Aphasia is an impairment of language caused by brain injury, typically from stroke. There are several types of aphasia: global aphasia results in minimal word production and comprehension; Broca's aphasia affects fluent speech but comprehension is better; Wernicke's aphasia affects comprehension more than fluent speech; and anomic aphasia mainly causes difficulty finding words. Aphasiology studies the clinical evidence of aphasias from brain injuries.

1. Psycholinguistics
Level-6
Aphasia

2. Aphasia
Aphasia is an impairment of language, affecting the production or comprehension
of speech and the ability to read or write. Aphasia is always due to injury to the
brain-most commonly from a stroke, particularly in older individuals. But brain
injuries resulting in aphasia may also arise from head trauma, from brain tumors,
or from infections.
1.Receptive (involving impaired language comprehension),
2.Expressive (involving language production), or a combination of both.
Aphasiology
Aphasiology is the particular field of study of aphasias in neurolinguistics that is
based on the clinical evidences collected by the neurologists through different
case studies of patients with linguistic disorder resulting from brain injury.

3. Varieties and special features of aphasia
*Over a century of experience with the study of aphasia has taught us that
particular components of language may be particularly damaged in some
individuals.
*We have also learned to recognize different types or patterns of aphasia that
correspond to the location of the brain injury in the individual case.

6. 1- Global Aphasia
*This is the most severe form of aphasia and is applied to patients who can
produce few recognizable words and understand little or no spoken
language. Persons with Global Aphasia can neither read nor write.
*Global Aphasia is caused by injuries to multiple language-processing areas
of the brain, including those known as Wernicke’s and Broca’s areas.
These brain areas are particularly important for understanding spoken
language, accessing vocabulary, using grammar, and producing words and
sentences.
*Global aphasia may often be seen immediately after the patient has
suffered a stroke or a brain trauma. Symptoms may rapidly improve in the
first few months after stroke if the damage has not been too extensive.
However, with greater brain damage, severe and lasting disability may
result.

7. Broca’s Aphasia
(Expressive or ‘Non-fluent aphasia')
*Individuals with Broca’s aphasia have trouble speaking fluently but their comprehension
can be relatively preserved. This type of aphasia is also known as non-fluent or
expressive aphasia.
*Patients have difficulty producing grammatical sentences and their speech is limited
mainly to short utterances of less than four words. Producing the right sounds or finding
the right words is often a laborious process. Some persons have more difficulty using
verbs than using nouns.
*A person with Broca’s aphasia may understand speech relatively well, particularly when
the grammatical structure of the spoken language is simple. However they may have
harder times understanding sentences with more complex grammatical construct. For
example the sentence “Mary gave John balloons” may be easy to understand but “The
balloons were given to John by Mary” may pose a challenge when interpreting the
meaning of who gave the balloons to whom.

8. *Individuals with Broca’s aphasia may be able to read but be limited in writing.
*Broca’s aphasia results from injury to speech and language brain areas such as the left
hemisphere inferior frontal gyrus, among others. Such damage is often a result of stroke
but may also occur due to brain trauma.
*Broca’s aphasia is named after the French scientist, Paul Broca, who first related a set of
deficits associated with this type of aphasia to localized brain damage.

9. Wernicke’s Aphasia
(Receptive or 'fluent aphasia')
*In this form of aphasia the ability to grasp the meaning of spoken words and
sentences is impaired, while the ease of producing connected speech is not
very affected. Therefore Wernicke’s aphasia is also referred to as ‘fluent
aphasia’ or ‘receptive aphasia’.
*Reading and writing are often severely impaired. As in other forms of aphasia,
individuals can have completely preserved intellectual and cognitive capabilities
unrelated to speech and language.
*Persons with Wernicke’s aphasia can produce many words and they often speak
using grammatically correct sentences with normal rate and prosody. However,
often what they say doesn’t make a lot of sense or they pepper their sentences
with non-existent or irrelevant words. They may fail to realize that they are
using the wrong words or using a non-existent word and often they are not fully
aware that what they say doesn’t make sense.

10. *Patients with Wernicke's aphasia usually have profound language
comprehension deficits, even for single words or simple
sentences. This is because in Wernicke’s aphasia individuals have
damage in brain areas that are important for processing the
meaning of words and spoken language. Such damage includes
left posterior temporal regions of the brain, which are part of
what is knows as Wernicke’s area, hence the name of the aphasia.
*Wernicke’s aphasia and Wernicke’s area are named after the
German neurologist Carl Wernicke who first related this specific
type of speech deficit to a damage in a left posterior temporal
area of the brain.

11. Anomic Aphasia
*Anomic aphasia is one of the milder forms of aphasia. The term is applied to
persons who are left with a persistent inability to supply the words for the very
things they want to talk about, particularly the significant nouns and verbs.
Their speech is fluent and grammatically correct but it is full of vague words
(such as ‘thing’) and circumlocutions (attempts to describe the word they are
trying to find). The feeling is often that of having the word on the tip of one’s
tongue, which results in their speech having lots of expressions of frustration.
*People with anomic aphasia understand speech well and they can repeat words
and sentences. In most cases they can read adequately. Difficulty finding words
is as an evident in writing as it is in speech.

12. Summary
*Global aphasia- produce few recognizable words and understand little or no
spoken language. Persons with Global Aphasia can neither read nor write.
*Broca’s aphasia- trouble speaking fluently but comprehension can be
relatively preserved.
*Wernicke's aphasia- meaning of spoken words and sentences is impaired,
while the ease of producing connected speech is not very affected.
*Anomic aphasia- inability to supply the words for the very things they want to
talk about.