What Is the Clonus Reflex?

Medically Reviewed by Poonam Sachdev on November 01, 2021
Written by Aditi Sathe
3 min read

Clonus reflex is a set of rhythmic, involuntary muscle movements. It is a neurological condition that affects the nerve cells that control muscle movements. Damage to the nerves, as in clonus, causes involuntary muscle contractions or spasms. It leads to muscle tightness and pain.

Clonus causes large, noticeable movements that are very different from typical twitches. It is usually triggered by an automatic response to a stimulus. The reflex leads to uncontrollable shaky movements.

Clonus occurs most frequently in the muscles that control the ankles and knees. It occurs less commonly in the jaw, fingers, wrists, elbows, biceps, and calves.

Clonus reflex is linked with damaged nerve pathways. The damage usually affects nerves responsible for voluntary muscle movements in the legs, hands, or face. The causes of this damage are not well understood.

Clonus is typically seen in people with neurological conditions like:

All these conditions are chronic and require specialized treatment. Depending on the underlying cause, the clonus reflex could get worse over time if not treated properly.

If an acute injury or illness causes clonus, muscle spasms are likely to go away completely with the right therapy over time.

The initial test for clonus starts with a physical exam. The doctor checks the area where contractions happen and records the associated level of pain. If you have the clonus reflex while at the doctor's office, they will also measure the frequency of the contractions. Health care professionals who specialize in neurological disorders can also induce clonus by physically moving the affected body parts.

To confirm a clonus diagnosis, your doctor might order a specific series of tests. Magnetic resonance imaging (MRI) can help identify damage to the cells or nerves. Other examinations may include blood tests, spinal fluid samples, and balance and coordination tests. 

A single test is usually not sufficient to diagnose clonus. A series of tests is necessary to identify any related, undiagnosed conditions you might have and to treat them.

Medications like sedatives and muscle relaxers are the most common treatments for clonus. They are usually prescribed to ease symptoms when you are first diagnosed with clonus. The most frequently used medications for clonus include:

Some of these medications may cause side effects like sleepiness, dizziness, fatigue, or lightheadedness. Talk to your doctor about the benefits and risks associated with each type of medication. If the side effects are affecting your ability to do daily activities, you might need to switch medications or try a different treatment. 

Botox injections and physical therapy also help relieve clonus symptoms. These are long-term treatment strategies you need to do regularly. They are often used alongside medication. 

In some cases, splints for the wrists and ankles may be helpful.

Ask your doctor about taking magnesium supplements, which may be effective in relaxing the muscles.

As a last resort, surgery can eliminate abnormal muscle movement caused by clonus. Surgery typically involves cutting away‌ parts of the damaged nerve. It is usually recommended if all other clonus treatment plans fail to provide relief.

While home remedies cannot cure clonus, they may be helpful in managing the symptoms. Taking a warm bath or using a heating pad will help alleviate muscle pain. An ice pack will soothe any persistent muscle aches you may have because of clonus.

Your doctor or physiotherapist may also recommend stretching or yoga to help improve muscle tone and increase your range of motion.