Topic 1: Neuroanatomy

Neurogenic Communication Disorders

• Consequence of nervous system damage.
• Location + size = severity and outcome —> closer to the language centers - worse outcomes
• Disorders:
-Aphasia
-Motor speech disorders (dysarthria, apraxia)
-Right Hemisphere Syndrome
-Dementia
-TBI

Nervous System

Central Nervous System
+Brain (cerebrum,
brainstem, cerebellum)
+Spinal cord
Peripheral Nervous System
+Spinal nerves (31 pairs)
+Cranial Nerves (12 pairs)

• Language Centers are in the Cerebrum!

• BS more swallowing problems

Cells of the Nervous System

1) Neurons (Nerve cells)

• conduct and receive electrical impulses

• responsible for actions of muscles, organs, glands

• sensory & motor

Types:

sensory —> light sound touch taste temperature smell

motor —> muscles/body parts move

interneurons

100 Billion Neurons

Each neuron has:

• cell body (soma) —> processes informatino that is sent in

• dendrites RECEIVE —> fingerlike — receive electrical impulses/info from other cells and give it to the cell body

• axon SEND —> extends from cell body sends nerve signals away to other parts of the nervous system (connect to muscle)

• Synapse = from cell to cell where axons meet (receptor site)

2) Glial cells (helper cells)

• GLIAL= glue

• connective tissue

• support neurons

• NO electrical impulses

• Job : regulate fluid, remove foreign substances, metabolism

excessive alcohol abuse

(connections damaged - metabolism isn’t what it used to be)

Damage to nerves

● Once axons are injured or destroyed
by disease/damage, do NOT
regenerate to the same extent
● Regeneration depends on type and
location of injury
● Peripheral nerves have better ability
to regenerate than central nerves

Severity, age, how long it took to get TX, underlying conditions (alzheimers + stroke), strokes prior?

FAST - face arm speech time

Peripheral nerves have better chance at recovering

Axon is thinner after connection is reestablished (weaker, more likely to be damaged, electrical impulse doesn’t travel as smoothly -

ex) delayed or related example saying dog instead of cat

Myelin

• thin layer of white, fatty substance

  • provides electrical insulation for nerve axons

  • some disease characterized by loss of myelin, which slows connection = weakness, impaired muscle control

• IMPORTANT DEF —> keeps electrical signal functioning and in the right spot (fast too)

Peripheral Nervous System: Cranial & Spinal nerves

• Cranial nerves (12 pairs) = control muscles in head and neck

BOTH sensory and motor function

• Spinal nerves (31 pairs) = serve structures in the torso and limbs.
• PNS serves as a channel for sensory information from the body’s
sensory receptors to CNS, and for motor commands from CNS to the
muscles.
• Sensory fibers in cranial nerves transmit information from sensory
receptors in the head and neck to the CNS.
• Most cranial nerves connect with the CNS in the midbrain, pons, and
medulla.

PNS: 2 functional systems

-Somatic nervous system-enables us to perceive sensory
stimuli and carry on volitional motor activity.
-Autonomic nervous system-self-regulating system that
controls the glands and vital functions such as breathing,
heartbeat, and blood pressure.

digestion, toxins, blood pressure

Cranial Nerve Review

Label the cranial nerves by #

1 Olfactory —> smell

2 Optic —> vision

3 Oculomotor —> eye movement & pupil reflex

4 Trochlear —> eye movement

5 Trigeminal —> face sensation & chewing

6 Abducens —> eye movement

7 Facial —> face movement and taste

8 Vestibulocochlear —> hearing and balance

9 Glossopharyngeal —> throat sensation, taste/swallow

10 Vagus —> movement, sensation, abdominal organs

MOTOR ONLY

11 Accessory —> neck movement

12 Hypoglossal —> tongue movement

Oh once one takes the anatomy final very good vacations are heavenly

Central Nervous System

• Includes: brain (cerebrum), brainstem, cerebellum, spinal cord

• Supports perception and discrimination of sensory stimuli and expression of emotion.

• Keeps processes like respiration and heartbeat going.

• Organizes and regulates behavior.

• Enables us to engage in mental processes such as thinking, remembering, and understanding information.

Brain

• Mass of nerve cells and supportive tissue in CSF [ Cerebrospinal fluid]

• Brain is completely dependent on a constant supply of oxygen and nutrients.

• Cerebrum: 2 hemispheres (L & R) sit atop brain stem

• Longitudinal cerebral fissure divides two hemispheres

• Hemispheres communicate via corpus callosum

• Receive sensory information from contralateral side of body and movement is affected on contralateral side of body

corpus callosum connect 2 sides of the brain —> contralateral issues

10 sec lose consciousness, 20 electrical currents stop, 2+ min permanent brain damage

Language in the LEFT

RIGHT —> emotions, music cognitive (memory/planning, pragmatics)

Brain Layers

• dura —> thickest and most durable

• arachnoid —> thinner than the dura

• subdural —> below the dura

• subarachnoid —> CSF

• pia mater — >adheres to the surface of the brain (soft and fragile) blood supply to the brain

CLOSER TO BRAIN - WORSE DAMAGE

Cerebral Ventricles

● 4 ventricles: 2 lateral, 3rd ventricle, 4th ventricle

● Each contain choroid plexus (produces CSF)

• CSF: cerebrospinal fluid [plasma] provides nourishment, shock absorber, protection/waste removal

● Blockage in any of these can result in pressure on brain

Major Gyri of Cerebral Hemispheres

Gyri thick folds of the brain (gray matter) —> nerve cells here

Hemispheres

Each hemisphere is divided into 4 lobes:

1. Frontal lobe [EF, personality, emotion]

2. Parietal [perception, sensory awareness]

3. Occipital [vision]

4. Temporal [receptive language, hearing]

Frontal Lobes

● Lateral cerebral fissure (Sylvian): lower boundary for frontal lobe

● Central sulcus: posterior boundary

● Regulate general activity levels, formulating intentions, plans, and patterns for volitional behavior responsible for planning and executive function

● Expressive Language

● Cognition

● Damage: Difficulty expressing communication, irregular behaviors, personality changes, attention, loss of flexible thinking, decision making, mood changes

sylvian fissure = lateral cerebral

Parietal Lobes

● Lies behind the central sulcus and above the lateral fissure in each hemisphere.

● Important for perception, integration, mediation of sensory information (ie., touch, body awareness, and visuospatial information)

damage: don’t know where they are in space, reading, writing, visual, neglect, perception of touch

Occipital Lobes - perception (receive and process)

● Posterior part of each hemisphere.

● Extend from the posterior boundary of the parietal lobe to the longitudinal cerebral fissure

● Contain primary visual cortex and visual association areas

● Processes visual information

damage: vision reading/writing, visual neglect, ability to identify colors

Temporal Lobes

● Lateral cerebral fissure marks its upper boundary and its lower boundary in on the underside of the hemisphere near the midline.

● Important for perception and processing of auditory stimuli.

● RECEPTIVE LANGUAGE

close to the ears, receptive, auditory stimuli (wernickes)

Damage: receptive language (difficulty understanding), looks like memory loss (can’t explain - looks like they forgot), attention

Brain-Cortex

▪ Cerebral cortex / Cerebrum: outer layer of cerebral hemispheres

▪ Major functional categories:

1) primary motor cortex

2) primary sensory cortex

3) primary auditory cortex

4) primary visual cortex

Brain Matter

● Grey Matter: brain cells

○ Outer surface containing nerve cells

○ Recall: responsible for directing motor/sensory stimuli

● White Matter: how FAST signals get sent b/w brain cells

○ Consists of axons

○ Damage to white matter:

■ Multiple sclerosis (MS): destroys myelin sheath

■ Alzheimer’s Disease: white matter changes result in plaque

Brain Stem

● Communicative and structural link between the brain and the spinal cord.

● Cranial nerves originate here*

● Pathway: motor nerve fibers from brain →spinal cord.

● Pathway: Sensory nerve fibers from periphery →brain.

● Damage to brain stem has effects both on motor and sensory functions.

Brain Stem

Divided into 3 parts:

1. Midbrain-connects the brain stem with the cerebral hemispheres

a. Cranial nerves III & IV (vision, hearing, movement)

b. Common disorder: Parkinson’s

2. Pons (middle)-contain several nuclei involved in hearing and balance plus the nuclei CNV, CN VI, CN VII.

3. Medulla (lower)-connects the pons and the spinal cord.

a. Contains nuclei for five cranial nerves (CN VIII-CN XII): Speech motor control, phonation, articulation, VP closure, swallowing, alertness, sleep

b. Damage: vertigo (dizziness), paralysis of muscles of the throat and larynx, and various combinations of sensory loss in limbs and sometimes face.

Diencephalon

● Regulation & integration of motor/sensory input

● Contain:

○ Thalamus

■ Receives motor input from cerebellum, basal ganglia, brainstem

■ Relays sensory input

■ Important in maintaining consciousness, alertness, attention

○ Basal ganglia [PD, huntingtons, CP, tardive dyskinesia]

■ Receives input from cortex (frontal lobe) and send to cortex

■ Reflex, posture, complex movements

Cerebellum

• Lies beneath the posterior temporal lobes.

• Does not initiate movements, but coordinates and modulates planned motor movements initiated elsewhere (primarily motor cortex).

• Regulates rate, range, direction, and force of movements.

• Cerebellar damage causes ataxia [without coordination]

• infection common, alcohol, drug use medication use

Spinal Cord

• 18 inches long in normal adult

• Extends from the first cervical vertebra to the first lumbar vertebra and then continues downward as a fine bundle of nerve fibers.

• Spinal cord connected to muscles and sensory receptors by spinal nerves.

• Functions:

1. Reflex arc: urgent messages (ie., pain + motor movement)

2. Sensory: upward to brain

3. Motor: from brain outward

Neurons/Nerve Tracts

1) Projection fibers-long distance carriers of CNS. Carry information from the brain to the brainstem and spinal cord or from periphery sensory nerves to the brain via spinal cord.

-Efferent (motor) projection fibers carry command and control signals from the brain to muscles and glands.

EXIT the brain (brain to body)

-Afferent (sensory) projection fibers carry sensory information from receptors in the periphery to CNS.

Affect=emotion

Sensory to CNS

Blood Supply in Brain

⚫ At any given time about 25% of the blood in the body is in the brain.

⚫ Mechanical process of getting blood to the brain begins at the heart, where pumping pressure pushes blood through the arteries.

⚫ Heart pumps oxygenated blood into the aorta, major artery from the heart.

Blood Supply Arterial/Carotid System

Blood Supply Vertebral System

Cerebral Arteris

Circle of Willis provides blood supply to 3 paired cerebral arteries:

● 2-Anterior cerebral arteries supply the upper and anterior regions of the frontal lobes and anterior corpus callosum.

● 2-Middle cerebral arteries fan-shaped distribution and supply most of lateral surfaces of the brain hemispheres, plus thalamus and basal ganglia.

● 2-Posterior cerebral arteries supply blood to the occipital lobes and lower parts of the temporal lobes.

Damage to Blood Supply

• Amount of brain tissue affected by occlusion of an artery depends on the location of the occlusion in the artery.

• Occlusions in the trunk or main branch of the cerebral artery affect large regions of the brain.

• Occlusions in peripheral branches affect smaller regions.

Stroke/CVA

● Brain damage caused by vascular disruptions such blockage of blood supply or bleeding.

Common Abrupt Symptoms: ▪weakness or numbness on one side of the body. ▪impairment of vision, especially in one eye.

▪difficulty speaking or understanding speech.

▪episodes of dizziness or falls. ▪severe headache, especially with any other symptoms

2 Types:

1. Ischemic (deprived of blood)

2. Hemorrhagic (caused by rupture of artery)

Ischemic Stroke

Occurs when an artery is blocked (occlusion) and part of the brain loses its blood supply

May be caused by:

1. Thrombosis: an artery is occluded by material accumulating at a fixed location

2. Embolus: an artery is abruptly occluded by material that moves through the blood and blocks an artery.

Hemorrhagic Stroke

▪ Caused by rupture or leakage of cerebral blood vessels.

▪ May be the result of weakness of a vessel wall or extreme fluctuations in blood pressure

1. Extracerebral hemorrhages-hemorrhages from blood vessels in the meninges or on the surface of the brain (bleeding outside brain).

2. Intracerebral hemorrhages-hemorrhages within brain or brainstem

Types of brain hemorrhage

• epidural hematoma

• subdural hematoma

• subarachnoid hemorrhage

• intracebral hemorrhage

Extracerebral Hemorrhages

3 types depending on WHERE blood accumulates:

1. Subarachnoid hemorrhage-bleeding between arachnoid and pia.

2. Subdural hemorrhage-bleeding beneath dura.

3. Epidural hemorrhage-bleeding between dura and skull.

● TBI usual cause of subdural and epidural hemorrhages

● After bleeding stops, left with a hematoma (subarachnoid, subdural, or epidural)--accumulation of clotted or partially clotted blood in the space created by the hemorrhage.

Intracerebral Hemorrhage

• Hemorrhage into the brain and brainstem (bleeding in brain tissues).

• Most common sites are the thalamus and basal ganglia

  • Also possible: Brainstem (especially pons) and cerebellum

• May be caused by aneurysm: pouch formed in weakened arterial walls

  • If aneurysm in cerebral artery bursts, severe aphasia is likely

Location of Stroke

● Directly determines areas affected

● Anterior Cerebral Artery Stroke:

○ Supplies Frontal lobe

○ Confusion, coordination, sensory function, personality, contralateral paralysis/paresis

● Middle Cerebral Artery Stroke:

○ Supplies Temporal lobe, anterolateral frontal lobe, parietal lobe

○ Aphasia, motor speech, visual field deficits, contralateral paralysis/paresis

● Posterior Cerebral Artery Stroke:

○ Supplies Occipital Lobe, inferior Temporal lobe

○ Visual field, vision, sensory impairment, agnosia, memory

Stroke Recovery

• Different rates of recovery

• Recovery depends on:

• 1. Type of stroke

• 2. Severity (How much brain tissue destroyed)

• 3. Location of the destruction

Ischemic

• recovery most rapid in first few days 2-4 weeks poststroke

• more difficult recovery than hemorrhagic

Hemorrhagic

• little improvement first few weeks

• followed by rapid recovery

• likely due to amount of initial brain swelling

Transient Ischemic Attacks TIA's

• Temporary disruptions of cerebral circulation accompanied by rapidly developing symptoms including:

  • sensory disturbance, limb weakness, slurred speech, visual anomalies, dizziness, confusion, mild aphasia, or other symptoms which resolve completely within 24 hours.

• Interruptions of blood supply to the brain that last more than 24 hours but leave minor deficits after few days.

• Typically, predecessor to a full blown stroke

Other causes of neurological damage

● Traumatic brain injury

● Intracranial tumors

● Hydrocephalus

● Infections/toxins/substance abuse

● Nutritional and metabolic disorders

Imaging Procedures

● Identifies lesion site

● X-rays

● CT or CAT scans

● MRI–Magnetic Resonance Imaging

● Carotid ultrasound

● Cerebral angiography

● Doppler ultrasound

Brain Atrophy

Vastly oversimplified but concise overview of major stroke syndromes

Neuro Assessment includes

● Patient and family interview

● Symptoms (initial and over time)

● Evaluation of motor systems:

○ Assess movement, reflexes, muscle tone, ROM, strength, voluntary movement

○ Nystagmus

● Evaluation of sensory systems

○ Body sensation

○ ℅ pain, numbness, or abnormal sensations

● Evaluation of mental status ● Cranial nerve assessment

Mental Status Exam

Provides information on:

● Level of consciousness

● Attention and concentration

● Orientation

● Memory

● Mood and behavior

● Thought, content, language and speech

Screeners

● Mini Mental Status Examination (MMSE) ● Modified Mini Mental Status Examination (3MS) ● Cognitive Abilities Screening Instrument (CASI) ● Brief Cognitive Rating Scale (BCRS) ● Brief Interview of Mental Status (BIMS) ● Montreal Cognitive Assessment (MoCA) ● Mini-Cog ● St Louis University Mental Status Exam (SLUMS) ● Cognitive Assessment Screening Test (CAST)

Cognition

• orientation to

  • self

  • time

  • place

  • memory

  • attention, concentration

  • mental flexibility

language

• naming

• repetition

• auditory comprehension

• reading comprehension

• writing

• visuospatial ability