Conduction Aphasia – Causes, Pathophysiology, Diagnosis and Treatment
Conduction aphasia is a very rare form of aphasia. This disorder is caused by any injury or damage to the nerve fibers which connect the Broca’s and Wernicke’s areas. This area is known as the arcuate fasciculus in the brain. This condition is also known as associative aphasia. People with conduction aphasia tend to frequently correct themselves. Hence, words can be either repeated or skipped. Read on to know more about the causes, pathophysiology, diagnosis and treatment of conduction aphasia.
The impact of conduction aphasia on writing and reading ability varies greatly from person to person. Similar to other types of aphasia, sensory loss or right-sided weakness can be present. Even though if they are able to understand spoken language, they may find it difficult to find the correct and suitable word to describe an object or person.
Causes of Conduction Aphasia
This condition is primarily caused by any injury or damage to the left hemisphere of brain. This area is the language-dominant hemisphere. Any form of lesions in the language centers or in between the connections are known to act as potential inducers of conduction aphasia. Damage patterns in patients with conduction aphasia have been specifically observed to form in the inferior and posterior temporal lobe of the brain. Also, it tends to affect the parieto-temporal junction of the brain.
The brain damage which causes conduction aphasia mainly occurs from a stroke. A stroke can result in both localized and widespread harm. Tumors and traumatic brain injury can also cause localized lesioning in the brain. This can potentially lead to conduction aphaisa.
Pathophysiology of Conduction Aphasia
It was earlier thought that conduction aphasia occurs due to a lesion formation in the arcuate fasciculus. This white matter, deep bundle connects the brain’s posterior temporoparietal junction to the frontal cortex. Scientists used to think that this white matter bundle transmitts information between the Broca’s area (language production) and Wernicke’s area (language comprehension). Researchers later theorized that a damage to the connection between these regions limits the patient’s speech monitioring.
Also, this disconnect can limit the patient’s ability to transmitt any information between the production and comprehension functions. This leads to paraphasic errors in the patient. This theory suits the Wernicke-Geschwind language model. This model localizes and compartmentalizes speech production and comprehension.
Diagnosis of Conduction Aphasia
People with this condition are capable of holding a normal conversation. Hence, this is a perfect opportunity to notice any signs of language disorder. The patients speak normally, although they frequently include paraphasias. If the patient is asked to reapeat something, he or she will face significant difficulty. He or she may try to self-correct repeatedly. But when a question is asked, they can answer fluently and spontaneously.
There are several standardized tests for correctly diagnosing and classifying the condition. These tests can successfully identify conduction aphasia with accuracy. Two common tests used for identifying conduction aphasia are the Western Aphaisa Battery (WAB) and the Bostson Diagnostic Aphasia Examination. These tests include a set of examinations, like asking the patient to reapeat words, read printed words and name pictures.
Treatment for Conduction Aphaisa
The mode of treatment is generally individualized. This primarily focuses on improving the specific language and communication skills. Also, the patients are asked to perform regular exercise with communication tasks. While using the Western Aphasia Battery, a regular therapy for patients with conduction aphasia has reavealed steady improvement. As the patients are deficit in repetition, this is considered to be the main target of treatment. One can treat the conduction aphasics with a treatment method focused on sentence repetition.