Acute Etiologies of Neurogenic Communication Disorders

Etiology

underlying medical cause of a symptom or deficit

Etiologies of Neurogenic Communication Disorders

* Stroke
* TBI
* Surgical trauma
* Degenerative disorders
* Infectious diseases

Idiopathic etiology

deficits or symptoms that are of an unknown cause

Central Nervous System

brain + spinal cord

Peripheral Nervous System

somatic (voluntary) and autonomic nervous (involuntary) system

Cerebrovascular Accident (CVA)

also known as a STROKE

Stroke

* 3rd leading cause of death in the US
* death is more common in women than men
* can occur within any area of the brain or brainstem

Factors that increase risk of strokes

Tobacco use, physical inactivity, atrial fibrillation, high blood pressure

Cause of Strokes

Brain tissue is permanently destroyed or temporarily does not function due to the decreased or absent blood supply to affected brain tissue

Anoxia

**complete** lack of oxygen to a cell

Hypoxia

**partial** lack of oxygen to a cell

6 to 8 minutes

how long the brain can survive without oxygen

Ischemic Stroke

Occurs when a blood vessel in the brain is occluded (makes up the majority of strokes)

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Symptoms include:

* loss of strength/sensation in one half of the body
* problems with speech and language
* changes in vison/balance

Thrombotic, embolic, and transient

three types of ischemic strokes

Ischemic core/infarct

Location of the focal damage of tissue within the brain following the stroke

The death of cells is called tissue necrosis and is irreversible

Ischemic penumbra

Surrounds the ischemic core

Too much blood lost to function but is still receiving enough blood to stay alive

Damage to penumbra can be reversed within two to four hours of medical attention

Thrombotic Stroke

Occurs when a thrombus forms and interrupts blood flow within the brain

Thrombus

An occlusion of blood vessels within the brain, usually due to atherosclerosis

Atherosclerosis

The build-up of fatty materials that accumulate slowly on the walls of the arteries, narrowing them and restricting blood supply

Embolic Stroke

Occurs when an embolus lodges within a blood vessel inside the brain and cuts off blood circulation to part of the brain

Embolus

A mass traveling through the circulatory system that lodges in a blood vessel in the brain

How a thrombus becomes an embolus

If a piece of a thrombus breaks off, travels, and lodges itself within a vessel to interrupt circulation within the brain

Transient Ischemic Attack (TIA)

“Mini stroke” or small Ischemia in the brain that resolves itself in 24 hours, and does not cause permanent deficits unless TIAs are returning

May be a warning sign of a larger oncoming stroke

Hemorrhagic Stroke

Occurs when a blood vessel within the brain ruptures, spilling blood into the brain and depriving the brain of blood flow

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Symptoms include…

* severe headache
* nausea
* vomitting

Causes of Hemorrhagic Strokes

Type of stroke common in individuals who…

* Have high blood pressure or hypertension
* Are engaged in high periods of physical activity
* Have a history of hemorrhagic strokes
* Experience alcohol abuse

Subarachnoid and Intracerebral

Two types of hemorrhagic strokes

Subarachnoid Hemorrhage

Occurs when there is a bleed between the surface of the cerebrum and the skull

Subarachnoid space

The area between the layers of tissue that protect the cerebrum

Intracerebral Hemorrage

Occurs when a blood vessel bursts within the brain itself

Hemorrhagic stroke damage

Three mechanisms of damage may occur:

* Blood supply to a portion of the brain has been interrupted due to a broken or burst blood vessel
* Blood spills out into the brain where it does not belong and causes damage
* Intracranial pressure increases due to the continued release of blood into the brain or between the surface of the brain and cranium

Aneurysm

An abnormal stretching or ballooning out of the wall of a blood vessel due to disease/hereditary factors or hypertension/atherosclerosis

Usually occurs in the Circle of Willis

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Symptoms include…

* severe headache
* nausea
* vomiting
* blurred vision
* sensitivity to light
* seizures
* loss of consciousness

Circle of Willis

Traumatic Brain Injury (TBI)

Serious and life-threatening brain damage that is the result of an external and forceful event

The immediate impact ranges from mild concussion, to coma, to death

Language and cognitive deficits are varied and complex, depending on what areas of the brain were damaged and to what extent

Neoplasm

Abnormal growth of cells in the brain that serve no purpose to the body

Oligodendroglioma

Tumors composed of myelin-producing cells (called oligodendrocytes)

Primary Tumor

Brain tumor that originates in the brain

Secondary Tumor

Cancerous tumor that spreads from another part of the body to the brain

Biopsy

Surgery to remove a piece of tissue for testing

Malignant brain tumors

Brain tumors that cause brain cancer

Grow quickly and spread to other body parts, so they must be treated with surgical removal and radiation

Benign brain tumors

Cannon spread to other parts of the body

Mass effect may occur

Surgical Trauma

Damage to brain tissue that may occur during brain surgery

May result in acquired speech, language/cognitive/swallowing deficits, secondary seizures, additional CVAs, infections, and increased intracranial pressure

Infection

Cause damage to the CNS and PNS, impacting cognition, motor, and language

types of infection

viral, fungal, bacterial, parasitic

Encephalitis

An acute infection and inflammation of the brain or spinal cord that is caused by a virus or bacterial infection

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Two types:

* Encephalitis Lethargica
* Rasmussen’s Encephalitis

Encephalitis Lethargica

Inflammation and damage to midbrain, basal ganglia, and substantia nigra

Display parkinsonian features

Difficulty initiating/ controlling volitional movement, inhibiting nonvolitional movement

Rasmussen’s Encephalitis

Idiopathic

Inflammation in left or right cerebral hemisphere

Unilateral tremor in an extremity contralateral to affected hemisphere

Hemispherectomy: removal of portions of or entire cerebral hemisphere

HIV/AIDS

A sexually transmitted disease that weakens the immune system (NeuroAIDS, HIV/AIDS, dementia)

Neurological symptoms of AIDS

Inability to learn new information, slowed processing, disfluent speech, impaired recall, reduced attention

Language is often unaffected!!

Creutzfeldt-Jacob Disease

Degerative and fatal brain disease t caused by a prion