Related Experiment Video
Updated: Jan 29, 2026
16:49
Multifocal Electroretinograms
Published on: December 4, 2011
18.9K
Multifocal Motor Neuropathy Presenting as Pseudodystonia.
Nidhi Garg1, Robert N S Heard2, Lynette Kiers3
1Brain and Mind Centre, Sydney Medical School The University of Sydney Sydney New South Wales Australia.
Movement Disorders Clinical Practice
|February 5, 2019
Summary
Multifocal motor neuropathy (MMN), an immune disorder, can cause severe cramping that mimics movement disorders. Intravenous immunoglobulin treatment effectively resolved these symptoms in four patients.
Area of Science:
- Neurology
- Neuroimmunology
- Peripheral Nervous System Disorders
Background:
- Multifocal motor neuropathy (MMN) is an immune-mediated condition typically presenting with progressive muscle wasting and weakness.
- Diagnosis often relies on identifying focal motor conduction block in neurophysiological studies.
Observation:
- Four MMN cases presented with prominent cramping, mimicking primary movement disorders.
- These patients exhibited symptoms suggestive of central nervous system pathology rather than peripheral nerve involvement.
Findings:
- All observed cases demonstrated focal motor conduction block on electrodiagnostic testing.
- Involuntary movements and cramping resolved completely after treatment with intravenous immunoglobulin (IVIg).
Implications:
- This study highlights an atypical MMN presentation, challenging the typical clinical picture.
- It suggests peripheral nerve disorders can manifest as movement disorders, potentially misdiagnosed as central nervous system conditions.
- The findings underscore the sensitivity of these movement disorder symptoms to standard MMN therapy, such as IVIg.
Related Concept Videos
00:46Motor Units
61.9K
A motor unit consists of two main components: a single efferent motor neuron (i.e., a neuron that carries impulses away from the central nervous system) and all of the muscle fibers it innervates. The motor neuron may innervate multiple muscle fibers, which are single cells, but only one motor neuron innervates a single muscle fiber.
61.9K
01:13Motor Units
8.1K
The motor unit is a fundamental component of the neuromuscular system and plays a crucial role in coordinating muscle contractions. It consists of a somatic motor neuron, which connects and controls multiple skeletal muscle fibers, forming a single functional segment. The axon of the motor neuron branches out and establishes synaptic connections known as neuromuscular junctions with individual muscle fibers within the motor unit.
Motor units come in different sizes, with smaller units...
Motor units come in different sizes, with smaller units...
8.1K
01:20Motor Unit Stimulation
3.8K
When the neuron of a motor unit fires an action potential, it triggers a series of events, leading to a twitch contraction in the muscle fibers. The process of excitation-contraction coupling is crucial in relaying the action potential to the muscle fibers.
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
3.8K
01:18Hierarchy of Motor Control
6.2K
The hierarchy of motor control refers to the different levels of organization and processing involved in controlling movement in the body. These levels range from higher cortical areas involved in planning and decision-making to lower spinal cord reflexes that respond automatically to external stimuli.
6.2K
01:11Direct Motor Pathways
4.5K
The direct motor pathways, also known as the pyramidal tracts, are a group of neural pathways that originate in the brain and descend through the spinal cord. They control the voluntary movement of the body. There are two major direct motor pathways: the corticospinal and the corticobulbar tracts.
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and...
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and...
4.5K
01:32Microtubule Associated Motor Proteins
10.6K
Eukaryotic cells have different motor proteins for transporting various cargo within the cell. These motor proteins differ based on the filament they associate with, the direction they move within the cell, and the type of cargo they transport. Motor proteins that associate with microtubules are known as microtubule-associated motor proteins. There are two families of microtubule-associated motor proteins —Kinesins and Dyneins. Both these proteins assist in the transport of cellular...
10.6K