Understanding Functional Neurological Disorder (FND)
The nervous system coordinates movement, sensation and our experience of the body. In FND, these processes do not work in their usual way. A person may intend to move a limb but be unable to do so, or experience movements that feel outside their control. [1][3]
“Functional” describes altered functioning. It does not mean that symptoms are fabricated, harmless or a matter of willpower. A normal scan does not make a person’s symptoms less real. [1][5]
How FND Can Develop
There is no single explanation that fits everyone. Current understanding involves interactions between attention, expectations, sensory processing, automatic movement and the experience of control over the body. These are ways of understanding altered nervous system functioning, rather than a complete explanation for every person’s symptoms. [1][3]
Symptoms may begin around physical illness, injury, pain or a stressful experience, although a clear trigger is not always found. Stress or trauma may be relevant for some people, but neither is required for FND. Having FND does not establish that a person has an underlying psychological problem. [1][3]
Signs and Symptoms of FND
FND is an umbrella term. People may experience one type of symptom or a combination, and the pattern can change over time. [2][3]
- Movement symptoms: limb weakness, tremor, jerking, unusual postures or difficulty walking.
- Sensory symptoms: altered sensation, numbness or changes in vision.
- Speech symptoms: difficulty speaking, changes in voice or disrupted fluency.
- Functional seizures: episodes that may involve altered awareness, unresponsiveness or involuntary movements.
Fatigue, pain and difficulties with concentration or memory may also accompany FND. These experiences have many possible causes and need to be considered individually. A symptom list cannot establish the diagnosis. [1][2]
Diagnosing FND and Distinguishing Other Conditions
Diagnosis usually involves a neurologist taking a history and looking for positive clinical features. These are recognisable patterns that support FND, rather than simply the absence of an explanation. For example, particular examination findings can show differences between automatic and deliberately attempted movement. [1][2]
Normal MRI or routine EEG results alone do not diagnose FND. Tests may be needed to assess other conditions, and a normal routine EEG does not rule out epilepsy. Your clinician should explain which findings support the diagnosis and what further assessment is needed. [2][6]
You should be able to ask questions, discuss uncertainty and receive a respectful explanation. New or substantially changed symptoms still need appropriate assessment; an FND diagnosis should not lead to every future symptom being attributed to FND. [5]
Functional seizures are genuine episodes that are not caused by the epileptic electrical activity responsible for epileptic seizures. They are sometimes called dissociative seizures. Their appearance alone may not reliably distinguish them from epilepsy. [3][6]
Assessment may include descriptions from the person and witnesses and, where appropriate, video-EEG recording of typical episodes. FND can coexist with epilepsy or other neurological conditions, so one diagnosis does not automatically exclude another. [2][6]
If functional seizures are diagnosed, ask your treating medical team for an individual management and safety plan. Decisions about medicines, driving and other safety issues belong with your clinicians; do not stop prescribed medicine on the basis of this article. [6]
Care and Recovery With FND
Care begins with an understandable explanation and a plan suited to the symptoms and the person. Depending on their needs, someone may receive neurological follow-up, physiotherapy, occupational therapy, speech therapy or psychological care. [1][3]
For movement symptoms, FND-informed physiotherapy may use education and supported practice of more automatic movement, alongside strategies for everyday activity. Psychological care may address distress or other relevant difficulties. These approaches work within a broader plan; psychological involvement does not imply that symptoms are imagined. [4][6]
Improvement is possible, including when symptoms have been present for a long time. Outcomes vary: some people recover substantially, while others continue to need support. Goals may include mobility, independence, wellbeing and participation as well as symptom change. No outcome or recovery timetable can be promised. [7]
The FND psychological support service page explains how psychological care is considered and tailored at Hennessy Clinical Psychology.
Living With FND and Seeking Professional Support
FND can interrupt work, study, relationships and ordinary activities. People deserve to be listened to and involved in decisions about their care. Feeling dismissed or being told that symptoms are “just stress” can add to the difficulty of living with the condition. [5]
Useful questions to take to a medical appointment include:
- Which findings support my diagnosis?
- Could another condition also be contributing?
- Who will coordinate my care and review changes?
- What should I do during an episode or if symptoms change?
- Which goals and activities should my care plan prioritise?
With your agreement, family members or other support people can help communicate your needs and understand the plan. A shared explanation should support your dignity and participation in care. [5][6]