as we know that rotatory/torsional nystagmus is due to activation of superior semicircular canals but in BPPV Most commonly posterior SCC is activated(means we should only have vertical nystagmus) then why we see peripheral nystagmus (vertical+torsional component) in BPPV??
All peripheral nystagmus will have a tortional component. If it is because of stimulation of superior or posterior semicircular canal , it will be vertical and if horizontal canal involved it will be horizontal .