1. A system for training an ambulatory user, the system comprising: a user-wearable device; one or more variably transmissive lenses coupled to the user-wearable device; a user-wearable electrical sensor coupled to the user-wearable device; an executive function training circuit configured to couple with the user-wearable electrical sensor, the executive function training circuit comprising: a brain activity detector configured to receive electrical signals from the user-wearable electrical sensor and detect one or more brain activities; an undesired executive function detector configured to detect one or more executive function portions of the one or more brain activities attributable to an undesired executive function; and a sensory feedback generator operatively coupled to the variably transmissive lenses and configured to provide feedback to the user regarding the undesired executive function by impairing the vision of the user through the one or more lenses through by reducing the transmissivity of the one or more variably-transmissive lenses.