Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Alterations in Muscle Tone ll

Alterations in Muscle Tone ll

Alterations in muscle tone are common manifestations of neurological disorders and reflect dysfunction within different nervous system regions. Spasticity, paratonia, and dystonia represent distinct forms of hypertonia, each with unique mechanisms, clinical features, and diagnostic importance.CharacteristicsSpasticity happens from upper motor neuron lesions and is characterized by velocity-dependent resistance to passive movement. Clinical features include:Exaggerated deep tendon reflexesClonus...

Alterations in Muscle Tone lll

Alterations in Muscle Tone lll

Rigidity and myotonia are distinct abnormalities of muscle tone that affect resistance and relaxation during movement. Although both involve altered muscle contraction, they arise from different neurological and muscular mechanisms.CharacteristicsRigidity is characterized by uniform resistance to passive movement across the entire range, independent of speed, affecting flexors and extensors equally. It may appear as lead-pipe rigidity (smooth, constant resistance) or cogwheel rigidity...

Spasmolytic Agents: Chemical Classification

Spasmolytic Agents: Chemical Classification

Spasmolytic agents are drugs used to alleviate muscle spasms and spasticity. They can be categorized into different chemical groups based on their mechanisms of action. Centrally acting spasmolytics primarily affect the spinal cord, while others directly target skeletal muscle cells.
A major class of centrally acting spasmolytics is the α2-agonist, such as tizanidine. These drugs bind to α2-adrenoceptors, inhibiting the release of the excitatory neurotransmitter glutamate. They also promote...

Classification of Skeletal Muscle Relaxants

Classification of Skeletal Muscle Relaxants

Skeletal muscle relaxants are a group of drugs that can reduce muscle stiffness and induce temporary paralysis to relieve pain. These agents can act centrally to reduce muscle tone or spasms in painful conditions such as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), or spinal injuries; they are called antispasmodics or spasmolytics.
Peripherally acting skeletal muscle relaxants interfere with the neurotransmission at the neuromuscular end plate to induce paralysis during...

Somatic Spinal Reflexes

Somatic Spinal Reflexes

Somatic spinal reflexes are rapid, involuntary muscular responses to external stimuli that involve the somatic musculature and the spinal cord.
One of the most well-known somatic spinal reflexes is the stretch reflex, which is activated by the sudden stretching of a muscle. This reflex involves the activation of specialized sensory receptors called muscle spindles, which are located in the muscle tissue and detect changes in the length and speed of muscle contractions. When a muscle is suddenly...

Centrally Acting Muscle Relaxants: Therapeutic Uses

Centrally Acting Muscle Relaxants: Therapeutic Uses

Centrally acting muscle relaxants reduce muscle tone and tension by interfering with the postsynaptic reflexes in the central nervous system.
Centrally acting drugs are classified into spasmolytic and antispasmodic drugs. Spasmolytic drugs such as baclofen, diazepam, and tizanidine inhibit spinal motor neurons and decrease muscle tone. Spasmolytic drugs are administered for severe and chronic spasms due to multiple sclerosis, cerebral palsy, stroke, and spinal cord and muscle injuries. However,...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Relationship Between Spinal Reflexes and Spastic Movement Disorders.

Physical medicine and rehabilitation clinics of North America·2026

Same author

Effect of corticospinal and reticulospinal tract damage on spastic muscle tone and mobility: a retrospective observational MRI study.

EBioMedicine·2025

Same author

Low multiscale entropy of ankle joint position during toe gait in children with cerebral palsy is related to contracture development.

Clinical biomechanics (Bristol, Avon)·2025

Same author

Generation and modification of human locomotor EMG activity when walking faster and carrying additional weight.

Experimental physiology·2025

Same author

Neural coordination of bilateral hand movements: evidence for an involvement of brainstem motor centres.

The Journal of physiology·2024

Same author

How does the brain deal with proprioception during stepping?

The Journal of physiology·2022

Search research articles

Related Experiment Video

Updated: May 17, 2026

Isokinetic Robotic Device to Improve Test-Retest and Inter-Rater Reliability for Stretch Reflex Measurements in Stroke Patients with Spasticity

Isokinetic Robotic Device to Improve Test-Retest and Inter-Rater Reliability for Stretch Reflex Measurements in Stroke Patients with Spasticity

Published on: June 12, 2019

Spasticity.

Volker Dietz¹, Thomas Sinkjaer

¹Balgrist University Hospital, Zurich, Switzerland. vdietz@paralab.ballgrist.ch

Handbook of Clinical Neurology

|October 27, 2012

Summary

Antispastic medications reduce reflex activity but do not improve movement disorders in spinal cord injury (SCI). These drugs can worsen weakness and should be used cautiously in mobile patients.

Area of Science:

Neurology
Rehabilitation Medicine
Movement Science

Background:

Spasticity, characterized by exaggerated reflexes and muscle hypertonia, is a common consequence of spinal cord injury (SCI).
Current antispastic treatments primarily target the reduction of reflex activity.
A discrepancy exists between clinical spasticity measures and functional movement disorders.

Purpose of the Study:

To examine the impact of spasticity on mobility.
To inform treatment strategies for spasticity, considering its effect on movement.
To differentiate between passive and active states in reflex function.

Main Methods:

Review of clinical observations and scientific literature on spasticity and movement disorders post-SCI.
Analysis of the role of reflexes (short- and long-latency) in central motor lesions.

More Related Videos

Methods to Quantify Pharmacologically Induced Alterations in Motor Function in Human Incomplete SCI

Methods to Quantify Pharmacologically Induced Alterations in Motor Function in Human Incomplete SCI

Published on: April 18, 2011

Related Experiment Videos

Last Updated: May 17, 2026

Isokinetic Robotic Device to Improve Test-Retest and Inter-Rater Reliability for Stretch Reflex Measurements in Stroke Patients with Spasticity

Isokinetic Robotic Device to Improve Test-Retest and Inter-Rater Reliability for Stretch Reflex Measurements in Stroke Patients with Spasticity

Published on: June 12, 2019

Methods to Quantify Pharmacologically Induced Alterations in Motor Function in Human Incomplete SCI

Methods to Quantify Pharmacologically Induced Alterations in Motor Function in Human Incomplete SCI

Published on: April 18, 2011

Investigation of secondary changes in muscle and connective tissue contributing to spastic tone.

Main Results:

Antispastic medications do not improve, and may worsen, functional movement disorders by increasing weakness.
Central motor lesions lead to loss of supraspinal drive and altered reflex behavior, causing paresis.
Spastic muscle tone, resulting from secondary tissue changes, can partially compensate for paresis, enabling basic functional movements.

Conclusions:

Antispastic medications are best suited for individuals with complete SCI.
In mobile patients with SCI, antispastic drugs should be administered with caution due to the risk of accentuating paresis.
Treatment of spasticity requires a nuanced approach that considers its impact on functional mobility.