CSD 515: WK 3

Directional Terms

-Anterior/Posterior

-Superior/Inferior

-Rostral/Caudal

-Dorsal/Ventral

Anatomical Planes

-Sagittal
-Coronal
-Transverse

The Nervous System

Major Divisions:
-Central Nervous System (Brain and Spinal cord)
-Peripheral Nervous System (Cranial and Spinal nerves)

CNS Protective Coverings

-Skull that surrounds the brain
-Vertebral column that protects the spinal cord

Three membranous coverings:
meninges
-Dura mater -> outermost layer closest to skull
-Arachnoid mater -> middle layer
-Pia mater -> innermost layer closest to brain

Cerebrospinal fluid (CSF) - between arachnoid and pia mater
-Mechanical buffer for protection
-Chemical mediator for metabolic functions

Brain

Major divisions:
-cerebrum
-cerebellum
-brainstem

Cerebrum

Cerebral hemispheres

Lobes:
-frontal
-temporal
-parietal
-occipital

Cortex
-contains the gray matter

Subcortical structures
-contains the white matter

Landmarks - Fissures
-medial longitude fissure
-central sulcus (fissure of Rolando)
-lateral sulcus (Sylvian fissure)
-superior temporal sulcus

Subcortical Structures

Basal ganglia:
-Caudate nucleus
-globus pallidus
-putamen

-contains dopamine -> lack of dopamine -> movement disorders ie. Parkinson's


Thalamus

Cerebral Connections

Association fibers:
-conn. areas within the hemisphere
-forms association tracts -> Short (within the lobes) and Long (btw. the lobes)
-Arcuate Fasciculus

Arcuate Fasciculus

travels from post. temp lobe to motor association cortex via the superior longitudinal fasciculus

Cerebral Connections - Commissural fibers

-connect areas between hemispheres
-corpus callosum - major commissural tract

Cerebrum...

Landmarks (Gyri):
-precentral gyrus
-postcentral gyrus
-angular gyrus
-supramarginal
gyrus
-sup., mid., & inf. temporal gyrus

Cerebrovascular accident (CVA)

Ischemic vs. Hemorrhagic strokes

Ischemic Strokes

-thrombotic—large artery atherosclerosis

-embolic—cardioembolism, lungs

Hemorrhagic Stroke

-subarachnoid—aneurysmal bleeding, Arteriovenous malformation (AVM)

-intracerebral—hypertension, AVM

Ballooning of blood vessel is an aneurysm

-due to weak blood vessel wall

-bursting releases blood, which damages tissues

The brain's blood supply moves up fr. the aorta

-Common carotid branches to form internal and external carotid arteries


-Vertebral arteries join to form

Middle Cerebral Artery

-Supplies entire lateral cortex
-Largest branch of internal carotid artery
-most likely to cause aphasia

The anterior and middle cerebral arteries supply brain areas critical to speech & language

-Anterior cerebral artery supplies medial frontal & parietal lobes, basal ganglia, corpus callosum

-Middle cerebral artery supplies lateral surfaces of frontal, motor strip, Broca's area, Wernicke's area

Basilar artery

-branches to supply the cerebellum and inferior temporal and occipital lobes

Function of CSF

-cushioning and shock absorption
-chemical protection
-exchange nutrients and wastes

Broadly, each lobe is supports in a different set of general functions

Frontal:
-higher-order cognition
-motor planning and motor control

Parietal:
-sensory reception, integration

Occipital:
-vision

Temporal:
-audition

Information moves from primary to association areas

Vision
-first occipital lobe, then further processing in parietal and temporal lobes

Motor function
-sensory data from parietal lobe goes to motor areas in frontal lobe

Effects of damage differ by hemisphere

Left hemisphere
-speech and language
-Left hemisphere damage
-sequential, rapid input

Right hemisphere
-faces and forms
-intonation, emotional cues
-Right hemisphere damage

The character of the speech disorder differs by location of the damage

-Lower motor neuron damage (cranial nerves)

-Cerebellar damage

Lower motor neuron damage (cranial nerves)

-Flaccid dysarthria
-weakness and low muscle tone (hypotonia)
-fasciculations (twitching) if cell bodies damaged
-reduced or absent reflexes

Cerebellar damage

-Ataxic dysarthria
-problems with motor coordination
-> coordinating rate, range, and force of movement.

Aphasia can also be considered a disruption to a network of brain areas

Speaking a heard word

1.Sound to primary auditory cortex
2.Wernicke's area analyzes sound to determine word meaning
3.Meaning is transmitted via arcuate fasciculus to frontal lobe.
4.Broca's area forms motor plan to speak word
5.Motor cortex implements the plan by sending signals to muscles

Damage to right hemisphere can also affect language abilities

Impaired ability to interpret humor

Impaired pragmatics—inappropriate responses

Loss of nuances and secondary meanings of words

Difficulty with multi-component thought integration and reasoning

Difficulty with organization

We cover more of RH dysfunction in week 10

Main point: Brain functions are supported by networks of brain areas: Example: Speech motor control

Motor strip (precentral gyrus) initiates voluntary muscle movements (BA 4)


Planning and integration from pre- motor area (BA 6)

Sense of muscle state and position in post-central gyrus (Parietal)

Broca's area involved in motor program for speech (BA 44, 45)

When lesions don't match symptoms

Read the chart and understand medical history thoroughly

Operating Rule for therapists: Treat what you see.

Possible Explanations:
-Network interruptions (white matter tracts, subcortical sites of lesion)
-Cross brain dominance
-Diaschisis
-Pre-morbid learning/pre-morbid linguistic and cognitive status (neuroplasticity)

diaschisis

Von Monakow, et al. (1969) initially proposed the concept in 1905

After focal brain injury, neurons in regions of intact brain, distant from, but anatomically and functionally connected to damaged area(s), become functionally impaired because of a loss of excitatory neural transmission from the injured area.

Can cause what appears to be a focal and significant aphasia, despite a neurologically intact peri-Sylvian region

Patterns of recovery

Two Stages:
Early - within first several weeks (Acute aphasia)
Late - months and years post stroke (Chronic aphasia)

Receptive skills improve more!
Receptive skills - necessary for recovery!

-Patients who "evolve" may show better outcome

Spontaneous Recovery

We do nothing and they recover on themselves

1-3 months post onset of aphasia

-Fastest recovery: 1 month post

-Drops precipitously at about 6-7 months post recovery

-Spontaneous recovery effectively over after 1 year post

-Clinical status at 3 months is very similar to clinical status at 12 months

Research: Consider time post in reading studies - should be studying treatment effects in chronic phases, rather than in spontaneous recovery phases

Prognostic factors: neural mechanisms

Initial Severity - very predictive

Not lesion size alone - lesion location more important!

Site of lesion and damage to penumbral areas

Pre-existing lesions or conditions

Neuroplasticity

Involvement of Wernicke's area

Involvement of subcortical white matter along with cortical areas of speech

In Broca's aphasia, extension of lesion anteriorly into areas responsible for executive functions

Prognostic factors: Personal

Age - Advanced age
-not really helpful for the recovery process

Gender

Handedness

Psychosocial elements

Pre-morbid education and experiences

Pre-morbid IQ and mental flexibility

Family involvement

Supported Conversation for Adults with Aphasia

-Trademarked approach (Aphasia Institute) to facilitate communication among adults with aphasia and their conversation partners

-Conversational partners are trained in SCA

Study evaluated communication among adults with aphasia and volunteers who did or did not have training in SCA
-Volunteers trained in SCA scored higher on measures of "acknowledging competence" and "revealing competence."
-Adults with aphasia who were paired with volunteers trained in SCA scored higher in "message exchange skills" and "social skills."

Why Should We Use SCA?

-Interaction (social implications): Acknowledge the competence of the adults with aphasia

-Information: Learn what the adult thinks and feels; provide information to the adult

-Training: Model behaviors for patient, family members, and peers

Components of Supported Conversation

-Acknowledging Competence

Revealing Competence—will require VERBAL and NON-VERBAL techniques
-Getting your message IN
-Getting their message OUT
-VERIFYING

Acknowledging Competence

Implicitly:
-Non-patronizing speech patterns (tone, rate, loudness, enunciation)
-Choice of topics
-Use humor appropriately
-Sensitivity to partner's attempts to communicate

Explicitly:
-"I know that you know."
-As the conversational partner, take ownership of breakdowns in conversations, "I'm sorry I'm confused. Let me try again."

Getting Your Message IN

Verbal techniques:
-short, simple sentences

Non-verbal techniques:
-Gestures (meaningful and slightly exaggerated)
-Writing (use key words)
-Other resources (communication book / draw pictures or use pre-printed pictures)

-provide extra time

Get Their Message OUT

-verbal techniques (e.g. ask yes/no questions)

Non-verbal techniques:
-gesture (provide models of nodding/shaking head or thumbs up/down)
-writing (choices, paper and pen available)
-resources (communication book, pain scale, drawing choices, paper and pen available)

Extra time

Verify

Verifying should involve a different modality

Verbal: "Let me check if I am understanding..."

Non-verbal:
-gesture
-writing (e.g. circle the answer)
-resource/drawing

Considerations with Use of SCA

Alter your communication according to your partner:
-Provide supports according to level of aphasia
-Provide more supports according to patient's needs (think about types of aphasia)

Don't need to fix everything:
-Acknowledge the breakdown
-Ask permission to come back to it later or to talk to a family member

Other Situations

-Getting the message OUT for people with dysarthria

-Communicating with people with cognitive problems (e.g., difficulty with topic maintenance, thought formation)