I love this new study* from my Washington University colleague, political science professor Matthew Gabel. He studied whether groups could do a better job of diagnosing Alzheimer’s than solitary experts. Alzheimer’s is difficult to diagnose, because there is no clear and unambiguous biomarker, like a blood test. Usually, the physician makes a subjective diagnosis, after interviewing family members and doing a few memory tests with the patient, but these diagnoses can be incorrect.
The researchers used a database of 45 deceased patients, who had brain autopsies that could prove definitively whether or not the patient actually had Alzheimer’s. From the same database, the task was to diagnose based on clinical information and PET scans, from long before, when it wasn’t yet clear whether the patient had Alzheimer’s or some other disorder such as frontotemporal dementia (which requires different treatment).
Gabel and his colleagues compared the diagnosis of an individual expert with that of a panel of six experts, and also with a panel of six trainees. The six experts (or trainees) worked together using the modified Delphi method, as follows: First, each person analyzes the data alone and generates their own diagnosis; these six individual diagnoses are then presented anonymously to the group. After viewing the six diagnoses, the group members discuss them and work to reach a consensus. Each panel was told to decide for themselves what constituted a “consensus” and how they would work toward it.
The modified Delphi groups were more accurate in their diagnosis than the solitary experts (in cases where the patient received different diagnoses). Even the six trainees outperformed the solitary experts. Once again, the genius of the group wins out over the solitary individual!
*Matthew J. Gabel; Norman L. Foster; Judith L. Heidebrink; Roger Higdon; Howard J. Aizenstein; Steven E. Arnold; Nancy R. Barbas; Bradley F. Boeve; James R. Burke; Christopher M. Clark; Steven T. DeKosky; Martin R. Farlow; William J. Jagust; Claudia H. Kawas; Robert A. Koeppe; James B. Leverenz; Anne M. Lipton; Elaine R. Peskind; R. Scott Turner; Kyle B. Womack; Edward Y. Zamrini
Arch Neurol. 2010;67(12):1506-1512.