Interference Pattern

Interference Pattern

Volume II - Part IV

Objectives
Tutorial
Workshop


Interference Pattern Generation


Force Generation

First Recruited Motor Unit

Frequency Modulation

Recruitment of Motor Unit

Interference Pattern Signal

Factors Affecting IP

Models of Disease Processes


Normal Muscle

Neuropathy

Upper Motor Neuron Disease

Myopathy

Assessment Strategies


Methods of Analysis

Our Opinion

Recruitment Frequency


Definition

Example

Recruitment Ratio


Definition

Example

Visual Assessment at Maximal Effort


Definition

Example

The Sound of EMG

Simple Rules

Quantitative Analysis: Turns and Amplitude (TA)


Definition

Minimal Effort

Mild Effort

Moderate Effort

Maximal Effort

Analysis with Normal Cloud

Myopathy

Neuropathy

Comments

Quantitative Analysis: Precision Decomposition


EMG with Increased and Decreased Force

Motor Unit Recruitment and Firing Pattern

IP in Normal Muscle (Biceps)


Recruitment Frequency

Recruitment Ratio

Full IP (Fast Sweep)

Min - Max Effort, 2 Trials

Neuropathy


Typical Findings

Increased Recruitment Frequency
(20+ Hz)

Increased Recruitment Ratio
(More than 5)

Reduced IP (Slow/Fast Sweep)

Reduced IP (5 Consecutive Sweeps)

Reduced IP, High Amplitude

Discrete IP (Slow/Fast Sweep)

Discrete IP (Single MUP)

Weak Muscle: Reduced IP
Normal/Low Amplitude

Irregular MU Firing: UMND

Myopathy


Typical Findings

Normal/Reduced Recruitment Ratio

Early Recruitment (Low Amplitude)

Increased Recruitment Frequency (?)

Full IP, Reduced Amplitude

Full IP, Reduced Amplitude

Low Amplitude at Low Force

Bimodal Amplitude at Higher Force

Bimodal Amplitude, Slow Sweep

Pratical Aspects


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