Basics of Electrodiagnostic Medicine Patrick Kortebein MD UAMS Department of Physical Medicine & Rehabilitation 4/10/06 Patrick Kortebein MD UAMS Department of Physical Medicine & Rehabilitation 4/10/06

Electrodiagnostic Studies  Nerve Conduction Studies (NCS)  Motor  Sensory  Other (F-wave, H-reflex)  Electromyography (EMG)  “Needle exam”  Nerve Conduction Studies (NCS)  Motor  Sensory  Other (F-wave, H-reflex)  Electromyography (EMG)  “Needle exam”

Purpose 1. Confirm a tentative clinical diagnosis 2. Exclude other disorders 3. Determine stage of disease e.g., location, severity, rate of progression, prognosis 4. Characterize disease e.g., axonal vs demyelinating 5. Identify subclinical disease 1. Confirm a tentative clinical diagnosis 2. Exclude other disorders 3. Determine stage of disease e.g., location, severity, rate of progression, prognosis 4. Characterize disease e.g., axonal vs demyelinating 5. Identify subclinical disease

Example 1. NCS- Motor / Sensory  Axonal vs Demyelinating process 1. NCS- Motor / Sensory  Axonal vs Demyelinating process

NCS: Common Nerves Upper Extremity:  Median  Ulnar  Radial Lower Extremity:  Peroneal  Tibial  Sural (sensory) *Normal Values- Variable Upper Extremity:  Median  Ulnar  Radial Lower Extremity:  Peroneal  Tibial  Sural (sensory) *Normal Values- Variable

Example 2. EMG  Muscle Electrical Activity  Rest  Volitional Activity 2. EMG  Muscle Electrical Activity  Rest  Volitional Activity

Reasons for Referral  Numbness/Paresthesias  Pain; radicular  Weakness; generalized/facial (MG)  Muscle atrophy  Muscle twitching/ fasciculations fasciculations  Numbness/Paresthesias  Pain; radicular  Weakness; generalized/facial (MG)  Muscle atrophy  Muscle twitching/ fasciculations fasciculations

Common Referrals  Motor Neuron: ALS  Radiculopathy (Cervical / Lumbar)  Peripheral Nerves (Motor/Sensory)  Carpal Tunnel Syndrome  Foot Drop  Polyneuropathy (*except small fiber)  AIDP (Guillain Barre’)  NMJ: Myasthenia Gravis  Muscle: Myopathies  Motor Neuron: ALS  Radiculopathy (Cervical / Lumbar)  Peripheral Nerves (Motor/Sensory)  Carpal Tunnel Syndrome  Foot Drop  Polyneuropathy (*except small fiber)  AIDP (Guillain Barre’)  NMJ: Myasthenia Gravis  Muscle: Myopathies

Timing of Referral  Acute vs Chronic  Acute nerve injury/damage  Nerve laceration (NCS)  Radiculopathy (~7-10 days to weeks)  Chronic nerve injury  Radiculopathy- persistent findings distinct from acute process (active vs inactive)  Acute vs Chronic  Acute nerve injury/damage  Nerve laceration (NCS)  Radiculopathy (~7-10 days to weeks)  Chronic nerve injury  Radiculopathy- persistent findings distinct from acute process (active vs inactive)

Referrals  Axial Neck / Low Back Pain  Generally, not indicated  Necessary?  Will it change your treatment plan?  Do you need assistance with diagnosis?  Axial Neck / Low Back Pain  Generally, not indicated  Necessary?  Will it change your treatment plan?  Do you need assistance with diagnosis?

Who performs NCS/EMG?  Neurologist  Physiatrist (PM&R)- required residency  Physical Therapist (rare)  Technicians (NCS only) Additional Training:  Fellowship  Board Certification  AANEM (Amer Assoc Nm & EDX Med)  Neurologist  Physiatrist (PM&R)- required residency  Physical Therapist (rare)  Technicians (NCS only) Additional Training:  Fellowship  Board Certification  AANEM (Amer Assoc Nm & EDX Med)

What tests are performed?  Depends on  Referral Question  Evaluation by examiner  EDX testing is an extension of the physical exam.  *Address the patients problem  General  NCS (e.g., CTS)  EMG (e.g., cervical radiculopathy)  NCS & EMG  Depends on  Referral Question  Evaluation by examiner  EDX testing is an extension of the physical exam.  *Address the patients problem  General  NCS (e.g., CTS)  EMG (e.g., cervical radiculopathy)  NCS & EMG

Cost?  Nerve Conduction Studies  Motor- $90/test  Sensory- $80/test  EMG (minimum 5 mm per extremity)  One extremity- $250  Nerve Conduction Studies  Motor- $90/test  Sensory- $80/test  EMG (minimum 5 mm per extremity)  One extremity- $250

Real world patient scenario  46 yo RH F restaurant owner  CC: Constant “numbness/tingling” right ulnar 2 digits for 1 month  HPI: Carries trays at work, No clear aggravating/alleviating position/activities, no weakness  Meds/Allergies: None, PMHx: None  UExt Neuro Exam: M/S/R normal, inc ulnar digits sensory Tinel’s at elbow- Positive  Dx?  46 yo RH F restaurant owner  CC: Constant “numbness/tingling” right ulnar 2 digits for 1 month  HPI: Carries trays at work, No clear aggravating/alleviating position/activities, no weakness  Meds/Allergies: None, PMHx: None  UExt Neuro Exam: M/S/R normal, inc ulnar digits sensory Tinel’s at elbow- Positive  Dx?

Real world patient scenario  Referral NCS:  Ulnar neuropathy at the elbow  Primary MD  NEUROMetrix in office  Testing performed- Inconclusive  Second study performed  Time  Expense  Patient discomfort  Referral NCS:  Ulnar neuropathy at the elbow  Primary MD  NEUROMetrix in office  Testing performed- Inconclusive  Second study performed  Time  Expense  Patient discomfort

Questions?