Various embodiments concern assessing a degenerative cognitive disorder of a patient based on a plurality of episodes of non-motor epileptiform bioelectrical activity. The non-motor epileptiform bioelectrical activity can be detected from one or more bioelectrical brain signals. A worsening cognitive disorder may be indicated by an increase in one or more of intensity, duration, and frequency of occurrence of the episodes of non-motor epileptiform bioelectrical activity. A therapy can be delivered to reduce one or more of intensity, duration, and frequency of occurrence of the episodes of non-motor epileptiform bioelectrical activity. The delivery of the therapy can be controlled based on the plurality of episodes of non-motor epileptiform bioelectrical activity.
