Aphasia and stroke

Defining the clinical syndromes Aphasia is an impairment in comprehension or production of language caused by neurological disease or injury. The study of aphasia has changed dramatically since it first began in the late nineteenth century. At that time, the brains of individual patients with various language impairments were examined at autopsy and observations were made about areas of the brain that were held responsible for various language tasks [1,2]. This was the method employed by Broca and Wernicke, leading to their novel hypotheses that damage to more inferior frontal areas in the left hemisphere (Broca's area) tends to result in poor spoken output, while more posterior lesions involving the temporal lobe (Wernicke's area) lead to comprehension deficits. By the early twentieth century, attempts to localize language had fallen out of favor in the U.S. This was until behavioral neurologist Norman Geschwind observed that aphasic patients in his practice differed from one another in the pattern of their language deficits. Throughout the rest of his career, he worked extensively to classify language impairments into specific aphasia syndromes [3].