Early diagnosis … Functional Neurological Disorder (FND): FND describes neurological symptoms like limb weakness, tremor, numbness or blackouts, related to the movement and sensation parts of the nervous system….. Functional neurological disorder (FND) is a problem largely impacting the function of the brain. It is considered a condition directly at the intersection of neurology and psychiatry – also known as a … The FND (Functional Neurological Disorder) guide provides further information about symptoms, diagnosis and treatment. Patients typically present with a sudden onset of symptoms that may include limb weakness, limb paralysis, gait disorder, tremor, myoclonus, dystonia, or sensory or visual disturbance.