How Can You Tell Focal Sensory Seizures From Panic and FND?

If you experience strange physical sensations—such as tingling, numbness, visual changes, a racing heart, or sudden intense fear—it is natural to wonder whether you are having a focal sensory seizure, a panic attack, or a functional neurological symptom. The most important thing to know is that all of these conditions cause real, physical events in your body. Functional neurological disorder (FND) and panic attacks are not “in your head” or imagined; they are genuine physiological responses that involve complex brain networks and autonomic nervous system activation ^[1][2].

Because these conditions can feel remarkably similar, doctors cannot usually tell them apart based on a single symptom. Instead, an experienced neurologist or epileptologist (a neurologist with special expertise in seizures) distinguishes them by carefully analyzing the exact sequence of your symptoms (semiology), watching videos of the events, and using specialized testing ^[3][4].

When to Seek Emergency Care

While it is important to understand your ongoing symptoms, some signs require immediate medical attention rather than waiting for a specialist appointment. Call local emergency services immediately if you or a witness notice:

• Sudden new one-sided weakness, numbness, or facial drooping ^[5].
• Sudden difficulty speaking or understanding speech ^[5].
• Sudden loss of vision or a severe, sudden headache ^[6].
• A seizure lasting 5 minutes or more, or repeated seizures without recovering in between.
• Difficulty breathing or a significant injury during an episode.
• A first-time episode or one that feels completely different from your usual spells.

Never delay emergency care to try and record a video of the event.

Analyzing the Pattern of Symptoms

When evaluating your episodes, doctors look for clues in how the symptoms begin, spread, and end. These are helpful tendencies, not strict rules for self-diagnosis:

• Stereotypy vs. Variability: Focal seizures are typically highly stereotyped, meaning they often unfold in the exact same sequence and last roughly the same amount of time during every episode ^[7]. Functional episodes or panic may show more variation in duration, which symptoms appear first, and how they progress ^[7][8]. However, some focal seizures vary, and panic or functional events can also recur in consistent patterns.
• Autonomic Symptoms and Fear: Panic attacks often involve intense fear accompanied by a racing heart, sweating, and shortness of breath ^[9]. However, focal seizures originating in the temporal lobe can cause the exact same feelings of sudden terror and autonomic physical responses ^[10][11]. For this reason, fear and a racing heart alone cannot determine whether an event is a seizure or a panic attack ^[10].
• Duration: Focal sensory seizures are often brief, frequently lasting less than one or two minutes ^[8][12]. Panic attacks and functional episodes can sometimes last much longer (over 10 minutes), though duration alone is not a strict rule, as some focal seizures can be prolonged and some functional events are brief ^[13][14].

The Role of Video-EEG and Testing

A routine, 20-minute electroencephalogram (EEG) is often normal between focal seizures, and a normal result does not rule out epilepsy ^[15].

While many epilepsy diagnoses are made clinically based on a detailed history, witness accounts, and examination, capturing a habitual (typical) episode on a Video-EEG can be incredibly helpful when the diagnosis is uncertain ^[16][3]. Prolonged Video-EEG monitoring in a hospital or at home aims to record your brainwaves and physical movements at the exact moment you feel the sensations ^[16][17].

A crucial warning about EEG results: Diagnosing focal sensory seizures can be tricky because the electrical misfiring may occur deep within the brain, far from the scalp electrodes. Because of this, a focal sensory seizure might not show up on a surface EEG ^[16][18]. Therefore, having a typical episode during an EEG without any visible scalp brainwave changes does not automatically prove the event is FND or panic ^[16].

Understanding a Positive Diagnosis of FND

Functional Neurological Disorder (FND) is a broad condition that can cause many symptoms. When it causes seizure-like episodes, they are often called functional seizures or dissociative seizures ^[1].

FND is not diagnosed simply by failing to find epilepsy on an EEG. It is a “rule-in” diagnosis. Doctors look for positive, recognizable clinical signs—such as specific patterns of movement (like extreme asynchronous limb movements), responses to distraction, or physiological features that differ from epileptic seizures ^[19][20]. A diagnosis requires the full clinical picture, not just one isolated sign or a normal test ^[21].

Epilepsy and Functional Episodes Can Coexist

It is entirely possible to have both epilepsy and functional seizures, or epilepsy and panic disorder ^[22][23]. In fact, people with epilepsy are at a higher risk for developing functional seizures ^[24]. If you have more than one “type” of episode, doctors may need to capture multiple events on Video-EEG to properly diagnose each one ^[4][24].

Ruling Out Other Mimics

Besides panic and FND, other medical conditions can mimic focal sensory seizures. A sudden spreading numbness, visual changes, or tingling could be a migraine aura, which typically spreads much more slowly (over minutes) than a seizure ^[25]. In older adults or those with vascular risk factors, sudden sensory changes or unusual movements could be a transient ischemic attack (TIA) or a vascular issue affecting blood flow to the brain ^[26][5]. Cardiac arrhythmias can also cause sudden racing heart, shortness of breath, and lightheadedness, mimicking panic ^[27]. Timing patterns and symptom spread are useful clues for the doctor, but any sudden, stroke-like symptoms should be treated as an emergency.

Medication and Next Steps

Because treatments differ significantly—anti-seizure medications for epilepsy, targeted therapies for FND, and anxiety management for panic—a precise diagnosis is critical ^[1].

Important: Never start, stop, or change your anti-seizure medication without explicit guidance from your prescribing doctor. Even if you suspect your symptoms are panic or FND, you may still need medication for coexisting epilepsy or other reasons.

To help your doctor:

• Keep an episode diary noting the exact start and end times, first symptom, spread, triggers, and any memory loss.
• If it is safe to do so (and never delaying emergency care), ask a witness to record a smartphone video of your typical episodes. They should never restrain you or put anything in your mouth.