Right Hemisphere Disorders (RHD)

1. Right Hemisphere Disorders (RHD)

2. 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)

3. 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

4. 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

5. 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

6. 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)

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

8. 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”

9. 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

10. 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

11. 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

12. 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

13. 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.

14. 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)

15. 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

16. 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

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

18. 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

19. 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”

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