1/2. Transient unilateral hearing loss induced by electrocortical stimulation.A 32-year-old patient with seizures experienced decreased right-ear hearing during electrocortical stimulation mapping of the left lateral superior temporal gyrus. Audiometric testing under headphones confirmed a reversible, moderate unilateral hearing loss. Under binaural listening conditions, auditory comprehension was impaired at the same site, whereas word repetition, environmental sound recognition, naming, and spontaneous speech remained intact.- - - - - - - - - - ranking = 1keywords = speech (Clic here for more details about this article) |
2/2. Auditory and electrophysiological patterns of a unilateral lesion of the lateral lemniscus.Auditory disorders resulting from focal brainstem lesions are rarely symptomatic. Isolated lesions of the inferior colliculus have previously been reported, whereas no detailed description of a localized involvement of the lateral lemniscus is yet available. We report a unilateral lesion of the lateral lemniscus by a bleeding in a cavernoma. Symptoms included strictly contralateral tinnitus and auditory impairment, with normal pure-tone and speech audiometry. Conversely, the dichotic listening test revealed an extinction of contralateral ear input. The brainstem auditory evoked potentials disclosed a reduced and delayed wave V only after contralateral ear stimulation, while the middle latency evoked potentials were normal. This observation shows that a unilateral lesion of the lateral lemniscus can produce auditory symptoms. The dysfunction of auditory pathways is associated with specific electrophysiological abnormalities that can be assessed by evoked potential recording.- - - - - - - - - - ranking = 1keywords = speech (Clic here for more details about this article) |