Experimental methods

What is the Western Aphasia Battery?

Answer: The Western Aphasia Battery is a behavioral test designed to assess linguistic and non linguistic skills that are used to determine if a person has a diagnosis of aphasia.

Language disorders such as nonfluent (Broca's) aphasia or fluent (Wernicke's) aphasia are common after a severe brain injury such as a stroke or dementia. In people with these language disorders, they have different types of difficulties with either the production or comprehension of language.

The Western Aphasia Battery is a test that was designed to assess the type of aphasia that a person is experiencing, and also the severity of the aphasia. It can be administered multiple times over months in order to see how well a patient is responding to the speech therapy paradigm. It can also be used to try to identify the location of where a brain injury is located.

This test can be administered to English speaking subjects with an age range from 18 to 89 years old. Specifically, the Western Aphasia Battery assesses auditory comprehension, speech, reading, and writing. In addition to testing language skills, there is also a general intelligence component of the test, of which basic drawing and calculation skills are assessed, and Ravens Progressive Matrices is often administered. Upon completion of the test, the patient is given an aphasia quotient (AQ) and a cortical quotient (CQ). 

The scores on 10 separate scores are combined, resulting in a final score that rates from 0 to 100, with a 0 meaning very severe aphasia and a 100 meaning no aphasia.

The patients will be asked to produce spontaneous, unrehearsed speech. For example, they will be asked common conversational questions or told to describe a picture. From these tests, it is possible to determine the quality of language content, fluency of speech, and ability to access lexical memory. 

Their repetition will be tested, as poor ability to repeat words is often seen in conduction aphasia. They will be given progressively longer words, and how accurately they are able to repeat those words can be scored. 

A word naming task will also be given. Here, we are able to assess the patient's ability to process semantics while they perform sentence completion or object naming tasks.

Finally, auditory verbal comprehension is tested. The patient will answer yes or no to progressively longer and more difficult prompts. 

The most current version of the test, called the Western Aphasia Battery-Revised, was published in 2006, and takes about an hour and a half for the full examination.

The WAB has very high inter-rater reliability with the exception of the speech fluency portion, which requires subjective scoring. It has high internal consistency.