Dementia is a rapidly growing socioeconomic and public-health problem that currently affects around 40% of individuals aged 90–95 years. Previous research has shown that damage to axons and neurons in Alzheimer's disease, the most common cause of dementia, begins decades before clinical signs appear.
In their article, Oskar Hansson (Lund University, Sweden) and colleagues explain that Alzheimer's disease is preceded by mild cognitive impairment, but that many patients with mild cognitive impairment can have a stable form. After 4–5 years of follow-up, their analysis revealed that 42% of patients with mild cognitive impairment developed Alzheimer's disease and 15% developed other types of dementia. The relative progression to Alzheimer's disease in patients with mild cognitive impairment was substantially increased in those who had abnormal concentrations of b-amyloid, total tau, and phosphorylated-tau biomarkers in their cerebrospinal fluid at the start of the study. Combination of total tau and beta amyloid identified inicipent Alzheimer's disease in patients with mild cognitive impairment with 95% sensitivity and 83% specificity. Hansson concludes: "If validated in other consecutive studies with long follow-up, these results may have an effect both on the diagnostic work-up and on the design of clinical trials of patients with mild cognitive impairment."
Kaj Blennow, Institute of Clinical Neuroscience, Department of Experimental Neuroscience, Sahlgrenska University Hospital, Mölndal S-431 80 Göteborg, Sweden. T) +46 31 343 1791
The Lancet Neurology