What it looks like
Irregular delta activity that persists in one region, with loss of the faster rhythms on that side. It indicates focal dysfunction of the underlying white matter and cortex and says nothing about cause. 11
What it means at the bedside
Stroke, tumour, haemorrhage, abscess, contusion and the post-ictal state all look alike. Continuous, unreactive delta with loss of ipsilateral fast activity implies a more severe lesion than intermittent slowing. New focal slowing needs imaging.