Upper Extremity NCS Lesion Localization and Characterization 2019 Annual AANEM Meeting Austin, Texas

Mark A. Ferrante, MD Professor, Department of Neurology Co-Director, Neurophysiology Fellowship Associate Director, Residency Training Program University of Tennessee Health Science Center Chief of Neurology Section Chief of Neurophysiology, Director of ALS Clinic VA Medical Center Memphis, Tennessee Disclosures

• Gator fan • Publishing royalties – AANEM • What We Measure and What It Means – Ferrante, 2012 – Cambridge University Press • Comprehensive Electromyography – Ferrante, 2018 – Demos Publishing • EMG Lesion Localization and Characterization – Ferrante and Tsao, 2020 Introduction

• Lesion localization and characterization – The major skills of the EDX provider – Lesion localization – Lesion characterization • Fiber type involved: sensory or motor • Pathology: Axon loss or demyelination • Severity • Temporal characteristics (needle EMG) – Acute, subacute, or chronic – Rate of progression – Introductory material  cases • Mechanisms of nerve injury – Large number • Pathology and pathophysiology – Limited • Myelin disruption (demyelination) – Conduction slowing (DMCS) – Conduction block (DMCB) • Axon disruption (Wallerian degeneration) – Conduction failure – Prior to Wallerian degeneration » Transient “conduction block” pattern Nerve Fiber Disruption • Focal demyelination – Focal effects • Focal axon disruption – Initially: Focal effects – Later: Distal effects – Wallerian degeneration

Ferrante MA, Tsao B. EMG Lesion Localization and Characterization, 2020 DMCS, uniform

The pathophysiologies associated with DMCS, non-uniform demyelination

DMCB Motor NCS are able to assess long segments of nerve

Forearm

Elbow

Below SG

Above SG

– Timing of Wallerian degeneration • Motor axon terminals and endplates degenerate first – NMJ transmission failure occurs before nerve fiber conduction failure – CMAP abnormalities precede SNAP abnormalities » CMAPs: day 3 to day 7 » SNAPs: day 6 to day 10

Ferrante MA. Comprehensive Electromyography 9 • NCS identify – Focal DM and early axon disruption • Between the stimulating and recording sites – Screens for Wallerian degeneration proximal to these sites • All the way to the cell bodes of origin Ferrante. Muscle and Nerve 2004;30:547-568. ANTERIOR PRIIMARY RAMI C5 C6 C7 C8 T1 Proximal Nerve Innervation For the motor NCS Rhomboids (dorsal scapular) Spinati (suprascapular) Deltoid (axillary) Myotomal charts indicate: Biceps (musculocutaneous) Brachialis (musculocutaneous)

Radial Nerve Innervation • the root innervation Brachioradialis Triceps • the nerve innervation Anconeus Extensor carpi radialis Extensor pollicis brevis Example: Biceps Extensor indicis

Median Nerve Innervation Pronator teres Flexor carpi radialis Flexor pollicis longus Pronator quadratus Abductor pollicis brevis

Ulnar Nerve Innervation Flexor carpi ulnaris Flexor digitorum profundus (D4,D5) Abductor digiti minimi Adductor polllicis First dorsal interosseous

POSTERIOR PRIMARY RAMI Cervical paraspinal muscles High thoracic paraspinal muscles

predominant contribution sometimes significant contribution minor contribution

Ferrante MA, Tsao B. EMG Lesion Localization and Characterization, 2020 LABC SNAP

Ferrante and Wilbourn, Muscle and Nerve, 1995 Med-D1 SNAP

Ferrante and Wilbourn, Muscle and Nerve, 1995 Superficial Radial SNAP

Ferrante and Wilbourn, Muscle and Nerve, 1995 Med-D2 SNAP

Ferrante and Wilbourn, Muscle and Nerve, 1995 Med-D3 SNAP

Ferrante and Wilbourn, Muscle and Nerve, 1995 Uln-D5 SNAP

Ferrante and Wilbourn, Muscle and Nerve, 1995 MABC SNAP

Ferrante and Wilbourn, Muscle and Nerve, 1995 C6

C6>7 C7>6 C6 C7

T1 C8

Ferrante and Wilbourn, Muscle and Nerve, 1995 Routine Screening NCS of Upper Extremity (Only weakly assesses upper plexus)

Radial C5 Med-D2 Uln-D5 C6 C7 C8 T1

Ulnar-ADM Median-APB NCS Assessment of Upper Plexus

LABC (100%) Med-D1 (100%) Radial (60%)* C5 C6 C7 C8 T1

Musculocutaneous-BC Axillary-Deltoid NCS Assessment of Middle Plexus

Med-D2 (80%)* Med-D3 (70%) C5 Radial (40%)* C6 C7 C8 T1 NCS Assessment of Lower Plexus

Uln-D5 (100%)*

C5 MABC (100%)

C6 C7 C8 T1

Radial – distal forearm Ulnar – ADM or FDI* Median – APB* NCS Assessment of Lateral Cord

LABC (100%) Med-D1 (100%) Med-D2 (100%)* C5 Med-D3 (80%) C6 C7 C8 T1

Musculocutaneous - BC NCS Assessment of Posterior Cord

Radial (100%)* C5

C6 C7 C8 T1

Axillary – Deltoid Radial – Proximal FA Radial – Distal FA NCS Assessment of Medial Cord

Uln-D5 (100%)* C5 MABC (100%)

C6 C7 C8 T1

Ulnar – ADM/FDI* Median – APB* • Which sensory NCS should be done first? – Perform “routine” sensory NCS + NCS to address the referral diagnosis + NCS to address the clinical features – Based on identified abnormalities, add others • For C6,7 abnormalities (Med-D2; SRN) – Add LABC and Med-D1 • For C8 abnormalities (Uln-D5) – Add MABC • Add contralateral studies when indicated EDX CASE STUDIES

Localization Pathophysiology Severity Temporal Case 1A

• 67yo RH male – Episodic hand numbness and tingling x 5 years, R > L – Present upon awakening – Precipitated by driving – Occur spontaneously while seated at rest • No neck pain • Examination normal – Hand sensation – Thenar eminence strength and bulk • Clinical features – Suggest bilateral CTS, right > left – Dominant limb first and worst • Exceptions – Profession and hobbies » Ferrante, Federal Practitioner, 2016;33:10-15

• Start NCS Median-D2 – Screening sensory NCS Ulnar-D5 • Start with RUE Superficial radial – More symptomatic side – If Median-D2 is normal, add palmar NCS » More sensitive to CTS CASE 1A UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT

NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 4.2 6.4 Ulnar-D5 C8 2.9 6.2 Superficial radial C6,7 2.4 13.5

Perform Contralateral NCS Median-D2 CASE 1A UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT

NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.6 12.0 4.2 6.4 Ulnar-D5 C8 2.9 6.2 Superficial radial C6,7 2.4 13.5 Median Palmar 2.4 18.2 Ulnar Palmar 1.9 12.5

Localization Bilateral Median: distal to the wrist stimulation sites Pathophysiology Demyelinating and axon loss on the right; demyelinating on the left Severity Mild to mild-moderate on the right and mild on the left Temporal Chronic by history (this is determined by the needle EMG findings)

Which Motor NCS? Routine motor NCS x RUE Median-APB x LUE UPPER EXTREMITY NERVE CONDUCTION STUDY CASE 1A WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.6 12.0 4.2 6.4 Ulnar-D5 C8 2.9 6.2 Spfcl radial C6,7 2.4 13.5 Median Palmar 2.4 18.2 Ulnar Palmar 1.9 12.5

Stim MOTOR Site Median-APB Wrist 3.4 7.6 4.1 5.8 Elbow 5.5 51 Ulnar-ADM Wrist 2.4 11.4 28.8 BE 9.6 52 26.8 AE 8.8 53 26.7

Localization Distal to the wrist stimulation site on both sides Pathophysiology DMCS and axon loss on the right, involving the sensory and motor nerve fibers DMCS on the left, involving the sensory nerve fibers Severity At least moderate on the right and mild on the left Temporal Chronic by history UPPER EXTREMITY NEEDLE EMG WORKSHEET Insertional activity Spontaneous Activity MUAP Analysis

CASE 1A MUAP MUAP Normal IPSWs SCP Other None Fibs Fascs Other Recruitment Morphology RIGHT APB X X Normal Normal FDI X X Normal Normal Pron teres X X Normal Normal

LEFT APB X X Normal Normal Case 1A Impression

1. Bilateral Median Neuropathies (e.g., carpal tunnel syndrome) • The above are demyelinating and axon loss in nature on the right and demyelinating in nature on the left, involve the sensory and motor nerve fibers on the right and the sensory nerve fibers on the left, and are located at or distal to the wrist on both sides. • Electrically, the abnormalities are moderate in severity on the right and mild in severity on the left. Case 1B

• 56yo RH male – Episodic hand numbness and tingling x 2 years, R > L – Present upon awakening – Precipitated by driving – Occur spontaneously while seated at rest • No neck pain • Examination normal – Hand sensation decreased • Median distribution – Thenar eminence muscles • Normal strength • Thenar eminence – Wasting, mild in degree CASE 1B UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT

NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 NR Ulnar-D5 C8 2.7 12.2 Superficial radial C6,7 2.4 17.8 Median Palmar NR

Localization Median nerve, lateral cord, upper plexus, C6/7 DRG Pathophysiology Axon loss, sensory nerve fibers Severity Unclear (at least moderate) Temporal Chronic by history

• Due to time constraints, we will only discuss the ipsilateral findings • Hx s/o CTS CASE 1A UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT

NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 NR Ulnar-D5 C8 2.7 12.2 Superficial radial C6,7 2.4 17.8 Median Palmar NR

Stim MOTOR Site Median-APB Wrist 4.6 4.8 Elbow 4.5 51 Ulnar-ADM Wrist 2.3 10.9 BE 10.3 57 AE 10.3 58

Localization Median nerve, distal to the stimulation site Pathophysiology Demyelination and axon loss; involves the sensory and motor nerve fibers Severity Unclear (at least moderate) Temporal Chronic by history Case 1C

• 43yo RH male – Episodic hand numbness and tingling x 10 years, R > L – Present upon awakening – Precipitated by driving – Occur spontaneously while seated at rest • No neck pain • Examination normal – Hand sensation decreased • Median distribution – Thenar eminence muscles • Normal strength • Severe thenar eminence wasting

CASE 1C UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT

NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 NR Ulnar-D5 C8 2.8 17.5 Superficial radial C6,7 2.4 24.9 Median Palmar NR Ulnar Palmar

Localization Median nerve, lateral cord, upper plexus, C6/7 DRG Pathophysiology Axon loss, sensory nerve fibers Severity Unclear (at least moderate) Temporal Chronic by history

• Due to time constraints, we will only discuss the ipsilateral findings • Hx s/o CTS, so continue with motor NCS UPPER EXTREMITY NERVE CONDUCTION STUDY CASE 1C WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 NR Ulnar-D5 C8 2.8 17.5 Spfcl radial C6,7 2.4 24.9

Median Palmar Ulnar Palmar

Stim MOTOR Site Median-APB Wrist NR Elbow Ulnar-ADM Wrist 2.4 8.3 BE 8.0 53 AE 8.0 52

Localization Median nerve at or distal to axilla Pathophysiology Axon loss, sensory and motor nerve fibers Severity Severe Temporal Chronic by history UPPER EXTREMITY NERVE CONDUCTION STUDY CASE 1C WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 NR Ulnar-D5 C8 2.8 17.5 Spfcl radial C6,7 2.4 24.9

Stim MOTOR Site Median-APB Wrist NR Elbow Ulnar-ADM Wrist 2.4 8.3 BE 8.0 53 AE 8.0 52 Median-L2 Wrist 5.4 1.1

Localization Median nerve at or distal to stimulation site Pathophysiology Axon loss, sensory and motor nerve fibers Severity Severe Temporal Chronic by history Case 2 • 70yo RH male referred for RH numbness and weakness – Symptom onset • 6 weeks ago, immediately following a 2-vessel stenting procedure – Axillary approach • Examination – Diminished sensation -- the lateral 3.5 digits (“splits 4”) and thenar eminence – Severe weakness • Median nerve-innervated hand intrinsic muscles • Anterior interosseous nerve-innervated muscles • Pronator teres and flexor carpi radialis muscles -- normal strength • Clinical thoughts – Iatrogenic median neuropathy CASE 2 UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT

NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D1 C6 NR Median-D2 C6,7 NR Median-D3 C6,7,8 NR Ulnar-D5 C8 2.9 15.2 Superficial radial C6,7 2.6 17.4

Localization Median nerve or lateral cord Pathophysiology Axon loss Severity At least moderate-severe Temporal 6 weeks by history

Add LABC sensory NCS to differentiate median nerve from lateral cord CASE 2 UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT

NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D1 C6 NR Median-D2 C6,7 NR Median-D3 C6,7,8 NR Ulnar-D5 C8 2.9 15.2 Superficial radial C6,7 2.6 17.4 LABC C6 2.6 11.2

Localization Median nerve or distal lateral cord Pathophysiology Axon loss Severity At least moderate to moderate-severe Temporal Subacute by history

Motor NCS Ipsilateral: Routine + Median-L2 Contralateral add Median-APB and Median-L2 CASE 2 UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D1 C6 NR Median-D2 C6,7 NR Median-D3 C6,7,8 NR Ulnar-D5 C8 2.9 15.2 Superficial radial C6,7 2.6 17.4 LABC C6 2.6 11.2

Stim MOTOR Site Median-APB Wrist 3.4 12.6 42.7 4.0 3.2 12.5 Elbow 2.8 38 11.2 Ulnar-ADM Wrist 2.5 9.1 BE 8.7 53 AE 8.7 52 Median-L2 Wrist 3.9 2.2 4.6 0.5

Localization Median nerve Pathophysiology Axon loss Severity Severe Temporal Subacute by history UPPER EXTREMITY NEEDLE EMG WORKSHEET Insertional activity Spontaneous Activity MUAP Analysis CASE 2 MUAP MUAP Normal IPSWs SCP Other None Fibs Fascs Other Recruitment Morphology RIGHT APB X 3+ Neurogenic, sev Normal FDI X X Normal Normal EI X X Normal Normal FPL X 3+ Neurogenic, mild Normal Pronator teres X X 1+ Normal Normal BC, LH X X Normal Normal TC, LH X X Normal Normal FCR X 2+ Normal Normal Lumbrical 2 X 3+ Neurogenic, sev Normal

Low cerv psp X X -- -- High thor psp X X -- --

Localization Median nerve Pathophysiology Axon loss Severity Very severe (based on severity of neurogenic recruitment) Temporal Acute-subacute (high amplitude fibrillation potentials) Case 2 Impression

1. Right Median Neuropathy • The above is axon loss in nature, involves the sensory and motor nerve fibers, and is severe in degree. • The lesion involves about 75% of the motor axons to the APB muscle and 75% of the motor axons to the second lumbrical muscle. • The lesion is located proximal to the departure site of the motor branch to the pronator teres muscle. Because the median nerve does not give off motor branches in the arm, more precise localization is not possible. • The lesion is acute to subacute given the high amplitude fibrillation potentials and the lack of chronic changes. This is consistent with the onset reported by the patient. Case 3

• 70yo RHD male – Awoke with left hand tingling and inability to extend his wrist and fingers 25 days ago – Examination • Decreased sensation superficial radial nerve distribution • Weakness of wrist extension without radial deviation • Forearm extension strength is normal

CASE 3 UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT

NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.3 18.1 Ulnar-D5 C8 2.7 10.8 Superficial radial C6,7 2.5 21.6 2.6 28.7

• The sensory NCS are normal • The superficial radial response asymmetry is of unclear significance • It may reflect axon loss, but if so it is minimal-mild in degree • Can proceed to motor BCS • Routine left motor NCS • Add the distal and proximal radial motor responses bilaterally CASE 3 UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.3 18.1 Ulnar-D5 C8 2.7 10.8 Spfcl Radial C6,7 2.5 21.6 2.6 28.7

MOTOR Stim Site Median-APB Wrist 3.6 8.7 Elbow 8.6 54.2 Ulnar-ADM Wrist 2.8 7.2 Elbow 7.1 55.3 Radial-EI Mid-FA 2.1 4.0 28.9 2.2 6.4 32.9 Elbow 3.8 28.2 Below SG 3.8 27.7 Above SG 0.8 3.8 Radial-ED Elbow 2.7 6.2 40.0 2.6 7.1 45.6 Below SG 5.7 38.5 Above SG 1.1 8.4

Localization Spiral groove Pathophysiology DMCB; possible minor axon loss (< 10%) Severity Severe for the DMCB Temporal 25 days based on history UPPER EXTREMITY NEEDLE EMG WORKSHEET Insertional activity Spontaneous Activity MUAP Analysis MUAP MUAP CASE 3 Norma IPSW SCP Other None Fib Fasc Other Recruitment Morphology l s s s LEFT FDI X X Normal Normal EI X 3+ Severe neurogenic Normal FPL X X Normal Normal Pron teres X X Normal Normal BC, LH X X Normal Normal TC, LH X X Normal Normal Deltoid, MH X X Normal Normal Brachiorad 3+ Severe neurogenic Normal ECR-longus X 3+ Severe neurogenic Normal ED X 2+ Severe neurogenic Normal Anconeus X X Normal Normal

Low C psp X X -- -- High T psp X X -- --

RIGHT EI X X Normal Normal Brachiorad X X Normal Normal

Localization Spiral groove Pathophysiology DMCB >> axon loss Severity Severe for the DMCB; mild for the axon loss Temporal c/w the 25 days reported Calculating Severity

Radial-EI Mid-FA 2.1 4.0 28.9 2.2 6.4 32.9 Elbow 3.8 28.2 Below SG 3.8 27.7 Above SG 0.8 3.8 Radial-ED Elbow 2.7 6.2 40.0 2.6 7.1 45.6 Below SG 5.7 38.5 Above SG 1.1 8.4

For the motor axons to the EI muscle AXON LOSS: 1 – 28.9/32.9 = 1 - 0.88 = 0.12 = 12% DMCB: 1 – 3.8/27.7 = 1 – 0.14 = 0.86 = 0.86 X 0.88 = 76% NORMAL: 100% - 88% = 12%

For the motor axons to the EDC muscle AXON LOSS: 1 - 40.0/45.6 = 1 - 0.88 = 0.12 = 12% DMCB: 1 - 8.4/38.5 = 1 - 0.22 = 0.78 = 0.78 X 0.88 = 69% NORMAL: 100% - 81%= 19% Case 3 Impression

1. Left Radial Neuropathy • The above is demyelinating conduction block >> axon loss in nature, involves the motor nerve fibers (and the sensory nerve fibers by clinical examination), is located within the spiral groove, and is severe in degree for the demyelinating conduction block component and mild for the axon loss component. • The findings are consistent with the 25-day onset reported by the patient. Case 4

• 52yo RHD female x left UE numbness and weakness – Pacemaker placement 2 months ago – Symptoms started immediately after procedure • Weakness – Forearm flexion (C5,6-MC) and pronation (C6,7-median) • Numbness along the lateral aspect of the forearm (LABC) and hand (median and radial) – Sparing the skin overlying the FDI muscle UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET CASE 4 LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.1 8.6 IS THIS CTS? Ulnar-D5 C8 2.8 12.3 Superficial radial C6,7 2.4 20.0

INTERPRETATION • The Med-D2 response is reduced in amplitude • POTENTIAL LOCALIZATION • Median nerve, lateral cord, upper/middle plexus, C6,7 DRG

ARE FURTHER SENSORY NCS INDICATED? • C6,7 DRG  add LABC and Med-D1 sensory NCS • On the contralateral side • Med-D2 for comparison purposes • LABC and Med-D1 UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET CASE 4 LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.1 8.6 3.0 28.3 Ulnar-D5 C8 2.8 12.3 Superficial radial C6,7 2.4 20.0 LABC C6 2.7 5.1 2.5 16.5 Median-D1 C6 3.2 7.2 3.1 21.9

Localization Lateral cord > upper plexus, C6 DRG Pathophysiology Axon loss Severity At least moderate (severity is best addressed by the motor NCS) Temporal 2 months by history

Which motor NCS should be performed? • Ipsilateral: Routine NCS; Musculocutaneous-BC; Axillary-Deltoid • Contralateral: Musculocutaneous-BC; Axillary-Deltoid CASE 4 UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.1 8.6 3.0 28.3 Ulnar-D5 C8 2.8 12.3 Superficial radial C6,7 2.4 20.0 2.5 24.1 LABC C6 2.7 5.1 2.5 16.5 Median-D1 C6 3.2 7.2 3.1 21.9

Stim MOTOR Site Median-APB Wrist 3.5 7.2 Elbow 7.1 56 Ulnar-ADM Wrist 2.8 8.3 Elbow 8.1 54 Musculo-BC Axilla 3.8 2.7 3.6 5.6 SCF 2.6 56 Axillary-Deltoid SCF 4.1 9.2 3.9 8.6

Localization Lateral cord Pathophysiology Axon loss Severity Moderate-severe (1 - 2.7/5.6) x 100% = 52% motor axons to biceps Temporal 2 months by history UPPER EXTREMITY NEEDLE EMG WORKSHEET

Insertional activity Spontaneous Activity MUAP Analysis CASE 35 MUAP MUAP Normal IPSWs SCP Other None Fibs Fascs Other Recruitment Morphology LEFT FDI X X Normal Normal EI X X Normal Normal FPL X X Normal Normal Pron teres X 3+ Normal Normal BC, LH X 3+ Mild neurogenic Normal FCR X 2+ Normal Normal TC, LH X X Normal Normal Deltoid, MH X X Normal Normal Brachioradialis X X Normal Normal Infraspinatus X X Normal Normal

Low cerv psp X X -- -- High thor psp X X -- --

RIGHT Pron teres X X Normal Normal BC, LH X X Normal Normal Brachioradialis X X Normal Normal Deltoid, MH X X Normal Normal Localization Lateral cord Pathophysiology Axon loss Severity Moderate-severe (1 - 2.7/5.6) x 100% = 52% motor axons to biceps Temporal Lack of collateral sprouting supports the 2-month history reported Case 4 Impression

1. Lateral Cord Brachial Plexus Lesion

The above is axon loss in nature, involves the sensory and motor nerve fibers, and is moderate-severe in degree. The temporal features of the abnormalities are consistent with an onset two months ago as reported by the patient(i.e., there is no

EDX evidence of reinnervation through collateral sprouting). Case 5

• 41yo LHD female – Fell onto outstretched left UE 1 month ago – Subjective • Numbness along the medial hand and forearm • Weakness of grip – Examination • Medial hand and medial forearm numbness • Hand weakness, including FDP-D4 • Extensor indicis weakness – Start with routine sensory NCS UPPER EXTREMITY NERVE CONDUCTION STUDY CASE 5 WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.1 30.3 Ulnar-D5 C8 NR S-Radial C6,7 2.3 21.5

Localization Ulnar nerve, medial cord, lower plexus, C8 DRG Pathophysiology Axon loss Severity At least mild-moderate (motor NCS are best for severity assessment) Temporal 1 month by history

When the Ulnar-D5 is abnormal, add the MABC If the MABC is normal, add the DUC Add the contralateral MABC UPPER EXTREMITY NERVE CONDUCTION STUDY CASE 5 WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.1 30.3 Ulnar-D5 C8 NR S-Radial C6,7 2.3 21.5 MABC T1 NR 2.4 12.4

Localization Medial cord, lower plexus, C8/T1 DRG Pathophysiology Axon loss Severity At least moderate (motor NCS are best for severity assessment) Temporal 1 month by history

What motor NCS? Ipsilateral: routine NCS, Ulnar-FDI, Radial-EI Contralateral: Ulnar-ADM, Ulnar-FDI, Radial-EI Case 5 – Sensory Responses

C5 Upper trunk

C6 C7 Lateral cord Middle trunk C8 Posterior T1 cord Lower trunk

Medial cord

CCF © 2002 UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET CASE 5 LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.1 30.3 Ulnar-D5 C8 NR 2.8 14.4 S-Radial C6,7 2.3 21.5 MABC T1 NR 2.4 12.4

Stim MOTOR Site Median-APB Wrist 3.6 4.6 3.5 13.7 Elbow 4.4 54 13.7 Ulnar-ADM Wrist 2.9 4.2 2.9 12.5 AE 4.1 52 12.4 Ulnar-FDI Wrist 3.9 5.1 3.7 9.2 AE 5.1 55 9.2 Radial-EI Forearm 1.7 1.3 1.8 4.3 Elbow 1.3 51 4.3

Localization Lower plexus Pathophysiology Axon loss Severity Severe Temporal 1 month by history (best determined by needle EMG) UPPER EXTREMITY NEEDLE EMG WORKSHEET Insertional activity Spontaneous Activity MUAP Analysis CASE 5 MUAP MUAP Normal IPSWs SCP Other None Fibs Fascs Other Recruitment Morphology LEFT APB X 2+ Mod neurogenic Normal FDI X 3+ Mod neurogenic Normal EI X 3+ Sev neurogenic Normal FPL X 3+ Mod neurogenic Normal Pron teres X X Normal Normal BC, LH X X Normal Normal TC, LH X 1+ Normal Normal

Low C psp X X -- -- High T psp X X -- --

RIGHT APB X X Normal Normal FDI X X Normal Normal EI X X Normal Normal

Localization Lower plexus Pathophysiology Axon loss Severity Severe Temporal c/w the 1 month history reported by the patient (no collateral sprouting) Case 6

• 26yo RHD female x LUE pain and numbness • Aching pain x 10 years – Medial aspect of the left arm and forearm • Numbness x several years – Intermittent, medial aspect of the left forearm and hand – Precipitated by supine • Left thenar eminence atrophy – Noticed by her friend • Weakness – D1 abduction, D1 flexion, D2 extension, finger abduction • Sensation – Diminished along the medial aspect of the forearm and hand • Routine sensory NCS

UPPER EXTREMITY NERVE CONDUCTION STUDY CASE 6 WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.1 51 Ulnar-D5 C8 2.7 16 S-Radial C6,7 2.2 59

The screening sensory NCS are normal The Ulnar-D5 response is suspicious Collect a contralateral Ulnar-D5 response UPPER EXTREMITY NERVE CONDUCTION STUDY CASE 6 WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.1 51 Ulnar-D5 C8 2.7 16 2.6 41.7 S-Radial C6,7 2.2 59

Add MABC (possibly bilaterally) If normal, add DUC UPPER EXTREMITY NERVE CONDUCTION STUDY CASE 6 WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.1 51.5 Ulnar-D5 C8 2.7 16.1 2.6 41.7 S-Radial C6,7 2.2 59.3 MABC T1 NR 2.5 15.8

Localization Medial cord or lower plexus Pathophysiology Axon loss Severity Absent for MABC; relatively abnormal for Ulnar-D5 (T1 > C8) Temporal Chronic by history (best determined by needle EMG)

What motor NCS? Ipsilateral: routine, Ulnar-FDI; Radial-EI (for localization) Contralateral: Ulnar-ADM, Ulnar-FDI, and Radial-EI NCS (for severity assessment) UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET CASE 6 LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.1 51.5 Ulnar-D5 C8 2.7 16.1 2.6 41.7 S-Radial C6,7 2.2 59.3 MABC T1 NR 2.5 15.8

MOTOR Stim Site Median-APB Wrist 3.6 2.2 3.5 12.4 Elbow 2.1 51 12.4 52 Ulnar-ADM Wrist 2.7 8.3 2.7 14.1 AE 8.1 53 14.0 56 Ulnar-FDI Wrist 4.2 7.9 4.1 15.3 AE 7.9 54 15.1 54 Radial-EI Forearm 1.6 2.1 1.7 4.6 Elbow 2.1 52 4.6 53

Localization Lower plexus Pathophysiology Axon loss Severity Severe (T1 > C8) Temporal Chronic by history (best determined by needle EMG) UPPER EXTREMITY NEEDLE EMG WORKSHEET Insertional activity Spontaneous Activity MUAP Analysis CASE 33 MUAP MUAP Normal IPSWs SCP Other None Fibs Fascs Other Recruitment Morphology LEFT APB X 3+ Severe neurogenic Severe CMAL FDI X 1+ Mild neurogenic Moderate CMAL EI X 1+ Mod neurogenic Moderate CMAL FPL X 2+ Mod neurogenic Moderate CMAL Pron teres X X Normal Normal BC, LH X X Normal Normal TC, LH X X Normal Mild CMAL

Low cerv psp X X -- -- High thor psp X X -- --

RIGHT APB X X Normal Normal FDI X X Normal Normal EI X X Normal Normal TC, LH X X Normal Normal

Localization Lower plexus Pathophysiology Axon loss Severity Severe (T1 > C8) Temporal Chronic (as reported by the patient) and progressive Ferrante MA, Tsao B. EMG Lesion Localization and Characterization, 2020 Case 7

• 71yo RHD male x suspected post-operative left ulnar neuropathy – Open heart surgery 26 days ago – Left grip weakness – Numbness along the medial aspect of the left hand

– Examination (not provided) • Check cutaneous distributions of ulnar and MABC nerves • Check strength of ulnar, FPL, and EI muscles UPPER EXTREMITY NERVE CONDUCTION STUDY CASE 7 WORKSHEET LEFT RIGHT NCS nAU PERFORMED LAT AMP CV C LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.0 14.7 Ulnar-D5 C8 NR Superficial radial C6,7 2.5 18.3

Add MABC (possibly bilaterally) If normal, add DUC (likely bilaterally UPPER EXTREMITY NERVE CONDUCTION STUDY CASE 7 WORKSHEET LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.0 14.7 Ulnar-D5 C8 NR Superficial radial C6,7 2.5 18.3 MABC T1 2.7 11.6 2.7 10.3 DUC C8 NR 2.9 7.3

Localization Ulnar nerve, medial cord, lower plexus Pathophysiology Axon loss Severity Moderate-severe (best determined by motor NCS) Temporal 26 days, per history provided by patient and referring physician

What motor NCS? Ipsilateral: Routine, Ulnar-FDI; Radial-EI (for localization) Contralateral: Ulnar-ADM, Ulnar-FDI, and +/- Radial NCS (for severity assessment) UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET CASE 7 LEFT RIGHT NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC SENSORY DRG Median-D2 C6,7 3.0 14.7 Ulnar-D5 C8 NR 8.1 8.1 Superficial radial C6,7 2.5 18.3 MABC T1 2.7 11.6 DUC C8 NR 2.9 7.3

MOTOR Stim Site Median-APB Wrist 3.7 7.3 3.6 9.1 Elbow 7.3 54 8.9 53 Ulnar-ADM Wrist 3.0 4.6 2.9 10.4 Elbow 4.5 55 10.1 58 Ulnar-FDI Wrist 3.9 4.1 3.9 8.6 Elbow 4.1 51 8.6 54 Radial-EI Forearm 2.3 1.1 2.2 3.4

Localization Lower plexus Pathophysiology Axon loss Severity Severe Temporal 26 days, as reported by the patient and the referring physician UPPER EXTREMITY NEEDLE EMG WORKSHEET Insertional activity Spontaneous Activity MUAP Analysis CASE 7 MUAP MUAP Normal IPSWs SCP Other None Fibs Fascs Other Recruitment Morphology LEFT APB X 2+ Mild neurogenic Normal FDI 2+ 3+ Mild neurogenic Normal EI 1+ 3+ Mod neurogenic Normal FPL X 2+ Mod neurogenic Normal Pron teres X X Normal Normal BC, LH X X Normal Normal TC, LH X 2+ Normal Normal

Low C psp X X -- -- High T psp X X -- --

RIGHT APB X X Normal Normal FDI X X Normal Normal EI X X Normal Normal TC X X Normal Normal

Localization Lower plexus Pathophysiology Axon loss Severity Severe Temporal c/w the 26 days reported by the patient and referring provider (no CMAL) Il Fine Questions