What is Aphasia? | Types of Aphasia | Causes of Aphasia
Posted Jan 24 2010 12:00am
By Rey Ryan for Nursingbuzz.com
Published: January 24, 2010
Aphasia is an acquired language disorder in which there is an impairment of any language modality. This may include difficulty in producing or comprehending spoken or written language.
Causes of Aphasia Aphasia usually results from lesions to the language-relevant areas of the temporal and parietal cortex of the brain, such as Broca’s area, Wernicke’s area, and the neural pathways between them. These areas are almost always located in the left hemisphere, and in most people this is where the ability to produce and comprehendlanguage is found. However, in a very small number of people, language ability is found in the right hemisphere. In either case, damage to these language areas can be caused by a stroke, traumatic brain injury, or other brain injury. Aphasia may also develop slowly, as in the case of a brain tumor or progressive neurological disease, e.g., Alzheimer’s or Parkinson’s disease. It may also be caused by a sudden hemorrhagic event within the brain. Certain chronic neurological disorders, such as epilepsy or migraine, can also include transient aphasia as a prodromal or episodic symptom. Aphasia is also listed as a rare side effect of the fentanyl patch, an opioid used to control chronic pain
People with aphasia may experience any of the following behaviors due to an acquired brain injury, although some of these symptoms may be due to related or concomitant problems such as dysarthria or apraxia and not primarily due to aphasia: inability to comprehend language, inability to pronounce, not due to muscle paralysis or weakness, inability to speak spontaneously, inability to form words, inability to name objects, poor enunciation, excessive creation and use of personal neologisms, inability to repeat a phrase, persistent repetition of phrases, paraphasia (substituting letters, syllables or words), agrammatism (inability to speak in a grammatically correct fashion), dysprosody (alterations in inflexion, stress, and rhythm), incompleted sentences, inability to read, inability to write
The following table summarizes some major characteristics of different types of aphasia:
Type of aphasia
Individuals with Wernicke’s aphasia may speak in long sentences that have no meaning, add unnecessary words, and even create new “words” (neologisms). For example, someone with Wernicke’s aphasia may say, “You know that smoodle pinkered and that I want to get him round and take care of him like you want before”, meaning “The dog needs to go out so I will take him for a walk”. They have poor auditory and reading comprehension, and fluent, but nonsensical, oral and written expression. Individuals with Wernicke’s aphasia usually have great difficulty understanding the speech of both themselves and others and are therefore often unaware of their mistakes.
Transcortical sensory aphasia
Similar deficits as in Wernicke’s aphasia, but repetition ability remains intact.
Conduction aphasia is caused by deficits in the connections between the speech-comprehension and speech-production areas. This might be damage to the arcuate fasciculus, the structure that transmits information between Wernicke’s area and Broca’s area. Similar symptoms, however, can be present after damage to the insula or to the auditory cortex. Auditory comprehension is near normal, and oral expression is fluent with occasional paraphasic errors. Repetition ability is poor.
Nominal or Anomic aphasia
Anomic aphasia, is essentially a difficulty with naming. The patient may have difficulties naming certain words, linked by their grammatical type (e.g. difficulty naming verbs and not nouns) or by their semantic category (e.g. difficulty naming words relating to photography but nothing else) or a more general naming difficulty. Patients tend to produce grammatic, yet empty, speech. Auditory comprehension tends to be preserved.
non-fluent, effortful, slow
Individuals with Broca’s aphasia frequently speak short, meaningful phrases that are produced with great effort. Broca’s aphasia is thus characterized as a nonfluent aphasia. Affected people often omit small words such as “is”, “and”, and “the”. For example, a person with Broca’s aphasia may say, “Walk dog” which could mean “I will take the dog for a walk”, “You take the dog for a walk” or even “The dog walked out of the yard”. Individuals with Broca’s aphasia are able to understand the speech of others to varying degrees. Because of this, they are often aware of their difficulties and can become easily frustrated by their speaking problems. It is associated with right hemiparesis, meaning that there can be paralysis of the patient’s right face and arm.
Transcortical motor aphasia
Similar deficits as Broca’s aphasia, except repetition ability remains intact. Auditory comprehension is generally fine for simple conversations, but declines rapidly for more complex conversations. It is associated with right hemiparesis, meaning that there can be paralysis of the patient’s right face and arm.
Individuals with global aphasia have severe communication difficulties and will be extremely limited in their ability to speak or comprehend language. They may be totally nonverbal, and/or only use facial expressions and gestures to communicate. It is associated with right hemiparesis, meaning that there can be paralysis of the patient’s right face and arm.
Transcortical mixed aphasia
Similar deficits as in global aphasia, but repetition ability remains intact.
Characteristics and symptoms depend upon the site and size of subcortical lesion. Possible sites of lesions include the thalamus, internal capsule, and basal ganglia.