Exam 2 Flashcards
Neuron regeneration (PNS)
- Regeneration does occur.
2. Schwann cells support cell regeneration and new axonal connections.
What is synaptic strengthening?
- Changes underlying strengthening
- presynaptic action potential -> increases release of neurotransmitter.
- larger current induced in post synaptic cell.
- Presynaptic activity must be consistently followed by post synaptic activity (Hebb’s rule).
- Induced by repetitive stimulation.
Effects of brain damage
Cell death Neural degeneration Diaschisis Altered cortical excitability Hypoperfusion
Neuron regeneration (CNS)
- Oligodendrocytes do NOT support cell regeneration.
- Damage more extensive than in PNS.
- Glial cells from scar tissue -> barrier to new axonal growth.
- Limited regeneration occurs, but not sufficient to make up for large cell loses.
Recovery of function
- learning reorganizes the damaged brain even w/o therapy.
- person develops compensatory behaviors that alter brain structure and function.
compensatory behaviors that alter brain structure and function
- ex. reliance on less affected limb in hemipelegia.
- can be adaptive and improve function.
- can be maladaptive and interfere with improvements that could be made with therapy.
Experience dependent plasticity relies on what?
- use it or lose it. 6. time matters.
- use it and improve it. 7. salience matters.
- specificity. 8. Age matters.
- repetition. 9. Transference.
- intensity. 10. interference.
Transcranial Magnetic Stimulation (TMS)
-adjunct to behavioral therapy-
- coil placed on skill induces current in the cerebral cortex.
- current suppresses or enhances cortical excitability.
Transcranial direct current stimulation (tDCS)
-adjunct to behavioral therapy-
- surface electrodes placed on skull.
- electrodes induce current in the brain.
- Influences neuronal excitability.
Neurological examination
- examine the cranial nerves, motor system, sensory system.
- examine reflexes.
- Higher cortical function.
* *Informs of structure and function.
EEG
Electroencephalogram
- studies electrical activity in brain.
- uses surface electrodes.
- used most often to diagnose seizures.
- informs of functon.
EMG/nerve conduction studies
EMG=Electromyography.
- used to diagnose neuromuscular disease.
- EMG: measure electrical activity of muscles at rest and during movement. Used to diagnose ALS, myasthenia gravis. Function.
- Nerve conduction study: Measures nerve impulse propagation in LMNs. Used to diagnose Guillain-Barre Charcot-Marie-Tooth. Structure and function
fMRI
functional magnetic resonance imaging.
- done in a MR scanner.
- indirect measure of neuronal function.
- Used for pre-surgical planning.
- resting state fMRI.
- *Funtion**
PET
Positron emission computed tomography.
- Measures metabolic rates for oxygen, glucose or blood flow (rCBF).
- radioactive tracer injected into vein -> tracer collects in organs/tissues.
- “GOLD STANDARD” for tumor detection.
- Aid in differential diagnosis of movement disorders.
- *Function**
Spinal tap
- CSF drawn from lumbar cistern.
- examined for: White blood cells (infection, tumor, demyelinating disease.
- Red blood cells (bleeding).
- Excess protein (tumor, infection, diabetes.)
- Glucose (elevated or decreased)
- *Structure**
cerebral angiography
visualize arteries.
- incision made in an artery.
- catheter passed through arterial system, then in to the carotid artery.
- contrast medium forced through catheter and thus into the cerebral circulation.
- x-rays are taken.
* *Structure**
plasticity
ability of the brain to change its structure and function over the course of the lifetime.
conditions where neuroplasticity occurs
- normal childhood brain development.
- Learning/memory throughout lifetime.
- Reorganization after brain injury.
developmental plasticity
-synaptogenesis and synaptic pruning-
synaptogenesis- new synapses created as a result of experiences.
synaptic pruning- the number of synapses are reduced, the stronger ones stay and the weaker ones are pruned.
in which order do the systems develop?
1st-> sensory system develops
2nd-> language system develops
3rd-> cognition develops
metaplasticity
Regulates plasticity so it occurs at the proper time and to the proper extent.
May be impaired in certain populations (eg. Autism)
Normal adult plasticity
The brain never stops learning/changing.
Changes in plasticity appear to underlie expertise..
physiological bases of plasticity in the normal adult.
- dendritic spines expand, allowing more interaction with other neurons.
- axons develop new connections (in passing or through sprouting).
- Glial cells affect the synaptic transmission, coordinate neural activity, and affect the excitability.
- unmasking
- synaptic strengthening
unmasking
- many brain networks are chronically inactive due to inhabition.
- These networks are released from inhabition and begin to function.
MRA
-magnetic resonance angiography
- visualize arteries.
- performed in MR scanner.
- with or w/o contrast.
- less invasive than traditional angiography.
- *structure**
CT/CAT scan
- computerized axial tomography -
- 3D images.
- with or w/o contrast.
- often used in the ER.
- CT w/o contrast is less sensitive to acute stroke the MRI.
- *Structure**
MRI
- magnetic resonance imaging -
- types: T1-weighted, T2-weighted, Diffusion (dwi)/Perfusion (pwi)-weighted, diffusion tractography imaging and FLAIR.
- with or w/o contrast.
- greater resolution than CT.
- patient must not move and must pass a safety screen.
- *structure**
doppler ultrasound
- extracranial or transcranial.
- sound waves transmitted into the body and reflected back to provide info about blood pressure and flow.
- *Structure**
Brain Biopsy
- brain tissue removed, usually through a needle.
- usually performed to sample a brain tumor but may be performed as a last resort for unexpected neurological problems.
- Tissue is studied.
- *Structure**
ionizing radiation
- from natural sources like soil and water.
- used in some imaging techniques:
- xrays 3. PET
- CT 4. flouroscopy
Higher cortical function
-assesses what/for in a neuro exam?-
- Apraxia
- orientation and memory
- speech and language
Reflex examination looks for..
- neuro exam -
- superficial and deep reflexes.
- exaggerated or diminution of reflex.
Sensory system
- neuro exam, looks for…?-
- anesthesia (without feeling)
- hypoesthesia (reduced feeling)
- hyperesthesia (increased feeling)
- deep and superficial sensation
Motor system
- neuro exam completed how? and looks for what?
- visual examination.
- palpation of muscles to determine tone.
- passive movement (with clinician moving the body part)
- active movement
Examination of cranial nerves
- neuro exam checks what? -
- nerves subserving the eyes (acuity, visual fields , movements, pupillary reflex)
- facial nerves (facial expression, whistling, etc.)
- facial sensation - through light touch, pin prick.
imaging the body, what does it tell us? what do we see?
resolution- detail that can be seen differs by technique.
contrast- exogenous (something introduced for better visability), endogenous (uses internal, natural things for better visability).
- Ionizing radiation -> natural sources.
what is ICD
International classification of diseases.
Part of the ICF family
Stucki and Sangha (1998) developed - Rehab CYCLE
what is it?
- designed to improve health status and QOL.
- helps to develop rehab goals.
- forms the basis for their RPS form
- > data sheet based on the ICF.
- > designed to be used by a multidisciplinary team
ICF coding
alphanumeric describes health and health related domains. b= body functions s= body structures d= activities and participation e= environmental
ICF number coding
0=no impairment .0=no barrier +0=no facilitator
1= mild impairment .1= mild bar. +1=mild fac.
2= moderate imp. .2= moderate bar. +2=mod. fac.
3= severe imp. .3= severe bar. +3=severe fac.
4= complete imp. .4= complete bar. +4=complete fac.
8= not specified .8= barrier not specified +8=fac. not spec.
9= not applicable .9= not applicable +9=not applicable
ICF activities and participation
performance qualifier (what a person does in his/her current environment. Capacity qualifier (ability to execute a task or action in a standardized environment
personal factors
- individual’s particular background.
- features not part of health condition/state.
- may include gender, race, fitness level, education, life experiences and personality.
- NOT coded in ICF due to cultural differences.
Definition of environmental factors
- physical, social and attitudinal environments in which people live and conduct their lives.
Definition of participation
Involvement in a life situation
definition of participation restrictions
problems being involved in life situations
definition of activity
execution of a task or action by an individual
definition of activity limitation
difficulty in executing tasks.
definition of impairment
problem in body function or structure
eg. significant deviation or loss.
models of disability
- Medical model: disability is a problem to be fixed.
- Social model: disability is a society-created problem.
- ICF: biopsychosocial model that integrates social and medical. -Biology, individual, and societal
What is ICF?
International Classification of Functioning Disability and Health.
- Created by WHO to describe standard language and framework for describing health.
- list of body functions and structure.
- list of domains of activity and participation
- Child and youth version (ICF-CY)
Tests used to diagnose neurological impairment
- Neurological examination.
- Electroencephalogram (EEG).
- Electromyography (EMG)/nerve conduction studies.
- Spinal tap.
- Imaging the body.
- brain biopsy.
Types of imaging
- cerebral angiography
- computerized axial tomography (CT/CAT)
- Magnetic Resonance Imaging (MRI)
- Magnetic Resonance Angiography (MRA)
- Functional Magnetic Resonance Imaging (fMRI)
- Positron Emission Computed Tomography (PET)
- Doppler Ultrasound.
