Insular strokes cause no vestibular deficits

Abstract

Background and purpose: In previous imaging studies, the posterior insular cortex (IC) was identified as an essential part for vestibular otolith perception and considered as a core region of a human vestibular cortical network. However, it is still unknown whether lesions exclusively restricted to the posterior IC suffice to provoke signs of vestibular otolith dysfunction. Thus, present data aimed to test whether patients with lesions restricted to the IC showed vestibular otolith dysfunction.

Methods: We studied 10 acute unilateral stroke patients with lesions restricted to the IC which were tested for signs of vestibular otolith dysfunction, such as tilts of subjective visual vertical, out of 475 stroke patients.

Results: None of the patients was with stroke exclusively affecting the IC-specified vertigo as a symptom. In addition, neither showed a deficit in the perception of verticality (subjective visual vertical tilts) nor showed any further vestibular otolith deficits, such as ocular torsion or skew deviation.

Conclusions: It seems that lesions of the posterior IC might have to be combined with lesions of adjacent regions of the cortical and subcortical vestibular network to cause vestibular otolith deficits.

Keywords: insula; lesion; stroke; subjective visual vertical; verticality; vestibular system.