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RNST (Repetative Nurve Stimulation Therapy)

Overview Understanding Clinical Use Key Features What to Expect Advantages Connect with us FAQs

Overview

Overview

Repetitive Nerve Stimulation Therapy (RNST) is an important diagnostic test used to evaluate neuromuscular transmission disorders such as myasthenia gravis, Lambert-Eaton syndrome, and congenital myasthenic syndrome. It helps identify abnormalities in the communication between nerves and muscles, which can cause muscle weakness.

At Heritage Hospitals, we understand that experiencing muscle weakness, fatigue, or exhaustion can be frightening. These symptoms may indicate an underlying neuromuscular condition requiring expert care.

Our Neuromedicine center provides comprehensive RNST test in Varanasi for accurate diagnosis and treatment of related disorders. Whether you have symptoms like drooping eyelids, double vision, difficulty swallowing, or muscle fatigability, our specialized team is here to help.

Understanding

RNST involves electrically stimulating a nerve repeatedly and recording the muscle response. The test assesses neuro-muscular transmission across the neuromuscular junction (NMJ).

During the test, a peripheral nerve is stimulated with a short electrical impulse. This nerve impulse travels to the muscle via the NMJ. In healthy individuals, the muscle response remains consistent. In disorders of neuromuscular transmission, the muscle response decreases with repeated nerve stimulations. The decrease in muscle response is quantified and indicates dysfunctional neuromuscular transmission.

RNST test is an extension of a single stimulation test, which only delivers one shock to the nerve and looks at one resulting compound muscle action potential (CMAP). RNST in Varanasi provides more diagnostic information by assessing multiple responses over time. The rate of CMAP decline can help determine the severity of the neuromuscular junction disorder.

Clinical Applications of RNST (Repetative Nurve Stimulation Therapy)

Clinical Applications of RNST (Repetative Nurve Stimulation Therapy)

The RNST test in Varanasi is used to diagnose various symptoms, including:

  • Insufficiency & Fatigability

  • Ptosis (Drooping of eyelids)

  • Diplopia (Double vision)

  • Dysphagia (Difficulty in swallowing)

  • Dysarthria (Slurred speech)

Some other common clinical applications of RNST include:

  • Myasthenia Gravis: RNST can confirm a diagnosis of myasthenia gravis and assess its severity. In MG, the CMAP amplitude declines significantly with repeated stimulation. The rate of decline correlates with disease severity.

  • Lambert-Eaton Syndrome: RNST shows an initial increased response followed by a declining response pattern in Lambert-Eaton syndrome. This reflects impaired presynaptic neurotransmitter release.

  • Congenital Myasthenic Syndromes: RNST may show similar decrementing response patterns as myasthenia gravis due to defects at the neuromuscular junction.

  • Motor Neuron Disease: RNST may be used to differentiate upper motor neuron disorders like Amyotrophic lateral sclerosis (ALS) from neuromuscular transmission defects.

RNST is also sometimes used to evaluate nerve injuries and peripheral neuropathies like Guillain-Barre syndrome and prior to starting anticholinesterase medications.

Key Features

Key Features

Some key features of the RNST test in Varanasi are:

  • Non-invasive Test: No injections or incisions involved. External electrodes are used to stimulate nerves and record muscle activity.

  • Quantifies Muscle Response: The amplitude and area of the evoked muscle response are precisely measured with each stimulation.

  • Assesses Fatiguability: Repeated stimulation assesses decremental response and fatigue of the NMJ.

  • Tests Various Nerves and Muscles: Different peripheral nerves and their corresponding muscles can be tested based on clinical presentation.

What to Expect with Diagnostic

What to Expect with Diagnostic

Procedure

Patients scheduled at the best RNST hospital in Varanasi, like Heritage Hospital, are guided through a simple preparation process:

  • Patients may be asked to avoid certain medications that could affect the test results.

  • Wear comfortable clothing with easy access to testing sites. Avoid restrictive and thick garments.

  • The skin where electrodes will be placed is cleaned to ensure optimal conductivity.

  • Make sure you are well-rested and fed before the test. Avoid stimulants like caffeine.  

RNST test in Varanasi involves delivering a series of brief electrical stimuli to a nerve while recording the muscle response. The nerve is stimulated repeatedly to see if the muscle response decreases with successive stimuli, which would indicate a neuromuscular transmission defect.

  • During the test, surface electrodes are placed on the skin over a muscle, usually one close to the point where a motor nerve enters the muscle.

  • A separate electrode is placed over the nerve that controls the muscle.

  • A stimuli generator delivers repeated electrical pulses to the nerve at a rate of 2-5 pulses per second for 30-60 seconds. This causes the nerve to depolarize and send stimuli to the muscle, resulting in muscle contraction.

  • The muscle response is measured via the electrode on the skin above the muscle, which detects the compound muscle action potential (CMAP). This measures the sum of the action potentials from all the muscle fibers activated by the nerve stimulus.

Post Procedure

Results are interpreted by a specially trained doctor, usually a neurologist. Results are typically available within a few days after testing. The doctor reviews the CMAP amplitudes and patterns to determine if they are consistent with a neuromuscular junction disorder. If the RNST test result is abnormal, further evaluation and treatment would be recommended. The EMG specialist analyzes the following:

  • Baseline muscle response to the first stimulation

  • The trend of muscle response over 10-20 repeated stimulations

  • Rate of decline of muscle activity

A normal study shows consistent muscle contraction with each stimulation. No significant decline is seen by the 10th stimulation, usually less than 10%.

Abnormal studies demonstrate a decremental response with >10% decline in muscle activity by the 10th stimulation. The rate of decline quantifies disease severity in neuromuscular conditions.

Advantages of RNST (Repetative Nurve Stimulation Therapy)

Precise Quantification

The RNST test precisely quantifies the degree of decrement of neuromuscular activity, which helps diagnose and grade the severity of conditions like Myasthenia Gravis and Lambert-Eaton syndrome.

High Sensitivity

Studies have proven that the RNST test has very high sensitivity in picking up dysfunctional neuromuscular transmission in patients with Myasthenia Gravis.

Disease Correlation

The RNST results correlate well with the clinical severity of muscle weakness and fatigability in most neuromuscular conditions, especially Myasthenia Gravis. Patients with severe weakness clinically tend to have a greater decremental response to RNST.

Treatment Monitoring

As the decrement noted on RNST corresponds with clinical status, the test is useful for monitoring a patient's response to immunotherapies over months to years.

Non-Invasive Procedure

The entire RNST test procedure is conducted externally using surface electrodes for stimulation and recording. There is no significant discomfort involved, making it an ideal outpatient department test.

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FAQ’s

RNST Test is used to treat myasthenia gravis and other similar illnesses.

In this procedure, Mild electrical stimulation repeatedly stimulates nerves.

RNST cost in Varanasi at Heritage Hospitals is Rs. 3000. This cost also includes material and pathology.

Yes, paying the RNST cost in Varanasi at Heritage Hospitals after admission is essential before the procedure. Some discounts may be considered in particular situations after approval from the administration. The payment should be made in one go.

RNST Test takes 30-45 minutes.

Technicians perform an RNST test in Varanasi at Heritage Hospitals.

This treatment is typical for our Technicians, who have more than ten years of expertise with them.

No, RNST Test does not require prior written consent.

There is no consent form to ask who can sign the consent form for RNST Test.

In the hands of a qualified, well-trained practitioner, nerve conduction and electromyography investigations are often well tolerated and represent a small risk of significant side events to patients.

Shampoo should be used to clean the skin thoroughly, and head oil should not be used.

After the process, shampoo should be used to wash the RNST paste out of the skin.

No, RNST Test needs no hospitalisation.

In most cases, no anaesthetic is required, but sedative medications may need to be administered in some cases—such as those involving children or combative patients.

It takes 1-2 hours for the RNST Test report to come.

No risks and complications are possible in RNST Tests

Your surgeon has two options for nerve repair: either remove the injured portion and reconnect healthy nerve ends or implant a stretch of the nerve from another area of your body. (nerve graft).

It is done for free within a set time frame if the results are unsatisfactory and the referring doctor considers it has to be repeated.

The RNST payments will be reimbursed if the procedure is unsuccessful or not performed for various reasons.