Exam 2 (Sensory, Pharmacology) Flashcards
Sensory Receptor
- First cell in any sensory pathway
- transforms a stimulus into electrical energy (signal)
- specialized
Labeled Line Code
(Sensory adaptaion/design)
How the brain associates a specific modality with a signal coming from a specific receptor
5 Specific Touch Receptor Types
Low threshold and rapidly adapting:
1) Meissner’s Corpuscles ·sensitive to touch and vibration
· Dense in tips of fingers
2) Pacinian Corpuscles
·sensitive to high freq vibration
Low threshold and slowly adapting:
3) Merkel’s Disks
·sensitive to pressure
4) Ruffins Corpuscles ·senstive to stretching of skin
Uncategorized
5) Hair follicles
2 Types of Proprioception
1) Conscious: info to cerebral cortex (dependent on joint receptors)
2) Non-Conscious: info to cerebellar cortex (mediated via muscle spindles and golgi tendon organ)
2 Types of Conscious Proprioception Receptors
1) Slowly Adapting- static aspects of kinesthesia (gives info over time)
· ex: posture
2) Rapidly Adapting- dynamic aspects of kinesthesia (consistently providing updates to brain)
·ex: smell of bakery is strong at first but then fades over time)
· What is Threshold?
·Low vs High Threshold
· Threshold: lowest stimulus intensity detectable half of the time (can be modified)
·Low Threshold- easy to excite
· High Threshold- more difficult to excite
How would impairments of conscious vs non-conscious proprioception appear?
1) Conscious: unsteady
2) Non-Conscious: staggered gait, uncoordinated
Sensation Mechanics
1) Threshold
2) Timing
3) Receptor Density and Field
Receptive Field
· Area of skin that, when stimulated, produces or changes responses in neuron
· Contains both excitatory and inhibitory neurons
· Small field, high density = strongest stimulus response (ex: tips of fingers)
Relationship between inhibition and Two-point discrimmination
·Two-point discrimination:
- function of receptor density and inhibition
- Strongest in feet, hands, face
- Weakest in back
· Lateral Inhibition enhances stimulus detection
What body part has higher density for touch receptors?
Finger tips
How do sensory impairments affect patients?
· Impacts ability to interact with outside world and sense position relative to it
· May have to sensitize patients
Dermatome
Innervation related to an individual dorsal root
Somatosensory Routes to Brain and Function
1) Dorsal Column Medial Lemniscal
· Discrimminative touch
· Vibration
· Conscious proprioception
· Joint and muscle sensation
· Kinesthetic sense (dynamic motion and movement awareness)
2) Anterolateral (General)
· Pain
· Pressure
· Temp
·Touch
Antereolateral Tract Functions
1)Anterior Spinothalmic Tract: crude touch, light touch, pressure
* AWARENESS AND RECOGNITION OF WHERE PAINFUL STIMULUS IS
2) Lateral Spinothalmic Tract: Pain and temp
* AWARENESS AND RECOGNITION OF WHERE PAINFUL STIMULUS IS
3) Spinoreticular Tract: emotional/arousal aspects of pain
* LEVEL OF ATTENTION TO PAIN
4) Spinomesencephalic Tract: control and inhibition of pain
* INHIBITION OF PAIN
Spinocerebellar Pathways
1) Dorsal Spinocerebellar Tract: unconscious proprioception to cerebellum, fine coordination of posture, LE movement
- UNCROSSED*
2) Ventral Spinocerebellar: simialr as above
Descending Modulation of Pain Pathways and Function
1) Serotonergic
2) Noradrenergic
Function: Inhibit 2nd neuron of Lateral Spinothalamic Tract, resulting in Analgesia (inability to feel pain)
Habituation vs Sensitization
· Habituation: decrease in response strength to a repeated stimulus
· Sensitization: increase in response strength to a repeated stimulus
Where does proprioception come from?
Receptors in muscles and joints
Somatic Sensation
Sensation about the body wall
Lesion to Posterior Parietal Cortex (PPC)
· Loss of association function (ex: feeling keys in pocket but unable to associate object with the name “keys”)
4 attributes of Stimulus Quality
1) Modality
2) Intensity
3) Location
4) Timing
4 Major Functions required to produce coherent sound
1) Increase size of receptor field
2) Influence of inhibition networks (help put focus on important things)
3) Sensory Cortex Hierarchy
4) Submodalities converge (brings the fragments together to make it make sense) (uni-modal becomes multimodal which allows for polysensory experience)
Affects of Cortical Sensory lesions
Sensory Impairments:
· Contralateral defecits
· Touch
· Position sense
· Stereognosis
· Two-point discrimmination
Astereognosis
· Inability to identify an object by touching/tactile stimuli even though primary sense data are intact
· Usually involves lesions to S2
What can parietal lobe damage result in?
Asterognosis or Agnosia
Visual Processing
· Right visual field gets processed in left side of brain
· Left visual field gets processed in right side of brain
(ex: right occipital cortex injury would result in left visual field deficit)
Retinal Photoreceptors Pathway to Cortex
1) Retinal Photoreceptors
2) Bipolar cells
3) Retinal ganglion cells (axons forms the optic nerve)
4) Lateral Geniculate Nucleus (of the thalamus)
5) Primary Visual cortex (of occipital lobe)
2 major brain processing pathways
1) Dorsal Pathway (vision for action)
- passes through PPC
- spacial recognition
- location matching
2) Ventral Pathway (vision for perception)
- object recognition
- face/location matching
Eye Defects
1) Myopia: near sighted (cant see distance)
2) Hyperopia: far sighted (cant see up close)
3) Astigmatism: cornea not spherical so impacts how light refracts into retina, light cant focus on just one point which causes blurriness and edges appear undefined
Eye Diseases
1) Cataract: clouding of the lens, causes blurry vision
2) Glaucoma: Pressure build up causing damage to retina, causes vision loss in periphery first
3) Macular Degeneration (2 types- wet or dry): causes blurriness in central vision, difficult in low light
4) Diabetic retinopathy: microaneurysms and hemorrhages causing damage to retinal cells and neurons, causing vision lost and blindness is affected areas
Vestibulo-Ocular Reflex (VOR)
· Stabilizes the eyes relative to external world
· Vestibular system detects brief changes in head position and quickly produces corrective eye movements in opposite direction
· Eyes move in opposite direction of head
VOR Cancellation
· Eyes move in same direction as head
· Cerebellum suppresses the VOR reflex
· Smooth Pursuit Cancellation
Optokinetic Reflex
· Eyes follow objects in motion while the head remains stationary
Optokinetic Nystagmus (OKN)
· Stabilizes gaze during movement of the large visual field
· Alternating pattern of slow and fast eye movements
· Eyes move in same direction as the image motion
Oculomotor Nerve Lesion Impairments
· Eyeball resting in “down and out” position and unable to elevate, depress, or adduct eye (due to paralysis of superior/inferior/medial rectus and inferior oblique)
· Dilated pupil
· Drooping of upper eye (ptosis)
Vertical Diplopia (double vision)
· Trochlear N lesion (Superior Oblique)
· double vision when looking down and in
Strabismus
· Abducens N lesion (Lateral rectus)
· most common ocular motor paralysis in adults
· eye pulled inward towards nose
General Components of Hearing
1) Outer ear: captures mechanical energy
2) Middle ear: transmits to ear’s receptive organs
3) Inner ear: transduces into electrical signals for the nervous system to analyze (involved in hearing and balance)
4) CNS
Central Auditory System
· Vestibulocochlear Nerve (CN 8):
- balance and hearing
- sensory nerve that carries signals from the cochlea to the brain
· Auditory Cortex (temporal lobe):
- part of brain where sound is perceived and analyzed
Primary auditory cortex lesion impairment
Deficits in processing information
Auditory Cortical Areas and Functions
· Wernicke’s area: interpretation of spoken words
· Broca’s area: speech production (motor)
4 Types of Hearing Loss
1) Conductive: sound waves dont make it to inner ear
·refer to PCP
2) Sensorineural: damage to inner ear or cochlear nerve
· Refer to neurologist
3) Mixed: conductive and sensorineural loss
·Refer to audiologist
4) Functional: patient doesnt hear or respond with emotional or psychological etiology
Auditory Pathologies
1) Peripheral
- congential hearing loss
- Presbycusis (age related)
- Vestibular or Facial Nerve
- Traume
- Infection/toxicity
2) Central
- CVA
- TBI
- Tumor
Categories of Sensation
1) Superficial (Touch, pain, temp., pressure)
2) Deep (proprioception, kinesthesia, vibration)
3) Cortical/Integrated (tactile localization, two point discrimmination, stereognosis, grapesthesia)
4) Special (Cranial nerves)
5) Protective (sensation threshold to detect pain)
Sensory Interpretation
1) Detect
2) Disciminaiton
3) Cortical interpretation
Combined/Cortical Sensation (Tested in patients with cortical injury)
· Stereognosis (object recognition)
· Tactile localizaiton
· 2 point discrimination
· Graphesthesia
· Barognosis (weight detection/comparison)
· Extinction (inability to feel 2 simultaneous stimuli on opposite sides)
- Test after establishing an intact sensory modality
What must be in tact if testing sensations that require interpretation?
Intact cortical area (primary/secondary/supplemental somatosensory cortices)
Types of Clinical Examination
1) Screen
2) Sensory Pattern Based
- peripheral nerve,
-dermatome
- sc pathway (modality, dermatome distribution, impact at and below level of injury)
- Cortical/subcortical processing (regional)
Factors considered for test selection
· Patient’s subjective report
· Diagnosis (location of problem in nervous system, rule in/out pathology)
· Impact on function
· Time
Guidelines for Testing
·1)Explain what you’re
2) Apply stimulus (patient should close eyes, test in dermatome/region/peripheral pattern)
3) Note response to stimulus
- modality
- deficit location
- degree of deficit
- boundaries
- compare BOTH sides
Sensory Impairment Terminology
· Paresthesia: abnormal SPONTANEOUS sensation WITHOUT cause
· Dysesthesia: abnormal UNPLEASANT sensation produced by a STIMULI
· Anesthesia: LOSS of sensation
· Hypesthesia: DECREASED sensitivity to a stimuli
· Hyperesthesia: INCREASED sensitivity to stimuli
· Analgesia: complete LOSS OF PAIN sensibility
· Hyperalgesia: INCREASED sensitivity to pain
· Hypalgesia: DECREASED sensitivity to pain
· Allodynia: pain produced by non-noxious stimuli
Interpretation of Sensory Exam
1) What do the findings mean?
- Hierarchy (dection, discrimination, cortical integration)
- Patter of loss (regional, dermatome, peripheral)
- Type of sensory loss (modality and location)
2) Consistency with medical diagnosis
3) Functional relevance
4) Risks (injury)
Intervention Strategies (Compensation vs Retraining)
1) Compensation:
- safety education
- injury prevention
- compensatory training for function
2) Retraining:
- sensory integration
- sensory retraining/stimulation
- Desensitization
Protective Sensation
· threshold to detect pain
· important to test in feet (ex: rock in shoe can wear away at skin)
Name the tract used to test each in a dermatomal pattern
1) Discrete light touch (finger): DCML
2) Pain: Lateral Spinothalamic
3) Proprioception: DCML
4) Crude Touch (cotton ball): Anterior Spinothalamic
Spinal Cord level injury testing
· Sensory problem expectation: at the level of lesion and 1-2 levels BELOW
· Test: Above level of lesion (area of dermis with intact sensation) and proceed distally
Anterior vs. Posterior SC lesion functional deficits example
· Anterior Lesion: inability to determine objects in pocket without looking at them
· Posterior: proprioception related activities such as walking/balance
OKN Nystagmus
Produced by smooth pursuit (slow phase eye movement) in one direction and saccades (fast phase) in opposite direction
ex: slow phase tracks object and fast phase resets eye in socket
Lab ex: spinning in chair to the right would result in slow phase to R; fast phase to the L
Cupula Displacement Steps
1) Head movement
2) Endolymph moves in opposite direction
3) Cupula displaced
4) Stereocilia move towards (excitation) or away (inhibition) from kinocilium
5) Neural firing (excitation or inhibition)
What direction does fluid move in respect to head turn?
Fluid will move in opposite direction of the head turn
Cupula
gelatinous mass that extends from hair cells to the roof of ampulla
Semicircular Canal Orientation
· 3 canals in each ear (anterior, post, horizontal)
· Detects angular acceleration
· Horizontal canal is 30° above horizontal plane
· Coplanar Pairing in push/pull manner
- ex: Left posterior canal inhibits, right anterior canal excites
Angular Acceleration vs. Linear Acceleration Detection
· Angular: detected by SCC canals
· Linear: detected by otoliths (saccule- vertical mvmnt, utricle- horizontal mvmnt)
Vestibulocortical Pathway Function
Conscious perception of vestibular sensation and sensation of movement
Vestibulospinal reflex (VSR)
· Postural Stablity: upright posture and balance
· via Medial and Lateral vestibulospinal tratcs
· Input to extensors
·
Pathologies of Vestibular System (Peripheral vs Central)
· Peripheral (SCC, otoliths, vestibular nerve, cochlea):
- vestibular organs (Labyrinthitis, Meniere’s Disease, Uni/Bilateral vestibular loss, BPPV)
- peripheral nerve (CN8)
- Acoustin neuroma
· Central (vestibular nuclie or white matter tracts):
- vascular (stroke)
- trauma
- tumor
Benign Paroxysmal Positional Vertigo (BPPV)
· Most common vestibular problem
· Occurs due to crystals falling into SCC and causing dizziness until they dissolve
· Vertigo with changes in head position
Nystagmus Types
1) Physiologic (can be induced)
2) Pathologic
Postural Control vs Postural Balance
· Postural Control: controlling body position in space for stability and orientation
· Postural Balance: control of center of mass (COM) over base of support (BOS)
Balance Types
· Static: maintain COM to BOS while at rest
· Dynamic: maintain COM over BOS while body is moving
· Reactive Postural Control: recovering a stable position after unexpected external force displaces COM or moves BOS
FEEDBACK
· Anticipatory Postural Control: activating muscles in anticipation of internally generated destabilizing forces
FEEDFORWARD
Sensory System of Balance
1) Somatosensory: position and motion of body to supporting surface
2) Vestibular: position and movement of head to gravity and inertial forces
3) Visual: position and motion of head to surrounding objects
· Info processed in vestibular nuclei complex (in pons/medulla) and cerebellum
Tests for Sensory Organization
· Sensory Organization Test: sway referenced surface and or surround tiltin A-P direction which follows person’s sway: eliminates orientation information
Clinical Test for Sensory Interaction in Balance (CTSIB)
· Test 6 conditions (firm vs foam surface with EO, EC, or visual conflict)
Communication
1) Verbal
· Linguistic (sign language, speaking, listening, writing, reading)
2) Non-verbal
·Paralinguistic (pitch)
· Nonlinguistic (hand gestures, eye contact)
Speech vs Language
· Language: arbitrary/social tool for communication
· Speech: involves motor coordination and verbal expression
Corticobulbar Tract
· Movement of face, neck, tongue, parts of extraocular eyes
· Controls skilled voluntary movements of muscles related to execution of speech
Language Components
1) Phonology: sound structure
2) Syntax: grammar
3) Morphology: smallest units w meaning (ex: present vs past tense)
4) Semantics: meaning or content
5) Pragmatics: appropriate use of language
What side of the brain is dominant in language?
Left hemisphere (right is important for nonlinguistic parts of speech)
Neuroanatomy of Language
1) Sensory (receives language)
1a) Primary Auditory Area (hears words but have no meaning yet)
· Heschls gyrus (Superior Temporal gyrus)
1b) Auditory Association Cortices
· Wernickes Area- sound interpretation/understanding (Superior Temporal gyrus)
2) Motor
· Brocas Area- frontal lobe
°Arcuate Fasiculus connect the 2 areas (broca and Wernicke)
Left Hemisphere Language Flow
1) Primary auditory area (sound)
2) Wernickes area (interpretation)
3) Brocas Area ( plan to speak)
4) Primary Motor Cortex (sends info to CNs and corticobulbar tract for speech production)
Neurogenic Communication Disorder
· Aphasia: loss of ability to understand or express speech
· Apraxia: trouble planning movement (pre motor cortex deficit)
· Dysarthria: difficult speaking and w muscles related to phonation and articulation (muscles involved in speech production)
· Dysphagia: swallowing disorder
Functional Language Components
1) Sensory: visual and auditory
2) Motor: oral, manual (writing), gestures (ASL)
Speech Apraxia
· Disruption of motor planning
· Errors in prosody (rhythm) and articulation
Types of Aphasia
1) Fluent- Wernickes (long sentences that dont make sense)
2) Non-Fluent- Brocas (can only do short simple phrases)
Types of Paraphasias
1) Semantic: mixing up words
2) Phonemic: Mixing up letters in words
Brocas Aphasia
· Expressive/non-fluent speech
· Phonemic Paraphasias: mixing up letters in words (nuzzle vs muzzle)
· Effortful speech/ halting, Agrammatism (bare minnimum words)
· Agraphia with/without alexia (writing and possible reading deficits)
· Buccofacial apraxia: trouble planning movement of facial muscles
· Right hemiparesis (paralysis)
Wernickes Aphasia
· Fluent, nonsensical speech
· Impaired comprehension
· Phonemic (mixing up letters) and Semantic (mixing up words) paraphasias
·Alexia without agraphia (impaired reading, writing is legible but disjointed)
·
Drug Classification
1) Agonist: affinity (binds easily) and efficacy (changes cell function)
· partial
·Mixed
2) Antagonist: affinity but NO efficacy
·competitive
· non-competitive
Pharmacokinetics
Effect of body on the drug
· Administration
· Absorption
· Distribution
· Storage
· Elimination
Routes of Administration
1) Enteral (alimentary canal)
- oral (subject to first pass effect)
- sublingual/buccal (not subject to first pass effect)
- rectal
2) Parenteral (more direct delivery)
- inhalation
- injection
-topical
- transdermal
Transdermal drug absorption/ PT usage
· Absorbed into subcutaneous tissue or peripheral circulation
· PT usage via phonophoresis (ultrasound waves) or iontophoresis (e-stim)
2 Stroke Types
1) Ischemic: blocks blood flow
· Thrombotic- clot that develops in the brain
- Embolic- clot that develops outside the brain
2) Hemorrhagic:
CVA stroke impairments
·Contralateral motor and sensory funciton
· Cognition
· Speech/language (Left CVA> Right CVA)
· Dysphagia
Left CVA vs Right CVA deficits
· Left CVA- speech/language deficits, reasoning, problem solving
· Right CVA- visual spatial impairments,
Middle Cerebral Artery Stroke vs Anterior Cerebral Artery Stroke
1) Middle Cerebral Artery Stroke
· Contralateral motor loss UE>LE
· Sensory Loss UE> LE
2) Anterior Cerebral Artery Stroke
·
Brain Tumor Clinical Presentaiton
· Headache
· Vomiting
· Papilledema (edema of optic nerve)
· Focal signs and symptoms
TBI Common Impairments
· Movement Disorder (tremor, dystonic, etc.)
· Cognitive Impairment
· Behavioral deficits
· Communication
TBI main impairment and intervention goal
· Main Impairment: cognitive function (MUCH GREATER IN TBIS THAN STROKE OR CNS TUMOR)
· Goal: functional retraining and facilitating neuroplasticity
SCI Anterior Cord Syndrom
· Loss of voluntary motor below
· pressure and joint sensation preserved
SCI Intervention
· Complete vs incomplete
· Lesion location
· Functional treatment is usually compensatory movement strategies
Guillain-Barre Syndrome (GBS)
· Rapid demyelination and inflammation of spinal and CNs (LMN)
· Symptoms worsen over 3-4 weeks, plateu, recover w/o severe neuro complication
· Symmetrical weakness distally (LE then UE) then progresses proximally (LMN signs)
· Reflexes absent
Multiple Sclerosis (MS)
· Chronic inflammatory autoimmune demyelinating disease of CNS (UMN and LMN)
· Symptoms: dyscoordination, balance impairments, sensory impairments, fatigue
· Treatment: gait and balance, fatigue management, energy conservation techniques
Post Polio Syndrome (PPS)
· Viral invasion of sc and/or brainstem motor neurons
·Treatment: balance, rest, exercise, orthotics and mobility aids
Amyotrophic Lateral Sclerosis (ALS)
· Progressive disease that affects UMN and LMN (sensory nerves SPARED) resulting into denervation of muscles
· LMN signs: weakness, atrophy, fasiculations (twitches), hyporeflexia
· UMN signs: weakness in UE extensors and LE flxors, hypertonia, hyperreflexia
·Treatment: muscles in close proximity may be affected differently thus important for PT to isolate specific muscles
Restorative vs. Preventative
·Restorative: late GBS, MS, early ALS
· Preventative: early GBS,MS, late ALS, PPS
Seizure Disorder Types
1) Partial (affects parts of cortex)
- simple
-complex
2) Generalized )affects entire cortex)
- Petit Mal/Absence
- Tonic Clonic
- Atonic Drop Attacks
- Status Epilepticus
First Line Antiseizure Drugs
· Phenytoin (Dilantin)
· Carbamazepine (Tegretol)
· Ethosuximide (Zarontin)
· Valproic acid (Depakote)
Antiseizure Drugs Mechanism of Action
· Inhibit firing of certain cerebral neurons by increasing inhibitory effects of GABA
· May decrease excitatory enzymes
· May alter membrane movement of sodium and calcium ions
Somatosensory 3 Major Divisions
1) S1- primary sensory (located in post central gyrus)
2) S2- secondary sensory cortex
3) Posterior Parietal Cortex (uses vision and tactile stimuli)
