Related Experiment Video
Updated: Jun 10, 2026
05:54
MRI-guided Focused Ultrasound Thalamotomy for Patients with Medically-refractory Essential Tremor
Published on: December 13, 2017
TENS is harmful in primary writing tremor
S Meunier1, J P Bleton, D Mazevet
1CRICM, INSERM UMR_S 975, CNRS UMR 7225, Paris F-75013, France.
Summary
Transcutaneous electrical nerve stimulation (TENS) did not improve primary writing tremor (PWT). In fact, 50 Hz TENS worsened PWT symptoms and cortical excitability, suggesting PWT and writer's cramp are distinct conditions.
Area of Science:
- Neurology
- Movement Disorders
- Neurophysiology
Background:
- Primary writing tremor (PWT) is a condition affecting handwriting, with its exact nature (dystonia vs. tremor) debated.
- Previous studies suggested Transcutaneous Electrical Nerve Stimulation (TENS) may benefit writer's cramp (WC).
Purpose of the Study:
- To investigate if TENS, specifically at 50 Hz, could improve symptoms in patients with PWT.
- To determine if PWT shares therapeutic responses with WC regarding TENS.
Main Methods:
- A randomized, double-blind, cross-over study involving nine PWT patients.
- Patients received 2-week periods of 5, 25, or 50 Hz TENS applied to wrist flexor muscles.
- Transcranial magnetic stimulation (TMS) assessed motor cortex excitability before and after TENS.
Main Results:
- TENS at 5 Hz and 25 Hz showed no effect on PWT symptoms or cortical excitability.
- TENS at 50 Hz significantly worsened both clinical symptoms and motor cortex excitability in PWT patients.
- These findings contrast with reported benefits of TENS in writer's cramp.
Conclusions:
- Transcutaneous Electrical Nerve Stimulation (TENS) is not an effective treatment for primary writing tremor (PWT).
- The differing responses to TENS in PWT and writer's cramp suggest they are distinct neurological conditions.
Related Concept Videos
01:11Alterations 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...
01:29Tetanus
Tetanus is a life-threatening neurological disorder characterized by persistent muscle contractions and spastic paralysis. It is caused by Clostridium tetani, a motile, Gram-positive, rod-shaped, obligate anaerobe. These bacteria produce terminal endospores, giving them a distinctive “lollipop” or “tennis-racket” appearance. They thrive in anaerobic environments, such as those found in deep puncture wounds.Once introduced into the body, the spores germinate into vegetative cells. These cells...
01:12Alterations 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...
01:21Skeletal Muscle Relaxants: Adverse Effects
Skeletal muscle relaxants are widely used for muscle paralysis and relieving pain following any muscle injury or stiffness. However, depending on the drug type, they can have adverse effects that range from mild to severe. Usually, nondepolarizing neuromuscular blockers have minimal side effects. For example, drugs like d-tubocurarine, cisatracurium, and rocuronium cause hypotension, whereas drugs like baclofen, when stopped abruptly, can lead to the recurrence of spastic conditions.
Unlike...
Unlike...
01:22Muscle Stimulation Frequency
The contraction strength of muscles is regulated by motor neurons, which modulate the frequency of action potentials dispatched to the motor units based on the body's requirements. This process of varying the muscle stimulation frequency allows muscles to contract with a force that is precisely tailored to the needs of the moment, whether lifting a feather or a heavy box.
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
01:24Centrally 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,...
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,...