). Deterioration in cognition was measured every 6 months over 2 years using the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog), the Mini-Mental State Examination (to assess cognition), the Interview for Deterioration in Daily Living Activities in Dementia (to assess function), and the Neuropsychiatric Inventory (to assess behavioral and psychological symptoms). The relationship between cerebral emboli and progression of dementia was analyzed using longitudinal regression modeling, adjusted for age, sex, diagnostic subtype, age at onset of dementia, and significant vascular risk factors.

Spontaneous cerebral emboli were detected in 63 (44%) dementia patients, 36 (43%) Alzheimer's disease patients, and 27 (45%) vascular dementia patients. ADAS-Cog scores revealed faster deterioration in cognitive functioning in patients with cerebral emboli over 2 years, with a mean increase in score of 15.4 in these patients, compared with only 6.0 for those without cerebral emboli. Similarly, Interview for Deterioration in Daily Living Activities in Dementia scores revealed more rapid deterioration in those with cerebral emboli, with a mean increase in score of 59.0 in these patients, compared with 17.9 for those without cerebral emboli. Neuropsychiatric Inventory scores also indicated faster decline in patients with cerebral emboli, with a mean increase in score of 12.0 in these patients, compared with a mean decrease in score of –3.8 for patients in whom no emboli were detected.

Spontaneous cerebral emboli predict more rapid progression of dementia over 2 years in both Alzheimer's disease and vascular dementia. Clinical trials on the inhibition of cerebral emboli in the prevention and treatment of dementia are needed.