<P> Patients with expressive aphasia, also known as Broca's aphasia, are individuals who know "what they want to say, they just cannot get it out". They are typically able to comprehend words, and sentences with a simple syntactic structure (see above), but are more or less unable to generate fluent speech . Other symptoms that may be present include problems with fluency, articulation, word - finding, word repetition, and producing and comprehending complex grammatical sentences, both orally and in writing . </P> <P> This specific group of symptoms distinguishes those who have expressive aphasia from individuals with other types of aphasia . There are several distinct "types" of aphasia, and each type is characterized by a different set of language deficits . Although those who have expressive aphasia tend to retain good spoken language comprehension, other types of aphasia can render patients completely unable to understand any language at all, unable to understand any spoken language (auditory verbal agnosia), whereas still other types preserve language comprehension, but with deficits . People with expressive aphasia may struggle less with reading and writing (see alexia) than those with other types of aphasia . Although individuals with expressive aphasia tend to have a good ability to self - monitor their language output (they "hear what they say" and make corrections), other types of aphasics can seem entirely unaware of their language deficits . </P> <P> In the classical sense, expressive aphasia is the result of injury to Broca's area; it is often the case that lesions in specific brain areas cause specific, dissociable symptoms, although case studies show there is not always a one - to - one mapping between lesion location and aphasic symptoms . The correlation between damage to certain specific brain areas (usually in the left hemisphere) and the development of specific types of aphasia makes it possible to deduce (albeit very roughly) the location of a suspected brain lesion based only on the presence (and severity) of a certain type of aphasia, though this is complicated by the possibility that a patient may have damage to a number of brain areas and may exhibit symptoms of more than one type of aphasia . The examination of lesion data in order to deduce which brain areas are essential in the normal functioning of certain aspects of cognition is called the deficit - lesion method; this method is especially important in the branch of neuroscience known as aphasiology . Cognitive science - to be specific, cognitive neuropsychology - are branches of neuroscience that also make extensive use of the deficit - lesion method . </P> <Table> Major characteristics of different types of acute aphasia <Tr> <Th> Type of aphasia </Th> <Th> Speech repetition </Th> <Th> Naming </Th> <Th> Auditory comprehension </Th> <Th> Fluency </Th> </Tr> <Tr> <Td> Expressive aphasia </Td> <Td> Moderate--severe </Td> <Td> Moderate--severe </Td> <Td> Mild difficulty </Td> <Td> Non-fluent, effortful, slow </Td> </Tr> <Tr> <Td> Receptive aphasia </Td> <Td> Mild--severe </Td> <Td> Mild--severe </Td> <Td> Defective </Td> <Td> Fluent paraphasic </Td> </Tr> <Tr> <Td> Conduction aphasia </Td> <Td> Poor </Td> <Td> Poor </Td> <Td> Relatively good </Td> <Td> Fluent </Td> </Tr> <Tr> <Td> Mixed transcortical aphasia </Td> <Td> Moderate </Td> <Td> Poor </Td> <Td> Poor </Td> <Td> Non-fluent </Td> </Tr> <Tr> <Td> Transcortical motor aphasia </Td> <Td> Good </Td> <Td> Mild--severe </Td> <Td> Mild </Td> <Td> Non-fluent </Td> </Tr> <Tr> <Td> Transcortical sensory aphasia </Td> <Td> Good </Td> <Td> Moderate--severe </Td> <Td> Poor </Td> <Td> Fluent </Td> </Tr> <Tr> <Td> Global aphasia </Td> <Td> Poor </Td> <Td> Poor </Td> <Td> Poor </Td> <Td> Non-fluent </Td> </Tr> <Tr> <Td> Anomic aphasia </Td> <Td> Mild </Td> <Td> Moderate--severe </Td> <Td> Mild </Td> <Td> Fluent </Td> </Tr> </Table>

What problem does damage to broca area cause