Other Insular Responses
Less common responses were vestibular sensations, which were described as a feeling of body motion (Figure 4.3) and auditory sensations, which were evoked by stimulating the very posteroinferior part of the insula (Figure 4.4). Speech impairments, which consisted of speech arrest, slurred speech, or lowering of voice intensity (Figure 4.5), were evoked both in the nondominant and dominant hemispheres for language. Gustatory and olfactory sensations were very rare and represented, respectively, 2.7% and 1% of all responses (Figure 4.5).
Overall, none of the clinical signs evoked by stimulation is absolutely specific of insular onset. An exception are nociceptive symptoms, which are highly suggestive of an insular lobe origin.12