Examples of positive signs in functional disorders that can be shared with a patient to explain the diagnosis
| Positive finding | |
|---|---|
| Motor symptoms | |
| Hoover’s sign27 (figure 1) | Hip extension weakness that returns to normal with contralateral hip flexion against resistance |
| Hip abductor sign28 | Hip abduction weakness returns to normal with contralateral hip abduction against resistance |
| Other clear evidence of inconsistency | For example, weakness of ankle plantar flexion on the bed but able to walk on tiptoes |
| Global pattern of weakness | Weakness that is global, affecting extensors and flexors equally |
| Movement disorder | |
| Tremor entrainment test29 | Patient with a unilateral tremor is asked to copy a rhythmical movement with their unaffected limb: the tremor in the affected hand either ‘entrains’ to the rhythm of the unaffected hand, stops completely or the patient is unable to copy the simple rhythmical movement |
| Fixed dystonic posture30 | A typical fixed dystonic posture, characteristically of the hand (with flexion of fingers, wrist and/or elbow) or ankle (with plantar and dorsiflexion) |
| Typical ‘functional’ hemifacial overactivity31 (figure 2) | Orbicularis oculis or orbicularis oris over-contraction, especially when accompanied by jaw deviation and/or ipsilateral functional hemiparesis |
| Balance/gait | |
| Reduced postural sway with distraction32 | Abnormal sway that resolves during tasks such as assessing numbers written on the back or using a phone |
| Non-epileptic attacks26 | |
| Prolonged attack of motionless unresponsiveness | Paroxysmal motionlessness and unresponsiveness lasting longer than a minute |
| Long duration | Attacks lasting longer than 2 min without any clear cut features of focal or generalised epileptic seizures |
| Closed eyes | Closed eyes during an attack, especially if there is resistance to eye opening |
| Ictal weeping | Crying either during or immediately after the attack |
| Memory of being in a generalised seizure | Ability to recall the experience of being in a generalised shaking attack |
| Presence of an attack resembling epilepsy with a normal EEG | A normal EEG does not exclude frontal lobe epilepsy or deep foci of epilepsy but does provide supportive evidence |
| Visual symptoms33 | |
| Fogging test | Vision in the unaffected eye is progressively ‘fogged’ using lenses of increasing dioptres whilst reading an acuity chart. A patient who still has good acuity at the end of the test must be seeing out of their affected eye |
| Tubular visual field | The patient has a field defect of the same width at 1 m as at 2 m |