Cognitive-Communication Disorders

Disorders of Consciousness

  • Definition: Severely altered consciousness with minimal evidence of self or environmental awareness.
  • Levels of Consciousness:
    • Level: Wakefulness (Level of consciousness)
      • Conscious wakefulness
      • Drowsiness
      • REM sleep
      • Light sleep
      • Deep sleep
    • Content: Awareness (Content of consciousness)
      • Lucid dreaming
      • General anesthesia
      • Coma
      • Locked-in syndrome
      • Minimally conscious state
      • Vegetative state
  • Minimally Conscious State:
    • Recognizable but inconsistent yes/no responses & response to stimuli
    • Re-emergence of functional communication
    • Responses are more reliable
    • Prone to episodes of disorientation & agitation
  • Acute Confusional State:
    *Complete loss of spontaneous or stimulus-induced arousal
  • Coma:
    • No purposeful motor activity, following commands, or response to stimuli
  • Vegetative State:
    • Wakeful unconsciousness
    • Spontaneous eye opening, but continued absence of communication or behavioral response to stimuli
  • Locked-in syndrome:
    • Not a disorder of consciousness, but included for comparison.
    • Normal sleep-wake cycles, sentence-level speech (often confused), reliable yes-no responses, object recognition, normal motor function.
  • Etiologies:
    • Brain injury:
      • Traumatic
      • Non-traumatic: anoxia, hypoxia, non-traumatic hemorrhage, seizure
    • Late-stage neurodegenerative disease

Right Hemisphere Disorders

  • Functions of the Right Hemisphere:
    • Perception of depth, distance, shapes
    • Localization of targets in space
    • Identification of figure-ground relationships
    • Math & visuospatial skills
    • Prosody
    • Facial expression
    • Gesture
    • Body language
    • Supra-linguistic communication
    • Music processing
    • Attention
  • Etiologies:
    • Brain injury:
      • Traumatic
      • Non-traumatic: anoxia, hypoxia, non-traumatic hemorrhage, seizure
    • Late-stage neurodegenerative disease
  • Prosopagnosia:
    • Inability to recognize a familiar face
    • Type of visual agnosia (inability to perceive visual stimuli appropriately, not due to damage to the eyes or optic nerve).
    • Can still recognize a familiar person by voice, smell, clothing, or distinctive features
  • Difficulty with facial expressions:
    • Less able to correctly identify emotions conveyed on faces of communication partners.
    • Leads to less informed and more literal interpretation of utterances
    • May have difficulty conveying meaning through facial expression, particularly on left side of the face
  • Prosodic deficits:
    • Difficulty comprehending emotional content of speech, especially with damage in right parietotemporal areas, leading to misinterpretations
    • Difficulty using prosody to express emotion or meaning (flat affect)
  • Inferencing deficits:
    • Inferencing: the ability to take previous knowledge and experience and apply it to the interpretation of meaning
    • Tend to “get stuck” on individual details without grasping the full meaning (gestalt)
    • Inappropriate perception of facial expressions, humor, sarcasm, and other nonliteral expressions
    • NOT due to a language disorder
  • Discourse deficits:
    • Discourse: exchange of communicative information between the speaker and listener
    • May be unaware of general topic, purpose, presence and limits of knowledge shared between communication partners, appropriateness of expression of certain ideas/emotions
    • Breakdowns in communication
  • Unilateral neglect:
    • Also known as “Hemispatial neglect,” “Contralateral neglect,” “Left neglect”
    • Deficit of attention to the left side following right parietal lobe lesion, without sensory deficits

Dementia

  • Definition: Loss of memory, language, problem-solving, and other thinking abilities that are severe enough to interfere with daily life; umbrella term.
  • Diagnostic Criteria:
    • Evidence of significant cognitive decline from previous level of performance in one or more cognitive domains:
      • Learning & memory
      • Language
      • Executive function
      • Complex attention
      • Perceptual-motor
      • Social cognition
    • Cognitive deficits interfere with independence in everyday activities
    • Cognitive deficits do not occur exclusively in the context of delirium
    • Cognitive deficits are not better explained by another mental disorder (e.g., major depressive disorder, schizophrenia)
  • Mild Cognitive Impairment (MCI):
    • Evidence of modest cognitive decline from previous level of performance in one or more cognitive domains:
      • Learning & memory
      • Language
      • Executive function
      • Complex attention
      • Perceptual-motor
      • Social cognition
    • Cognitive deficits do not interfere with independence in everyday activities
    • Cognitive deficits do not occur exclusively in the context of delirium
    • Cognitive deficits are not better explained by another mental disorder (e.g., major depressive disorder, schizophrenia)
  • Etiologies:
    • Neurodegenerative disease:
      • Alzheimer’s disease
      • Frontotemporal lobar degeneration
      • Lewy body disease
      • Parkinson’s disease
      • Huntington’s disease
      • Prion disease
    • Traumatic brain injury
    • Substance/medication use
    • Infection: e.g., HIV
  • Alzheimer’s Disease:
    • Progressive, neurodegenerative disease
    • Pathologic accumulation of proteins into amyloid plaques (A) and neurofibrillary tangles (tau)
    • Characteristic spread, starting in medial temporal lobes
      • Preclinical phase: 20+ years
      • Clinical: 8-10 years
    • Mostly idiopathic
    • No cure
  • Stages of Alzheimer’s Disease:
    • Early stage:
      • Declarative memory deficits
      • Wandering, getting lost
      • Anomia
      • Impaired reasoning/judgement
      • Personality & behavior changes
    • Moderate stage:
      • Increasing memory loss and confusion
      • Difficulty recognizing family and friends
      • Difficulty learning new things
      • Impulsive behavior
      • Hallucinations, delusions, and paranoia
    • Severe stage:
      • Cannot communicate verbally
      • Completely dependent on others for their care
      • Limited movements; bed-bound
  • Communication deficits in early Alzheimer’s Dementia:
    • Word omissions
    • Slight anomia
    • Drift from topic to topic
    • Difficulty comprehending new information
    • Difficulty understanding humor, analogies, sarcasm, and indirect/non-literal statements
    • Vague speech
    • May talk too long
    • May not appropriately initiate conversation due to apathy
  • Communication deficits in mid-stage Alzheimer’s Dementia:
    • Anomia disrupts conversation
    • Reliance on automatic speech
    • Sentence fragments
    • Difficulty understanding grammatically complex sentences
    • Repeats ideas, forgets topics, talks more about past events
    • Loss of sensitivity to conversational partners
    • Rarely corrects mistakes
  • Communication deficits in late Alzheimer’s Dementia:
    • Marked anomia
    • Neologisms
    • Some grammar preserved
    • Severe comprehension deficits
    • Empty speech
    • Perseveration
    • Echolalia: unsolicited repetition of vocalizations
    • Unaware of surroundings and context

Traumatic Brain Injury (TBI)

  • Definition: Serious damage to the brain resulting from external force.
    • Coup-Contrecoup
    • Rotational forces
    • Sudden acceleration
    • Closed-head or open-head/penetrating
  • Phineas Gage Case Study:
    • 1848, Vermont
    • 25-year-old railroad foreman
    • Premature explosion drove tamping iron (1.1 m x 6 mm; 6 kg) through left cheek and out of the top of his skull
    • Remained conscious until wound became infected
    • Regained consciousness after 4 weeks
    • Blind in left eye, left facial weakness
    • No apparent neurological deficits initially
    • Developed epilepsy and died in 1861
    • Personality changes: fitful, irreverent, indulging in profanity, impatient, a child in his intellectual capacity with the animal passions of a strong man; friends said he was “no longer Gage.”
  • Cognitive deficits following TBI:
    • Disorders of consciousness
    • Disorientation
    • Agitation: feeling of irritability or severe restlessness
    • Attentional impairments:
      • Selective, sustained, alternating, divided attention
    • Memory loss:
      • Retrograde: before injury – pretraumatic
      • Anterograde: after injury – posttraumatic
    • Executive dysfunction
    • Personality changes
  • Communication deficits following TBI:
    • Determined by location and extent of damage in the brain & level of alertness
    • May have slow speech rate or flat affect
    • Speech may be irrelevant, confabulatory, circumlocutory, tangential, fragmented, non-cohesive, but linguistically acceptable
    • Adequate comprehension if speech is structured and literal
    • Comprehension suffers with changes in topic or if meaning depends on metaphor, humor, sarcasm, etc.
    • Errors consistent with inadequate verbal planning, problem-solving, or inhibition

Summary

  • Cognitive processes, including alertness, attention, memory, and executive function, are required for successful communication
  • Cognitive-communication disorders depend on the etiology, location, and nature of the underlying neural deficit
  • Common etiologies of cognitive-communication disorders are disorders of consciousness, right hemisphere disorder, dementia, and TBI