WASHINGTON – Electroencephalography combined with novel software can distinguish mild cognitive impairment (MCI) from prodromal Alzheimer’s disease years before clinical symptoms become evident, according to a longitudinal assessment of patient data from a memory clinic in Iceland.
Monitoring electrophysiology could be used to select subjects for clinical trials who have yet to, but likely will, develop Alzheimer’s, said the investigators, led by Kristinn Johnsen, Ph.D., chief scientific officer at MentisCura, an Icelandic company developing the technology.
The software applied statistical pattern recognition to a large set of electroencephalography (EEG) features gathered from 169 individuals with MCI from the Memory Clinic at National University Hospital, Reykjavik, Iceland, over the course of 10 years’ follow-up to predict conversion from MCI to Alzheimer’s within 3-4 years, with a sensitivity of 87% and specificity of 79%.
During follow-up, 68 were diagnosed with AD after varying times ranging from 1 to nearly 10 years. Another 56 subjects had MCI that remained stable for at least 3 years, the researchers noted in a poster presented at the Alzheimer’s Association International Conference 2015.
A total of 24 subjects developed other dementias, and 21 were lost to follow-up. The groups were similar at baseline in gender, age in the mid-70s, and Mini-Mental State Examination score.
A Kaplan-Meier plot of the patients who were pegged as being likely to convert based on the stratification index revealed a curve similar to that of patients who had Alzheimer’s at baseline, with divergence of the curves occurring only after 3-4 years. In contrast, a Kaplan-Meier plot of the conversion of the full MCI cohort to Alzheimer’s separated from the curve of patients who had Alzheimer’s at baseline almost immediately.
The EEG software is already in routine clinical use in Iceland, with more than 700 patients with suspicion of dementia having been examined, according to Thora Thorgilsdottir of MentisCura. The technology has not yet been approved by the Food and Drug Administration and is available in the United States only for investigational purposes.