Many different conditions cause hearing impairment including inflammation, trauma, aging (presbyacusis), ototoxic drugs, genetic disorders, and stroke. As the blood supply to the auditory system originates from the vertebrobasilar system, hearing loss and tinnitus are common with vertebrobasilar territory ischemic stroke. This chapter reviews the clinical spectrum of hearing impairment associated with stroke. Central hearing impairment results from lesions central to the cochlear nucleus from the brainstem auditory nuclei to the auditory cortex in the temporal lobe. Central hearing abnormalities characterized by difficulty understanding spoken communication usually result from lesions of the central auditory pathways rostral to the cochlear nucleus. Brainstem stroke can cause auditory symptoms such as hearing loss, phantom auditory perceptions (tinnitus and hallucinations), and hyperacusis. Cortical deafness, pure word deafness, auditory agnosia for environmental sounds, and amusia are well-known central auditory disorders associated with hemispheric stroke.

Functional neuroimaging has contributed new insights in the field of aphasia research. Techniques like repetitive transcortical magnetic stimulation (rTMS), Wada testing, and cortical stimulation during neurosurgery with grid mapping, all of which inhibit distinct areas of the brain, have determined which nodes of the networks visualized in functional neuroimaging are critical for each function. The neurological examination of a patient with aphasia can be broken down into six major categories: naming, fluency, repetition, comprehension, reading, and writing. The classical aphasia syndromes result from the infarction of defined vascular distributions, each typically associated with a specific set of neurological deficits, also caused by damage to that particular region of the brain. Patients who develop aphasia following acute stroke typically recover well with only mild long-term language deficits. Many of the techniques currently employed by speech-language pathologists focus on treatment of the damaged component of the system.