Aphasia Notes

Aphasia

  • Wallace, 2014: Regardless of time left, each life has value; elders' gray hair signifies wisdom.

Related Disorders and Etiologies

  • Right Hemisphere Disorders (RHD)
  • Primary Progressive Aphasia (PPA)
  • Traumatic Brain Injury (TBI)
  • Dementia

Basic Epidemiology Terms

  • Incidence:
    • Number of newly diagnosed cases of a disease.
    • Incidence rate = new cases / # persons at risk
    • Another term for illness, not deaths.
  • Prevalence:
    • Total number of cases of a disease existing in a population.
    • Prevalence rate = # of cases / total population
  • Mortality:
    • Another term for death.
    • Mortality rate = # deaths / total population

Aphasia Definitions

  • Oliver Sacks: Aphasia results in the inability to communicate verbally, leading to frustration and isolation.
  • Daniel Webster: Communication is the most important power to retain as it enable to regain any loss.
  • Basic Definition:
    • Acquired communication disorder.
    • Neurological cause.
    • Affects reception and expression of language.
    • Not a sensory, motor, or intellectual disorder.

Prevalence of Aphasia

  • Simmons-Mackie et al., 2018:
    • Cumulative prevalence in the US (stroke, TBI, brain tumor) ranges from 2,463,681 to 4,108,469 people.
    • Conservative estimate: approximately 2,500,000 people living with aphasia in the US.

Stroke Definition

  • Temporary or permanent disruption in blood supply to the brain; technically cerebrovascular accident (CVA).
  • Most Common Symptoms:
    • Sudden numbness on one side of body.
    • Difficulties speaking/understanding.
    • Abrupt dizziness.
    • Sudden severe headache.

BE FAST

  • Educational resources from Dr. Jessica Richardson about BE FAST.
  • Available in English, Spanish, and Navajo.

Stroke Facts

  • Nearly 1 in 4 strokes happen in people who have had a stroke (Tsao et al., 2023).
  • Every ~3 minutes someone dies of stroke (CDC, 2023).
  • Strokes can occur at any age (65% happen in ages 65+).
  • Every 40 seconds, someone in the USA has a stroke (Tsao et al., 2023).
  • Leading Causes: High blood pressure, high cholesterol, obesity, and diabetes.
  • Stroke is a leading cause of long-term disability.
  • Stroke risk is nearly twice as high for Black adults compared to White adults.

Blood Supply to the Brain -- Quotables

  • Bhatnagar: Brain cells depend on uninterrupted oxygenated blood supply and cannot store energy; ischemia effects are rapid and disabling.
  • Brookshire: The brain is remarkably intolerant of sudden reductions in its oxygen and glucose supplies.

Blood Supply to the Brain -- Key Arteries

  • Anterior cerebral arteries (ACA)
  • Anterior communicating artery
  • Internal Carotid Arteries (ICA)
  • Middle cerebral arteries (MCA)
  • Posterior Cerebral Arteries (PCA)
  • Basilar Artery
  • Superior cerebellar artery (SCA)
  • Anterior Inferior Cerebellar Artery (AICA)
  • Vertebral Arteries
  • Posterior Inferior Cerebellar Arteries (PICA)

Vascular Pathology

  • Vascular pathologies are either:
    • Occlusive (blockage) – Ischemic (~85%)
    • Hemorrhagic strokes (~15%)
  • Time is brain:
    • 5-10 sec without blood = unconsciousness
    • 20-25 sec without blood = low neural electrical activity
    • 4-6 min = irreversible brain damage

Ischemic (blockage) Strokes

  • Thrombotic: The blood clot develops in blood vessels inside the brain.
  • Embolic: The blood clot develops elsewhere and travels to the brain.
  • Risk factors:
    • Atherosclerosis / arteriosclerosis
    • Lifestyle factors, other medical conditions, medical history.

Transient Ischemic Attack (TIA)

  • Limited periods of reduced or restricted blood flow.
  • Symptoms depend on the site of TIA.
  • TIAs are medical emergencies.
  • Often called mini-stroke, but that’s not an accurate name.
  • It lasts a few minutes to several hours.
  • MAJOR stroke predictor.

Ischemic Stroke

  • Penumbra: area around the lesion (perilesional, peri-infarct).
  • Edema: Brain swelling around the lesion.

Treatments for Ischemic Stroke

  • Tissue Plasminogen Activator (tPA):
    • Made of a protein that can dissolve blood clots.
    • Used in ischemic strokes, contraindicated in hemorrhagic strokes.
    • Administer within three hours of stroke onset.
  • Tyrosine Kinase Inhibitor (TKI):
    • New
    • Potentially given WITH tPA
  • Tenecteplase (TNK):
    • Also made of a protein that can dissolve blood clots.
    • Results in less unintended bleeding.
    • Can be given in a bolus within 30 minutes

Hemorrhagic Strokes

  • Occurs when a blood vessel in the brain suddenly bursts.
  • Pressure builds up in the nearby brain tissue, causing more damage.

Types of Hemorrhage

  • Intracerebral hemorrhage: Bleeding from a blood vessel within the brain.
    • Causes: aneurysm, arteriovenous malformation (AVM), trauma.
  • Subarachnoid hemorrhage: Leakage of blood into the subarachnoid space.
    • Causes: aneurysm, trauma, and tumors.

Hemorrhagic Stroke (MRI)

  • Examples: Aneurysm, Arteriovenous Malformation
  • Common locations of aneurysms: anterior cerebral artery (40%), middle cerebral artery (34%), internal carotid artery (20%), posterior communicating artery (4%), basilar artery.

Stroke Recovery Patterns

  • Ischemic stroke: More predictable recovery pattern
  • Hemorrhagic stroke: Less predictable recovery pattern

Cerebral Perfusion

  • Blood flow at the level of capillaries.
  • Generally measured by cerebral blood flow (CBF).
    • Volume of blood delivered to a tissue mass per unit of time.
    • Milliliters per 100 grams of tissue per minute (mL/100 g/min).
    • Gray matter = ~60 ml/100g/min
    • White matter = ~30-40 ml/100g/min

Cerebral Perfusion in Acute Stroke Recovery

  • Hillis et al., 2001:
    • Reperfusion was correlated with comprehension improvement (in 5 out 6 participants).
    • Also correlated with naming for all participants.
  • Hillis et al., 2005:
    • N=50 participants.
    • Association between hypoperfusion and visual neglect.
  • Fridriksson et al., 2002:
    • Correlation between hypoperfusion and aphasia severity at 24 hours post-stroke.
  • Impaired cerebral perfusion is commonly reported in acute and subacute phases of stroke recovery.

Cerebral Perfusion in Chronic Stroke Recovery

  • Richardson et al. in 2011:
    • Decrease in left hemisphere perfusion, primarily in peri-infarct tissue.
    • Strong relationship between increased infarct size and decreased perfusion.
  • Fridriksson et al., 2012
    • Each patient's lesion was sectioned into 7 adjacent 3 mm perilesional regions.
    • Sections extended 24mm beyond the infarct rim.
  • Fridriksson et al., 2012; Richardson et al., 2012:
    • CBF in residual naming areas was a significant predictor of change in correct naming.
    • Structural damage and/or hypoperfusion in the left inferior frontal gyrus predicted the presence of chronic AOS.

Treatment Approaches for Cerebral Perfusion Deficits

  • TMS (Transcranial Magnetic Stimulation)
  • tDCS (transcranial Direct Current Stimulation)

Aphasia Causes

  • Sudden Onset: Stroke
  • Insidious: Tumors, Other progressive diseases
  • Traumatic Brain Injury (TBI)
  • Obstructive Hydrocephalus
  • Toxic Damage

Traumatic Brain Injury (TBI)

  • Open head injuries / Penetrating head injuries
  • Closed head injuries/ Blunt traumatic brain injuries.
  • The majority are people who have fallen or who have been in motor vehicle accidents, sporting activities, military combat, victims/perpetrators of violence, or unexpected trauma.

Traumatic Brain Injury symptoms

  • Cognitive-communicative impairments
Frontal Lobe Syndrome / dysexecutive syndrome
  • Cluster of behavioral, affective, and cognitive symptoms resulting from frontal lobe damage.
  • Executive function and pragmatic deficits.
  • “Personality change.”
  • Case study of patient EVR (Eslinger and Damasio, 1985):
    • Resection of a meningioma.
    • Exhibited dramatic personality changes.
    • Both his marriage and his career suffered.
Concussion and mild TBI
  • Concussion is the mildest form of TBI
  • FDA, 2018: UCH-L1 and GFAP proteins (blood test)

Aphasia Causes - Continued

  • Intracranial tumors
    • Abnormal masses of tissue in the brain or skull.
      • Cells grow and multiply uncontrollably
    • Cancerous or noncancerous
    • Categorized as:
      • Primary
        • Originate in the brain
        • Examples: meningioma and glioma
      • Secondary or metastatic
        • Originate in another part of the body
        • More common than primary
  • Common symptoms:
    • Headaches
    • Seizures
    • Personality or behavior changes
    • Weakness or paralysis in one side of the body
    • Loss of balance
    • Confusion and disorientation
    • Memory loss
  • Surgical treatment success depends on:
    • The extent
    • The location
    • The time of diagnosis
  • Obstructive Hydrocephalus
    • Non-communicating hydrocephalus.
    • CSF flow is blocked in the passages that connect the ventricles.
    • In chronic hydrocephalus, the brain becomes more vulnerable to aging-related changes.
  • Toxic damage
    • Toxemia: poisoning, irritation, or inflammation of nervous system tissue caused by exposure to harmful substances.
    • Toxic encephalopathy: reversible brain dysfunction caused by factors like systemic toxemia, metabolic disorders, and hypoxia during acute infections.
    • Drug use and stroke.
  • Dementias
  • Primary Progressive Aphasia (PPA)

History of Aphasiology

  • Egyptian surgeon BCE: notes loss of use of words.
  • Hippocrates 400 BC: Brain exercises greatest power.
  • 1315 (Bologna): First officially sanctioned systemic human dissection.
  • Vesalius 1500: First nervous system insights
  • Gesner 1770: Speech amnesia
  • Marc Dax Early 1800s: Hemispheric asymmetry. Correlation between brain structure and function
  • Franz Joseph Gall Early 1800s
  • Paul Broca Mid 1800s: Mr. Tan-Tan (Leborgne) and named it Aphemia; Correlation between brain structure and function.
  • Carl Wernicke Mid to late 1800s: