Delirium may double cognitive decline in Alzheimer's

Experiencing an episode of delerium may almost double of the rate of cognitive decline in Alzheimer’s disease (AD) patients, says a study in Neurology. The study of over 400 Alzheimer’s patients, 72 of whom developed delirium and 336 of whom did not, found that among delirium patients the average decline in performance on the Information-Memory-Concentration (IMC) test was from 2.5 points per year before an episode of delirium to 4.9 per year (p=0.001). Across both study groups, the change in IMC score was approximately three times faster in those who had delirium compared to those who had not. Patients with delirium were significantly more likely to have a positive family history of dementia and a shorter duration of dementia-related symptoms prior to diagnosis. The delirium group also showed less cognitive impairment by IMC scores at baseline compared to the nondelirium group. “From a clinical standpoint, this study suggests that over 12 months, patients with AD who become delirious experience the equivalent of an 18-month decline compared to those who do not experience delirium,” the study’s authors said. They said that their research was particularly important because although delirium occurs in up to 89% of patients with Alzheimer’s while they are hospitalised, it is potentially preventable. They suggested that potential changes to the standard care for patients with dementia could include close monitoring for delirium, and, when in high-risk settings, utilisation of delirium-prevention strategies. These could include proactive geriatric consultation, educational interventions targeted towards staff and avoidance of medications with a high risk for delirium. Neurology 2009;72:1570-1575....