Aka nonfluent speech
This is labored, slow and nonfluent speech
They often get frustrated with their speech difficulties
-anomia
they have difficulty finding the word
-difficulty with articulation
They sometimes will switch letters or mispronounce words, but it is usually comprehendible. They often realize their mistake and correct it.
-agrammaticism
They have problems using and understanding function words (words with grammatical function). They tend to only use content words. In fact this is the only comprehension problem and it is usually not evident until they are tested.
Broca’s area lies in the left frontal lobe. However, Broca’s aphasia is usually associated with damage that extends beyond the area of the cortex identified as Broca’s area. For example, Tony and Hannah Damasio report that the damage must extend to surrounding regions of the frontal lobe and underlying subcortical white matter.
In 1996, Nina Dronkers published a paper in Nature, describing her study of anatomical images derived from a number of individuals suffering from Broca’s aphasia and found a critical location for control of speech articulation—the left precentral gyrus of the insula. The insular cortex is located on the lateral wall of the cerebral hemisphere behind the anterior temporal lobe. This is corroborated by PET studies (Stromswold, 1996).
Other areas of the brain can also contribute to speech articulation. For example, damage to the cerebellum, which is important for the sequencing of motor skills can also lead to articulation difficulties.
AKA FLUENT APHASIA
Their speech is fluent, just not meaningful, or understandable.
Their speech is melodic (prosody) and they use social conventions (taking turns) when speaking with another individual
They have no comprehension of what others are saying
They often seem unaware that they have a deficit
-anomia
meaningless speech
-no comprehension
It has been postulated that severe Wernicke’s aphasia is really a combination of damage to a wide area and that more select damage produces more select deficits.
PURE WORD DEAFNESS
These individuals have fine speech production, but they can NOT RECOGNIZE speech sounds
As one patient says, “ I can hear you talking, I just can’t understand what you’re saying.”
It seems as though their recognition of sounds that have rapidly changing components, like words, is disrupted. They can recognize nonspeech sounds like doorbells, or dogs barking. They also understand words, because they can often understand someone by reading their lips or reading written words.
They have lost the ability to recognize speech sounds that fall within a time range of a few milliseconds to a few tens of milliseconds. So they have less difficulty with long vowels, but a lot of difficulty with stop consonants, like d/ t/ k/.
This is caused by damage to auditory inputs into Wernicke’s area OR to Wernicke’s area itself.
These individuals have an inability to understand speech or to produce meaningful speech. However, they CAN repeat words.
This is due to damage to the posterior regions adjacent to Wernicke’s area. Since these individuals can repeat words, it suggests that there is some connection between Wernicke’s area and Broca’s area that is NOT involved with the meaning of words, but rather simple recognition and repetition (the arcuate fasciculus). It has been hypothesized that the posterior region is an interface between Wernicke’s area that recognizes speech sounds and the cortical areas that store the meaning of words.
Some suggest that Wernicke’s aphasia is really a combination of pure word deafness and transcortical sensory aphasia.
CONDUCTION APHASIA
These individuals have fine, fluent speech, good comprehension.
They can NOT repeat words, particularly function or nonsense words. Often, content words can be repeated but they may say a word with the same meaning, rather than the same word that was heard (i.e. house, home).
This is caused by damage to the arcuate fasciculus, a pathway that connects Wernicke’s to Broca’s area. Information actually travels in both directions along the arcuate fasciculus, and it is believed that this connection is involved in keeping the short-term memory of a sound of a word alive. This is referred to as the PHONOLOGICAL LOOP. Thus, one working model suggests that speech sounds can be sent from Wernicke’s area to Broca’s area via the arcuate fasciculus, but that information on the meaning of words is sent via another pathway.
So where are the meanings of the words stored?
It is believed that they are in the cortex. And, in fact, damage to various cortical areas can produce:
ANOMIC APHASIAS
Speech of these individuals is fluent and grammatical, their comprehension is excellent, but they have difficulty finding the appropriate words. They often employ CIRCUMLOCUTIONS (literally, “speaking in a roundabout way”). For example, instead of saying, “table”, they may say, “that thing in the dining room with the legs…”
Some cases are quite specific. For example, some individuals can not name common nouns, others may not name proper nouns, or others may not be able to name verbs. This is particularly interesting because it has implications for how information may be compartmentalized in the cortex.
Keep in mind, that the brain is plastic. That is, if there is a small lesion, there may only be temporary deficits from which the individual recovers. In the developing brain, the reorganization can be far more extensive. Individuals who are born with very little left hemisphere may still acquire language.
Also keep in mind, that language is complex, and relies on attention, memory and a variety of various cognitive functions. Usually, the brain damage may affect a number of neuronal systems.