Right Hemisphere Syndrome

Right hemisphere syndrome Graphics courtesy of Deccan HeraldOpens in new window

In right-handed individuals, the right hemisphere of the brain (RH) is usually associated with prosody (controlling the emotional tone of speech), understanding facial expressions, sustaining attention, and visual-spatial control. Also, the left hemisphere is associated with language and motor control; the RH controls motor functions and perceptions on the left side of the body, while the left hemisphere controls them on the opposite side.

Stroke, brain trauma (e.g., traumatic brain injury), or disease (such as brain tumor) that damages regions of the RH may result in a condition called right hemisphere syndrome (RHS).

Symptoms of RHS may include attention difficulties, visual-perception and motor problems, cognitive or emotional impairment, and alterations of body perception.

Motor and visual-spatial perception difficulties may include problems with topographic memory (memory of familiar surroundings), dressing and constructional apraxia (inability to perform coordinated movements), motor impersistence (inability to sustain purposeful movement), prosopagnosiaOpens in new window (inability to recognize faces), and poor comprehension of facial expressionOpens in new window.

Communication and perceptual difficulties may result in aprosodia (inability to control the emotional tone of speech) or amusia (loss of musical ability). Cognitive and emotional difficulties may include anosognosia (lack of awareness that one is sick or has a disability), confusion, apathy, flattened expression or affect (displaying little emotion), reduplication (belief that two versions of a person or place exist simultaneously), impaired judgment or decision making, or socially inappropriate behavior.

RHS can result in misidentification of people, including the delusion that someone has a double (a doppelganger); this is known as Capgras syndromeOpens in new window. RHS may cause significant problems on the left side of the body, including hemiplega (paralysis) and hemispatial neglect (lack of attention or awareness of one side of the body).

Congenial or developmental RHS in children is characterized by difficulties with attention, slow performance (processing) speed, emotional and interpersonal difficulties, visual-spatial problems, and nonverbal learning disabilities (especially difficulty with math).

Anosognosia is a condition in which an individual is unaware that he has been affected by illness or ability (e.g., when paralyzed following a stroke). The term anosognosia, from the Greek (a, “without”; noso, “disease”; gnosia, “knowledge”), was first described in 1914 by French neurologist Joseph Jules Francois Felix Babinski (Heilman, Barrett, & Adair, 1998).

  • Anosognosia is accompanied by a lack of concern about one’s condition, with little or no display of emotion (Damasio, 1994). If an individual is unaware that there is something wrong, s/he may delay in seeking medical care, which could seriously impact outcomes (prognosis) or impede rehabilitation efforts.
  • Anosognosia can be accompanied by an inability to make appropriate personal or social decisions, socially inappropriate behavior, or dangerous behavior.

While some researchers have posited that anosognosia is a psychological defense mechanism (i.e., denial or repression), clinical evidence suggests that anosognosia is a cognitive result of neurological impairment (Damasio, 1994; Heilman et al., 1998).

Anosognosia is caused by damage to the right somatosensory cerebral cortices, which are responsible for external and internal senses and perception of the body (body image), and to the white matter in the right hemisphere, which transmits signals between various body regions and the motor and prefrontal cortices (Damasio, 1994).

Disruptions of body perception and awareness (body image or schema) combined with left-side paralysis or neglect may result in somatoparaphrenia, in which an individual does not believe that one of his body parts (or an entire side of his body) belongs to him. For example, an individual with RHS may believe that his paralyzed left arm belongs to the therapist who is working with him or that it belongs to his son (who is in another location).

When typical symptoms of RHS are observed in a right-handed individual with damage in the left hemisphere of the brain, this is known as crossed right hemisphere syndrome (Marchetti, Carey, & Della Sala, 2005). Genetic, hormonal, or developmental factors may lead to atypical patterns of brain lateralization (functions in different brain regions or hemispheres than the majority of the population).

Aphasia (loss of language abilities) usually occurs with strokes affecting the left hemisphere. In crossed aphasia, damage to the right hemisphere (in a right-handed person) causes aphasia. Early cases of crossed aphasia were noted by Farge (1877) and Bramwell (1899; Marchetti et al., 2005).

Data from crossed aphasia and crossed RHS indicate that rules of cerebral dominance are not always the case; that is, there is not always strict division (lateralization) of brain functions (e.g., language in one hemisphere, visual spatial in the other). Reports of exceptions, such as in crossed RHS, help neuroscientists learn more about how the brain functions.

RHS is diagnosed by clinical examination, neuropsychological resting, and imaging studies, most often functional magnetic resonance imaging (fMRI) or computed tomography (CT) scans.

Other types of imaging, such as SPECT (single photon emission computed tomography), PET (position emission tomography), or DTI (diffusion tensor imaging), may yield useful information about blood speech and language therapy, physical therapy, occupational therapy, cognitive rehabilitation, and psychotherapy.

See also:
  1. Damasio, A. (1994). Descartes’ error: Emotion, reason and the human brain. New York: Putnam.
  2. Heilman, K.M., Barrett, A.M., & Adair, J.C. (1998). Possible mechanisms of anosognosia: A defect in self-awareness. Philosophical Transactions of the Royal Society of London, Series B, 353, 1903 – 1909.
  3. Marchetti, C., Carey, D., & Della Sala, S. (2005). Crossed right hemisphere syndrome following left thalamic stroke. Journal of Neurology, 252, 403 – 411.
  4. Robertson, I.H., & Halligan, P.W. (1999). Spatial neglect: A clinical handbook. Hove, England: Psychology Press/Taylor and Francis.
  5. persecution.
Image