Neurophysiology

ELECTRO

ENCEPHALO

GRAPHY

:- To check the records of brain waves, and to detect the level of electrical activity in the brain is

called EEG

The "10-20 System" of Electrode PlacementThe "10-20 System" of Electrode Placement

The 10-20 System of Electrode Placement is a method used to describe the location of scalp electrodes. These scalp electrodes are used to record the electroencephalogram (EEG) using a machine called an electroencephalograph. The EEG is a record of brain activity. This record is the result of the activity of thousands of neurons in the brain. The pattern of activity changes with the level of a person's arousal - if a person is relaxed, then the EEG has many slow waves; if a person is excited, then the EEG has many fast waves. The EEG is used to record brain activity for many purposes including sleep research and to help in the diagnosis of brain disorders, such as epilepsy.

One second of EEG signal

Historically four major Historically four major types of continuous types of continuous rhythmic sinusoidal rhythmic sinusoidal

EEG waves are EEG waves are recognized recognized

(alpha, beta, delta and (alpha, beta, delta and theta).theta).

•Alpha (Berger's wave):-:-The frequency range from (8 The frequency range from (8 Hz to 13 Hz). It is characteristic of a relaxed, alert state of consciousness . Alpha rhythms are best detected with the eyes closed. Alpha attenuates with drowsiness and open eyes, and is best seen over the occipital (visual) cortex.

•Beta :-

The frequency range 13-30 Hz. Low amplitude beta The frequency range 13-30 Hz. Low amplitude beta with multiple and varying frequencies is often with multiple and varying frequencies is often associated with active, busy or anxious thinking and associated with active, busy or anxious thinking and active concentration. Rhythmic beta with a dominant active concentration. Rhythmic beta with a dominant set of frequencies is associated with various set of frequencies is associated with various pathologies and drug effects. pathologies and drug effects.

Delta:-

The frequency range up to 4 Hz and is often The frequency range up to 4 Hz and is often associated with the very young and certain associated with the very young and certain encephalopathies and underlying lesions. It is seen in stage 3 and 4 sleep.

•Theta:- The frequency range from 4 Hz to 8 Hz and is associated The frequency range from 4 Hz to 8 Hz and is associated with drowsiness, childhood, adolescence and young with drowsiness, childhood, adolescence and young adulthood. This EEG frequency can sometimes be adulthood. This EEG frequency can sometimes be produced by produced by hyperventilation. Theta waves can be seen . Theta waves can be seen during during hypnagogic states such as trances, states such as trances, hypnosis, deep , deep day dreams, day dreams, lucid dreaming and light and light sleep and the and the preconscious state just upon waking, and just before preconscious state just upon waking, and just before falling asleepfalling asleep.

Some examples of EEG waves.Some examples of EEG waves.

THE BASIC PRINCIPLES OF EEG DIAGNOSISTHE BASIC PRINCIPLES OF EEG DIAGNOSIS

What abnormal results mean What abnormal results mean

Seizure disorders (such as epilepsy or convulsions) Seizure disorders (such as epilepsy or convulsions) Structural brain abnormality (such as a brain tumor or Structural brain abnormality (such as a brain tumor or

brain abscess) brain abscess) Head injury, encephalitis (inflammation of the brain) Head injury, encephalitis (inflammation of the brain) Hemorrhage (abnormal bleeding caused by a ruptured Hemorrhage (abnormal bleeding caused by a ruptured

blood vessel) blood vessel) Cerebral infarct (tissue that is dead because of a blockage Cerebral infarct (tissue that is dead because of a blockage

of the blood supply) of the blood supply) Sleep disorders (such as narcolepsy) Sleep disorders (such as narcolepsy)

Note:- Note:- EEG may confirm brain death in someone who is in a comaEEG may confirm brain death in someone who is in a coma..

ATYPICAL BUT NORMAL WAVE FORMSATYPICAL BUT NORMAL WAVE FORMS

K ComplexesK Complexes

K Complexes occur in sleep when arroused - thus K complexes are seen with noises or other stimuli especially in stage 2 sleep. The K complex is often followed by an arrousal response - namely a run of theta waves of high amplitude. Following this the EEG shows sleep again or the awake state.

Lambda and POSTSLambda and POSTS

Lambda and POSTS are similar morphologically, and have a triangular shape.They occur posteriorly and symmetrically. POSTS stands for 'positive occipital transients of sleep' and occurs in stage 2 sleep. Lambda occurs in the awake patient when the eyes stare at blank surfaces. Both are normal wave forms and can occur singly or inlong or short runs.

V Waves

V waves occur in the parasaggital areas of the two sides and take the form of sharp waves or even spikes which show in the biparietal regions(vertex) withphase reversal at the midline in tranverse montages or at the vertex in front-to-back ones. They are seen in stage 2 sleep along with spindles, K complexes, POSTS, etc..

MU activity

Mu activity is a rhythm in which the waves have a shape suggestive of a wicket fence with sharp tips and rounded bases. It may show phase reversal between two channels. The frequency is generally half of the fast activity present.

Psychomotor VariantPsychomotor Variant

Psychomotor variant is a rare rhythm which appears to be an harmonic of two or more basic rhythms causing a complex form. As can be seen it is higher in amplitude than the surround and the waves have a notched appearance. It is quite assymetrical and is often mistaken for paroxysmal activity. It is benign. It is also known as

Fourteen and Six RhythmFourteen and Six Rhythm

Fourteen and six activity is most often seen in children and adolescents. As seen it takes the form of 6 Hz and 14 Hz waves sometimes going in the same direction(up or down) and in others in opposite directions. It is typically seen in sleep or drowsiness and is usually seen in monopolar recordings.

ELECTROELECTRO

MIOMIO

GRAPHYGRAPHY

Amplifier parameters Channels

Sensitivity Scaling for analysis

fo fu 50 Hz notch Rctf. Ext.Input

Auto-matic offset

Spontanous 1 0,1 mV/div 0,1 mV/div 10 kHz 5 Hz x x

MAP-Analyse 1 0,1 – 0,2 mV/div 0,1 mV/div 10 kHz 5 Hz x x

Maximal-innervation 1 1 mV/div 1 mV/div 10 kHz 5 Hz x x

Aquisition-parameters

Monitor time Analysis time Trigger-mode Averagermode

Sweeps (no. of passes) ArtefactDetection

Spontan-aktivität 10 ms/div 10 ms/div Internal Standard --- ---

MAP-Analyse 10 ms/div 10 ms/div Internal Standard --- ---

Maximal-innervation

100 ms/div 100 ms/div Internal Standard --- ---

An electromyogram (EMG) is a test that is used to record the electrical activity of muscles. When muscles are active, they produce an electrical current. This current is usually proportional to the level of the muscle activity.

EMGs can be used to detect abnormal muscle electrical activity that can occur in many diseases and conditions, including muscular dystrophy, inflammation of muscles, pinched nerves, peripheral nerve damage.

The EMG helps to distinguish between muscle conditions in which the problem begins in the muscle and muscle weakness due to nerve disorders. The EMG can also be used to detect true weakness, as opposed to weakness from reduced use because of pain or lack of motivation.

NEEDLE EMG CRANIAL MUSCLESNEEDLE EMG CRANIAL MUSCLES

Frontalis

Masseter

Orbicularis Oculi

Orbicularis Oris

Sternocleidomast

oid

Tongue -

Genioglossus

Trapezius

NEEDLE EMG | FOOT MUSCLESNEEDLE EMG | FOOT MUSCLES

Abductor Digiti Quinti - Foot

Abductor Hallucis

Extensor Digitorum Brevis

First Dorsal

Interosseous - Foot

NEEDLE EMG | FOREARM MUSCLESNEEDLE EMG | FOREARM MUSCLES

Anconeus

ANCONEUS

EXTENSOR DIGITORUM COMUNIS

BRACHIORADIALIS

EXTENSOR CARPI RADIALIS (Lt.)

EXTENSOR INDICIS

FLEXOR CARPI RADIALIS (Rt.)

FLEXOR CARPI ULNARIS

SUPINATOR

FLEXOR DIGITORUM PROFUNDUS

FLEXOR POLLICIS LINGUS

PRONATOR TERES

NEEDLE EMG | HAND MUSCLESNEEDLE EMG | HAND MUSCLES

ABDUCTOR POLLICIS BRAVIS

FIRST DORSAL INTEROSSEOUS

ABDUCTOR DIGITI MINIMI (HAND)

NEEDLE EMG | LEG MUSCLESNEEDLE EMG | LEG MUSCLES

EXTENSOR HALLUCIS LONGUS

GASTROCNEMIUS (MEDIAL HEAD)

EXTENSOR DIGITORUM LONGUS

ANTERIOR TIBIAL

SOLEUS

PERONEAL LONGUS

GASTROCNEMIUS

NEEDLE EMG | PARASPINAL MUSCLESNEEDLE EMG | PARASPINAL MUSCLES

Multifidus - Rostral Insertion

Multifidus - Perpendicular

Insertion

Multifidus - Caudal Insertion

NEEDLE EMG | ARM AND SHOULDER MUSCLESNEEDLE EMG | ARM AND SHOULDER MUSCLES

BICEPS BRACHLI

DELTOID (MIDDLE)

DELTOID (ANTERIOR)

INFRASPINATUS

LEVATOR SCAPULA

Pectoralis Major - Clavicular

Pectoralis Major - Sternocostal

RHOMBOID (MAJOR)

RHOMBOID (MINOR)

SUPRASPINATUS

SERRATUS ANTERIOR

TRICEPS BRACHII (LONG HEAD)

TRICEPS BRACHII (Lateral head)

NEEDLE EMG | THIGH AND PELVIS MUSCLESNEEDLE EMG | THIGH AND PELVIS MUSCLES

LLIACUS

GULUTEUS MEDIUS

GLUTEUS MEXIMUS

BICEPS FEMERIS

ABDUCTOR LONGUS

VASTUS MEDIALIS

VASTUS LATERALIS

Semitendinosus

Semimembranosus

NERVE

CONDUCTION

VELOCITY

:- To check the electrical activity of

nerves

Amplifier parameters

Channels Sensitivity Scaling for analysis

fo fu 50 Hz notch

Rctf. Ext. Input

Input

Motoric NCV

1 2 mV/div 2 mV/div 3 kHz 5 Hz x

Sensory NCV

1 10 µV/div 5 µV/div 3 kHz 20 Hz x x

Mot. Sens. NCV

2 2 mV/div 2 mV/div 3 kHz 20 Hz X

10 µV/div 5 µV/div 3 kHz 20 Hz

Myasthenia

1 2 mV/div 2 mV/div 3 kHz 20 Hz


Monitor time Analysis time Trigger-mode Averager Sweeps (no. of passes)

Artefact

mode Detection

Motoric NCV 20 ms/div 2 ms/div internal standard 20 ----

Sensory NCV 10 ms/div 2 ms/div internal standard 20 ----

Mot. Sens. NCV

20 ms/div 2 ms/div internal standard 20 1,0 ms

Myastenia 20 ms/div 2 ms/div internal standard ---- 2,0 ms

Stimulation-parameters

Stim. Ferquency

Stim. Mode Duration Stimulation current step

Traces

Motorische NLG

1,0 Hz Single puls 200 µs automatic 3

Sensible NLG 3,0 Hz Single puls 200 µs automatic 2

Mot. Sens. NLG

2,0 Hz Single puls 200 µs automatic 2

Myasthenia 3,0 Hz Single puls 200 µs automatic 10 automatic trace advance

Reflex



fo fu 50 Hz notch

Rctf. Ext.Inpu

t

Auto-matic offset

Blink reflex 2 100 µV/div 100 µV/div 3 kHz 20 Hz x

H-Reflex 1 1 mV/div 1 mV/div 3 kHz 20 Hz x

F-Wave 1 200 µV/div 200 µV/div 10 kHz 5 Hz x


Monitor time

Analysis time Trigger-mode

Averagermode

Sweeps (no. of passes)

ArtefactDetection

Blink reflex 20 ms/div 10 ms/div internal Standard --- ---

H-Reflex 20 ms/div 10 ms/div internal Standard --- ---

F-Wave 5 ms/div 5 ms/div internal Standard 10 ---


Stim. Ferquency


Traces

Blink reflex 0,5 Hz Single puls 200 µs 0,5 mA 2

H-Reflex 0,5 Hz Single puls 500 µs Automatic 10 automatic trace advance

F-Wave 1,0 Hz Single puls 100 µs Automatic 10 automatic trace advance

Nerve conduction studies have been Nerve conduction studies have been found to be medically necessary for the found to be medically necessary for the

following indicationsfollowing indications ??

Carpal tunnel syndrome Diabetic neuropathy Disorders of peripheral nervous system Disturbance of skin sensation Fasciculation Joint pain Muscle weakness Myopathy

Nerve root compression Neuritis Neuromuscular conditions Pain in limb Plexopathy Spinal cord injury Swelling and cramps Trauma to nerves. Myositis

Major nerves of ULs (Upper Limbs) are:-

MEDIAN MOTOR / APBDistance = 5cm

Stim Points:Elbow / Wrist

MEDIAN SENSORY / IndexDistance = 8cm


ULNAR MOTOR / ADMDistance = 5cm

Stim Points:Above Elbow / Below Elbow / Wrist

ULNAR SENSORY / VthDistance = 8cm


RADIAL SENSORY / Dors HndDistance = 10cm

Stim Points:Forearm

Major nerves of LLs (Lower Limbs) are:-

PERONEAL MOTOR / EDBDistance = 7cm

Stim Points:Above/Below-Fibular Head/Ankle

PERONEAL SENSORY Distance = 14cm

Stim Points:Dist / Prox

POSTERIOR TIBIAL MOTOR Distance = 14cm

Stim Points: Pop Fossa / Ankle

SURAL SENSORY / Beh MallDistance = 14cm

Leg

H-Reflex (Soleus)

H-Reflex Potentials

NERVE ENTRAPMENT GUIDE NERVE ENTRAPMENT GUIDE PERONEAL NEUROPATHYPERONEAL NEUROPATHY

WHAT IS INVOLVEDWHAT IS INVOLVED

Peroneal Nerve

LOCATIONLOCATION

Most frequently at the Head of the Fibula

Could be just above or below it involving the Common Peroneal Nerve or the Deep or Superficial branches selectively

COMMON SYMPTOMSCOMMON SYMPTOMS

Foot drop

Patient unable to pull foot or toes up

Usually unilateral, could be bilateral

No associated pain

Main complaint is tripping, falling

Occasional leg/top of foot numbness

Symptoms always present, no night/day preference

RADIAL NEUROPATHYRADIAL NEUROPATHY (WRIST DROP)(WRIST DROP)


LOCATIONLOCATION

Radial Nerve

Most frequently at the Spiral Groove of the humerus

Could be at the Axilla (Saturday Night palsy)

Or in the Forearm (Posterior Interosseous Syndrome)


Wrist drop, Patient unable to extend wrist or fingers up

Almost always unilateral

No associated pain

Occasional forearm/hand/thumb numbness

Symptoms always present no night/day preference

NERVE SHOULDER / ARM / NERVE SHOULDER / ARM / HAND PROBLEMS HAND PROBLEMS

/TARSAL TUNNEL SYNDROME/TARSAL TUNNEL SYNDROME


Posterior Tibial Nerve

LOCATIONLOCATION

Posterior Tibial nerve entrapment at the Tarsal Tunnel in the foot at the level of the medial malleolous


Foot, Ankle, Sole pain/burning and aching

Worse at night

Occasional numbness/tingling sole of foot

No muscle weakness

Usually unilateral

Difficulty walking because of pain and discomfort with shoes

Positive Tinel (tingling upon tapping nerve) sign behind the medial malleolous

SHOULDER / ARM /HAND PROBLEMSSHOULDER / ARM /HAND PROBLEMS /ULNAR NEUROPATHY/ULNAR NEUROPATHY


LOCATIONLOCATION

Ulnar Nerve

Most frequently at the Elbow from leaning on it or trauma


Weak hand, dropping objects, difficulty turning keys, ignition, doorknobs

Numbness/tingling fourth, fifth fingers

Wasting of the interosseii muscles

Occasional elbow soreness

Symptoms not related to night/daytime

Frequently on both sides

SHOULDER / ARM / HAND PROBLEMS SHOULDER / ARM / HAND PROBLEMS /CARPALTUNNEL SYNDROME/CARPALTUNNEL SYNDROME


LOCATIONLOCATION

Median Nerve at the wrist

The Carpal Tunnel, at the wrist


Worse in the dominant hand

Dropping objects

Numbness tingling, hand/wrist ----> Thumb, Index and/or Middle finger

May radiate up the arm, occasionally to the shoulder

Symptoms primarily at night. Patient wakes up and shake their hands to obtain relief

Frequently bilateral, although may only be symptomatic on one side

VEPVEP

BAEPBAEP

SSEPSSEP

VISUAL

EVOKED

POTANTIAL

:- To check the electrical activity of optic (eyes) nerve.




Auto-matic offset

1 20 µV/div 2 µV/div 100 Hz 0,5 Hz x x


Monitor time

Analysis time

Trigger-mode

Averagermode


Artefacttreshold

ArtefactDetection

20 ms/div

50 ms/div Internal Standard 50 95 ---


Stim. Ferquency Stim. Type Stim. Field Size Pattern

Stim. Mode

Contrast Traces

1 Hz Pattern Full Standard Check Invert light 3

BRAIN

AUDITORY

EVOKED

POTENTIAL

:- To check the electrical activity of

hearing nerves.



fo fu 50 Hz notch

Rctf. Ext.Input

Auto-matic offset

1 10 µV/div 200 nV/div 3 kHz 100 Hz x


Monitor time

Analysis time

Trigger-mode

Averagermode


Artefacttreshold

ArtefactDetection

20 ms/div 1 ms/div Internal Standard 2000 15 500 µs


Stim. Ferquenc

y

Stim. Type

Stim. Field Polarity Volume stimulus Volume noise Contrast

15 Hz Click 200 µs alternated 70 dB relativ 40 dB, relativ 4

SOMATO

SENSORY

EVOKED

POTENTIAL

Somatosensory Evoked Potential (SSEP) is a test showing the electrical signals of sensation going from the body to the brain. The signals show whether the nerves that connect to the spinal cord are able to send and receive sensory information like pain, temperature, and touch. When ordering electrical tests to diagnose spine problems, SSEP is combined with an electromyogram (EMG), a test of how well the nerve roots leaving the spine are working.

An SSEP indicates whether the spinal cord or nerves are being pinched. It is helpful in determining how much the nerve is being damaged. SSEP is used to double check whether the sensory part of the nerve is working correctly.




Auto-matic offset

SEP N. tibialis 2 10 µV/div 2 µV/div 1 kHz 2 Hz x x

SEP N. medianus 1 10 µV/div 2 µV/div 1 kHz 2 Hz


Monitor time

Analysis time Trigger-mode

Averagermode


ArtefactDetection

Aquisitionparameters

SEP N. tibialis 20 ms/div 10 ms/div Internal Standard 400 --- ---

SEP N. medianus 20 ms/div 10 ms/div Internal Standard 200


Stim. Ferquency


Traces

SEP N. tibialis 3 Hz Single puls 200 µs Automatic 4

SEP N. medianus 3 Hz Single puls 200 µs Automatic 2

REPETITIVE

NERVE

STIMULATION

RNS TEST IS USED FOR RNS TEST IS USED FOR MYASTHENIA GRAVIS: MYASTHENIA GRAVIS:

DIAGNOSTIC TESTSDIAGNOSTIC TESTS

Decremental response to RNS in Myasthenia Gravis

MYASTHENIA GRAVISMYASTHENIA GRAVIS

Tensilon test: Before (left); After (right)

Cogan

Repetitive Nerve Stimulation

NERVE CONDUCTION QUICK SET-UPS | BLINK / FACIAL

H-Reflex (Soleus) H-Reflex Potentials

Transcranial Doppler (TCD) ultrasound is a non-invasive method to estimate the blood flow velocities in the large intracranial vessels of the circle of Willis. Using established TCD techniques, sections of the internal carotid artery (ICA), middle cerebral artery (MCA), anterior carotid artery (ACA), posterior cerebellar artery (PCA) and the basilar and periorbital arteries can be examined. TCD typically uses a 2 MHz pulse ultrasound which produces a velocity spectrum throughout the cardiac cycle.

MCA:- Middle Cerebral ArteryMCA:- Middle Cerebral Artery

ACA:- Anterior Cerebral ArteryACA:- Anterior Cerebral Artery

PCA:- Posterior Cerebral ArteryPCA:- Posterior Cerebral Artery

Vertebral Artery Vertebral Artery

Basilar Artery Basilar Artery

Vertebral ArteryVertebral Artery Basilar ArteryBasilar Artery

Neurophysiology

Documents

Transcript of Neurophysiology