Right Hemisphere Damage and Aphasia: A Neurological Overview

Pragmatic and Social Communication

While a person with RHD may have intact grammar, they often struggle with the "hidden rules" of conversation. This includes difficulty understanding figurative language, idioms, sarcasm, and abstract language. Socially, this may manifest as poor eye contact, difficulty with turn-taking, or an inability to maintain a topic.

Exam Tip: If a question asks you to differentiate between Anosognosia and Prosopagnosia, remember: Anosognosia is a lack of awareness of a deficit, whereas Prosopagnosia is a specific perceptual deficit in recognizing faces.

Aphasia: Language Modality Impairments

Aphasia is an impairment of language that can affect four primary modalities: auditory comprehension (understanding), verbal expression (speaking), reading, and writing.

Primary Types of Aphasia

The type of aphasia is often determined by the location of the lesion within the left hemisphere.

1. Broca’s Aphasia: Associated with left frontal damage, this is a nonfluent aphasia. Speech is slow, effortful, and characterized by agrammatism (e.g., "Want... coffee"). While expression is severely limited, comprehension is relatively intact, and patients are often highly aware of their struggles, leading to frustration.
2. Wernicke’s Aphasia: Associated with posterior left MCA lesions, this is a fluent aphasia. Speech flows easily but is "empty" of meaning and characterized by poor comprehension. Patients often have reduced awareness of their errors.
3. Global Aphasia: The most severe form, involving profound deficits across all four modalities. This is typically caused by a large occlusion of the MCA trunk.

Understanding Paraphasias

When patients with aphasia struggle to find the correct word, they may produce paraphasias:

• Semantic Paraphasia: Replacing a word with a related one (e.g., saying "bus" instead of "train").
• Phonemic Paraphasia: A sound substitution within a word (e.g., "tephelone" for "telephone").
• Neologism: The production of entirely new, non-existent words (e.g., "plinter" for "fork").

Aphasia Therapy Approaches

Rehabilitation for aphasia is not "one size fits all." It focuses on both restoration (trying to bring back lost function) and compensation (finding new ways to communicate).

Targeted Linguistic Therapies

• Semantic Feature Analysis (SFA): A restorative approach where patients describe the attributes of a target word (category, function, appearance, etc.) to improve word retrieval.
• Response Elaboration Therapy (RET): Designed to increase the length and content of spontaneous speech by using WH-questions to expand a patient's initial response.
• Melodic Intonation Therapy (MIT): Uses the rhythm and melody of music to support verbal output, often helping those with nonfluent speech.
• Constraint-Induced Aphasia Therapy (CIAT): A high-intensity approach that "constrains" the use of compensatory methods (like gesturing) to force the use of spoken language.

Functional and Social Frameworks

• Script Training: Focuses on practicing specific, functional conversational scripts (e.g., ordering coffee) to ensure real-world carryover.
• Promoting Aphasics' Communicative Effectiveness (PACE): An activity-based approach that encourages the use of any modality—speech, drawing, or gestures—to achieve successful communication.
• Life Participation Approach to Aphasia (LPAA): A holistic philosophy that prioritizes the patient's personal goals and their ability to participate in real-life activities.
• CAPE Framework: A comprehensive model focusing on Connecting people, Augmentative and Alternative Communication (AAC), Partner Training, and Education.

Summary Table for Quick Review