Right Hemisphere Disorder Overview

Right Hemisphere Disorder

• Considered a less significant aspect of human evolution compared to the left hemisphere.
• Largely overlooked until the 1960s, when corpus commissurotomy (cutting the corpus callosum) allowed for the study of each hemisphere's functions.
• Normal right hemisphere functions involve nonlinguistic communication aspects such as prosody, facial expressions, and body language.
• Important for emotional expression, visuospatial skills (perception and relationships), and understanding the bigger picture.
• Right hemisphere disorders involve deficits due to right cerebral hemisphere damage. These are often cognitive-communication disorders instead of aphasia.
• Language abilities are usually intact if the left hemisphere is unharmed but non-linguistic communication cues are essential for social communication.
• Common causes include stroke, seizure disorders primarily in the right temporal lobe, infection, and other diseases.

Communication Deficits

• Communication deficits in right hemisphere disorders manifest as issues with pragmatics (proper communication).
• Areas affected include comprehension/production of prosody, facial expressions, and inferencing/discourse.
• Difficulty in correctly interpreting these cues can lead to misunderstanding.
• Individuals can recognize a person but have difficulty understanding the bigger picture or relational details.

Facial Recognition/Prosopagnosia

• Facial recognition is a specific and complex skill, sometimes disrupted.
• Prosopagnosia (facial blindness) is the inability to recognize faces, due to damage to visual association areas of the occipital lobe, not visual impairment itself.
• Individuals may recognize objects but not faces.

Attentional Deficits (Neglect)

• Inability to attend to sensory stimuli from one side of the body or environment is known as neglect.
• Most commonly, the left side is overlooked.
• Neglect can affect spatial recognition and object acknowledgement for the impacted side and often involves multiple sensory modalities to varying degrees.

Prosodic Deficits

• Prosody in speech involves pitch, stress, timbre, and tempo, enriching speech with emotional context.
• Right hemisphere damage can impact the comprehension and production of prosodic components thus leading to monotone speech.
• This affects the ability to express and interpret emotions conveyed through speech which leads to communication difficulties.

Inferencing Deficits

• Trouble correctly interpreting and applying prior knowledge in the context of current events or information.
• Impacts understanding nuances like sarcasm, humor, and other nonliteral language which negatively impacts communication.

Discourse Deficits

• This involves the communicative exchange between speaker and listener and is commonly impacted by a damaged right hemisphere.
• Shared background knowledge is not properly recognized, and difficulties with turn-taking and message clarity may occur.

Visuospatial Deficits

• Damage to brain regions can impair the ability to perceive multiple details simultaneously.
• Simultagnosia is specifically the difficulty in processing multiple visual stimuli simultaneously.

Toxicity

• The severity of the deficit depends on the extent of brain damage.
• Small lesions can create localized issues, while larger ones affect multiple cognitive areas.

Dementia

• Dementia involves the global and progressive loss of brain function.
• It's a syndrome, rather than a specific disease; a range of conditions can cause it.
• Includes notable memory impairments, but also other deficits in activities of daily living (ADLs).
• Several types of dementia exist, including Alzheimer's disease, Huntington's disease, vascular dementia, and frontotemporal dementia.
• Key features of Alzheimer's include memory and language issues due to neurofibrillary tangles and amyloid plaques.