Neuro Exam 3

What can prolonged misuse of a muscle cause?

Contractures

What is sensation necessary for?

Goal Directed Movement?

Use of sensory information to prepare for movement

Feedforward

Use of sensory information during or after a movement

Feedback

A decision is made in the anterior part of the frontal lobe, then ____

The Motor Planning Areas

Control Circuits

basal ganglia, cerebellum

Descending Tracts

Corticospinal Corticobrainstem Tracts

Spinal Interneurons

Influence type of info from LMN to Muscle

Lower Motor Neurons

Directly innervate skeletal muscle

Skeletal Muscle

Contract to produce movement

***Cerebral Motor Cortex and Brain Stem, Synapse with motor neuroms located in the brain stem and spinal cord. Basal Ganglia and Cerebellum adjust the activity of the descending tracts

Upper Motor Neuron

***Ventral Horn of spinal cord and brain stem, synapse with skeletal msucle fibers. spinal cord and brain stem determine activity

Lower Motor Neuron

• Most common basal Ganglia Disorder

• Death of Dopamine

• Clinical Diagnosis involves HYPOKINESIS, RIGIDITY, and RESTING TREMOR

• 80% of Dopamine cells die before signs of disease appear

• Onset age 50-79

• Both Motor and Non-Motor Disease

Parkinsons Disease

4 Cardinal motor signs of PD

Tremor, Rigidity, Bradykinesia/Akinesia, Rigidity, Postural Instability

Are non-motor challenges if PD just as debilitating as motor challenges?

Yes

***lateral corticospinal tract

Most important pathway controlling voluntary movement of limbs.

• Selective motor control

• Ability to activate individual muscles independently

***Corticobrainstem Tract

Voluntary control of muscles in the head and neck

*** Upper facial Muscles are innervated___

Bilaterally

***Lower facial muscles are innervated____

Contralaterally

An interuption of corticobrainstem fibers will cause paralysis of ___ but not ____ facial muscles on opposite sides

Lower, Upper

***If a stroke creates a leision that disrupts the corticobrainstem pathway, the deficit will occur on the ______ _____ ____ because the upper face recieves bilateral projections. This is called Facial droop

Contralateral Lower Face

***Alpha Motor Neurons

Innervate the skeletal muscle and cause contraction

***Gamma Motor Neurons

Innervate the muscle spindle to help maintain its sensitivity to changes in muscle length

***An AMN and all the muscke fibers it innervates is known as the ____

• Type 1 is slow twitch

• Type 2 is fast twitch

Motor Unit

Henneman Size Principle

areas that require precision have more motor units while areas that require power have more muscle fibers per unit

Muscle Tone

Resistance to stretch

Hypotonicity

Loss of tone

Hypertonicity

Increased tone in muscle

Paresis

Weakness or inability to generate muscle force to produce movement

Paralysis

Total loss of volitional control

Hemiparesis

Weakness on half of body, Paralysis of one or more joints

Paraplegia

Paralysis of the trunk and legs

Tetraplegia

All 4 extremeties

***Hypertonia

UMN Lesions, Acute is LMN Lesions, basal Ganglia Disorders

***Hypotonia

LMN Lesions, Acute UMN Lesions, causes by brain hypoxia/ischemia/intercranial hemmorrhage/ and genetic disorders

***Decerebrate Rigidity

Lesion between midbrain and pons, Rigid EXTENSION of limbs and trunk, internal rotation of the UE and plantar flexion

***Decorticate Rigidity

Upper Midbrain or bilateral cerebral cortex, Upper limbs are FLEXED, lower limbs are extended

Spinal and cerebral shock

Occurs at time of insult, descending motor commands are interrupted and become inactive, Persons loses significant volitional movement and is largely paralyzed

***Babinski Reflexes

***Clonus

Abnormal reflex of involuntary, rhythmic contractions

***Atrophy

Loss of Muscle Bulk

***Disuse Atrophy

Loss of muscle bulk related to lack of use

***Neurogenetic Atrophy

From Damage to nervous system (Complete peripheral nerve lesion)

Areflexia

Decrease or loss of reflexes

Paresis

Decreased ability

Paralysis or flaccidity

Total Loss to generate muscle force

Poliovirus (LMN)

An Infection that targets motor neuron cell bodies an destroys them.

Post-polio Syndrome

Most common Lower motor neuron disease

Post-Polio

Muscle and joint weakness

fatigue

atrophy

breathing and swallowing problems

pain

sleep-related breathing disorders

decreased tolerance of cold temperatures

Parkinsons

brady/hypokinesia

termors

rigidity

postural instability

Basal-gangia disorder(UMN)- substansia Nigra

Amytropic lateral sclerosis (UMN and LMN)

Bilateral disease, Idiopathic, Progressive,

ALS

UMN+LMN

Paresis (Flaccidity and Rigidity)

Hyporeflexia, Hypotonia, Atrophy

Positive Babinski sign, Hyperreflexia, Atrophy

Brown Sequard Syndrome

Damage to half the cord

Pain/temp- contralateral

light touch/proprioception/sterignosis- ipsilateral

Loss occurs 2-3 dermatomes below due to collateral branching

Brown Sequard Syndrome

Ipsilateral UMN Lesions below the level of the lesion

Ipsilateral LMN Lesions at the level of the lesion (Flaccidity)

transverse cord

Loss of voluntary movement, pain/temp, DCML, Bladder(At or below T12) both sides

Anterior Cord

Affects anterolateral and lateral corticospinal tracts and LMNs within the cord

Loss of voluntary motor both sides

Loss of pain and temp both sides

Complete motor paralysis

Severe flexion injury

Position and vibration sense preserved

centeral Cord Syndrome

Cervical level lesion

Anterolateral pathway impairment (Hyperextension injury)

Loss of voluntary motor both sides

Loss of pain/temp both sides

Loss of DCML both sides

May Spare Sacral function

Posterior Cord Syndrome

loss of fine touch, pressure, vibration, and proprioception

Rare

SENSORY ATAXIA

Degenerative

Demyelinating disorders. External compression, Blockage of PSA

Sensory Ataxia

Decreased coordination, decreased proprioception, poor balance, decreased sensation or vibration and fine touch

Cerebellar Dysfunction

Doesn’t interfere with sensory perception or muscle strength.

Damage=Impaired coordination and postural control, decreased cognitive/social/emotional fucntion.

Ataxia

Jerky, innacurate movements

Dysarthria

Slurrred speach

Dysdiadochokinesia

Inability to preform rapidly repeating alternating movements

Dysmetria

Inability to accuratly move an intended distance

Action Tremor

Shaking during voluntary movement increased when approaching intended target

Basal Ganglia

Goal directed behavior

social behavior

Emotional/otivational circut

Oculomotor

Motor

What do diseases of the basal ganglia cause

Excessive movement or insufficient movement

Huntingtons Disease

Basal Ganglia(UMN) -Striatum

Autosomal dominant, Neurodegenerative

DNA Triplet Repeating

Symptoms are motor, cognitive, or psychiatric

life expectancy 15yrs

CHOREA(Involuntary jerky movements)

Difficulty decision making, organizing, planning, multitasking, progresses to dementia

Dystonia

Contraction of muscles yielding abnormal posture, twisting, and repetetive movements.

Genetic and non-progressive

No cure but managed with medications

Cervical dsytonia is the most common (Neck muscles twisting)

Gaze stabilization- maintain visual contact while head is moving

vestibulochloear reflex

Equilibrium and posture

Semicircular canals, utricle, and saccule

hearing

Cochlea

Vestibular Nerve Path

Semicircular ducts otholithic (Utricle and Saccule), Vestibular nerve, Vestibular nuclei (Up- vestibular cortex) (Down- Cerebellum), spinal cord

Vestibular nuclei send what kind of vestibular information to the vestibular cortex for conscious awareness?

Afferent

vestibular Apparatus

Semicircular ducts, utricle, and saccule

In addition to recieving input from semicircular canals, utricle, and saccule, they recieve ___?

Proprioceptive, tactile, and auditory information

The Vestibular Nuclei activate movements to support what?

Gaze and Equilibrium

Bony Labirynth

Cochlea, Vestibule, and Semicircular Canal

Cochlea (Anteromedial)

Hearing

Vestibule (Mid Portion)

Static Functions, connects cochlea and semicircular canal

maintains balance and orientation

Projections to brainstem

Semicircular canal (Posterior lateral)

Kinetic Functions

kinetic Labirynth

3 semicircular canals- hair cells that respond to motion of the endolymph

ROTATIONAL MOVEMENT (Right angles)

Cupula in ampulla that has hair cells in membrane that moves when head moves

Cupula- Directions, not right angles

Static Labirynth

Otolithic organs, utricle, and saccule

macular crystals bend and activate hair cells

LINEAR ACCELERATION AND DEACELERATION

Nystagmus

Involuntary back and forth eye movement

Benign paroxysmal Positional Vertigoo:Canalithiasis

acute onset of vertigo and nystagmus. Rapid head change can result in dizziness, subsiodes in 2 minutes

Cause: Crystals from otolithic organs (Utricle and Saccule) float into semicircular canals and create abnormal sensations of head movement

Vestibular Neuritis

inflammation of vestibular nerve caused by a virus

Unsteadiness, nausea, vertigo

Last up to 3 days

Unaffected hearing

Meiniers Disease

Abnormal fluid pressure in inner ear

Sensation of fullness, tinnitus, vertigo, nausea, vomiting, hearing loss

Can occur spontaneously without head movement