What are 'Positive Signs'?
In modern neurology, FND is diagnosed based on Positive Signs—specific patterns of movement or sensation that could only occur if the brain's hardware is intact. These signs prove that the nervous system is capable of normal function but is being temporarily blocked.
Hoover's Sign
Perhaps the most famous sign for functional leg weakness. If a patient is unable to push their weak leg down intentionally, the clinician has them focused on pushing their *other* leg up against resistance.
Tremor Entrainment
Used for functional tremors. The clinician asks the patient to tap a specific rhythm with their "good" hand.
Hip Abductor Sign
Similar to Hoover's, but for the hip muscles. It looks for weakness that disappears when the patient is using the opposite muscle group.
Signs of Dissociative Seizures
For patients with seizures, neurologists look for "Semiology"—the specific way the seizure looks. Positive signs for PNES include:
- Forced Eye Closure: Active resistance to having eyes opened during an episode.
- Side-to-Side Head Movement: A common sign in PNES that is very rare in epilepsy.
- Rapid Recovery: Returning to full awareness almost immediately after a long episode.
The Sign of 'Internal Focus'
Why These Signs Matter
These signs are not just for the doctor; they are for the patient. Being shown that your leg is actually strong (via Hoover's sign) can be a powerful therapeutic moment, proving to you that your body is not "broken" and that recovery is possible.