Conversion Disorder

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Conversion Disorder is also known as Functional Neurological Symptom Disorder and is characterised by neurological symptoms (weakness, abnormal movements, or nonepileptic seizures for instance) that are incompatible with a neurologic distress but nevertheless cause distress and impairment. This article mainly focuses on motor and sensory symptoms.

Clinical Features

The goal of the assessment is to identify inconsistences between symptoms and recognised disease.

Historical Factors

Compared to patients with "organic" disease, patients with conversion disorder tend to be younger. Hemiparesis or monoparesis is the most common presentation, but sensory abnormalities can also occur. Conversion disorder presentation patients also have more fatigue, sleep problems, pain, memory/concentration problems, gastrointestinal problems, headache, back pain, joint pain, neck pain, and blackouts.

Many cases are said to have la belle indifference in that they appear unusually cheerful despite their symptoms. However in nearly all cases patients say that were trying to appear cheerful so that the examiner didn't think they were mentally ill.

Examination

There is some limited evidence of the following examination signs being useful in identifying conversion disorder:

Proposed classification of positive signs by Daum and colleagues.

Highly Reliable Signs	Reliable Signs	Suggestive Signs
Giveway weakness	Spinal injuries Centre (SIC) test	Irregular drift (arm stabilisation)
Drift without pronation	Sternocleidomastoid test	Non digiti quinti sign
Co-contraction	Collapsing weakness	Falls always towards support
Splitting the midline	Non-concavity of the palm	Non-economic posture
Splitting of vibration sense	Inconsistence of direction	Non-economic posture
Hoover's sign	Mingazzini: irregular drift	Sudden knee buckling
	Systematic failure	Tremulousness
	Non-anatomical sensory loss
	Leg dragging
	Hesitation
	Psychogenic Romberg
	Bizarre excursion of trunk
	Expressive behaviour

Hoover's sign:

Here the patient is unable to extend the right hip and press the heel into the bed on direct testing. The normal left leg is flexed off the bed (resistance can be added) and there is involuntary right hip extension.

This is a common finding in conversion disorder and is used upon finding hip flexion or hip extension weakness or direct testing. It is based on the crossed extensor reflex.

• Hip flexion weakness: In health patients and in patients with an organic hemiparesis when they are in a supine position and flex their weak hip they will automatically extend their normal hip. This can be felt by placing the hand under the normal heel and feeling downward pressure. If the examiner feels nothing then this suggests conversion disorder. This means that effort is not being transmitted to either leg
• Hip extension weakness: The patient flexes their good leg against resistance while keeping your hand under the heel of the weak leg. If you feel downward pressure that was not there on direct testing this is an inconsistency that is suggestive of conversion disorder.

Hoover's sign can still be positive in patients with organic disease for example if the patient wants to prove to you that they are weak, distress, or difficulty in understanding your instructions. Pain can also affect the sign in several ways.

There has been early research on applying this sign to arm weakness with shoulder abduction and adduction.

Dragging monoplegic gait: Here there is a striking "dragging gait" where one leg is dragged with the knee extended and the hip internally or externally rotated. This is not a common finding.

Co-contraction sign: There is simultaneous contraction of agonist and antagonist muscles. For example during muscle strength testing of the agonist biceps muscles there is also contraction of the antagonist triceps muscle in conversion disorder

Give-way or collapsing weakness: The patient is asked to exert force in a particular direction while the examiner lightly exerts force in the opposite direction. In conversion disorder there is an abrupt decrease in resistance as the limb suddenly gives way. This sign can be falsely positive in chorea, pain, joint problems, and difficulty in understanding instructions.

Drift without pronation: The patient is asked to hold their supinated arms in the air with fingers adducted and eyes closed. In conversion disorder the affected limb by drift downwards but without the accompanying pronation seen in upper motor neuron lesions.

Sternocleidomastoid test: The patient is asked to rotate their head against resistance. In conversion disorder there is difficulty in rotating towards the affected side.

Global or inverted pyramidal pattern of weakness: for example extensors being weaker than flexors rather than the organic expected opposite finding.

Midline splitting: The cutaneous branches of the intercostal nerves overlap and so any midline splitting in most organic diseases should be 1 to 2cm from the midline. Exact midline splitting occurs in thalamic disease and conversion disorder.

Midline splitting of vibration: In conversion disorder there may be splitting of altered vibration sense over the forehead and sternum. As these are single bones splitting should not occur in organic disease.

Spinal Injuries Centre (SIC) Test: The patient is in a supine position while the examiner passively lifts the patient's knees to a flexed position with the feet flat on the bed. The examiner releases the patient's knees. If the patient is able to maintain the flexed position then this is a positive test for conversion disorder. In severe paralysis the patient should not be able to maintain their knees in the flexed position with the paretic limb spontaneously dropping into extension.

Classification

The following subtypes have been observed

• Nonepileptic seizures
• Weakness and paralysis
• Abnormal movement
• Speech symptoms
• Globus sensation
• Sensory symptoms
• Visual symptoms
• Cognitive symptoms

Diagnosis

In the DSM V criteria conversion disorder is no longer a diagnosis of exclusion. It is based on finding incompatibility between the symptoms and recognised medical conditions. It uses both negative and positive signs.

• A: One or more symptoms of altered voluntary motor or sensory function
• B: Clinical findings provide evidence of incompatibility between the symptom and recognised neurological or medical conditions
• C: The symptom or deficit is not better explained by another medical or mental disorder
• D: The symptom or deficit causes clinically significant distress or impairment in social, occupation, or other important areas of functioning or warrants medical attention.

Prognosis

The prognosis is often poor