Basics of Electrodiagnostic Medicine

Basics of Electrodiagnostic Medicine

Patrick Kortebein MDPatrick Kortebein MDUAMS Department of Physical Medicine UAMS Department of Physical Medicine

& Rehabilitation& Rehabilitation4/10/064/10/06

Patrick Kortebein MDPatrick Kortebein MDUAMS Department of Physical Medicine UAMS Department of Physical Medicine

& Rehabilitation& Rehabilitation4/10/064/10/06

Electrodiagnostic StudiesElectrodiagnostic Studies

Nerve Conduction Studies (NCS)Nerve Conduction Studies (NCS) MotorMotor SensorySensory Other (F-wave, H-reflex)Other (F-wave, H-reflex)

Electromyography (EMG)Electromyography (EMG) ““Needle exam”Needle exam”

Nerve Conduction Studies (NCS)Nerve Conduction Studies (NCS) MotorMotor SensorySensory Other (F-wave, H-reflex)Other (F-wave, H-reflex)

Electromyography (EMG)Electromyography (EMG) ““Needle exam”Needle exam”

PurposePurpose

1. Confirm a tentative clinical diagnosis 2. Exclude other disorders3. Determine stage of disease

e.g., location, severity, rate of progression, prognosis4. Characterize disease

e.g., axonal vs demyelinating5. Identify subclinical disease

1. Confirm a tentative clinical diagnosis 2. Exclude other disorders3. Determine stage of disease

e.g., location, severity, rate of progression, prognosis4. Characterize disease

e.g., axonal vs demyelinating5. Identify subclinical disease

ExampleExample

1. NCS- Motor / Sensory1. NCS- Motor / Sensory Axonal vs Demyelinating processAxonal vs Demyelinating process

1. NCS- Motor / Sensory1. NCS- Motor / Sensory Axonal vs Demyelinating processAxonal vs Demyelinating process

NCS: Common NervesNCS: Common Nerves

Upper Extremity:Upper Extremity: MedianMedian UlnarUlnar RadialRadial

Lower Extremity:Lower Extremity: PeronealPeroneal TibialTibial Sural (sensory)Sural (sensory)

*Normal Values- Variable*Normal Values- Variable

Upper Extremity:Upper Extremity: MedianMedian UlnarUlnar RadialRadial

Lower Extremity:Lower Extremity: PeronealPeroneal TibialTibial Sural (sensory)Sural (sensory)

*Normal Values- Variable*Normal Values- Variable

Example Example

2. EMG2. EMG

Muscle Electrical ActivityMuscle Electrical Activity RestRest Volitional ActivityVolitional Activity

2. EMG2. EMG

Muscle Electrical ActivityMuscle Electrical Activity RestRest Volitional ActivityVolitional Activity

Reasons for ReferralReasons for Referral

Numbness/ParesthesiasNumbness/Paresthesias Pain; radicular Pain; radicular Weakness; generalized/facial (MG)Weakness; generalized/facial (MG) Muscle atrophyMuscle atrophy Muscle twitching/Muscle twitching/ fasciculationsfasciculations

Numbness/ParesthesiasNumbness/Paresthesias Pain; radicular Pain; radicular Weakness; generalized/facial (MG)Weakness; generalized/facial (MG) Muscle atrophyMuscle atrophy Muscle twitching/Muscle twitching/ fasciculationsfasciculations

Common ReferralsCommon Referrals

Motor Neuron: ALSMotor Neuron: ALS Radiculopathy (Cervical / Lumbar)Radiculopathy (Cervical / Lumbar) Peripheral Nerves (Motor/Sensory)Peripheral Nerves (Motor/Sensory)

Carpal Tunnel SyndromeCarpal Tunnel Syndrome Foot DropFoot Drop Polyneuropathy (*except small fiber)Polyneuropathy (*except small fiber)

AIDP (Guillain Barre’)AIDP (Guillain Barre’) NMJ: Myasthenia GravisNMJ: Myasthenia Gravis Muscle: MyopathiesMuscle: Myopathies

Motor Neuron: ALSMotor Neuron: ALS Radiculopathy (Cervical / Lumbar)Radiculopathy (Cervical / Lumbar) Peripheral Nerves (Motor/Sensory)Peripheral Nerves (Motor/Sensory)

Carpal Tunnel SyndromeCarpal Tunnel Syndrome Foot DropFoot Drop Polyneuropathy (*except small fiber)Polyneuropathy (*except small fiber)

AIDP (Guillain Barre’)AIDP (Guillain Barre’) NMJ: Myasthenia GravisNMJ: Myasthenia Gravis Muscle: MyopathiesMuscle: Myopathies

Timing of ReferralTiming of Referral

Acute vs ChronicAcute vs Chronic Acute nerve injury/damage Acute nerve injury/damage

Nerve laceration (NCS)Nerve laceration (NCS) Radiculopathy (~7-10 days to weeks)Radiculopathy (~7-10 days to weeks)

Chronic nerve injuryChronic nerve injury Radiculopathy- persistent findings distinct from Radiculopathy- persistent findings distinct from

acute process (active vs inactive)acute process (active vs inactive)

Acute vs ChronicAcute vs Chronic Acute nerve injury/damage Acute nerve injury/damage

Nerve laceration (NCS)Nerve laceration (NCS) Radiculopathy (~7-10 days to weeks)Radiculopathy (~7-10 days to weeks)

Chronic nerve injuryChronic nerve injury Radiculopathy- persistent findings distinct from Radiculopathy- persistent findings distinct from

acute process (active vs inactive)acute process (active vs inactive)

ReferralsReferrals

Axial Neck / Low Back PainAxial Neck / Low Back Pain Generally, not indicatedGenerally, not indicated

Necessary?Necessary? Will it change your treatment plan?Will it change your treatment plan? Do you need assistance with diagnosis?Do you need assistance with diagnosis?

Axial Neck / Low Back PainAxial Neck / Low Back Pain Generally, not indicatedGenerally, not indicated

Necessary?Necessary? Will it change your treatment plan?Will it change your treatment plan? Do you need assistance with diagnosis?Do you need assistance with diagnosis?

Who performs NCS/EMG?Who performs NCS/EMG?

NeurologistNeurologist Physiatrist (PM&R)- required residencyPhysiatrist (PM&R)- required residency Physical Therapist (rare)Physical Therapist (rare) Technicians (NCS only)Technicians (NCS only)Additional Training:Additional Training: FellowshipFellowship Board Certification Board Certification

AANEM (Amer Assoc Nm & EDX Med)AANEM (Amer Assoc Nm & EDX Med)

NeurologistNeurologist Physiatrist (PM&R)- required residencyPhysiatrist (PM&R)- required residency Physical Therapist (rare)Physical Therapist (rare) Technicians (NCS only)Technicians (NCS only)Additional Training:Additional Training: FellowshipFellowship Board Certification Board Certification

AANEM (Amer Assoc Nm & EDX Med)AANEM (Amer Assoc Nm & EDX Med)

What tests are performed?What tests are performed?

Depends on Depends on Referral QuestionReferral Question Evaluation by examinerEvaluation by examiner

EDX testing is an extension of the physical EDX testing is an extension of the physical exam.exam.

*Address the patients problem*Address the patients problem GeneralGeneral

NCS (e.g., CTS)NCS (e.g., CTS) EMG (e.g., cervical radiculopathy)EMG (e.g., cervical radiculopathy) NCS & EMGNCS & EMG

Depends on Depends on Referral QuestionReferral Question Evaluation by examinerEvaluation by examiner

EDX testing is an extension of the physical EDX testing is an extension of the physical exam.exam.

*Address the patients problem*Address the patients problem GeneralGeneral

NCS (e.g., CTS)NCS (e.g., CTS) EMG (e.g., cervical radiculopathy)EMG (e.g., cervical radiculopathy) NCS & EMGNCS & EMG

Cost?Cost?

Nerve Conduction StudiesNerve Conduction Studies Motor- $90/testMotor- $90/test Sensory- $80/testSensory- $80/test

EMG (minimum 5 mm per extremity)EMG (minimum 5 mm per extremity) One extremity- $250One extremity- $250

Nerve Conduction StudiesNerve Conduction Studies Motor- $90/testMotor- $90/test Sensory- $80/testSensory- $80/test

EMG (minimum 5 mm per extremity)EMG (minimum 5 mm per extremity) One extremity- $250One extremity- $250

Real world patient scenarioReal world patient scenario

46 yo RH F restaurant owner46 yo RH F restaurant owner CC: Constant “numbness/tingling” right CC: Constant “numbness/tingling” right

ulnar 2 digits for 1 monthulnar 2 digits for 1 month HPI: Carries trays at work, No clear HPI: Carries trays at work, No clear

aggravating/alleviating position/activities, aggravating/alleviating position/activities, no weaknessno weakness

Meds/Allergies: None, PMHx: NoneMeds/Allergies: None, PMHx: None UExt Neuro Exam: M/S/R normal, inc ulnar UExt Neuro Exam: M/S/R normal, inc ulnar

digits sensorydigits sensory

Tinel’s at elbow- Positive Tinel’s at elbow- Positive Dx?Dx?

46 yo RH F restaurant owner46 yo RH F restaurant owner CC: Constant “numbness/tingling” right CC: Constant “numbness/tingling” right

ulnar 2 digits for 1 monthulnar 2 digits for 1 month HPI: Carries trays at work, No clear HPI: Carries trays at work, No clear

aggravating/alleviating position/activities, aggravating/alleviating position/activities, no weaknessno weakness

Meds/Allergies: None, PMHx: NoneMeds/Allergies: None, PMHx: None UExt Neuro Exam: M/S/R normal, inc ulnar UExt Neuro Exam: M/S/R normal, inc ulnar

digits sensorydigits sensory

Tinel’s at elbow- Positive Tinel’s at elbow- Positive Dx?Dx?

Real world patient scenarioReal world patient scenario

Referral NCS:Referral NCS: Ulnar neuropathy at the elbowUlnar neuropathy at the elbow

Primary MDPrimary MD NEUROMetrix in officeNEUROMetrix in office Testing performed- InconclusiveTesting performed- Inconclusive Second study performedSecond study performed

Time Time ExpenseExpense Patient discomfort Patient discomfort

Referral NCS:Referral NCS: Ulnar neuropathy at the elbowUlnar neuropathy at the elbow

Primary MDPrimary MD NEUROMetrix in officeNEUROMetrix in office Testing performed- InconclusiveTesting performed- Inconclusive Second study performedSecond study performed

Time Time ExpenseExpense Patient discomfort Patient discomfort

Questions?