Cognitive Communication & Right Hemisphere Disorder

Instructor Information
  • Course: SLT503
  • Instructor: Ffion Roberts
  • Institution: Prifysgol Wrecsam, Wrexham University
Session Aims

By the end of this session you should be able to:

  1. Describe common cognitive-communication changes following right hemisphere damage.
  2. Explain theoretical accounts of right hemisphere language processing.
  3. Identify pragmatic, prosodic, and cognitive contributors to communication difficulties.
  4. Consider the SLT (Speech and Language Therapy) role in assessment and management.
Right Hemisphere Damage/Disorder (RHD)
  • Prevalence:
    • Estimated that 50% of adults with right hemisphere damage experience one or more deficits in cognition and communication (Blake, 2018).
  • Distinction from Aphasia:
    • People with RHD do not have aphasia but can exhibit deficits in language comprehension and production.
  • Common Deficits:
    • Apragmatism: Difficulty in conveying and comprehending intent and meaning.
    • Aprosodia: Difficulty in recognizing and expressing prosody.
    • Disorders of cognition impact communication effectiveness and efficiency which can include:
      • Attention
      • Memory
      • Executive Function
      • Anosognosia: Lack of awareness regarding one's own deficits.
Localisation of Right Hemisphere Functions
  • The clinical presentation of RHD is heterogeneous and unpredictable.
  • No clear patterns of co-occurrence suggesting underlying mechanisms or subtypes.
  • Currently, there is no established localization of functions within the right hemisphere.
Importance of the Right Hemisphere for Language

Two key theoretical accounts explain the role of the right hemisphere in language processing:

  1. Coarse Coding Hypothesis
  2. Suppression Deficit Hypothesis
Right Hemisphere Semantic Processing
Coarse Coding Hypothesis (Beeman, 1998)
  • Definition:
    • Fine Coding: Occurs predominantly in the left hemisphere, where a small set of dominant meanings or closely related features are activated, quickly inhibiting all others.
    • Coarse Coding: Occurs in the right hemisphere; a broader activation includes both dominant and subordinate meanings and multiple semantic features and maintains activation longer than the left hemisphere.
  • Implications for Comprehension:
    • Maintained broad activation aids comprehension by allowing re-interpretation of meanings as context evolves.
    • Overlap of semantic fields supports inference generation.
    • Example: "She looked with dismay at the flies and the odour coming from the basket of apples" implies "rotten" despite it not being immediately obvious from the individual words.
    • Facilitates comprehension of non-literal language through an initial literal interpretation that can be reinterpreted.
Suppression Deficit Hypothesis
  • Based on Gernsbacher’s Structure Building Framework of Comprehension (Gernsbacher, 1990).
  • Mechanism:
    • Context can enhance or suppress specific semantic features.
    • Individuals with RHD are less efficient at suppressing contextually inappropriate meanings (Tompkins et al. 1999) but do not process them inaccurately, only more slowly.
    • This inefficiency in semantic processing adversely affects comprehension, particularly in cognitively demanding tasks like discourse.
Apragmatism
  • Definition:
    • Disorder in conveying and/or comprehending meaning or intent through linguistic, paralinguistic, and/or extralinguistic modes of communication (Minga et al. 2022).
  • Identification and Treatment Challenges:
    • Can be subtle, making it difficult to identify, measure, and treat.
  • Common Impairments:
    • Topic maintenance, discourse coherence, slow inference generation, turn-taking, question use, integration of contextual nuance, content-deprived speech, disinhibition, and tangential discourse.
Assessment and Treatment of Apragmatism
  • Assessment:
    • Coarse coding and suppression deficits are challenging to assess.
    • Various questionnaires and pragmatic assessments available.
    • Specific discourse assessments in RHD batteries.
    • Utilize sections from aphasia tests for discourse assessment.
  • Treatment Approaches:
    • Contextualization Treatment (Context-Based Therapy), social communication strategies, structured feedback, modeling, rehearsal, self-monitoring training, biofeedback, and group work.
Aprosodia
  • Definition:
    • A deficit in discriminating, identifying, or classifying prosodic patterns that convey emotion, grammar, or pragmatics.
  • Types of Prosody:
    • Affective Prosody: Communication of emotional content.
    • Linguistic Prosody: Uses prosody to convey meaning such as intonation patterns.
    • Indexical Prosody: The idiosyncratic prosody that makes an individual's voice recognizable.
Assessment and Treatment of Aprosodia
  • Assessment:
    • Limited published assessments specifically for prosody.
    • Importance of gathering patient and family/friend opinions.
    • Utilization of perceptual assessments to measure prosody.
  • Treatment Strategies:
    • Some evidence suggests typical motor speech therapies for prosody yield benefits.
    • Cognitive-affective treatment techniques (Rosenbek et al. 2006).
    • Compensatory strategies and affective prosody recognition training for receptive deficits (Durfee et al. 2021).
Anosognosia
  • Definition:
    • Reduced awareness of one's deficits, often not binary; may vary by type of deficit awareness (e.g., aware of some deficits but not others).
  • Impact:
    • Many individuals with RHD do not recognize changes in their speech, language, or cognition, affecting motivation for rehabilitation (Azouvi & Peskine, 2012).
  • Research Focus:
    • Most research emphasizes anosognosia in hemiplegia.
Cognitive Deficits in RHD
Attention
  • Various forms of attention contribute to communication and may be localized to multiple areas in both hemispheres.
  • Deficits seen in RHD include:
    • Difficulty maintaining topic focus.
    • Trouble maintaining focus during cognitively demanding tasks such as discourse.
    • Unilateral Inattention/Naglect:
    • Inability to attend to items on the left side of their body or environment, affecting reading/writing (neglect dyslexia/dysgraphia).
    • Types of Neglect:
      • Personal neglect, peripersonal neglect, extrapersonal neglect.
Memory
  • A set of processes involving attention, encoding, storage, and retrieval of information.
  • RHD is found to cause more deficits in visual memory than verbal memory and may significantly affect autobiographical and working memory.
  • Common Issues:
    • Prospective memory deficits are also prevalent following brain injuries.
Executive Function
  • Comprises higher-level cognitive processes essential for goal-directed tasks.
  • Components:
    • Initiation, planning, organization, self-monitoring, reasoning, and problem-solving.
  • Executive function deficits frequently seen in adults with RHD, although it is unclear if these deficits are more prevalent than in left hemisphere damage.
Assessment and Treatment of Cognitive Components
  • Assessment:
    • Speech and Language Therapists (SLTs) assess cognition and consider cognitive implications in usual assessments.
    • Integration of informal measures and collaboration with the multi-disciplinary team (MDT) is essential.
  • Treatment:
    • Implementation of compensatory strategies, environmental supports, and task-specific treatment/systematic instruction.
Key Take-Homes
  • RHD can substantially impact communication.
  • Difficulties often encompass pragmatics, prosody, and cognition.
  • Deficits may be subtle yet significantly impactful on communication effectiveness.
  • Discourse analysis is a crucial area of focus for understanding communication challenges.
References
  • Azouvi P., Peskine A. (2012) Anosognosia and denial after right hemisphere stroke. The Behavioural and Cognitive Neurology of Stroke, Cambridge University Press.
  • Blake, M., Frymark, T., and Venedictov, R. (2013) An Evidence-Based Systematic Review on Communication Treatments for Individuals With Right Hemisphere Brain Damage American Journal of Speech-Language Pathology. American Speech Language Hearing Association.
  • Blake, M. (2022) Communication Disorders Associated with Right-Hemisphere Brain Damage. In Papathanasiou, I. and Coppens, P. (2022), Aphasia and related neurogenic communication disorders. (pp 405 – 423) Burlington, MA: Jones & Bartlett Learning.
  • Blake, M. (2022) Cognitive Disorders Associated with Right-Hemisphere Brain Damage. In Papathanasiou, I. and Coppens, P. (2022), Aphasia and related neurogenic communication disorders. (pp 435 – 447) Burlington, MA: Jones & Bartlett Learning.
  • Manasco, H. (2020), Introduction to Neurogenic Communication Disorders. 3rd ed. Burlington: Jones & Bartlett Learning.
  • Durfee AZ, et al. (2021) Explicit Training to Improve Affective Prosody Recognition in Adults with Acute Right Hemisphere Stroke. Brain Sci. 11(5):667. doi: 10.3390/brainsci11050667.
  • Ferré, P., et al. (2011) Clinical Focus on Prosodic, Discursive and Pragmatic Treatment for Right Hemisphere Damaged Adults: What's Right? Hindawi Limited.
  • Fleming, J. et al. (2015) The efficacy of prospective memory rehabilitation plus metacognitive skills training for adults with traumatic brain injury: study protocol for a randomized controlled trial. Trials.
  • Minga, J., et al. (2021) Making sense of right hemisphere discourse using RHDBank. Topics in Language Disorders, 41(1), 99-122.
  • Minga, J., et al. (2022) Apragmatism: The renewal of a label for communication disorders associated with right hemisphere brain damage. Wiley.
  • Papathanasiou, I. and Coppens, P. (2022), Aphasia and related neurogenic communication disorders. Burlington, MA: Jones & Bartlett Learning.