You probably noticed in the dataset some “normal” observations with very strange clocks (less than 4 digits, no hands, etc.). In the training dataset, it’s almost 50% of “normal” observations.
One assumption is that these patients are affected by a disease which is not Alzheimer (Parkinson, Lewy-body, …), so considered as “normal” in our classification puzzle.
Sharing this particularity to the model could be helpful … I tried to split the main class in 2:
- “true normal”