neuro assessment Flashcards
HOW DOES THE CNS COMMUNICATE WITH THE PNS? (think neurons)
VIA NEURONS AND NERVE FIBERS
Sensory neurons from the PNS transmits information to the CNS for processing
CNS sends signal via motor neurons back to the PNS to respond
Dendrite
(dend is the receiver)
Dendrite
Receives stimulation in order for the cell to become active
Cell body (Soma) - what does it do?
(soma has the info)
Cell body (Soma)
Processes information
axon
Axon
Conducts and transmits impulses to other neurons or end organ; varies in length from few centimeters up to few feet
Myelin sheath - produced by what in the PNS?
(schwann has PNS)
Myelin sheath
Produced by schwann cells in the PNS
Insulates the axon; allows for faster conduction
Axon terminal
Axon terminal
Releases neurotransmitter
NEUROTRANSMITTERS
Chemicals that are released by the presynaptic cells at the end of the axon
These chemicals bind to the receptors at the post-synaptic dendrites to initiate an electrical impulse
Whether there is depolarization “action potential” depends on the number of presynaptic cells firing (summation) or the frequency with which one cell fires (temporal summation)
Excitatory neurotransmitters - examples
(excite the GHN)
Excitatory neurotransmitters
Norepinephrine, glutamate, histamine
Inhibitory neurotransmitters - ex.
(inhibited by G)
Inhibitory neurotransmitters
Gamma-amino butyric acid ( GABA), glycine
Drugs and toxins can modify or block these neurotransmitters
Both excitatory and inhibitory
(sneeze in the dope for both)
Both
Acetylcholine, Dopamine
FUNCTIONS OF A NEURON - can they regenerate?
Functions:
Initiates (nerve impulse), receives and processes messages from internal and external signals
Neurons are not mitotic: therefore “can not regenerate” themselves if damaged.
Thus, primary tumors of neurons are rare
However recent evidence shows astrocytes play in role in reducing neuroinflammation during damage and may proliferate after certain CNS injuries
Sensory neuron
Sensory neuron
Activated by sensory input from sensory receptor neurons
Interneurons
Interneurons
transmits impulses between nearby motor and sensory neurons (bypasses signal to brain as in reflex arc to prevent injury)
Motor neuron
Motor neuron (Upper and Lower Motor neuron)
Sensory input processed by the cerebral cortex transmits impulses via upper and lower motor neurons to elicit a motor response
UPPER MOTOR NEURON
(up must go down)
Located in the cerebral cortex
Signal travels down Corticospinal tract (descends to spinal cord to control movements below neck)
LOWER MOTOR NEURON - where is it located?
(the lower horn)
Located in anterior horn of the spinal cord
Controls skeletal muscles
Corticobulbar tract (ends at the brain stem; controls mov’t of cranial nerves)
UMN LESION (damage to motor neurons) - what are the symptoms?
(uma is a spaz)
Spasticity
Hypertonia
hyper-reflexia
+Babinski reflex
Muscle atrophy due loss of innervation
LMN LESION
(lame is flaccid)
Flaccidity
Hypotonia
Hypo-reflexia
- Babinski
Muscle atrophy due to disuse
PROTECTING THE NEURONS: GLIAL CELLS (NEUROGLIA)
(glee protects me)
FUNCTION:
Surround neurons, provide support and insulation
Most abundant cells in the brain (comprise ½ the mass of the brain and spinal cord)
Left Hemisphere
Logic and reasoning
Math and Science
Speech, words, and language
Detail oriented
Reality based
Right Hemisphere
Creativity/imagination
Impulse control
Feelings and intuition
Spatial perception
Abstract meaning
ANATOMY OF THE BRAIN
The brain includes:
The cerebrum (left/right cerebral hemispheres) 4 lobes
The cerebellum
The brain stem 3 parts (midbrain, pons, medulla oblongata)
Broca’s area: on TEST - where is it located?
(broc expresses himself in the front)
Located in the frontal lobe (left hemisphere)
Wernicke’s area: where is it located? and what type of language?
(Wernicke is receptive in the temple)
Located in the temporal lobe (left hemisphere)
Enables the processing of words into coherent thought and recognition of the idea behind the written or heard words
Responsible for receptive language
Limbic System: Emotion and Motivation - parts of the limbic system? (FAT CHH - ic)
Amygdala
Hippocampus
Thalamus
Hypothalamus
Cingulate gyrus
Fornix
Basal Ganglia
Group of structures located centrally in cerebrum
Responsible for:
Initiation, execution, and completion of movements
Learning and emotional response
Autonomic movements (blinking, swallowing, swinging of arms)
CEREBELLUM
(belly dancer is fine)
Receives input from the cerebral cortex, spinal cord, sensory and inner ear
Coordinates:
Voluntary movements
Sense of body position
Balance and equilibrium
Speech
Fine movements
BRAIN STEM - on TEST (brain stem is the worst stroke you can have) - parts of the brainstem
(stem is having PMM)
Consists of :
Midbrain
Pons
Medulla oblongata
Grey Matter - composed of what?
(TBD grey)
Mainly composed of cell bodies, dendrites and axon terminals of neurons
White Matter
(myla is white)
Mainly composed of myelinated axons connectingall the neurons in the brain and spine
WHAT IS PROTECTING YOUR BRAIN
Skull – physical barrier
Meninges
Blood Brain Barrier
Cerebral Spinal Fluid
Dura mater
(dura ble skull and arachnoid)
Dura mater – tough membrane between the skull and arachnoid
Arachnoid
(bathethe arachnoid)
Arachnoid bathed in CSF and contains blood supply
Pia mater
(pia is full of fluid)
Pia mater – additional barrier, secretion and containment of CSF
THE BLOOD BRAIN BARRIER (BBB)
Complex of tightly joined endothelial cells of the cerebral capillaries and astrocyte end feet together keep some substances of plasma out of the CSF and brain
CEREBROSPINAL FLUID (CSF) - where is it located?
(school is sub ventricles)
Located in the subarachnoid and *ventricles
FUNCTION OF CSF - 3 things
Buoyance- allows brain to float in the cranium
Protection – cushions the brain from impact
Chemical stability – removes waste and optimizes environment for neurons
CEREBRAL CIRCULATION
Internal carotid artery supplies blood to the cerebrum
Anterior cerebral artery
Middle cerebral artery
Posterior cerebral artery
Vertebral artery
From the subclavian artery join to form the basilar artery to provide blood flow to the cerebellum
CEREBRAL CIRCULATION - Pontine branches
(ponte puts in basil stem)
Pontine branches
Branches from the basilar artery providing blood to brain stem
CEREBRAL CIRCULATION - Circle of Willis - on TEST
(Willis is my collateral)
Circle of Willis
Arterial structures that provides collateral circulation through alternate arteries to prevent brain ischemia
VERTEBRAL COLUMN - what about sacral and coccygeal?
There are 4 curves in the spine:
7 cervical
12 thoracic
5 lumbar
5 fused sacral
4 fused coccygeal
The spinal cord passes through the vertebrae
THE SPINAL CORD - where does it end? and what covers it?
Spinal cord : ends between L1 and L2.
Axons from the lumbar and spine extend downward and exit the intervertebral foramen
Note the meninge layers also cover the spinal cord
PERIPHERAL NERVOUS SYSTEM - comprised of which nerves? (2 types)
PNS: comprises of spinal nerves and cranial nerves
31 pairs of spinal nerves (8 cervical, 12 thoracic, 5 lumbar, 5 sacral and I coccygeal)
NERVE TRACTS - 2 types - you know this
Ascending tracts: nerve fibers that carry sensory stimuli from periphery (e.g. skin, muscle, blood vessels) toward the brain
Descending tracts: nerve fibers that carry impulses responsible for motor movement
Peripheral Nervous System - Dermatomes - innervated by what?
Dermatomes: Area on the skin that is innervated by spinal nerves. Each of these spinal nerves relay sensation from a particular region of skin to the brain
Peripheral Nervous System - Sensory receptors
Sensory receptors: located throughout the body to monitor and transmit sensation of pain, temp, touch, vibration, pressure, visceral sensation and proprioception.
Plexus - passes through where? and injury to plexus can cause what?
Plexus: areas where the nerves join together.
Cervical, brachial, lumbar and sacral
Often passes through or are surrounded by bones. Injury can cause entrapment to many nerves
NEUROLOGICAL ASSESSMENT
Establish a basement
Mentation, vision, speech, motor, sensation, reflex
For past medical hx, ask about:
Medical, family, diet, cancers, infections, bowel and bladder functions
Social Hx: substance abuse, living situation, social support, sleep pattern
Surgical hx: traumas and surgeries
Nutrition: chewing or swallowing issues. Vitamin supplements such as B1, niacin, B6 that are required for CNS function
NEUROLOGICAL ASSESSMENT
There is no clear consensus regarding the optimal order of performing or presenting the neuro exam. “Be systematic”
A thorough neuro exam should include :
Mental status
Cranial nerve exam
Motor system exam
Reflexes
Sensation test
Compare Left and Right sides to each other
Compare upper to lower extremities
NEUROLOGICAL ASSESSMENT: Mental Status Examination - on TEST (CA)
Components are:
General appearance and behavior
LOC: Change in LOC is the first indication of decline in CNS function
Level of consciousness:
Arousal: a state of wakefulness that an individual exhibits. It is mediated via RAS (awake, alert, lethargic, obtunded, stuporous, comatose)
Awareness: encompasses all cognitive functions that embody awareness of self, environment and affective states
NEUROLOGICAL ASSESSMENT: Mental Status Examination - cognition - how to measure attention?
Orientation to person, time, place, situation
General knowledge (e.g. who is the current president)
Memory: immediate (what did you have for breakfast), recent (where did you go to HS) and remote
Executive functioning
Note impairment such as dementia and delirium
Calculation
Attention: Count backward from 100 by 5. Stop when they reach 65, say the alphabet backwardsv
How to Assess Memory - Long term/remote
Memory: very important part to note loss of memory as it can be an early sign of dementia and Alzheimer’s
Assess for
Long term/remote: ask birth date, schools attended, place of birth …any info you can verify
Mental Status Examination - Language and copying
Language and copying
Can they follow commands
Any hesitancy in speech
Point to an item and ask patient to name it
Draw something simple and ask to copy
Reading/comprehension only if patient can read
MOTOR EXAM - Cerebellar and coordination test (think balance) and which test?
Gait and balance
Rapid alternating movement
Finger to nose testing or heel to shin testing
REFELX TESTING - grade, and what’s important?
Relaxation is key during the reflex exam
The joint under consideration should be about 90 degrees and fully relaxed
Reflexes are graded by 0-5 scale. However, comparison between reflexes in one part of the body with another is much more important than the absolute reflex grade.
SENSORY EXAM
Light touch
Vibration
Pain:
Nociceptive:
Somatic pain
Visceral
Neuropathic
Nerve pain
Temperature
AGE RELATED NEURO CHANGES - CNS - neurons?
CNS:
Normal loss of neurons → ↓in brain mass
AGE RELATED NEURO CHANGES - pupil size?
Pupil size decrease and slower accommodation to light changes
X-ray for bone density
Cerebral angiography - what to watch out for? (2 main things)
To evaluate cerebral, carotid and vertebral circulation
Using contrast medium may sting or have burning sensation behind the eyes or in the face when injected, feeling flushed
Check allergies to contrast dye
Dyes can cause allergic reaction and vasospasm. If this occurs, stop the test. Can cause ischemia and hemiparesis.
Monitor puncture site for bleeding and pulse
Bed rest and immobilization of limb for the prescribed number of hrsv
Diagnostics: best test for neurologic problems?
CT scan - Quickest, easiest and least expensive method for diagnosing a neurologic problem
Can distinguish bone, soft tissue and CSF or blood
Can help identify tumors, infarcts, bleeding, and hydrocephalus
Diagnostic: what is the most sensitive test?
MRI - Most sensitive for detecting abnormalities of the brain and spinal cord
May use gadolinium: non-iodine based contrast
Screening form required to rule out contraindications for MRI
Diagnostic: PET SCAN (Positron Emission Tomography)
A type of nuclear medicine procedure that measures metabolic activity of tissue cells.
Preparation
NPO except water 6 hrs prior to exam
Limit carb intake 24 hrs prior to exam
Hold diabetic medications and sources of glucose per doctor’s orders
Used to detect cancers, heart disease and brain disorders
Provides information about function such as blood flow, glucose and O2 metabolism
Diagnostic: Lumbar Puncture (LP)
Lumbar puncture or spinal tap: A needle is inserted into the subarachnoid space to obtain pressure readings and to collect CSF
Nursing role:
During procedure: help position patient and provide physical and emotional support.
Post procedure: monitor puncture site and report signs of severe headache
Diagnostic: Electroencephalogram (EEG)
Detects electrical activity in the brain
Useful in diagnosing brain disorders, especially epilepsy, seizure disorder, level of induced coma
cranial nerve 1
olfactory (cover one nostril)
pupil check
check if they constrict - 2nd time if they’re symmetrical
cranial nerve 2
optic (paper 20 inches from pt about)
3,4,6 cranial nerve check
checking your eye muscles
check peripheral vision
cover one eye
receptive aphasia
when someone is able to speak well and use long sentences, but what they say may not make sense. They may not know that what they’re saying is wrong,
if block in carotid = symptoms
can be headache, dizziness
reflex arc
Reflexes: an involuntary and nearly instantaneous movement in response to a stimulus. A reflex is made possible by neural pathways called reflex arc which can act on an impulse before that impulse reaches the brain.
need to know slide 58 and 59
on test
mylin sheath - produced by what in the CNS?
Produced by oligodendrocytes in the CNS
neurotransmitters that inhibit pain
Endorphins and Enkephalins: inhibits pain
lower motor neuron - is it one side, or both?
*Notice contralateral involvement of muscle
the skull - how many bones
The skull: protects the brain from trauma. Consists of:
8 cranial bones
14 facial bones
Amygdala
Amygdala: fear, anger, anxiety
Hippocampus
Hippocampus: formation of new memories
Thalamus
Thalamus: relay center of sensory inputs to the cerebral cortex
Hypothalamus
Hypothalamus: regulates ANS and the endocrine system
Cingulate gyrus
Cingulate gyrus: pain and emotion
Fornix
Fornix: the primary outgoing pathway from the hippocampus
brainstem - vital function
Vital function: Respiratory and cardiac functions
brainstem - Reflexive function
Reflexive function: swallowing, gag, digestion, vomiting
Reticular Activating System (RAS)
Net-like formation of nerve cells along brainstem
brainstem - Responsible for
sleep-wake cycle, alertness and arousal
grey matter - what does it control?
Controls higher functions of the CNS: emotions, cognition, consciousness
white matter - what does it do?
Conducts, processes, and sends signals up and down the spinal cord.
Meninges
physical barrier and contains blood supply
Blood Brain Barrier
limits metabolite, chemical/toxic entry
Cerebral Spinal Fluid
cushions and optimizes environment
what can cross the BBB?
O2, glucose, CO2, ETOH and anesthetics crosses freely
what can’t cross the BBB?
Large molecules such as albumin, toxins, and many antibiotics cannot cross BBB
CSF - color?
Clear, colorless
CSF - specific gravity, glucose, and pH?
Specific gravity: 1.007
Glucose: 45-75
No RBCs
pH: 7.35
CSF - produced where?
Produced by the ependymal cells of the Choroid plexus: complex of tiny blood vessels in the lateral, 3rd & 4th ventricles of the brain
PNS - dorsal root
ON TEST - Dorsal root travels afferent path: -carries sensory information from the peripheral toward the CNS***
PNS - Ventral root
Ventral root travels efferent path: - carries impulse away from the CNS toward the periphery for motor control
sensory receptors also include what?
Also includes the “special senses” of vision, taste, smell, hearing, sight
neuro assessment - LOC
Components are:
General appearance and behavior
LOC: Change in LOC is the first indication of decline in CNS function
neuro assessment - Arousal
Level of consciousness:
Arousal: a state of wakefulness that an individual exhibits. It is mediated via RAS (awake, alert, lethargic, obtunded, stuporous, comatose)
neuro assessment -Awareness
Awareness: encompasses all cognitive functions that embody awareness of self, environment and affective states
how to assess memory - Recall/recent
Recall/recent: how good a historian are they (if the info is consistent). Dates of appointment? Date of admission?
how to assess memory - Immediate or new
Immediate or new: 3 non-related words and ask to repeat after a couple of minutes
motor exam - strength test
Strength testing
– push and pull test against resistance
motor exam - Tone
Tone
Passive movement of limbs should elicit slight resistance. Note tics, tremors, spasticity, flaccidity
sensory exam - Stereognosis
ability to recognize objects in hand
sensory exam - Graphesthesia
ability to recognize writing on the skin purely by the sensation of touch
age related changes - PNS
PNS
Degeneration of myelin → slower conduction → decline in neuromuscular coordination
orthostatic hypotension more common
temperature regulation less optimal (vulnerable to hypo and hyperthermia)
Slower reflexes
brocka’s area - what type of language?
Composed of neurons responsible for the formation of speech (expressive language)
It requires activation of the vocal cords which must occur at the same time as the tongue and mouth movement
age related changes - CNS - ventricles?
Widening of the ventricles
age related changes - CNS - blood flow? and CSF?
Cerebral blood flow and CSF production decline
age related neuro changes - memory?
Memory, vision, taste, smell, muscle strength decline
Touch and position sense decrease: ↑ Fall risk
Vibration sense in hands and feet may decline
Loss of hearing in the high pitched ranges
Require more time for thought processing. Intelligence not affected
Long term memory better than short term memory
Insomnia, wakefulness at night (require less sleep than when younger)
what xray for bone density?
Cerebral angiography
CT scan - does it use contrast?
Can be done with or without contrast (using contrast yields more detailed imaging)
