investigational basis of clinical neurophysiologyphcol.szote.u-szeged.hu/jegyzet/elphys/nf...
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Investigational basis of clinical neurophysiology
Edina Timea Varga MD, PhD
Department of Neurology, University of Szeged
27th October 2015
What is clinical neurophysiology?
What is clinical neurophysiology? ?
Clinical neurophysiology • Specialty
• Extension of neurology + special lab examinations
• To study
central nervous system (CNS)
peripheral nervous system (PNS)
autonomic nervous system (ANS)
• To treat
PD - Parkinson’s disease: DBS – deep brain stimulation
Epilepsy: DBS/VNS – vagal nerve stimulation/operation
Tumors, lesions: resective surgery
Spinal cord lesions, etc…
EEG – electroencephalography
EP – evoked potentials: visual/acustic/somatosensory/magnetic/cognitive
EMG - electromyography
ENG/NCS – electroneurography/nerve conduction study
RNS - repetitive nerve stimulation
Sleep studies: PSG – polysomnopgraphy, …
Autonomic nervous system: sympathetic skin respone test, RR-interval,…
Clinical neurophysiology
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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Resting potential
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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Resting potential
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
-70 uV
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http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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Na+/K+ pump: 3 Na+ out, while K+ in
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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Na+/K+ pump: 3 Na+ out, while K+ in
depolarisation
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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Na+/K+ pump: 3 Na+ out, while K+ in
depolarisation
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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depolarisation
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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depolarisation
repolarisation
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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repolarisation
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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return to resting potential
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
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return to resting potential
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axo
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return to resting potential
axo
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return to resting potential
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return to resting potential
Purves et al. Life The Science of Biology IVth Edition 1995.
Action potential can be visualized on an oscilloscope
oscilloscope
mem
bra
ne
po
ten
tail
(mV
)
Purves et al. Life The Science of Biology IVth Edition 1995.
Action potential can be visualized on an oscilloscope
oscilloscope
mem
bra
ne
po
ten
tail
(mV
)
pair of electrodes
Purves et al. Life The Science of Biology IVth Edition 1995.
Action potential can be visualized on an oscilloscope
oscilloscope
mem
bra
ne
po
ten
tail
(mV
)
pair of electrodes
the electrodes detect an AP as a voltage change across the axonal membrane
this signal is amplified and fed into the osilloscope
a beam of eelctrones sweeps across the screen in a set periode of time
Purves et al. Life The Science of Biology IVth Edition 1995.
Action potential can be visualized on an oscilloscope
oscilloscope
mem
bra
ne
po
ten
tail
(mV
)
Alternating electric charges on two plates makes electrone beam sweep across screen
Amplified signal from axon moves electron beam ↑&↓. When inside on axon is +, beams move ↑. When inside of axon is -, beam moves ↓.
Purves et al. Life The Science of Biology IVth Edition 1995.
Action potential can be visualized on an oscilloscope
oscilloscope
mem
bra
ne
po
ten
tail
(mV
)
Alternating electric charges on two plates makes electrone beam sweep across screen
Amplified signal from axon moves electron beam ↑&↓. When inside on axon is +, beams move ↑. When inside of axon is -, beam moves ↓.
research daily routine
A.C. 43. Scribonius Largus 1755, Charles Le Roy
Electric torpedo fish Pain relief and eliciting phosphene
1855, Duchenne de Boulogne
L’Electrisation Localisee Pascual-Leone&Wagner
Ann Rev Biomed Eng 2007; 9:527-565.
Transcranial direct current stimulation - historical background
Spontaneous neuronal discharge can be modulated by direct current in a polarity-dependent way
Creutzfeldt et al;
Exp Neurology 1962; 5:436-452.
basic neuronal activity
anodal stimulation
cathodal stimulation
Transcranial direct current stimulation
Terzuolo&Bullock Proc NAS USA 1956; 42:687-694.
Cathodal stimulation hyperpolarisation of neuronal membranes decreases cortical excitability
Anodal stimulation depolarisation increased cortical excitability
Bindman et al; Nature 1962; 196:584-585.
Priori et al; Neuroreport 1998; 9:2257-2260.
Nitsche&Paulus J Pysiol 2000; 527(3):633-639.
Transcranial direct current stimulation
The effect depends on: Current intensity Current density Stimulus duration Anatomical structures
After-effect (AE) depends on: Current intensity Stimulus duration
www.google.com
M1
V1
CSWS – continuous slow waves of sleep
idiopathic childhood epilepsy
continuous epileptiform discharges during sleep
neurocognitive decline
behavioural dysfunctions
epileptic seizures
limited therapeutic approaches
M S-de-Boer Epilepsia 2009.
Varga et al. Epilepsy Res 2011.
Stimulator: Neuro Conn GmbH, Ilmenau, Germany
The effect of tDCS was measured on EEG, by quantifying the percentage of non-REM sleep containing spike-and-slow-waves.
The aim of the study to detect the possible therapeutic effect of cathodal tDCS on
the epileptiform EEG discharges (BESA) neuropsychological tests (if positive effect on EEG)
Materials and methods Subjects: CSWS patients (age>5 years) were recruited (10/4) tDCS:
cathodal tDCS (1.0 mA, 20 min) over the focus current density: 30 µA/ cm2 electrodes: 0,9% NaCl (35 cm2) control stimulation = sham stimulation
daily routine
EEG EEG -- electroencephalographyelectroencephalography
localisationlocalisation
International 10/20 system
F – frontal
P – parietal
T – temporal
O – occipital
C – central
Fp – frontopolar
z - zero (vertex):
Fz, Cz, Pz)
A – auricula
even number– right side odd number– left side
www.ilae.org
http://stock-clip.com/video-footage/eeg
ElectrodesElectrodes
a-b-c : superficial
(Ag/AgCl)
d - clip
e – needle electrode
f –nasopharyngealis
needle electrode
Fisch & Spehlmann
CommonCommon referencereference
DoubleDouble bananabanana
Normal (adult) background activity
AmplitudeAmplitude redution redution forfor eyeeye openingopening
HyperventilationHyperventilation –– normalnormal reactionreaction (8 (8 yearsyears))
4 Hz, ampl. 500 uV
Muscle artifact
MyoclonusMyoclonus ((gengen. . spikespike and and slowslow wavewave))
MyoclonusMyoclonus ((gengen. . spikespike and and slowslow wavewave))
MyoclonusMyoclonus ((gengen. . spikespike and and slowslow wavewave))
LeftLeft temporaltemporal ((interictalinterictal) ) slowslow wavewave and and spikespike
GeneralizedGeneralized spikespike and and slowslow wavewave activityactivity
IGE – idiopathic generalized epilepsy
Nerve conduction studies (NCS)
motor NCS
sensory NCS
http://bcs.whfreeman.com/thelifewire9e Purves et al. Life The Science of Biology IVth Edition 1995. http://chadwaterbury.com http://emedicine.medscape.com/article/1846028-overview http://jdr.sagepub.com http://www.erikstalberg.com/
Nerve conduction studies (NCS)
motor NCS
sensory NCS
Nerve conduction studies (NCS)
motor NCS
sensory NCS
time (ms)
volt
age
(u
V)
Nerve conduction studies (NCS)
motor NCS
sensory NCS
latency
latency
duration
duration
amp
litu
de
am
plit
ud
e
AIM??
• axonal /demyelinating injury
• focal/genearlised
• localisation
↓amplitude=axonal loss ↓condiction velocity=demyelinisation ↑latency=demyelinisation
Carpal tunnel syndrome
Carpal tunnel syndrome
Medial and lateral plantar nerve
superficial electrodes sensory nerve conduction
Medial and lateral plantar nerve
Motor nerve conduction study
registration with needle electrode registration with superficial electrode
Near nerve technique
tarsal tunnel syndrome Morton’s metatarsalgia
Ulnar nerve neuropathy
Ulnar nerve neuropathy
Near nerve technique
Ulnar nerve neuropathy
Near nerve technique
Ulnar nerve neuropathy
Near nerve technique
closer to the nerve higher detectable answer more precise information
AIM??
neurogen/myogen lesion acute/chronic reinnervation
↓amplitude, ↓duration,↑polyphasy→myogenic
↑amplitude, ↑duration,↑polyphasy→neurogenic
prescence of abnormal resting activity
reinnervation potentials
Investigation of neuromucular junction
Indication: Myasthenia gravis Lambert-Eaton Myasthenic Syndrome
• RNS - repetitive nerve stimulation
sensitivity:
• Ocular MG= 50%,
• Generalised MG= 75%
• Single fiber EMG:
sensitivity: 95%
Stalberg, Uppsala Nandedkar
EVOKED POTENTIALS
• VEP – visually evoked potentials
• (S)SEP – (somato)sensory evoked potentials
• MEP – motor evoked potentials
• BAEP (alias: ABR, BERA) – brainstem auditory evoked potentials
VEP - visually evoked potentials
http://tidsskriftet.no/article/3011088/en_GB
SEP somatosensory evoked potentials
http://tidsskriftet.no/article/3011088/en_GB
SEP somatosensory evoked potentials: median nerve
• Erb
• Cv
• Fz-A1
• C4-A1
• P4-A1
• C4-Fz
• P4-Fz
SEP somatosensory evoked potentials: median nerve
SEP somatosensory evoked potentials: median nerve
missing cortical answer in an MS patient
• F.pop.
• L1
• Cz-A1
• Pz-A1
• Cz-A2
• Pz-A2
• Cz-Fz
• Pz-Fz
SEP somatosensory evoked potentials: tibial nerve
missing cortical answer in an MS patient
SEP somatosensory evoked potentials: tibial nerve
MEP - motor evoked potentials
http://www.gettyimages.co.uk/detail/photo/woman-having-a-transcranial-magnetic-high-res-stock-photography/487737741
BAEP - brainstem evoked potentials
I. wave: N. VIII. III. wave: cochlear nucleus, oliva superior IV-V. wave: •lemniscus lateralis- colliculus inferior IPL – interpeak latency: I-III, III-IV.
http://www.myvmc.com/investigations/brainstem-auditory-evoked-potential-baep/
Clinical neurophysiology in the treatment…
OperativeOperative treatmenttreatment of of
epilepsyepilepsy -- lesionectomylesionectomy
www.desitin.no/images/Epilepticus-sic-curabitur.jpg
TTreatmentreatment of of epilepsyepilepsy ((e.ge.g.).)
DBS -deep brain stimulation
VNS – vagal nerve stimulation
hippocampectomy
research daily routine future
https://www.youtube.com/watch?v=Al5RhaJgxxU
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Thank you for your attention