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.

Myasthenia gravis is caused by antibodies that bind to postsynaptic acetylcholine receptors of the neuromuscular junction of skeletal muscle. The majority of patients with myasthenia gravis present to the emergency department (ED) with an exacerbation of the disease or complications of their medications. Brainstem stroke can present with altered mental status, ptosis, diplopia, and pupillary abnormalities. MRI with diffusion-weighted imaging can reliably distinguish acute brainstem stroke from myasthenia gravis. One reliable diagnostic tool for myasthenia gravis is the edrophonium (Tensilon) test, which may help to differentiate a cholinergic crisis (that is, overmedication of cholinesterase inhibitors) from a myasthenic crisis, and guide subsequent therapy. Careful attention to airway support is of primary importance in the myasthenic patient. Immunosuppressive agents are useful for long-term suppression of the disease. All patients with airway compromise require intensive case unit (ICU) admission.