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Investigational basis of clinical neurophysiology
Edina Timea Varga MD, PhDDepartment 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 treatPD - Parkinson’s disease: DBS – deep brain stimulationEpilepsy: DBS/VNS – vagal nerve stimulation/operationTumors, lesions: resective surgerySpinal cord lesions, etc…
EEG – electroencephalographyEP – evoked potentials:
visual/acustic/somatosensory/magnetic/cognitiveEMG - electromyographyENG/NCS – electroneurography/nerve conduction
studyRNS - repetitive nerve stimulationSleep studies: PSG – polysomnopgraphy, …Autonomic nervous system: sympathetic skin
respone test, RR-interval,…
Clinical neurophysiology
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
Resting potential
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
Resting potential
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
-70 uV
axon
mem
bran
e
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
Na+/K+ pump: 3 Na+ out, while K+ in
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
Na+/K+ pump: 3 Na+ out, while K+ in
depolarisation
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
Na+/K+ pump: 3 Na+ out, while K+ in
depolarisation
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
depolarisation
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
depolarisation
repolarisation
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
repolarisation
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
return to resting potential
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
return to resting potential
http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf
axon
mem
bran
e
return to resting potential
axon
mem
bran
e
return to resting potential
axon
mem
bran
e
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
bran
e po
tent
ail (
mV)
Purves et al. Life The Science of Biology IVth Edition 1995.
Action potential can be visualized on an oscilloscope
oscilloscope
mem
bran
e po
tent
ail (
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
bran
e po
tent
ail (
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
bran
e po
tent
ail (
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
bran
e po
tent
ail (
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 LocaliseePascual-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 - electroencephalography
localisation
International 10/20 system
F – frontalP – parietalT – temporalO – occipitalC – centralFp – frontopolarz - zero (vertex): Fz, Cz, Pz)A – auricula
even number– right sideodd number– left side
www.ilae.org
http://stock-clip.com/video-footage/eeg
Electrodes
a-b-c : superficial (Ag/AgCl)
d - clip
e – needle electrode
f –nasopharyngealis needle electrode
Fisch & Spehlmann
Common reference
Double banana
Normal (adult) background activity
Amplitude redution for eye opening
Hyperventilation – normal reaction (8 years)
4 Hz, ampl. 500 uV
Muscle artifact
Myoclonus (gen. spike and slow wave)
Myoclonus (gen. spike and slow wave)
Myoclonus (gen. spike and slow wave)
Left temporal (interictal) slow wave and spike
Generalized spike and slow wave activity
IGE – idiopathic generalized epilepsy
Nerve conduction studies (NCS)
motor NCS
sensory NCS
http://bcs.whfreeman.com/thelifewire9ePurves et al. Life The Science of Biology IVth Edition 1995.http://chadwaterbury.comhttp://emedicine.medscape.com/article/1846028-overviewhttp://jdr.sagepub.comhttp://www.erikstalberg.com/
Nerve conduction studies (NCS)
motor NCS
sensory NCS
Nerve conduction studies (NCS)
motor NCS
sensory NCS
time (ms)
volta
ge (u
V)
Nerve conduction studies (NCS)
motor NCS
sensory NCS
latency
latency
duration
duration
ampl
itude
ampl
itude
AIM??
• axonal /demyelinating injury
• focal/genearlised
• localisation
↓amplitude=axonal loss↓condiction velocity=demyelinisation↑latency=demyelinisation
Carpal tunnel syndrome
Carpal tunnel syndrome
treatment depends on EF rate
(mild/moderate/severe)
Medial and lateral plantar nerve
superficial electrodes sensory nerve conduction
Medial and lateral plantar nerve
Motor nerve conduction study
registration with needle electroderegistration 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
Localisation of operation depends on
the location of conduction block
Ulnar nerve neuropathy
Near nerve technique
closer to the nervehigher detectable answermore 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 stimulationsensitivity:
• Ocular MG= 50%, • Generalised MG= 75%
• Single fiber EMG:sensitivity: 95%
Stalberg, UppsalaNandedkar
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…
Operative treatment of epilepsy - lesionectomy
www.desitin.no/images/Epilepticus-sic-curabitur.jpg
Treatment of epilepsy (e.g.)
DBS -deep brain stimulation
VNS – vagal nerve stimulation
hippocampectomy
research daily routine future
https://www.youtube.com/watch?v=Al5RhaJgxxU
?
Thank you for your attention
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