Crawling sensation behind head.

Hi This is for my mother aged 75 mri suggested grade 2 non spondylytic anterolisthesis of l4 over l5...and diffuse disc herniation at l3 l4 level...this is her condition from 5 years no further degradation is able to cook and manage herself ..goes for light walks wears a lumbar belt half day... Does basic yoga..of late from two years she complains of some pulling sensation like some crawling behind head...like somthing is running around back of head above neck...we showed out fly doctor who prescribed priaxine helped for four months now back again ..what could be the cause is it nerve compression..tested for vertigo came negative...ent doc medecines didn't help...she has no balance issues.feels nausea.