The reason why ambiguity and confusion exist in the minds of the general community and even those who suffer from aphasia and/or apraxia in regards to what these terms mean is because both conditions involve expression skills and are quite often brought on after a stroke or an accident involving injury to the brain. The two conditions, however, are very different though they can co-exist in a person.
Aphasia is caused by any injury, lesion, tumor or infection that affects the left hemisphere of the brain in the frontal, temporal or parietal lobes. The left hemisphere of the brain is composed of Broca’s area, Wernicke’s area and the neural pathways that lie in between, which if damaged or adversely affected can result in many conditions, one of which is the onset of aphasia.
Apraxia, on the other hand, may occur from damage caused to the motor speech area also known as Broca’s area. This is located in the frontal lobe of the cerebrum.
Aphasia is a disability with communication which involves how we use language. It affects the ability to process language. This means there exists a problem in either of the two ways in which we communicate – receiving of information (through reading, hearing and visual) and expression of information (through speaking and writing). So, a person may have receptive aphasia where they can hear what is being said and can see it visually but cannot understand it or they may have expressive aphasia whereby he or she wishes to say something but has trouble using writing skills or putting the right words verbally to express that message. On the other hand, apraxia patients suffer not from the ability to come up with the right word/term but are unable to activate their speech muscles to form those words. So they may know exactly what they want to say and have the word ready for it, but their speech motor abilities deceive them.
Thus the therapies and approach to treatment also varies. Aphasia patients are prescribed therapy which helps them restore their language skills through making the patients understand spoken language as well as by stimulating the process of word finding.