From the Guidelines
Aphasia types are primarily classified into Broca's, Wernicke's, conduction, global, transcortical motor, transcortical sensory, and anomic aphasia, each associated with distinct lesion sites in the brain, including areas such as Broca's area, Wernicke's area, the arcuate fasciculus, and the angular gyrus. The classification of aphasia is based on the clinical features and the corresponding brain lesion sites.
- Broca's aphasia results from damage to the left inferior frontal gyrus (Broca's area) 1, causing non-fluent speech with preserved comprehension.
- Wernicke's aphasia stems from lesions in the left posterior superior temporal gyrus (Wernicke's area) 1, producing fluent but meaningless speech with poor comprehension.
- Conduction aphasia occurs with damage to the arcuate fasciculus connecting Broca's and Wernicke's areas 1, characterized by fluent speech with good comprehension but poor repetition.
- Global aphasia results from extensive damage to perisylvian language areas, causing severe impairment in all language functions.
- Transcortical motor aphasia (lesions anterior/superior to Broca's area) presents with non-fluent speech but preserved repetition.
- Transcortical sensory aphasia (lesions posterior/inferior to Wernicke's area) features fluent speech with poor comprehension but intact repetition.
- Anomic aphasia, associated with damage to the angular gyrus or temporal-parietal junction, manifests primarily as word-finding difficulties despite otherwise fluent speech and good comprehension. These classifications help clinicians localize brain damage and develop appropriate rehabilitation strategies, as studies have shown that the location and extent of brain damage can predict language recovery and response to treatment 1. For example, damage to the left posterior middle temporal lobe can negatively affect aphasia therapy outcome in the chronic phase 1, and measures of neural network connectivity combined with initial behavioral deficit severity can account for variance in response to anomia treatment 1. Therefore, understanding the types of aphasia and their associated lesion sites is crucial for providing effective treatment and rehabilitation for individuals with aphasia.
From the Research
Types of Aphasia
The types of aphasia can be categorized based on the site of lesion in the brain. The main types include:
- Broca's aphasia: characterized by non-fluent speech, resulting from damage to Broca's area in the frontal lobe of the left hemisphere 2, 3
- Wernicke's aphasia: characterized by fluent speech with poor comprehension, resulting from damage to Wernicke's area in the temporal lobe of the left hemisphere 2, 3
- Anomic aphasia: characterized by difficulty with naming objects, resulting from damage to the temporal lobe of the left hemisphere 2, 3
- Global aphasia: characterized by severe difficulty with both expressive and receptive language, resulting from extensive damage to the left hemisphere 2, 3, 4
- Conduction aphasia: characterized by difficulty with repetition and word-finding, resulting from damage to the arcuate fasciculus, a bundle of nerve fibers connecting Broca's and Wernicke's areas 2, 3
- Transcortical motor aphasia: characterized by non-fluent speech with relatively preserved comprehension, resulting from damage to the frontal lobe of the left hemisphere, outside of Broca's area 2, 3
- Transcortical sensory aphasia: characterized by fluent speech with poor comprehension, resulting from damage to the temporal lobe of the left hemisphere, outside of Wernicke's area 2, 3
- Mixed aphasia: characterized by a combination of different aphasic syndromes, resulting from extensive damage to the left hemisphere 5, 4
Site of Lesion
The site of lesion in the brain can affect the type and severity of aphasia. For example:
- Lesions in the left perisylvian language cortex can result in fluent aphasia with semantic jargon 5
- Lesions in the basal ganglia, thalamus, and/or deep white matter can result in subcortical aphasia, characterized by word fluency, motor speech output, or sentence generation impairments 6
- Lesions in the deep white matter and basal ganglia can negatively impact language performance 6