Examining inferencing abilities of persons with aphasia: A case study

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Examining inferencing abilities of persons with
aphasia A case study
Diana Petroi, M.S., CCC-SLP Melinda Corwin,
Ph.D., CCC-SLP
2
Introduction

• Studies on neurologically intact and
  brain-damaged individuals have shown that various
  aspects of theory of mind processing are mediated
  by both hemispheres (Vollm et al., 2005 Happe,
  Brownell, Winner, 1999).
• Several studies have found theory of mind,
  including pragmatics and discourse, to be
  impaired in those with right hemisphere damage
  (RHD) (Happe, Brownell, Winner, 1999).
• More recent research (e.g., Tompkins, Scharp,
  Fassbinder, Meigh, Armstrong, 2008) has
  proposed that RHD is not necessarily associated
  with theory of mind deficits. Rather, task
  processing demands may interfere with
  individuals performances.
• Because language is mediated by the left
  hemisphere, it is only natural to consider its
  role in theory of mind processing as well
  however, few studies have investigated theory of
  mind processing in individuals with left
  hemisphere damage (LHD) who have been diagnosed
  with aphasia.
• Previous findings suggest that language deficits
  in persons with aphasia may extend to and
  influence resource allocation abilities such that
  adequate task performance is hindered (Murray,
  Holland, Beeson, 1997 Tseng, McNeil,
  Milenkovic, 1993), which can have implications
  not only in clinical settings but also in
  functional contexts.
• In addition to impaired resource allocation
  abilities, individuals with aphasia may have
  impaired abilities in accurately monitoring their
  performances (Clark Robin, 1995).

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Purpose

• Purpose case study designed to examine
  inferencing abilities in persons with aphasia due
  to LHD
• Hypotheses
• (1) Individuals with aphasia will exhibit longer
  response times on mental inferencing tasks
  compared to the response times of non-brain
  damaged individuals.
• (2) Individuals with aphasia will exhibit more
  errors when responding to inference items related
  to the internal beliefs or motives of others
  compared to inference items related to physical
  causes or non-inference (filler) items.
• (3) Individuals with aphasia will perceive
  inference task difficulty differently than
  individuals without brain damage (i.e., graduate
  students).

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Methods

• Participants
• 3 participants with aphasia due to LHD
• At least a high school education
• Right-handed premoridly
• Adequate visual and hearing acuity as well as
  ability to indicate responses to testing stimuli
• No dementia or other neurological degenerative
  diseases
• No alcohol or substance abuse
• 2 graduate students controls for duration,
  accuracy, and perceived difficulty rating data

Western Aphasia Battery Aphasia Quotient
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Methods

• Procedures and Measures
• 3 types of oral and written stimuli (see Appendix
  for examples)
• Mental inferencing inferences regarding
  characters internal beliefs or motives
• Physical causation inferencing comparable to
  mental inferencing stimuli but involved explicit
  contradictions (e.g., something not working or
  unanticipated occurrences)
• Fillers did not involve inferencing, overt
  contradictions, or propositional conflicts
• Participants read/listened to stimuli texts,
  indicated true/false responses to corresponding
  statements (2 per story), and rated perceived
  level of difficulty for each set of stimuli.

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Results
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Results
Overall Percent Accuracy
Participants
8
Results
Accuracy of Responses Based on Type of Stimuli
100
100
83
83
75
67
67
67
67
Participants
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Results
Average Perceived Level of Difficulty (100 mm
scale)
55.74
Scale 0 Easy 100 Hard
46.56
22.0
17.22
3.28
Graduate students
Participants
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Discussion

• Individuals with aphasia exhibited overall longer
  response times on mental inferencing questions
  compared to non-brain damaged graduate students
  response times. Response times varied among
  participants with aphasia, which may be due to
  impaired linguistic abilities as discussed by
  Erickson, Goldinger, and LaPointe (1996).
• Participants with aphasia did not exhibit greater
  difficulties responding to mental inferencing
  questions as opposed to physical causation
  inferencing or filler questions. In fact, 2 of 3
  participants performed as well or better on
  mental inferencing questions compared to the
  other two question types. Tompkins, Scharp,
  Fassbinder, Meigh, and Armstrong (2008) found
  similar results and suggested other types of
  impairments may be present.
• Participants perceived task difficulty
  differently than individuals without brain damage
  (i.e., perceived the task as minimally difficult
  despite lower performance/accuracy). This was in
  contrast to results found by Clark and Robin
  (1995) and Murray, Holland, and Beeson (1997).

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Discussion

• Performance patterns observed across participants
  with aphasia
• Recency effectappeared to make it difficult for
  some participants to retain information at the
  beginning of a text by the time they reached the
  statements at the end
• Careless mistakes or rushing through and
  responding incorrectly
• Impaired language abilitiespoor comprehension
  may affect physical causation inferencing and
  non-inference (filler) processing
• Severity and type of aphasiadid not appear to
  affect participants performance
• Implications
• Avoid the assumption that persons with LHD and
  aphasia do not have (physical or mental)
  inferencing deficits or comprehension
  impairments, and assess these areas thoroughly.
• Consider the possibility of impaired resource
  allocation negatively affecting performance
  during task completion.

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Conclusion

• Perhaps participants had impaired resource
  allocation abilities and/or difficulty
  comprehending information within the texts rather
  than mental inferencing difficulties.
• Poor resource allocation appeared to affect
  participants abilities to process at least part
  of the stimuli presented.
• Impaired resource allocation, particularly when
  tasks involved increased attentional demands, has
  been found in other studies comparing persons
  with aphasia and persons without brain damage
  (Murray, Holland, Beeson, 1997 Tseng, McNeil,
  Milenkovic, 1993).
• Current and previous findings suggest that
  existing language deficits of individuals with
  aphasia can be accompanied by inefficient
  allocation of resources, which can negatively
  affect performance on tasks that require
  attention, whether or not those tasks involve
  inferencing.

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Appendix

• Mental inferencing text (Items A and B - missed
  by 1 participant)
• Tom, a burglar who has just robbed a shop, is
  making his getaway. As he is running home, Mary
  Davis, a police officer on her beat, sees him
  drop his glove. She doesn't know that Tom is a
  burglar, she just wants to tell him he dropped
  his glove. But when she shouts out to the
  burglar, "Hey, you! Stop!", he turns around, sees
  the officer, and gives himself up. He puts his
  hands up and admits that he robbed the local
  shop.
• A. Tom thinks the officer knows he is guilty.
  (True) B. Tom thinks the officer knows he is
  innocent. (False)
• Filler text (Item B - missed by all 3
  participants)
• Mike and Carol wanted to purchase a home by the
  end of the summer. They wanted to live in the
  country where it was peaceful and quiet. They
  always dreamed of having a large yard with many
  flower and vegetable gardens. Their realtor
  showed them several houses for sale, and then
  they finally found the one they wanted. It was a
  Victorian home with a huge yard located on a dead
  end street. Carol turned to Mike and said, I
  just know we are going to be happy here.
• A. Mike and Carol did not want to purchase a
  home by the end of the summer. (False) B. Mike
  and Carol wanted to purchase a home by the end of
  the spring. (False)
• Physical causation text (Items A and B - missed
  by 2 of the 3 participants)
• Bob shares an office with his co-worker Sandy,
  who has worked with him for years. The office is
  on the 8th floor of a building. Sandy always
  walks up the 8 steep flights of stairs to their
  office, and never sees anyone else in the
  stairwell. Bob refuses to walk and always takes
  the elevator because he carries many files every
  day and thinks that 8 flights is just too far to
  walk. One morning, Sandy saw many other employees
  in the stairwell, including Bob climbing the
  stairs with his heavy briefcase.
• A. Bob saw that the elevator was working.
  (False) B. Bob saw that the elevator was
  broken. (True)

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Selected References

• Clark, H.M., Robin, D.A. (1995). Sense of
  effort during a lexical decision task Resource
  allocation deficits following brain damage.
  American Journal of Speech-Language Pathology, 4,
  143-147.
• Erickson, R.J., Goldinger, S.D., LaPointe, L.L.
  (1996). Auditory vigilance in aphasic
  individuals Detecting nonlinguistic stimuli with
  full or divided attention. Brain and Cognition,
  30, 244-253.
• Gallagher, H.L., Frith, C.D. (2003). Functional
  imaging of theory of mind. Trends in Cognitive
  Sciences, 7, 77-83.
• Happe, F., Brownell, H., Winner, E. (1999).
  Acquired theory of mind impairments following
  stroke. Cognition, 70, 211-240.
• Murray, L.L., Holland, A.L., Beeson, P.M.
  (1997). Auditory processing in individuals with
  mild aphasia A study of resource allocation.
  Journal of Speech, Language, and Hearing
  Research, 40, 792-808.
• Tompkins, C.A., Scharp, V.L., Fassbinder, W.,
  Meigh, K.M., Armstrong, E.M. (2008). A
  different story on theory of mind deficit in
  adults with right hemisphere brain damage.
  Aphasiology, 22, 42-61.
• Tseng, C.H., McNeil, M.R., Milenkovic, P.
  (1993). An investigation of attention allocation
  deficits in aphasia. Brain and Language, 45,
  276-296.
• Vollm, B.A., Taylor, A.N.W., Richardson, P.,
  Corcoran, R., Stirling, J., McKie, S., et al
  (2006). Neuronal correlates of theory of mind and
  empathy A functional magnetic resonance imaging
  study in a nonverbal task. Neuroimage, 29, 90-98.