Single-trial identification of failed memory retrieval

We show that it is possible to distinguish unsuccessful from successful retrieval of study items based on single-trial EEG recorded during the test phase of 3 separate recognition memory experiments. The overall classification accuracy across all 34 classification problems was 58.4 %. The classification accuracy monotonically increased to 68.03 % by only classifying trials with high classifier confidence levels. The likelihood of remembering a study item for trials with the 10% highest and lowest classifier outputs were 0.80 and 0.45 respectively. This suggests that the classifier outputs are reflecting the level of retrieval during the test phase. These findings combined with previous single-trial results predicting subsequent memory from EEG recorded during and prior to memory encoding will provide a basis for a passive brain-computer interface (BCI) system for improving memory.