New revised criteria could mean that a considerable number of patients currently diagnosed with mild or very mild Alzheimer’s, might in fact be reclassified as having MCI (mild cognitive impairment), John C. Morris, M.D., of Washington University School of Medicine in St. Louis, wrote in Archives of Neurology.
The Alzheimer’s Association, along with the NIA (National Institute of Aging) revised the criteria for MCI after convening a work group. The new criteria have considerably widened the meaning of functional independence, Dr. Morris explained. Mild problems are now permissible for an MCI diagnosis, such as some daily chores and activities, which may include paying bills, cooking and shopping. Needing assistance or aids to perform such tasks are also permissible in the criteria for an MCI diagnosis.
Morris evaluated the functional ratings of 17,535 individuals who had been enrolled at federally funded Alzheimer’s Disease Centers – their clinical and cognitive data were stored at the National Alzheimer’s Coordination Center. They had been diagnosed with either Alzheimer’s disease, MCI or normal cognition. Their average age was 74.6 years.
According to the study, 92.7% of those who had been diagnosed with mild Alzheimer’s, and 99.8% of those diagnosed with very mild Alzheimer’s disease dementia could be reclassified as having MCI, according to the revised criteria.
Before the criteria revision, MCI differed from AD (Alzheimer’s disease) in that several factors which disrupted activities of daily living would point towards a diagnosis of AD. The author explains that the new criteria now “obscures this distinction”.
Morris commented:
“The elimination of the functional boundary between MCI and AD dementia means that their distinction will be based solely on the individual judgment of clinicians, resulting in nonstandard and ultimately arbitrary diagnostic approaches to MCI.
This recalibration of MCI moves its focus away from the earliest stages of cognitive decline, confounds clinical trials of individuals with MCI where progression to AD dementia is an outcome, and complicates diagnostic decisions and research comparisons with legacy data.”
Morris suggests that the new MCI criteria “laudably recommend” an origins (etiologic) diagnosis “MCI due to AD”, when the doctor feels that the AD causes the patient’s cognitive dysfunction.
Morris concluded:
“The diagnostic overlap for MCI with milder cases of AD dementia is considerable and suggests that any distinction is artificial and arbitrary. Already, many individuals with MCI are treated with pharmacological agents approved for symptomatic AD, indicating that clinicians often do not distinguish the two conditions when faced with issues of medical management.
It now is time to advance AD patient care and research by accepting that ‘MCI due to AD’ is more appropriately recognized as the earliest symptomatic stage of AD.”
Written by Christian Nordqvist