Investigational basis of clinical neurophysiologyphcol.szote.u-szeged.hu/jegyzet/elphys/NF...

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

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return to resting potential

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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

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(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

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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

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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

EMG - electromyography

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