Describing the many different forms of aphasia seems akin to herding cats. There are at least eight types of aphasia, and the boundaries between them are more fluid than concrete. Additionally, due to the marvelous neuroplasticity of the human brain, a more severe type of aphasia can resolve to a less severe type over a period of time. This means that diagnosis is rarely a straightforward endeavor, and that a previously correct diagnosis could be found to be incorrect six months later.
Perhaps the most salient distinction between types of aphasia is that of fluent versus nonfluent. Fluent aphasias (e.g., conduction aphasia, transcortical sensory aphasia) are associated with lesions in areas of the brain supplied by the inferior division of the middle cerebral artery, while nonfluent aphasias (e.g., global aphasia, transcortical motor aphasia) are associated with lesions in areas of the brain supplied by the superior division of the middle cerebral artery. Individuals with a fluent aphasia typically exhibit difficulty with receptive language, while individuals with a nonfluent aphasia typically exhibit difficulty with expressive language.
The most common type of fluent aphasia is Wernicke’s aphasia. Individuals with Wernicke’s aphasia present with normal prosody, rate of speech, and articulatory agility, but the content of their speech is “empty.” This means that while a person with Wernicke’s aphasia can typically effortlessly produce speech (occasionally to an excessive degree, in a condition known as logorrhea), their speech generally conveys reduced amounts of information. Difficulty retrieving words, particularly nouns, is common, so keywords are often replaced with non-specific words (e.g., “it,” “the thing”). Communication is further hindered by neologistic (e.g., “leoz” for “belt” ), semantic (e.g., “glass” for “water”), and phonemic (e.g., “kuckle” for “buckle”) paraphasias. Individuals with Wernicke’s aphasia also present with impaired self-monitoring skills and comprehension deficits. Individuals with Wernicke’s aphasia are liable to become frustrated because they do not comprehend why they cannot understand others, or why they are not being understood.
The most common type of nonfluent aphasia is Broca’s aphasia. Whereas a person with Wernicke’s aphasia will primarily exhibit deficits with regards to comprehension of language, a person with Broca’s aphasia will primarily exhibit deficits with regards to production of language. An individual with Broca’s aphasia will often present with slow, choppy speech, and will produce telegraphic utterances. These short utterances consist primarily of nouns and often convey more information than the “empty” speech characteristic of Wernicke’s. Motor speech disorders leading to distorted articulation (e.g., apraxia of speech, dysarthria) and other motoric impairments (e.g., right-sided hemiparesis) are more likely to co-occur with Broca’s aphasia. Individuals with Broca’s aphasia typically present with relatively intact comprehension and self-monitoring skills. Individuals with Broca’s aphasia are liable to become frustrated because they are aware that they are experiencing difficulty communicating.
The information above provides a small glimpse into how different two individuals with aphasia can be. An estimated one million people in the United States alone have aphasia, and one individual with aphasia can present with entirely different symptoms than another. Yet, there are some universal principles that hold true when communicating with any individual with aphasia. Flexibility and patience are primary among these. Even when speech is impaired, individuals with aphasia can be remarkably skilled at communicating via other modalities, such as gesturing or drawing. Likewise, strategies such as writing key information down or changing your intonation can be effective in boosting comprehension. Everyone has something important to share when we take the time to listen.
Rebecca Kellogg, M.S. Candidate, Speech and Language Pathology, 2015, Department of Biobehavioral Sciences, Teachers College,