Arising from: Whitehouse PJ (2007) Nat Clin Pract Neurol 3: 62–63 doi:10.1038/ncpneuro0403

Arising from: Petersen RC (2007) Nat Clin Pract Neurol 3: 60–61 doi:10.1038/ncpneuro0402

The two Viewpoints presented in this month's issue of Nature Clinical Practice Neurology reflect the current divide in the field of mild cognitive impairment (MCI). Some researchers and clinicians are more supportive of the concept than others, but while research is ongoing, these contradictory opinions will persist. Peter Whitehouse claims that the term MCI confuses patients and families, yet Ronald Petersen believes that patients are appreciative of the fact that this is a useful construct. As with other debates concerning MCI, there is not yet sufficient evidence in the literature to strongly support either view. We should be cautious not to disregard the continuing debates and discussions that facilitate progression in the field. Peter Whitehouse insinuates that many conferences are supported by industry dollars, although this is not always the case. For example, the First Key Symposium on Mild Cognitive Impairment in Stockholm1 was financed entirely from academic sources. The intention of this symposium was to provide the opportunity to conduct a consensus conference without the influence of the pharmaceutical industry. The consensus group included a dynamic and international mix of both clinicians and researchers, from geriatrics, neurology, genetics, neuropsychology, as well as those working on biomarkers and neuroimaging. Discussion was focused both on evidence from previous research and on defining new perspectives. In fact, the consensus paper contained recommendations suggesting that research should focus on the same things that Peter Whitehouse raises in his Viewpoint, namely the need for establishing and proposing tools for identifying cognitive impairment, and the need for clearly defining norms.

Although Peter Whitehouse raises pertinent questions for debate within the field, his negative commentary should not distract from our goal, which is to find an early marker of Alzheimer's disease before it has developed into a full dementia syndrome. In fact, there are numerous points on which clinicians and researchers have already reached a general level of convergent agreement.2 We do not disagree that there are limitations to the concept and construct of MCI, but it is important not to dismiss a decade of research that has led to considerable progress in our knowledge on the evolution of Alzheimer's disease.