Study Notes on Right Hemisphere Brain Damage

Hemispheric Specialization and Lateralization

• Left Hemisphere ($LH$) Dominance: Primarily responsible for language, words, letters, speech, grammar rules, reading, writing, and arithmetic.
• Right Hemisphere ($RH$) Dominance: Specializes in holistic and gestalt-like processing, including geometric patterns, faces, emotional expression, music, and nonlanguage sounds.
• Spatial Ability: The $RH$ handles mental rotation of shapes, sense of direction, and distance.

Overview of Right Hemisphere Damage ($RHD$)

• Definition: Neurological damage to the right cerebral hemisphere resulting in cognitive, perceptual, or behavioral disruptions.
• Cognitive-Linguistic Disorder: Unlike typical aphasias (associated with the $LH$), $RHD$ involves language difficulties stemming from cognitive and extralinguistic deficits.
• Etiology: Causes include cerebro-vascular accidents ($CVA$/stroke), ischemic or hemorrhagic events, tumors, head trauma, and degenerative diseases.

Perceptual and Attentional Deficits

• Left Neglect: Failure to perceive or attend to stimuli on the left side. Patients may bump into objects on their left, dress only the right side of their body, or leave food on the left side of a plate.
• Anosognosia: A clinical lack of awareness or recognition of one's own disease or neurological dysfunction.
• Prosopagnosia: Face blindness or facial recognition deficits specifically linked to the fusiform face area and striate cortex.
• Auditory Agnosia: Impaired recognition of environmental or nonverbal sounds despite adequate hearing.
• Visuoperceptual Deficits: Lowered Performance $IQ$ relative to Verbal $IQ$ on the $WAIS$ due to impaired visuospatial reasoning.

Affective and Communicative Impairments

• Affective Deficits: Difficulty understanding or expressing emotions through facial expressions, prosody, and voice cues.
• Aprosodia: Characterized by a flat, monotone vocal contour and the inability to detect emotional tones (e.g., happy, sad, angry) in others.
• Pragmatics: Difficulty with implied, abstract, or alternative meanings; impaired narrative skills and problems with higher-level cognitive-linguistic integration.
• Language Production: Word-finding problems occur during divergent thinking tasks; patients generate fewer words and struggle with lexical semantics more than phonology or syntax.

Cognitive and Reading Deficits

• Memory and Executive Function: Impairments in planning, problem-solving, and remembering complex designs or sequences.
• Orientation: Frequent disorientation regarding $Person$, $Place$, $Time$, and $Situation$.
• Neglect Dyslexia: A specific reading disorder where patients omit or misread the left side of words or the left side of a page.
• Syntactic Difficulty: Problems comprehending thematic roles in complex structures, such as passive sentences.