Motor Unit Potential Analysis

Motor Unit Potential Basics

Generation

Measurements

Technique of Recording/Measurement

Manual

Amplitude Trigger and Delay Line

Multi Motor Unit Analysis/Decomposition

Assessment Strategies

Patterns of Abnormality

Assessment: Mean Values

Assessment: Individual MUP

MUP Amplitude

Normal

Increased

Reduced

Phases and Turns

Normal

Increased

MUP Duration

Normal

Increased

Reduced

MUP and SFEMG

Stable

Unstable

Interpretation of Stability

Monopolar Needle

Recording Territory

Motor Unit Changes in Neuropathy

Disease Processes	Two Normal Motor Units	Loss of Motor Unit
Few Weeks Later	Few Months Later	Few Years Later
New Weakness: MU Fractination	New Onset: Loss of Reinnervated MU

Severe Trauma to Nerve

Loss of Most Motor Units

Regeneration of Motor Units

Myopathy

Disease Processes	Normal Motor Unit	Short Simple MUP
Tall Thin MUP	Complex Long Duration MUP

Neuromuscular Junction Diseases

NMJ Disease

Examples of Normal MUPs

Multi MU Analysis	Simple	Serrations
Polyphasic	Stable: Filters 500 - 10,000 Hz

Examples from Patients with Neuropathy

Multi Motor Unit Analysis	Long Polyphasic	Unstable MUP
Giant, Fast Firing	"Jiggle" With Late Component	Neurogenic Jitter and Block
Low Amplitude Unstable MUP

Examples from Patients with Myopathy

Multi MUP Analysis	Short and Simple	Short Polyphasic
Long Polyphasic	Tall and Thin