Right hemisphere brain damage

Right hemisphere brain damage, often abbreviated as RHD, is damage to the right hemisphere of the brain. 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 emotional problems and in particular on speech prosody. The damage may be due to physical incidents, stroke, 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 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, connotation and thematic content has been observed in patients following RHD. Paralinguistic comprehension problems involving sarcasm, irony, 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) and may at times also report euphoria. 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.

The visual and cognitive effects of RHD produced by a stroke 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.