If a patient has 'gluten encephalitis' how long of a strict gluten free diet until the neurological symptoms improve? thank you?

I assume you are referring to 'gluten-sensitive enteropathy.' Neurological symptoms include being emotionally withdrawn, fretful, and irritable. Affected individuals has to be on gluten-free diet lifelong.

Celiac disease can cause complications from head to toe, but true inflammatory encephalitis is not an association. Perhaps your terminology should preferably focus on the emotional symptoms, "brain fog" and even fatigue, all of which can accompany gastrointestinal issues. The dietary measures should be managed lifelong as noted.