Functional neurological disorder

It’s often helpful to think of your brain as a computer. In someone who has FND, there’s no damage to the hardware, or structure, of the brain. It’s the software, or program running on the computer, that isn’t working properly.

The problems that cause FND are going on in a level of the brain that you cannot control. It includes symptoms like arm and leg weakness and seizures. Other symptoms like fatigue or pain are not directly caused by FND, but are often found alongside it.


The problems that cause FND are going on in a level of the brain that you cannot control. It includes symptoms like arm and leg weakness and seizures. Other symptoms like fatigue or pain are not directly caused by FND, but are often found alongside it.

Symptoms

FND can have many symptoms that can vary from person to person. Some people may have few symptoms, and some people may have many.

A diagnosis of FND should be made because you have one or more clinical features that a specialist can recognise as typical of FND. It shouldn’t be made just because scans or tests for other neurological conditions that have similar symptoms are normal.

What is a clinical feature? A clinical feature is a distinctive way that your symptom presents that is unique to FND. For example, it could be that your eyes close during seizures, or that limb weakness briefly disappears during certain physical tests. Clinical features are what specialists use to identify FND from other neurological conditions with similar symptoms.

Functional limb weakness Functional limb weakness is when a leg or an arm doesn’t work properly. In FND, this happens because of a problem with how the nervous system is functioning. It can cause a range of symptoms, including: problems walking heaviness down one side dropping things feeling like a limb isn’t part of you Functional limb weakness can often look a symptoms of a stroke or multiple sclerosis. If you have FND, any scans you have will show no damage to the brain to explain the weakness. A specialist will diagnose functional limb weakness based on specific clinical features (symptoms) they find when they examine you. Read more about functional limb weakness

Functional seizures A functional seizure (also called a dissociative seizure) is an episode where someone loses either their awareness of, or their ability to interact with, their surroundings. It may look like an epileptic seizure or a faint. A functional seizure can appear as: uncontrolled shaking suddenly going motionless and unresponsive staring without responding to surroundings Some people are aware that seizures are about to happen, while others experience them without warning. A specialist will ask you and your friends or family about what happens during a seizure, and will look at any video footage you can provide. They’ll use this evidence to decide if it’s epilepsy, a faint or a functional seizure. Read more about functional seizures

Functional tremor Tremor is uncontrollable shaking of part of the body. It’s most often found in the arms and legs. Functional tremor can come and go throughout the day, and change in speed and strength. A specialist will diagnose functional tremor based on specific features of your symptoms that they find when they examine you. Read more about functional tremor

Functional dystonia Functional dystonia is a type of muscle spasm. It causes a part of the body to become stuck in an unusual position. This can be for a short or a long period of time. Someone with functional dystonia will often present with curled fingers, a clenched hand, or an ankle that turns in. Read more about functional dystonia

Functional gait disorder Functional gait disorder describes the problems walking that you may experience as part of FND. You may find you have a dragging leg, that you feel unsteady when walking, or that you make excessive movements when walking. A specialist will diagnose functional gait disorder based on clinical features, like the way your walking changes when doing different activities. Read more about functional gait disorder

Functional facial spasm Functional facial spasm is when there are muscle spasms in the face. These can lead to problems like a narrowing of the eye or the pulling of the mouth or jaw upwards, downwards or to the side. Read more about functional facial spasm

Functional tics A tic is a fast repetitive movement or sound that happens suddenly. Functional tics can be a symptom of FND. Functional tics can look similar to the tics in Tourette’s syndrome. A specialist will look at the clinical features of your tics to make a diagnosis. It’s quite common to have both functional tics and Tourette’s syndrome.

Functional jerks and twitches A symptom of FND can be jerks or twitches, which is when someone makes sudden movements. Everyone experiences random jerks occasionally, like when you jolt awake as you’re falling asleep. In FND, however, these uncontrolled jerks and twitches can become much more frequent. Read more about functional jerks and twitches

Functional drop attacks Functional drop attacks are when someone falls to the ground suddenly, without losing consciousness. Read more about functional drop attacks

Functional sensory symptoms A symptom of FND can be numbness, pins and needles, or a feeling that a limb isn’t part of your body. Read more about functional sensory symptoms

Functional cognitive symptoms Problems with your memory or concentration can be a symptom of FND. You might find that you: lose track while doing things, for example being unable to remember why you went into a room go blank, for example when trying to recall your pin number lose track during conversations misplace important things, like your keys or phone forget words It’s normal to experience these things occasionally. For someone with functional cognitive symptoms, these things happen so often that they interfere with work and home life. The cognitive symptoms of FND can sometimes be mistaken for dementia. Specialists will look for features that are typical of functional cognitive symptoms when diagnosing FND. Read more about functional cognitive symptoms

Functional speech and swallowing difficulties Functional speech and swallowing difficulties can be a symptom of FND. You might experience: slurred speech a new stutter difficulties finding the right word unintentionally mixing words up whispering or hoarse speech (dysphonia) difficulty swallowing, including feeling like there’s something stuck in your throat A specialist will diagnose functional speech and swallowing difficulties based on specific features. Read more about functional speech and swallowing difficulties

Persistent postural perceptual dizziness (PPPD) PPPD (sometimes called functional dizziness, triple PD or 3PD) can be a symptom of FND. The dizziness in PPPD is typically experienced constantly, and gets worse while walking or in crowded environments. There are many causes of dizziness. Most people with PPPD have another cause of dizziness at the same time. A specialist will diagnose PPPD based on specific features when they assess you. Read more about PPPD

Functional visual symptoms Visual symptoms can be a part of FND. You may experience changes to your vision, like: blurred vision double vision photophobia (sensitivity to light) reduced vision A specialist will diagnose functional visual symptoms based on specific features that they find when they examine you. Read more about functional visual symptoms

Dissociative symptoms Dissociative symptoms are common in FND, although there are many other causes. These symptoms can be hard to describe, but are often described as feeling: that your body is disconnected from you that your body doesn’t belong to you disconnected from the world around you spaced out that you are floating that you are having an out-of-body experience there but not there You may also be able to hear what’s going on around you, but not be able to respond. These experiences are called dissociation, and can link into other FND symptoms. Read more about dissociative symptoms

There are other symptoms or conditions that are commonly associated with FND. These include:

chronic pain, including fibromyalgia, back and neck pain, and complex regional pain syndrome persistent fatigue sleep problems including insomnia (not sleeping enough) and hypersomnia (sleeping too much) migraines and other types of headache and facial pain irritable bowel syndrome and other problems with the function of your stomach and bowel anxiety and panic attacks depression post-traumatic stress disorder chronic urinary retention despite all tests being normal (which may be diagnosed as Fowlers syndrome) dysfunctional breathing