What Is Dysmetria?

Dysmetria is when someone is moving an arm or leg to a target and aims incorrectly, such as by overreaching. It is a sign of certain neurological problems or vision problems and can be detected during a physical examination.

Usually, dysmetria is picked up on a neurological examination done by a healthcare provider. But sometimes, a person may notice dysmetria symptoms as they are going about activities of daily life.

This article will discuss dysmetria, including its symptoms, what part of the brain affects dysmetria, its underlying causes, how dysmetria is assessed, its diagnosis, and its treatment.

Dysmetria Symptoms

Sometimes dysmetria doesn’t cause obvious symptoms, and it is only noticed in a physical examination. But dysmetria may also cause noticeable day-to-day problems, such as overreaching, underreaching, or reaching to the left or the right of your aim.

This can happen when you are trying to pick something up or use an object. In rare situations, the effects of having dysmetria may lead to physical harm, such as poking your eye when you intend to scratch your face.

A key feature of dysmetria is that a person knows where they intend to reach or place an object but cannot measure the distance the way they want to.

Symptoms and difficulties that can occur due to dysmetria are:

• Problems walking
• Dropping objects
• Impaired fine motor coordination, such as writing or drawing
• Inability to properly use eating utensils or a toothbrush 
• Trouble tying shoes
• Inability to put objects in their exact place

These issues can be very concerning if they occur repeatedly. Sometimes people with dysmetria are aware of the problem. But if it occurs along with serious conditions, such as a large stroke, a person might not notice. In that situation, caregivers could be the first to notice the symptoms of dysmetria.

Dysmetria may occur along with other neurological symptoms.

Symptoms that may occur along with dysmetria include:

• Ataxia (a type of balance problem)
• Tremors (involuntary rhythmic muscle contraction that causes shaking)
• Double vision or blurred vision
• Impaired balance
• Coordination problems
• Motor (movement) weakness
• Speech difficulties
• Visual or spatial neglect
• Confusion

These other symptoms may occur if the cause of dysmetria involves extensive brain damage, such as a stroke (blocked blood flow or bleeding in the brain) or a brain tumor.

Causes

Accuracy in movement requires brain and vision functions to work together, along with appropriate strength, tone, and coordination of motor movements. Dysmetria can occur when there is difficulty with assessing distances or moving correctly due to an impairment of any of these functions.

Several different types of brain damage or visual problems can lead to dysmetria. A disease affecting the cerebellum is especially likely to cause dysmetria, but damage to the cerebral cortex or brain stem can lead to dysmetria too.

Impaired vision may lead to dysmetria as well. Less often, issues such as hearing problems or confusion may cause dysmetria.

Conditions that can lead to dysmetria include:

• Stroke (blood supply to the brain is blocked or a blood vessel bursts in the brain)
• Brain tumor
• Multiple sclerosis: An autoimmune condition that attacks the protective sheaths of nerves and produces lesions in the cerebellum and cerebrum
• Brain malformations: Such as Chiari malformation or Dandy-Walker syndrome
• Spinocerebellar ataxia: A hereditary disease
• Cerebellar degeneration: Can be genetic, hereditary, or part of a neurodegenerative condition
• Immune disorders, such as lupus
• Meningitis: Infection or inflammation of the tissue surrounding the brain
• Encephalitis: Infection or inflammation of the brain tissue
• Paraneoplastic syndromes: In which cancer produces antibodies that attack the cerebellum
  
• Glaucoma: High pressure in the eye damages the optic nerve 
• Macular degeneration: Degeneration of the part of the light-sensitive retina in the eye responsible for sharp central vision
• Head trauma or trauma to the eye 
• Increased intracranial pressure: Excess fluid in the brain or pressure from something inside the brain

Diagnosis

Dysmetria is typically detected during a physical examination. It is rarely the only complaint a person has, but it may be the only noticeable problem if it’s caused by a very small stroke, multiple sclerosis, or a small brain tumor. 

The first step in assessing dysmetria is a detailed physical exam, including a thorough neurological examination. During the physical examination, you will be asked to move your finger from your nose or chin to the examiner’s hand. A person with dysmetria might not accurately touch the examiner’s finger and could reach too close or too far.

You may also be asked to place your heel on your opposite knee and to move your heel down to your ankle in one motion. If you have dysmetria, you might be unable to place your heel where you aim to put it. 

Visual testing is necessary during an evaluation of dysmetria to evaluate visual acuity (how well a person can see) and visual fields (whether a person can see to the right, left, up, and down).

A visual examination will also determine whether there are any unusual eye movements, limitations in eye movements, or double vision. Nystagmus (jerking movements of the eyes) is a common sign of cerebellar disease.

Diagnostic Tests

Additional studies, such as imaging studies, may be necessary to identify whether an abnormality can be visualized in the brain. Usually, a diagnosis of dysmetria will involve brain magnetic resonance imaging (MRI), which uses strong magnetic fields and radio waves to produce detailed images.

Sometimes laboratory tests are ordered to help identify the cause of dysmetria. Blood tests may identify inflammatory cells associated with immune disorders. In some instances, antibodies associated with paraneoplastic syndrome can be the first sign of cancer.

A lumbar puncture (spinal tap) may be performed to help support a diagnosis of multiple sclerosis, meningitis, or encephalitis. During this procedure, a needle is used to draw a small amount of cerebrospinal fluid from around the spinal cord in the lower back. It is analyzed in the laboratory.

Treatment

Dysmetria is a physical sign of neurological disease—it isn't a disease. It's important to get treatment for the cause of dysmetria. Additionally, physical therapy can help overcome dysmetria or adapt to the limitations caused by dysmetria.

Usually, treating the underlying cause can prevent further neurological damage, but it doesn't always correct dysmetria.

For example:

• Treatment for multiple sclerosis with medication may resolve dysmetria.
• Surgery to remove a brain tumor or for cancer-causing paraneoplastic syndrome might help dysmetria fully or partially resolve. 
• Antibiotics can fully treat bacterial meningitis.
• Immune suppression can alleviate inflammatory causes of dysmetria, but the condition may flare up again.

Physical and occupational therapy can benefit almost anyone with dysmetria because therapy may help a person learn how to move more accurately. And it's especially necessary when dysmetria is caused by permanent damage due to a degenerative condition, stroke, head trauma, or eye disease.

Prognosis

Dysmetria outcomes can vary. In some situations, dysmetria can improve if the cause is a reversible or treatable illness, like multiple sclerosis or a brain tumor.

However, in some situations, such as a stroke, dysmetria will not improve. But rehabilitation techniques may help a person adjust and learn how to move in a more controlled way. 

Coping

Living with dysmetria can be very stressful. If you have this problem, it’s crucial that you make accommodations to avoid injuries. This is not something that you should take on completely on your own.

It’s important to seek guidance from an occupational therapist. They will be able to work through the day-to-day problems that can occur due to dysmetria. They can help you learn how to move around safely. Your healthcare provider can refer you to an occupational therapist.

Summary 

Dysmetria is a symptom of several different neurological and visual disorders. Some aspects of dysmetria are noticeable, but a medical evaluation is necessary to diagnose dysmetria. It is often detected during a neurological examination.

A stroke is the most common cause of dysmetria. It is important to get treatment for the underlying cause to prevent worsening dysmetria and to help the condition resolve, if possible.

Strategies such as physical therapy and occupational therapy are vital to improve movement and help with safety during day-to-day activities.