Aphasia

Aphasia, sometimes spelled Aphemia, is a communication disorder characterized by the loss or impairment of the ability to produce and/or comprehend language due to damage in specific regions of the brain. The term originates from the Greek word "aphatos," meaning "speechless."

Aphasia affects language comprehension and expression.

Aphasia typically results from brain injury affecting the left hemisphere, where the language center is located in most people. This damage can be caused by a stroke, traumatic brain injury, brain tumor, or progressive neurological diseases such as primary progressive aphasia. Although rare, in some individuals (particularly left-handed people), language functions may be dominant in the right hemisphere.

Overview

A person with aphasia may:

• Speak fluently but without meaning
• Struggle to form coherent speech
• Understand speech but not write
• Display reading (alexia) or writing (agraphia) difficulties

These symptoms vary depending on the extent and location of the brain damage. Aphasia often co-occurs with other speech disorders like dysarthria and apraxia of speech. While the brain of a child can adapt to such damage with neuroplasticity, adults have more limited capacity for compensation.

Assessment

Evaluation of aphasia ranges from quick bedside assessments to in-depth standardized language tests like the Western Aphasia Battery or the Boston Diagnostic Aphasia Examination.

Types of Aphasia

The classification of aphasia is often based on lesion location and behavioral symptoms. The most widely recognized system is the Boston-Neoclassical Model.

Broca's aphasia

Also known as expressive aphasia, Broca's aphasia results from damage to the inferior frontal gyrus (Broca's area). Individuals:

• Speak in short, effortful phrases
• Omit small grammatical words
• Often understand speech relatively well
• Are aware of their difficulties
• May have associated right-sided hemiparesis or hemiplegia

Example: Saying "Walk dog" instead of "I will take the dog for a walk."

Wernicke's aphasia

Also known as receptive aphasia, this fluent type of aphasia stems from damage to the posterior superior temporal gyrus (Wernicke's area). Individuals:

• Speak in fluent but nonsensical language
• May invent new words (neologisms)
• Are often unaware of their deficits
• Typically do not experience motor impairments

Example: "The smoodle pinkered and I want to get him round."

Global aphasia

This is the most severe form and occurs when large portions of the left hemisphere are damaged. Individuals with global aphasia:

• Have profound impairments in speaking, understanding, reading, and writing
• Often retain limited communication ability

Anomic aphasia

Characterized by difficulty retrieving words, especially nouns and verbs. Patients:

• Know what they want to say but cannot find the words
• Speak fluently with frequent pauses
• Are aware of the word-finding difficulty

Conduction aphasia

Results from damage to the arcuate fasciculus, the pathway connecting Broca’s and Wernicke’s areas. Patients:

• Speak fluently and understand language
• Have difficulty with repetition
• Often produce phonemic errors (e.g., "papple" for "apple")

Transcortical motor aphasia

Similar to Broca’s aphasia but repetition is preserved. Caused by lesions near but not in Broca’s area.

Transcortical sensory aphasia

Similar to Wernicke’s aphasia with preserved repetition. Caused by lesions in the temporoparietal junction.

Mixed transcortical aphasia

Also known as isolation aphasia. Comprehension and spontaneous speech are impaired, but repetition is preserved.

Neuropsychological Perspective

The Cognitive Neuropsychological Model views language as modular. Impairment can occur in distinct modules:

• Phoneme recognition
• Lexical retrieval
• Semantic processing

Evaluation tools such as the PALPA (Psycholinguistic Assessment of Language Processing in Aphasia) help localize the disrupted modules and guide speech-language therapy.

Other Aphasia-Related Conditions

• Apraxia of speech – Motor planning disorder, not a language issue
• Alexia (disorder) – Impaired reading
• Agraphia – Impaired writing
• Jargon aphasia – Fluent but meaningless speech with invented words
• Landau-Kleffner Syndrome – Acquired epileptiform aphasia in children
• Primary progressive aphasia – Neurodegenerative form

All Types of Aphasia

• Broca’s aphasia
• Wernicke’s aphasia
• Global aphasia
• Anomic aphasia
• Conduction aphasia
• Transcortical motor aphasia
• Transcortical sensory aphasia
• Mixed transcortical aphasia
• Subcortical aphasia
• Jargon aphasia
• Alexia
• Agraphia

Aphasia in Popular Culture

• In Star Trek: Deep Space Nine episode "Babel," a viral form of aphasia spreads on the station.
• In House M.D. (Season 2, Episode 10), a patient displays word-substitution aphasia after trauma.
• In the play Fuddy Meers, a character with aphasia highlights the disconnect in communication.

External Links

• NIDCD – National Institute on Deafness and Other Communication Disorders
• National Aphasia Association
• Aphasia Center of California
• AphasiaNow Resources
• Aphasia Simplified – Info for patients and caregivers

References

• Goodglass, H., & Kaplan, E. (1972). Assessment of Aphasia and Related Disorders. Philadelphia: Lea & Febiger.
• Coltheart, M., Kay, J., & Lesser, R. (1992). PALPA: Psycholinguistic Assessments of Language Processing in Aphasia. Hove: Erlbaum.
• Hale, S. (2003). The Man Who Lost His Language. Penguin Books.

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