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Real symptoms, normal scans: understanding FND
Functional neurological disorder (FND) is a real neurological condition. It can cause weakness, tremor, jerks, walking or speech changes, seizures, dizziness, fatigue and brain fog, usually with normal scans.
FND is an umbrella term. It includes functional movement disorder (FMD), functional seizures, and persistent postural-perceptual dizziness (PPPD, or 3PD). It often follows a concussion, illness, injury or period of high stress.
You are not faking it. You are not imagining it. It is not "all in your head." FND is real, involuntary and treatable, and among the most common conditions seen in neurology clinics.
Assessment and care at Venn Med, Midtown Toronto. Patients come from across the GTA and Ontario, and some travel from further afield for an intensive program.
What it is
"Functional" means the problem is in how brain networks are working, not in the brain's structure. The hardware is fine; the software needs an update.
Your brain constantly predicts what should happen next, like your foot hitting the ground. In FND those predictions keep mismatching reality, disrupting automatic movement and your sense of control over your body. Working around the errors all day is like a computer with too many tabs open: it still works, but it runs slowly and drains its battery. That is why fatigue and overwhelm are so common.
PPPD is dizziness or unsteadiness on most days for three months or more, worse when upright, moving or in busy visual scenes. It is a chronic functional vestibular disorder, not a structural or psychiatric one.
FND used to be called conversion disorder. We now know it is not purely psychological. Some people with FND have a history of stress or trauma, and many do not.
Why standard tests miss it
Scans look for structural damage, and in FND there usually isn't any. Standard exams ask whether you can do a task, not whether you do it efficiently, quickly, accurately and for long enough.
What we measure
We measure eye movements (VOG/vHIT), balance and sway (CAPS), postural reflexes and muscle tone, and screen for limits such as blood flow to the brain. FND can sit alongside other conditions, such as dysautonomia or orthopedic problems, so we look for those too rather than assuming every symptom is FND. Through our F4 Comprehensive Care™ model, care can include functional medicine, manual therapy and psychology where helpful.
Treatment directs attention outward: movement tied to a task or target, choices that rebuild your sense of control, and work that is challenging but feels safe. It's not about trying harder. It's about helping the brain rediscover trust in the body.
Common questions
Can FND be treated?
Yes. Treatment retrains how the brain predicts and controls movement: movement tied to a task or target, choices that rebuild your sense of control, and work that is challenging but feels safe. A clear explanation of the condition is part of treatment.
How is FND diagnosed if my scans are normal?
FND is diagnosed from specific positive signs on examination, not only by ruling other conditions out. Scans usually look normal because the problem is in how brain networks work, not in their structure.
Is PPPD a type of FND?
Yes. Persistent postural-perceptual dizziness is a chronic functional vestibular disorder: dizziness or unsteadiness on most days for three months or more.
Is FND caused by stress?
Not always. Some people with FND have a history of stress or trauma, and many do not. It often follows a concussion, illness or injury.
When to get assessed
Consider an assessment if you:
Have been diagnosed with FND, FMD or PPPD and are not improving
Have movement, balance or dizziness symptoms with normal scans
Have tried therapy before and stalled.
If your symptoms aren't improving, start your enquiry.
This page is educational and is not a substitute for medical advice.