bioe221 sn09 neurologicalcns...• it is the “final common pathway” as it funnels many neural...

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BIOE221

Session 9

Neurological Assessment –

CNS & Cranial Nerves

Bioscience Department


Session Objectives

o Review the major structures and functions of the nervous

system in order to be able to assess its motor, sensory

and integrative functions

o Identify the common symptoms relating to neurological

disorders

o Demonstrate examination of the neurological system by

assessing certain cranial nerves and cerebellar function

o Recognise clinical findings with these techniques


Organisation of the Nervous System

o The nervous system can be divided into two

parts:

• Central nervous system (CNS)

–CNS - brain and spinal cord

• Peripheral nervous system (PNS)

–Somatic, Autonomic and Enteric nervous

systems

– includes 12 pairs cranial nerves, 31 pairs

spinal nerves and all their branches


Structural & Functional

Relationship

(Jarvis, 2016, p.633)


Major Sensory and Motor

Pathways

(Jarvis, 2016, p.635-636)


Spinal Cord

Sensory & Motor Tracts

(Tortora & Derrickson, 2009, p.481)


Upper Motor Neurons

o Upper motor neurons are a complex of all the descending motor fibres that can influence or modify the lower motor neurons

• Located completely within the CNS

• Convey impulses from motor areas of the cerebral cortex to the lower neurons in the anterior horn cells of the spinal cord

o UMN diseases e.g. CVA, cerebral palsy, MS

o Upper motor neuron weakness is likely to lead to

• Increased muscle tone (compare with the other side)

• Increased reflex response

• Creates weakness – particularly of the triceps, finger extensors and handgrip


Lower Motor Neuronso LMN are located mostly in the peripheral nervous system

• The cell body of the lower motor neuron is located in the anterior grey column of the spinal cord, the nerve extends from here to the muscle

• It is the “final common pathway” as it funnels many neural signals here and it provides the final direct contact with the muscles

• Any movement must be translated by LMN

o LMN disease e.g. spinal cord lesions, poliomyelitis

o Lower motor neuron weakness is likely to lead to

• Decreased muscle tone

• Muscle fasciculation's

• Muscle wasting - evident within 2-3 weeks of onset

• Reflexes that are depressed or absent


Motor Neuron Findings and

Interpretations

Variable

(findings)

UMNL LMNL

Muscle tone Increased (spasticity) Absent (flaccidity)

Bulk Normal/minor disuse

atrophy

Marked atrophy

Abnormal

movements

None Fasciculation

Reflexes Hyperreflexia, clonus Hyporeflexia, areflexia

(adapted from: Jarvis, 2012, p.673)


Cranial Nerves

o Cranial nerves enter and exit the brain rather than the

spinal cord

o The 12 pairs of cranial nerves supply primarily the head

and neck

o Only the Vagus nerve (CN10) travels to the heart,

respiratory muscles and Gastro intestinal organs


Cranial Nerves

(Jarvis, 2016, p.638)


Case History Questions

o Headache

o Head injury

o Dizziness/ vertigo

o Seizures

o Tremors

o Weakness

o Loss of Coordination

o Numbness or tingling

o Difficulty swallowing

o Difficulty speaking

o Significant

neurological past

history

o Environmental/

occupational hazards


Neurological Examination

o The neurological examination takes into consideration:

• Mental state

• Cranial nerves

• Motor system

• Sensory system

• Reflexes

o The neurological examination should incorporate the

examinations from other relevant systems in order to

refine your differential (e.g. pins & needles could be

neurological or peripheral vascular).


Neurological Examination Ordero Mental status

o Test selected cranial nerves

o Motor system - inspect & palpate

• Muscles (size, strength, tone, involuntary movement

o Cerebellar function

• Gait, Romberg Test, coordination and skilled movements e.g.

rapid alternating movements.

o Sensory system

• Ask the person to identify various sensory stimuli in order to test

the intactness of the PNS fibres and higher cortical

discrimination

– Pain, temperature, sharp/dull

– Vibration, position, tactile discrimination

– Reflexes – deep tendon reflexes or stretch reflexes


Mental StatusAssessment of mental status should include:

o Appearance

• Posture should be upright and relaxed

• Body movements should be voluntary and coordinated

• Dress should be age and culturally appropriate

o Behaviour

• Should be awake and alert

• Able to make and maintain appropriate eye contact

• Speech should be relaxed, fluent and understandable

o Cognitive function

• Orientated to time, place and person (TPP)

• Able to maintain attention

o Thought processes

• The person thought should be logical, coherent and relevant


Cranial NervesCranial Nerve Motor Sensory

I – Olfactory - Ask about sense of

smell

II – Optic - Ask about visual

acuity

III, IV, VI –

Oculomotor, Trochlear,

Abducens

Observe for eyelid

drooping (Ptosis)

Pupil reactions

Eye movements up,

down and side-to-side

Pupil reactions

(Parasympathetic)

V – Trigeminal Observe jaw

alignment during teeth

clenching

Light touch to cheek,

forehead & chin

(cotton wool)

VII – Facial Nerve Observe for symmetric

smile

Ask about sense of

taste(Adapted from: Jarvis, 2016, p.644-647)


Cranial NervesCranial Nerve Motor Sensory

IX, X –

Glossopharyngeal,

Vagus

Observe swallowing or

observe uvular

elevation when saying

“ahhh”

Listen to quality of

speech

Ask about presence of

gag reflex

XI – Spinal Accessory Observe symmetry

and tone of SCM and

Trapezius

Observe shoulder

shrug

-

XII – Hypoglossal Observe tongue

medially aligned and

no tremors when

extended.

-

(Adapted from: Jarvis, 2016, p.644-647)


Motor System AssessmentMotor system assessment involves inspection and palpation of

the various muscle groups taking note of: (This is also a

component of the musculo-skeletal assessment)

o Size

• Left vs Right should demonstrate symmetry

• Observe for atrophy or hypertrophy

o Strength

• Use active resistance in the mid-range of motion (flexion)

to assess muscle strength bilaterally

o Tone

• Observe for symmetry of muscle tone bilaterally

• Palpate for muscle tone in the relaxed position

o Involuntary movement

• Observe for unintentional or involuntary movements


Abnormalities in Muscle Movement

Tremors

• Involuntary shaking, vibrating, trembling of opposing muscle groups

• Results in a rhythmic, back and forth movement of one or more joints

• May occur at rest or with voluntary movement

• All tremors disappear with sleep

• Causes: cerebellar disease, MS, Parkinsons, emotional stress, alcohol

and drug withdrawal

Fasciculation

o Rapid continuous twitching of resting muscle or part of muscle, without

movement of the limb that can be seen or felt

o Types:

• Fine – occurs with motor neuron disease, associated with atrophy

and weakness

• Coarse - occurs with cold exposure or fatigue and is not significant


Abnormalities in Muscle Movement

o Seizures

• Paroxysmal disease characterized by altered or loss of consciousness, involuntary muscle movement and sensory disturbances

• Causes: epilepsy, high fevers in infant and toddlers, neurological disease or drug complications

o Chorea

• Sudden, rapid, jerky, purposeless movement involving limbs, trunk or face

• Occurs at irregular intervals, not rhythmic or repetitive, more convulsive than a tic: all are accentuated by voluntary acts;

• Common with Huntington’s disease


Cerebellar Function

Cerebellar function is involved with balance,

coordination and proprioception:-

o Rapid alternating movements

o Gait

o Romberg test


Rapid alternating movements

(Jarvis, 2012)


Motor System for Cerebellar

FunctionBalance tests

o Gait

• normal – smooth, rhythmic, effortless, coordinated

• opposing arm swing, smooth turns

o Romberg test

• watch for maintenance of posture & balance

– positive – loss of balance

– cerebellar ataxia (MS/ alcohol intoxication)

– loss of proprioception/ loss of vestibular function


Observation of Gait

o Do they limp?

o Are they unsteady?

o Do they hold on to things

o Do they appear stiff (spastic)?

o Do they have foot drop?

o Do their arms swing when they walk?


Gait Patterns

Spastic hemiparesis

Cerebellar ataxia

Parkinsonian

Scissors

(Jarvis, 2016, p.683-684)


Gait Patterns

Steppage or footdrop

Waddling

Short leg

(Jarvis, 2016, p.683-684)


Gait

o Spastic hemiparesis

• Arm immobile against body, flexion of the shoulder, elbow, wrist and fingers, adduction of shoulder. Leg stiff and extended. Circumducts hip with each step (drags toes in a semicircle)

• Cause: UMNL of the corticospinal tract e.g. CVA, trauma

o Cerebellar ataxia

• Staggering, wide based gait; difficulty with turns, uncoordinated movement. Positive Romberg sign.

• Cause: Alcohol or barbiturate effect on cerebellum, cerebellar tumor, MS

o Parkinsonian

• Posture stooped; trunk pitched forward; elbows, hips and knees flexed. Steps are short and shuffling. Hesitation to begin walking, difficult to stop suddenly. Person holds their body rigid, walking and turning as one fixed unit. Difficulty with any change in direction.

• Cause: Parkinson’s disease, certain drugs

o Scissors

• Knees cross or are in contact, like holding an orange between the thighs, the person uses short steps, and walking requires effort.

• Cause: paraparesis of legs, cerebral palsy, MS


Gaito Steppage or Footdrop

• Slapping quality – looks as if walking up stairs and finds no stair there. Lifts knee and foot high and slaps it down hard and flat to compensate for footdrop

• Causes: Weakness of peroneal and anterior tibial muscles; due to LMN lesion at spinal cord e.g. poliomyelitis, herniated IV disc

o Waddling• Weak hip muscles – when the person takes a step, the opposite hip

drops, which allows compensatory, lateral movement of the pelvis. The person often has marked lumbar lordosis and a protruding abdomen

• Causes: Hip girdle muscle weakness due to muscular dystrophy, dislocation of the hips

o Short leg• Leg length discrepancy > 2.5 cm. Vertical telescoping of affected

side, which dips as the person walks. Appearance of gait varies depending on amount of accompanying muscle dysfunction

• Causes: Congenital dislocated hip; acquired shortening due to disease, trauma


Eye Examination

o Examiner Ask’s / Observes:

- Vision difficulties?

- Pain?

- Strabismus/ Diplopia?

- Redness, swelling?

- Watering, discharge?

- Past history of ocular problems?

- Glaucoma?

- Use of glasses or contact lenses?

- Self-care behaviours

30


Pupillary Light Reflex (CNIII)

o Check pupils for

• Size

• Regularity

• Equality

• Direct light reaction

• Consensual light reaction

• Accommodation

PEARL

Pupils Equal and Reacting to

Light


Examination of the Eye

32

Diagnostic Positions Test(Jarvis, 2016, p.293 &313)


Visual Changes (not examinable)

o Visual changes can be uniocular or binocular

o Double vision (diplopia) usually results from damage to cranial nerves II, III, IV, VI

o Flashers and Floaters

• Common in > 65 year age and in those with myopia (short sightedness)

• Caused by vitreous degeneration

o Haloes

• Coloured lights around bright light

• Result from fluid in the cornea acting as a prism

• Seen in angle-closure glaucoma


Resources

Jarvis, C. (2016). Physical Examination & Health

Assessment (7th ed.). Sydney: Saunders.

Tortora G.J., & Derrickson B. (2014). Principles of

Anatomy & Physiology (14th ed.). Hoboken, NJ: John

Wiley & Sons.

Blumenfeld, H. (n.d.). Strength of individual muscle

groups, vRetrieved December 9, 2015, from

http://www.neuroexam.com/neuroexam/content.php?p=

29

http://www.neuroexam.com/neuroexam/content.php?p=29


Web sites to View Abnormal gaits

o ataxic gait

http://www.youtube.com/watch?v=FpiEprzObIU

o all types of gait demonstrations

http://library.med.utah.edu/neurologicexam/html/gait_abnormal.html

o cerebellar gait

http://www.lifehugger.com/mov/1066/Cerebellar_gait

o tandem test with loss of cerebellar function

http://www.aan.com/globals/axon/assets/5546.mov

http://www.youtube.com/watch?v=FpiEprzObIU

http://library.med.utah.edu/neurologicexam/html/gait_abnormal.html

http://www.lifehugger.com/mov/1066/Cerebellar_gait

http://www.aan.com/globals/axon/assets/5546.mov


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