2nd February 2024

Diagnosis

History 

In addition to the usual history, the following points are important to consider:

• Dissociation at the time of the disorder is a common feature
• Depersonalisation (feeling a part of themselves is unreal) and derealisation (Feeling everything around is unreal) are common features in FNSD. 
• Panic disorder can be a common presentation.
• La-belle indifference: This is about being cheerful despite the diagnosis of a disability. This can be a feature of conversion and or factitious disorder.

Examination

FNSD is not a diagnosis of exclusion. There can be some positive signs of functional disorder that can be elicited here.

Common features of Conversion disorder noted

1. Non- Epileptic Attack Disorder (NEAD)
2. • Prolonged episode
   • Closed eyes during episode or resistance to opening
   • No injury to the tongue, No falls, No collapse
   • Crying during and after the episode
   • Ability to recall the whole incident 
   • Prolonged amnesia post-episode
3. Functional limb weakness
   • Hoover’s sign positive: Involuntary extension of the “normal” leg occurs when flexing the contralateral leg against resistance. To perform the test, the examiner should hold one hand under the heel of the “normal” limb and ask the patient to flex the contralateral hip against resistance (while the patient is supine), asking the patient to keep the weak leg straight while raising it.
4. Visual problems
   • Fogging test is where the individual can still read with the affected eye despite altering the lens in the normal eye
   • Tubular field vision at any distance
5. Tremor Test: Tremor entrainment test is a specialised test that helps to identify unilateral tremors that are functional