Lower Motor Neurons Disease

Upper Motor Neuron Tracts

Upper Motor Neuron Tracts

Which part of the Motor System delivers signals to spinal interneurons and LMNs?

Lower Motor Neurons

Which part of the Motor system delivers signals directly to the skeletal muscles and elicits contraction of muscle fibers?

Top down ( Brain to Muscle)

Voluntary movements are controlled from _____ to _____ .

Axial and Proximal muscles

The Medial aspect of the anterior horn controls …

Distal Muscles

The Lateral aspect of the anterior horn controls…

Extensor Muscles

The Anterior aspect of the anterior horn controls…

Flexor Muscles

The Posterior aspect of the anterior horn controls…

ALS (amyotrophic lateral sclerosis)

Which disorder affects the upper motor neurons that arises from the cortex and brainstem as well as cranial/spinal lower motor neurons?

Lower Motor Neuron Disease

The following clinical findings are consistent with

• weakness

• flaccid paralysis of involved muscles

• muscle atrophy

• degeneration of muscle fibers over time

• histological-reaction (degeneration 10-14 days of injury)

• reflexes of the involved muscles are diminished/absent

• No abnormal reflexes are obtainable

It is when the distal portion of the nerve and the mylin following a lesion is reabsorbed.

What is Wallerian Degeneration?

The time it takes to build enough ACH to send an AP

What is distal latency on an EMG?

Onset Latency and Peak Latency

What are the 2 ways that latency is measured (Sensory Nerve AP)?

The time measured from the stimulus to the initial deflection from baseline

What is Onset Latency?

The time measured from the stimulus to the peak of the spike

What is Peak Latency?

It will appear normal b/c you are still testing the healthy portion of the axon ( normal DL and CV)

If the conduction block is proximal to both simulation sites what do you expect to see in the CMAPs?

Barely any signal will go through due to the “break” in the pathway so DL will be increased and CMAP amplitude will decrease

If the conduction block is distal to both simulation sites what do you expect to see in the CMAPs?

The DL and distal CMAP will be normal but the proximal CMAP will show decreased amplitude

If the conduction block is between both simulation sites what do you expect to see in the CAMPs?

Slows down the time as well as possibly no recovery

Once the protective layer of the nerve (endoneurium and perineurium) is damaged how does it affect the level of recovery?

Decreased amplitude of both distal and proximal CMAP

When it comes to pure Axonal Loss, what would we see in the EMG?

Increased distal latency and slow conduction velocity

When it comes to pure Demyelination, what would we see in the EMG?

If the nerve is viable or not

What is one guiding factor we can determine looking at an EMG?

Stretch Injury, Lacerations, Compression and Repetitive stress injury

What are some of the major causes of (local)Peripheral Neuropathies?

Cancers, Infections, Inherited Neuropathies (Guillain-Barre), Diabetes (2), Kidney disorders (high levels of ammonia), Autoimmune diseases, Vascular disease, Vitamin Deficiencies and Alcoholism

What are some of the major causes of (systemic )Peripheral Neuropathies?

UMN injury

If you see signs of hyper-reflexive that usually correlates to UMN or LMN injury

LMN injury

If you see signs of hypo-reflexive that usually correlates to UMN or LMN injury