Etiologies of Acquired Neurogenic Language Disorders

What is a stroke?

- Cerebrovascular accident (CVA); brain attack

- Temporary/permanent disruption of blood supply to the brain

- Most common cause of primary neurogenic speech and language disorders

- Occlusive (Ischemic)

- Hemorrhagic

Occlusive (Ischemic)

80-85%

Hemorrhagic

15-20%

Occlusive types of strokes

restriction in blood supply due to a blockage in an artery

- thrombotic

- embolic

Thrombotic (most common)

blockage buildup in an area

Embolic

plaque buildup that moves through the body and causes blockage away from origin

Hemorrhagic Types

rupture blood vessel, excessive bleeding

- intracerebral

- subarachnoid

- subdural

- epidural

Aneurism

artery gets a weak spot in its walls, stretches and bulges

- can be repaired surgically before causing a stroke

Arteriovenous Malformation

- abnormally developed artery or vein (occurs prenatally)

-- high blood pressure can cause more susceptibility to rupture

-- 24-45 more common

Hemorrhagic Strokes Characteristics

- Disrupts the blood supply to the brain

- Leaks blood into brain and can cause damage to other areas

Hematoma in the brain

accumulation of blood

Intracerebral

- in the brain tissue

- cortical areas, subcortical areas, consciousness, nervous system functions

- bleeding and swelling

Subarachnoid

- between the arachnoid and dura mater

- more associated with traumatic brain injury

Subdural

below the dural layer

Epidural

epidural layer

What causes a stroke

- atherosclerosis

- consequences

- lifestyle-related factors

Atherosclerosis

- buildup of matter in an artery

- lipids, fatty cells, cholesterol, cell debris

Consequences leading to stroke

- narrow artery channels

- reduced elasticity

Life-style related factors

- diet

- lack of exercise

- high stress

- smoking

--- genetics can also play a role

Potential Stroke Triggers: things that have been identified leading up to the onset of a stroke

- Excessive alcohol intake within the past day or week

- Infection (e.g., COVID-19, cold, flu, urinary tract infection) within the last week or month

- Excessive eating

- Positive emotions

- Negative emotions, psychological distress, anger

- Sudden posture change, especially when startled within the previous 2 hours

- Birthday

- Drug use

- Anesthesia

- Surgery

- Physical exertion

Predisposing Factors

- vascular abnormalities

- hematological pathologies

- type 1 diabetes

- age

- sex

Type 1 diabetes

diagnosed as a child

Age

chances double every decade over 55

Sex

o Women may be more likely (not a strong statistic)

o Consider lifestyle, pharmaceutical

Physiological Effects of stroke

- edema

- electrochemical changes

Edema

- may increase intracranial pressure

- swelling in the areas around the blockage

Electrochemical changes

o Changes in the production of neurotransmitters

o Production and uptake can be affected

o Removal of toxins

Functional- Diaschisis

- one area affected due to the effect of another area usually communicating with it

Infarct

area of dead tissue, other areas may recover but nothing reversible for dead area

Ischemic Penumbra

Margin of tissue around the infarct

The first 8-16 seconds

may result in loss of consciousness

After 20-25 seconds

changes to electrical activity in neurons

After 3-5 minutes

may result in irreversible damage

BEFAST

- balance

- eyes

- face

- arm

- speech

- time

Balance

loss of balance

Eyes

lost vision

Face

face drooping

Arm

arm weakness

Speech

speech difficulty

Time

time to call an ambulance

Thrombolytic drug treatment for ischemic stroke only (tPa)

- Treatment that can be administered if they are certain that it is an ischemic stroke

- Busts up the plaque

- Loosens the blockage

- Must be done between 3-4.5 hours

- If given to a hemorrhagic patient, they can bleed to death

Transient Ischemic Attack (TIA)

- Mini stroke

- A temporary blockage of the blood supply to any area of the brain

- Usually lasts less than 30 minutes (in some cases: up to 24 hours)

- Often occur before a full-blown stroke

o The warning signs for TIA are the same as those for strokes

Causes of TIA

o A thrombus or an embolus

o A change in blood pressure

Noticeable changes after TIA

challenges with motor, sensory, cognitive, or linguistic functions

Hypoperfusion

- An insufficiency in blood supply to the brain due to

o Heart problems

o Hemorrhaging elsewhere in the body

§ Not a stroke or TIA per se

§ It may cause necrosis (brain tissue death) if blood flow is not resumed within a critical time period (reperfusion)

Lifestyle Factors

- smoking

- diet/weight management

- physical activity

- manage stress/mental well being

Pharmacological Intervention

- hypertension medications

- anticoagulants

- antiplatelets

- vasodilators

Surgical Intervention

- endarterectomy

- angioplasty

Stroke Mortality

150,000 die annually in US

Survival and life after stroke

o 50% can go back home

o Highly variable

Effects of a stroke

o Ischemic

o Note: a-fib risk

o Hemorrhagic *intracerebral

80%

of aphasia cases come from a stroke

Ischemic Stroke Recovery

o 1st 2-4 weeks

--- First 2 weeks neurological progress

--- Due to a reduction in swelling

o Middle severity ranges

--- More than mild, more measurable recovery over time

o Destroys nerve fiber tracts

o Spontaneous language recovery 3 months within the first year

Hemorrhagic Stroke Recovery

o Slower initially

--- Slower medical recovery

--- More bleeding, potential surgery

o Rapid, then stable

o 6 months

--- Spontaneous neurological healing should have taken place

o Does not destroy nerve fiber tracts

--- How much was destroyed in the brain

TBI Numbers

- 14-25

-

- 15-19

- 2x male

- 823.7 per 100,000

- $Billions in the us

Open Head

open the skull, gun shot, knife wound

Closed Head

acceleration, deceleration injuries

Translation Injury

Head is stuck in the direction of the strike

Coup-contercoup injury

brain displaced backwards and injures both sides

Rotational

Rotated brain, sheering of axons

Depending on severity

the more diffused the damage can be

Communication symptoms likely to be experienced by TBI survivors

- cognition

- language

- speech

- hearing

- behavior

Cognition

impaired memory (verbal and non-verbal), sensory integration, attention, executive functions, reasoning, etc.

Language

- difficulties with word finding, comprehension and production of abstract language, verbal reasoning, verbal learning, pragmatic abilities

- Dyslexia, dysgraphia, paraphasias

Speech Symptoms

- slowed and slurred speech

- inappropriate intonation

Hearing

- hearing loss (conductive and sensorineural)

- speech discrimination problems

- central auditory processing disorders

Behavior

personality changes, mood changes, depression, hyperactivity, etc.

Memory Impairment

o Working

o Short-term

o Long-term

o Procedural/implicit

o Declarative/explicit

o Episodic

o Semantic

o Prospective

o Source

Amnesia

o Anterograde

o Retrograde

o Paramnesia

Blast Injuries

- Blast induced (BI) TBIs

- Result from rapid phases of over and under pressurization of air compared to normal atmospheric pressure

o War related explosives

Four broad categories of blast injuries

- primary

- secondary

- tertiary

- quaternary

primary

result from "wave-induced changes in atmospheric pressure"

secondary

caused by objects set into motion (e.g. flying debris, structural collapse)

tertiary

caused by an individual being set into motion as a result of an explosion and hitting a solid surface

quaternary

caused by blood loss from bodily injury or exposure to toxic gas associated with an explosion

Leading causes of pediatric TBI

o Falls (50.2%)

o Struck by/against events (24.8%)

o Motor vehicle accidents (6.8%)

o Assault (2.9%)

o Unknown/other (15.3%)

Primary cause for infants, toddlers, and preschoolers

o Falls and assaults (shaken baby syndrome or other physical abuse)

Shaken baby syndrome

- A form of child abuse that happens when an infant or small child is violently shaken

- Consequences

o Learning disabilities

o Physical disabilities

o Visual disabilities or blindness

o Hearing impairment

o Speech disabilities

o Cerebral Palsy

o Seizures

o Behavior disorders

o Cognitive impairment

o Death

What are concussions and mild TBI?

- A "complex pathophysiological process affecting the brain, induced by biomechanical forces"

- Often considered synonymous with mild TBI (mTBI)

- May or may not be accompanied by loss of consciousness

- The consequences are not always temporary

- A risk factor for future onset of mild cognitive impairment and dementia

Post-Concussive syndrome

o Symptoms from a concussion, lasts for weeks or months

o High school athletes, 10% will have post concussive syndrome

o Some age groups as high as 30%

o Some believe structural damage is the cause of post concussive syndrome

Others believe it's a psychological factor

Post-concussive syndrome signs and symptoms

- Headaches

- Dizziness

- Fatigue

- Irritability

- Anxiety

- Insomnia

- Loss of concentration and memory

- Ringing in the ears

- Blurry vision

- Noise and light sensitivity

- Rarely, decreases in taste and smell

Risk Factor

- Increased age

- Women more likely to be diagnosed, just could be women seek more medical care

- Falls -> the most common cause of TBI (

- Prevention

appropriate safety monitoring and accommodations

- Motor vehicle related TBIs -> The second most common cause

- Prevention

Wearing helmets, seatbelts, etc

Sports related injuries

- prevention

Wearing helmets

Bacteria and Viruses

- Microscopic organisms that may cause inflammation in the brain

- Neurogenic communication disorders due to bacterial/viral infections

Encephalopathies

infections that affect the cortex

Meningitis

an inflammation of the meninges surrounding the brain

Meningoencephalitis

an inflammation caused by an infection

HIV

Human immunodeficiency virus

AIDS

acquired immunodeficiency syndrome

Other infections impacting cortical function

- Prion Disease

o Aka., spongiform encephalopathies

o Leads to neurogenerative conditions

o Creutzfeldt-Jakob Disease (CJC)

Neoplasms

- Literally means "new growth"

- Aka tumor

- Two major types of tumors

Malignant

cancerous

Benign

non-cancerous

Etiologies

o Primary tumors result from uncontrolled growth of two types of cells

--- Glial Cells (Gliomas)

--- Meningeal Cells (Meningioma)

o Secondary (metastatic) tumors are spreading tumors arising from elsewhere in the body and travel to the brain via the blood supply or lymphatic system

Toxemia

- Poisoning, irritation or inflammation of nervous system tissue due to toxic substances

- Toxic encephalopathy

Examples of Toxins

o Alcohol

o Recreational drugs

o Excessive use of certain dietary substances

Toxemia Variable Symptoms

o Reduced cognition

o Somnolescence

o Personality changes

Diabetes Mellitus (DM)

o A chronic disorder of carbohydrate metabolism caused by

--- Abnormal insulin function

--- Insulin deficiency