Right Hemisphere Disorders (RHD)

In 1974, William O. Douglas, Associate Supreme Court Justice suffered a stroke  He recovered quickly, checked himself out of rehab.  In court he dozed and asked irrelevant questions and rambled on. He was asked to resign “he came back to his office, buzzed for his clerks and asked to participate in, draft, and even publish his own opinions separately; and he requested that a tenth seat be placed at the Justices’ bench.” (Gardner, 1982)

Ok, the history  Historically, non-dominant hemisphere strokes were not referred to slp clinics  Mainly because the primary disorders are related to nonverbal cognitive systems  Don’t display word-finding and grammatical deficits associated with aphasia

Zoom to today, (history lesson is done!!)  Non dominant strokes now referred usually for:  Pt has a swallowing problem or motor speech deficit  Pt has an old RHD recently suffered a left hemisphere stroke  Pt has communicative difficulties caused by right hemisphere stroke---as with Justice Douglas

Language Evaluations  We might typically begin with an aphasia assessment tool, but:  RHD pts are most often not aphasic in that they can normally process most words and sentence in isolation

Language Comprehension  Sometimes perform as poorly as aphasic subjects  Can display good word comprehension, with mild deficit when presented with up to 4 semantically similar picture options  Not usually deficient short term memory span  Can follow directions (Token Test)

 Difficulty arranging words into a grammatical sentence  Problems with sentence comprehension with thematic roles in passive sentences  Subtle!

RHD: Language Production  Tend to name common objects effectively  Word finding problems occur on divergent thinking (expansion) tasks  Tend to generate fewer words (fluency)  More problems with lexical semantics than with phonology and syntax  Errors increase with processes that are “less automatic”

RHD: language production  May score similarly on clinical tests but for different reasons!  Because RHD pts have impaired attention, perception and organizational skills  So let’s look at the primary cognitive impairments caused by right hemispheric stroke

RHD: awareness of deficits  Anosognosia: lack of awareness or recognition of disease or disability  “lack of insight” or “imperception of disease”  Essentially, pts are unable to become aware of the neurological dysfunction  But, denial of impairment is a psychological defense mechanism---a pt who is strictly in denial is considered to be capable of awareness of deficit

 Anosognosia is usually observed as lack of awareness of paralysis  Self awareness of deficits was not correlated with actual task performance (Pendley and Ramsberger, 19960

Visuospatial Functions  WAIS scores show a pattern that is reversed relative to aphasia  RHD pts are likely to have a discrepancy score in which the Performance IQ (requires visuospatial recognition and reasoning skills) is lowered relative to the Verbal IQ

 Left neglect is more common that right neglect--- pts with posterior RHD bump into things on their left, leave food on the left side of a plate, dress only the right side, draw on the right side of an object  Wheel chair accidents!  Crossing Out Test, Line cancellation Test, etc.

Auditory-Vocal Modalities  Auditory agnosia: impaired ability to recognize sounds despite adequate hearing  May refer to deficient recognition of nonverbal or environmental sounds (auditory sound agnosia)

Emotion  Complex relationship between the limbic and the autonomic nervous systems---a message recognized in the cognitive cortex  Although both hemispheres are involved, the RH is dominant for emotion  RHD pts may display flat affect or indifference that accompanies left neglect  Hypoarousal to emotional pictures

Attention and Reading  RHD: tend to misread the beginning of words,  Some omit or misread words on the left side of the page  Some have both of these problems  Misreading the left side of words or left side of a page indicates neglect dyslexia

Emotion and Prosody  Aprosodia:  Flat contour or monotone  Failure to identify emotional tone in mundane sentences  Unable to detect happy, sad or angry faces

Interpreting Situations  RHD: difficulty recognizing emotion or humor in pictured scenes; unlike aphasics!  RHD: difficulties with sorting implicit themes like “love” from explicit themes like getting a hug  Suggests that RHDs have a problem with inferring the nature of situations when it is not concrete or obvious

Metaphor comprehension  “Metaphor is a pragmatic convention used for studying comprehensions of speaker-meaning that differs from literal content” (Marquart, 2000)  Inference is presumed to be a necessity  Interpreting idioms like “bury the hatchet” or “shoot the bull”

Discourse  RHDs recall main ideas better than details and explicit information  Tend to “miss the point”