Test 3: Etiologies of Neurogenic Communication Disorders

Etiologies of Neurogenic Communication Disorders Examples

cerebrovascular disorders, traumatic brain injury, epilepsy, multiple sclerosis, Parkinson's disease, Huntington's disease, Alzheimer's disease

Cerebrovascular Disorders

most common cause of aphasia, motor speech disorders, swallowing disorders

Any abnormality of brain resulting from pathologic process of blood vessels

Cerebra

brain

Vascular

blood vessels

Stroke [cerebrovascular accident (CVA)]

is the sudden appearance of neurologic symptoms as a result of severe interruption of blood flow

What happens when blood flow in the brain is interrupted?

The tissue is dependent on blood flow resulting in tissue death, if brain tissue dies, the function of the tissue that dies is profoundly affected

Symptoms can either be

acute (right away) or chromic (have for a long time)

Acute symptoms may include

weakness (esp. hemiparesis - one sided body weakness), paralysis (esp. hemiplegia - one sided body paralysis), dizziness, confusion, headache, visual disturbance (esp. hemianopia - one sided visual field loss), aphasia, dysarthria, etc.

In stroke survivors, usually there is...

gradual improvement over weeks and months towards more focal impairments (most rapid recovery is days and weeks after stroke, then slows down)

Stroke impairments reflect

both the location and size of stroke (bigger the stroke, the poorer the prognosis of recovery, symptoms are dependent on where the stroke happens)

One of the leading causes of death and chronic disability in Canada

Strokes, it makes up > 50% of neurologic disorders seen in a general hospital

Ischemic Stroke

Most common type, Results from a blocked blood vessel (approx. 80% of all strokes)

Types of ischemic strokes

thrombosis and embolism

Thrombosis

artery is gradually occluded by accumulation of material at a given site (fatty deposit, blood clot, air bubble, cholesterol), at some point it is so occluded the blood can't pass through

Possible deposits

air bubble, extra cholesterol, dislodged tissue

Embolism

artery is suddenly occluded by material that travelled to that site from a larger vessel, vessel is blocked because the clot breaks down and get launched into a smaller vessel and blocks it

Which type of ischemic stroke is more common? What do S-LPs normally see?

Thrombosis are more common than embolism, but an SLP sees more embolic strokes (because the MC artery starts off broad, but the smaller branches can get blocked - MCA serves language areas of brain)

Infarct

is an area of dead tissue (necrosis) that results from obstruction of blood vessels that normally supply the area.

Infarcation

The blood clot stops the flow of blood to the brain, and anywhere down stream from the blockage will die - the dead tissue is called an infarcation

Tissue Plasminogen Activator (tPA)

A medication that dissolves clots for ischemic strokes (between 4 hours after the onset of symptoms). The sooner you take the medication, the more likely that you will not have long term consequences

How does tPA help patients having an ischemic stroke?

it reduces the amount of cell death, improves recovery, reason for urgency of time associated with strokes

What happens if tPA is given for a hemorrhagic stroke?

The patient will die as it doesn't allow the blood to clot

Transient Ischemic Attack (TIA)

"Mini Stroke" - a temporary blockage, but it eventually breaks down or gets pushed through - normal blood flow or mechanisms are able to push it through or break it down, Increases stroke risk, Fairly short lived and patient recovers completely

What causes TIA?

Caused by temporary interruption of blood supply to brain (from small embolus, partial stenosis, or vasospasm)

Symptoms of TIA are similar to?

Similar to ischemic stroke symptoms, but typically last < 5 min with complete recovery

What arteries meet at the circle of willis?

The internal and vertebral arteries that meet at the circle of willis, which provides blood flow redundancy (blockage on one side goes the other way)

What are the important vessels that branch off of the ciurcle of willis?

Anterior cerebral artery - dorsal surface and front of frontal lobe, Middle cerebral artery - lateral surface of the cortex (language centers), Posterior cerebral artery - ventral surface

Stroke in the anterior cerebral artery of the left frontal lobe symptoms

right sided motor impairment (hemiplegia or hemiparesis), executive functions (planning, decision making, judgement, reasoning, higher intellectual thought)

Stroke in the posterior cerebral artery of the right occipital lobe symptoms

hemianopia in the left visual field

Very large middle cerebral artery stroke impacting the whole left hemisphere symptoms

global aphasia and right sided hemiplegia, right sided somatosensory impairments, and some visual field loss (optic radiations come up into the occipital lobe and are probably affected)

Hemorrhagic Stroke

Occurs when blood vessel in or around the brain ruptures, spilling blood into the brain or the area surrounding the brain (approx 20% of all strokes), Abrupt onset of symptoms, Often poor prognosis, Blood vessel ruptures and spills blood into the tissue which results in cell death, Tend to happen in younger people

Main risk factors of hemorrhagic stroke

high blood pressure, aneurism (balloon like swelling of blood vessel, blood vessel wall weakens from blowing up like a balloon)

Types of hemorrhagic strokes

extracerebral (outside of brain, in subarachnoid space) and intracerebral (inside the brain, likely from a MCA branch) hemorrhage strokes

Video - American Heart Association

Symptoms seen - Difficulty talking (slow, choppy), Dysarthria, Apraxia, Aphasia, Language comprehension, Vision loss, Motor impairment (profound effect on communication)

Traumatic Brain Injury (TBI)

Strong external force applied to head (moving head strikes stationary object or vice versa)

Two main closed head ways of TBI

Acceleration mechanism (ex: head hits pavement after falling off motorcycle - head is moving) and non-acceleration mechanism (ex: head is stationary and something hits it)

What is the most common cause of brain damage in people < 40 years

TBI

TBI can result from

vehicle accidents, falls, and sports

What are key risk factors for TBIs

Age and gender are key factors

One TBI increases

the risk for more TBIs, TBIs can impact frontal lobe that reduces judgement and decision making, therefore people place themselves in riskier situations

Effects of mild TBI can be

cumulative (e.g., Dementia Pugilistica - repeated effects of TBI that accumulate)

Open Head Injury

Skull is crushed or penetrated by foreign object (e.g., bullet), or fragments of bone, accounts for majority of fatalities following head trauma

Outcomes for open head injury

They vary, but some survivors remain conscious and have relatively good recoveries with only focal impairments. Symptoms depend on location of injury (e.g., hemiplegia, hemianopia, aphasia, hearing loss)

Phineas Gage

Worked on the railway line, and an iron rod went through his frontal lobe, Remained conscious and was left with relatively mild deficits (had executive problems), Highlighted that people can have good recoveries from open head injuries and helped scientists understand what the frontal lobe does, Personality change

Primary effects of open head injury

Happen right at the time of injury, sets into play all of the other secondary events that can be more damaging than the actual injury

Examples of primary effects

Destruction of brain tissue at site of entry and along path of object, Damage to meninges, Intracranial bleeding due to damaged blood vessels

Potential Secondary Effects of open head injury

Destruction of brain tissue during surgical removal of foreign object, Ischemia (i.e., interruption of blood flow to tissue), Edema (i.e., reactive swelling of brain tissue), Brain infection, Post-traumatic epilepsy

Why do strokes affect speech more than hearing?

More redundancy in hearing, so stroke does not affect hearing as much

Younger people are more likely to be in ________ and older people and kids are more likely to have ________

car accidents, falls

Who are more susceptible to TBI?

Younger men are more likely to be in car accidents and suffer from TBIs

Closed Head Injury

Blow to head which subjects brain to variety of mechanical forces, Skull remains relatively intact, acceleration has wide-spread damage

Effects of Primary Injury of closed head injury

Brain contusions are typically seen at site of impact (i.e., coup lesion). As well, pressure during impact causes brain to hit opposite side of skull (i.e., contrecoup lesion). The orbitofrontal and anterior temporal regions are the most common sites of contusion and are caused by the brain rubbing against the base of the skull. Diffuse microscopic lesions that result from twisting or shearing of neurons (known as diffuse axonal injury). May be responsible for persistent neurologic deficits (Struggle with concentration, memory, fatigue, struggle with bright light). Damage to major fiber tracts (e.g., corpus callosum)

Potential Secondary Effects of closed head injury

Edema (i.e., reactive swelling of brain tissue and collection of fluid). Increases intracranial pressure. Intracranial bleeding (i.e., hemorrhage) which may become a semisolid, localized mass (i.e., hematoma)Extracerebral bleeding, Hydrocephalus (i.e., disturbed flow and excessive accumulation of CSF resulting in dilation of ventricles and raised intracerebral pressure), Ischemic brain damage, Post-traumatic epilepsy

Behavioural effects of TBIs

Discrete impairment of those functions mediated by site of contusion (esp. executive system dysfunction from prefrontal damage) But also more generalized impairment from widespread neuronal damage (e.g., decrease in mental speed, concentration, cognitive efficiency) TBI severity and recovery varies markedly

Epilepsy

Characterized by sudden, brief attacks that may alter motor activity, sensory experiences (visual experiences), and levels of consciousness. very common in accompanying other disorders, disorder of elliptical function

What causes epilepsy?

Caused by abnormal electrical discharges in gray matter of brain (typically arise of areas of scar tissue)

Prevalence of epilepsy

1/20 will experience at least 1 seizure in lifetime, 1/200 will develop chronic seizure disorder

Symptomatic seizures

can be identified with a specific cause (e.g., trauma, tumor), Can present symptomatically (associated with something else, could be as secondary consequence to a TBI)

Idiopathic seizures

develop spontaneously without other neurologic disorders, No primary mechanism, develops spontaneously without another diagnoses

Classification of Epilepsy

focal or partial seizures and generalized seizures

Partial / Focal Seizures

Occur in 2/3 patients with epilepsy, Begin in one part of brain (focal) and may or may not spread to other regions

Prevalence of partial/focal seizures

occurs in 2/3 patients with epilepsy

In simple-partial seizures

there is no alteration in consciousness (e.g., Jacksonian seizures)

In complex-partial seizures

consciousness is impaired, usually in temporal lobe (temporal lobe seizures), may be associated with ongoing cognitive and emotional difficulties

Complex-partial seizures may cause

absences, hallucinations, affective symptoms (related to mood), automatisms (repetitive motor sequences that is not appropriate to the time)

Generalized Seizures

More widely known, but less common. Doesn't start from one focal location, but everywhere in the brain at one point in time has abnormal activity. Bilaterally symmetrical without focal onset (e.g., tonic-clonic seizures). Fall to the ground and individual has rigid contractions, the individual is unconscious.

Prevalence of generalized seizures

Occurs in 1/3 patients with epilepsy

Left frontal lobe seizure

Symptoms include right sided motor contractions and speech production difficulties

Treatment of Epilepsy

pharmacotherapy or surgery

Pharmacotherapy treatment of epilepsy

Anticonvulsant drugs control seizures in about 70% of patients. Common medications include Dilantin and Gabapentin. Medications inhibit electrical discharges throughout the brain

Surgical treatment of epilepsy

Seizures need to originate from focal area and interfere significantly with patient's functioning & quality of life, May be associated with post-surgical cognitive deficits. Surgeons will remove the area of scar tissue that is causing focal seizures (Wilder Penfield). This surgery is often very successful and life changes very dramatically for the better

Class 9

Etiologies of Neurogenic Communication Disorders Pt 2 (November 2, 2022)

Multiple Sclerosis

Degenerative disorder characterized by patchy loss of myelin (i.e., plaques) in motor and/or sensory tracts of brain and/or spinal cord (disorder of demyelination, breaks down our fast messaging around the nervous system). Degenerative - worsens with time, the brain is progressively breaking down, prominent speech and audiological manifestation

_____ is not degenerative, as people typically recover

stroke

Plaque

areas of demyelination

MS Symptoms

hearing loss, visual disturbances, somatosensory disturbances, motor disturbances, swallowing, speech/articulation (it depends where the plaques occur)

Initially with MS, the body

repairs the plaques so the symptoms will go away

Usual age of diagnosis for MS

< 40 yrs

Prevalence of MS

Relatively common neurologic disease (Canada has highest rate in world; 2x more frequent in women)

Cause of MS

it is unknown, but likely due to autoimmune response

Symptoms of MS are

unpredictable and vary from person to person, but generally include: Motor symptoms (e.g., weakness, loss of coordination), Sensory disturbances (e.g., vision, audition, somatosensory), Speech disturbance (e.g., dysarthria, hypophonia), Cognitive impairment (esp. attention, short-term memory) and Extreme fatigue

Rapid onset of symptoms is usually followed by

complete remission for weeks to years

Subsequent MS episodes

are unpredictable and associated symptoms remit less completely or not at all

MS Pathological vs. Clinical Course of Disease

relapsing-remitting pattern as MS occurs, Changes can be going on at a neuronal level, but they are so subtle, they aren't noticed, Neurons can't regenerate, so once the axons break down, you can't get the neurons back, Attacks are very unpredictable, and eventually the symptoms are long-lasting (however most people stay in a relapsing-remitting pattern)

MRI Scans for MS

Abnormal changes show up bright white, Bright white = plaque, periventricular

Periventricular

(next to the ventricles) close to this is the basal ganglia and thalamus

MS video

Selma Roberts, Spasmodic dysphonia, Plaques develop on the cranial nerves affecting the larynx, Fatigue

Motor Disorders

Marked by abnormalities in controlling movement and posture due to basal ganglia dysfunction, Produce cognitive/communicative deficits as well, especially as they progress

Hypokinetic

(e.g., Parkinson's disease) - loss of movement

Hyperkinetic

(e.g., Huntington's disease) - extra movement

Parkinson's Disease

Hypokinetic disorder, Fairly common neurologic disease, Mean age of onset in 60's, Begins insidiously - don't notice at first, comes on very gradually, Over time, more symptoms arise (rate of change is variable), Slowly progressive (usually 10-20 yrs before symptoms cause severe disability)

Effect on Basal Ganglia for Parkinson's disease

Includes marked degeneration of substantia nigra and loss of dopamine projections to BG, Parkinson's develops due to the loss of projections from the substantia nigra up to the basal ganglia

Positive Symptoms of Parkinson's Disease

Refers to the development of abnormal behaviours, Includes - Tremor at rest (esp. "pill-rolling"), Rigidity (increased tone in extensor and flexor muscles, "cogwheel rigidity"), Akathesia (involuntary movements)

Ridgity in Parkinson's

Muscles feel rigid and don't move in a flexible way Cogwheel rigidity: muscles don't move smoothly

Pill rolling (Parkinson's)

looks like they are rolling pills between their fingers

Akathesia (involuntary movements)

Absence of something related to movement, Look similar to movements of Huntington's disease

Negative Symptoms of Parkinson's Disease

Degeneration of normal behaviours, includes - Postural disorders (difficulty maintaining posture), Righting disorders (difficulty standing up) - difficulty starting movement and stopping movement, Locomotive disorders (shuffling gait, festination), Speech disturbances (esp. aprosodia, hypophonia, dysarthria) - lack of prosody, decreased volume, hypokinetic dysarthria, Akinesia (slowness of movement, masked face)

Phonological Aspects of Parkinson's Disease

Psychological symptoms vary like motor symptoms, Slowed thinking, attention & ECF impairments are common, May have general cognitive deterioration (Parkinson's dementia)

Treatment of Parkinson's

No cure, Pharmacologic (esp. dopamine agonists), Surgery - lesion part of the basal ganglia (globus pallidus), Deep brain stimulation

Deep brain stimulation

electrode is placed in the brainstem, and the person can remotely control the brainstem; if they are having trouble getting out of a chair, press the button and the jolt can help the person get out of the chair.