Broca's area

Broca's area or the Broca area /broʊˈkɑː/ or /ˈbroʊkə/ is a region in the frontal lobe of the dominant hemisphere (usually the left) of the hominid brain with functions linked to speech production.

Language processing has been linked to Broca's area since Pierre Paul Broca reported impairments in two patients. They had lost the ability to speak after injury to the posterior inferior frontal gyrus of the brain. Since then, the approximate region he identified has become known as Broca's area, and the deficit in language production as Broca's aphasia, also called expressive aphasia. Broca's area is now typically defined in terms of the pars opercularis and pars triangularis of the inferior frontal gyrus, represented in Brodmann's cytoarchitectonic map as areas 44 and 45 of the dominant hemisphere. Studies of chronic aphasia have implicated an essential role of Broca's area in various speech and language functions. Further, fMRI studies have also identified activation patterns in Broca's area associated with various language tasks. However, slow destruction of the Broca's area by brain tumors can leave speech relatively intact suggesting its functions can shift to nearby areas in the brain.

Expressive aphasia

Expressive aphasia (non-fluent aphasia) is characterized by the loss of the ability to produce language (spoken or written). A person with expressive aphasia will exhibit effortful speech. Speech may only include important content words and leave out insignificant words, like "the". This is known as "telegraphic speech". The person may still be understood, but sentences will not be grammatical. In very severe forms of Expressive Aphasia, a person may only speak using single word utterances. It is one subset of a larger family of disorders known collectively as aphasia. Expressive aphasia differs from dysarthria, which is typified by a patient's inability to properly move the muscles of the tongue and mouth to produce speech. Expressive aphasia also differs from apraxia of speech which is a motor disorder characterized by an inability to create and sequence motor plans for speech. Comprehension is typically only mildly to moderately impaired in expressive aphasia due to difficulty understanding complex grammar. This contrasts with receptive aphasia, which is distinguished by a patient's inability to comprehend language or speak with appropriately meaningful words. Expressive aphasia is also known as Broca's aphasia in clinical neuropsychology and agrammatic aphasia in cognitive neuropsychology and is caused by acquired damage to the anterior regions of the brain, including (but not limited to) the left posterior inferior frontal gyrus or inferior frontal operculum, also described as Broca's area (Brodmann area 44 and Brodmann area 45) Expressive aphasia is also a symptom of some migraine attacks.