Right hemisphere brain damage
Encyclopedia
Cerebral hemisphere
A cerebral hemisphere is one of the two regions of the eutherian brain that are delineated by the median plane, . The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres has an outer layer of grey matter called the cerebral cortex that is...
of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
. It is associated with a number of cognitive and behavioral difficulties in humans. Research has for long focused on the effect and the role of RHD on emotion
Emotion
Emotion is a complex psychophysiological experience of an individual's state of mind as interacting with biochemical and environmental influences. In humans, emotion fundamentally involves "physiological arousal, expressive behaviors, and conscious experience." Emotion is associated with mood,...
al problems and in particular on speech prosody
Prosody (linguistics)
In linguistics, prosody is the rhythm, stress, and intonation of speech. Prosody may reflect various features of the speaker or the utterance: the emotional state of the speaker; the form of the utterance ; the presence of irony or sarcasm; emphasis, contrast, and focus; or other elements of...
. The damage may be due to physical incidents, stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
, or aging.
For over a century, the left brain hemisphere had been the key focus of clinical research on language disorders. It is now well established that language and cognition
Cognition
In science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...
can be seriously impaired by unilateral RHD. Specific cognitive tests can now help diagnose the existence of RHD versus left hemisphere damage. However, not all individuals with RHD may have problems in language or communication and some may have no discernible symptoms. Patients with RHD perform poorly in three specific tasks, compared to those with left hemisphere damage: characterizing emotions in faces; matching emotional expressions; and grouping pictorially presented and written emotional scenes.
Deficit in the use and understanding of innuendo
Innuendo
An innuendo is a baseless invention of thoughts or ideas. It can also be a remark or question, typically disparaging , that works obliquely by allusion...
, connotation and thematic content has been observed in patients following RHD. Paralinguistic comprehension problems involving sarcasm
Sarcasm
Sarcasm is “a sharp, bitter, or cutting expression or remark; a bitter jibe or taunt.” Though irony and understatement is usually the immediate context, most authorities distinguish sarcasm from irony; however, others argue that sarcasm may or often does involve irony or employs...
, irony
Irony
Irony is a rhetorical device, literary technique, or situation in which there is a sharp incongruity or discordance that goes beyond the simple and evident intention of words or actions...
, etc. have also been detected in these patients. Individuals with RHD also find it difficult to extract the theme of a story, or arrange sentences based on the theme of a story. This type of difficulty also applies to visual languages such as deaf sign languages. However, patients with RHD may be oblivious to some of their impairments (anosognosia
Anosognosia
Anosognosia /æˌnɒsɒgˈnəʊsɪə/ is a condition in which a person who suffers disability seems unaware of the existence of his or her disability. Unlike denial, which is a defense mechanism, anosognosia is rooted in physiology...
) and may at times also report euphoria
Euphoria
Euphoria is an emotional and mental state defined as a sense of great elation and well being.Euphoria may also refer to:* Euphoria , a genus of scarab beetles* Euphoria, a genus name previously used for the longan and other trees...
. Adults with RHD may exhibit behavior that can be characterized by insensitivity to others and preoccupation with self; unawareness of the social context of conversations; and verbose, rambling and tangential speech
Tangential speech
Tangential speech is a communication disorder in which the train of thought of the speaker wanders and shows a lack of focus, never returning to the initial topic of the conversation....
.
The visual and cognitive effects of RHD produced by a stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
have been well documented in the artistic style of famous painters for several decades now. In many cases, RHD produces dramatic shifts in artistic style. In the case of one artist, paintings after RHD began to have words inserted into pictures.