Functional Neurology

FND

References

• Neuro Symptoms dot org - https://neurosymptoms.org/en/

Useful website with a general overview of all the different types of symptoms in FNDs. Good for patients. Worth a look.

• Conversion Disorders Epidemiology - Up to Date / Needs Log In

• Conversion Disorders Assessment - Up to Date / Needs Log In

• Conversion Disorders Treatment - Up To Date / Needs Log In

Introduction

Conversion disorder or Functional Neurological Symptom Disorder FND

Definition

Neurologic symptoms (eg, weakness, abnormal movements, or nonepileptic seizures) that are inconsistent with neurologic disease, but cause distress and/or impairment

Prevalence

• 1 in 2000 people

• 2% of internal medicine inpatients

• 6% of neurology inpatients

• 4% of neurology outpatients

Sociodemographic

More common in

• Younger age

• Female sex

• Greater disability including physical and social functioning

Premorbid clinical factors

Stressful life events are more common in patients with conversion disorder. Meta-analysis of 34 studies versus healthy or control patients showed the following more likely in conversion disorder

• Emotional neglect (50% versus 20%)

• Sexual abuse (25% versus 10%)

• Physical abuse (30% versus 10%)

13 studies found that some patients with conversion disorder had no history of stressful life events or maltreatment in 10-70%

Pre-existing disorders and symptoms may predispose patients to develop conversion disorder. Patients with conversion disorder were more likely to have:

• Psychiatric disorders (Depressive, Anxiety, and Personality Disorders)

• Somatic symptoms (Pain, Fatigue, Cognitive Impairment)

• Irritable bowel syndrome

Preceding Factors

• Neurological illness (Migraine, peripheral nerve pathology, stroke)

• Physical injury

Perpetuating Factors

Symptoms may be perpetuated by

• Beliefs that there is an irreversible neurologic disease

• Comorbdit psychiatric disorders

• Financial benefits

• Litigation

• Physical deconditioning

Clinicians can make things worse

• Failing to give a clear explanation and positive diagnosis of symptoms

• Prescribing inappropriate drugs and appliances e.g. crutches

• Unnecessary operations and procedures

• Misattributing to irrelevant radiological or lab findings

Pathophysiology

Cognitive Behavioural Model Hypothesis 1

• Processing of perception and behaviour mostly occurs outside of awareness and conversion symptoms may result from psychological influences at these lower levels of processing.

• Suggested that patients with conversion disorder initially encounter a stimulus for a particular symptom, such as weakness from migraine.

• This generates a mental representation of the memory of paralysis.

• Excessive anxiety about becoming paralysed and/or hypervigilance in looking for evidence of paralysis in oneself may activate the mental representation to the point that it overrides sensory input and distorts awareness and behaviour.

• Selective attentional bias leads patients to persistently focus on evidence that they are paralysed and ignore evidence that they are not.

Cognitive Behavioural Model Hypothesis 2

• Another theory proposes that conversion disorder involves dissociative experiences

• Dissociation is subjectively perceived as disconnection from oneself (depersonalisation), or the environment (derealisation)

• During dissociation, awareness and integration of thoughts, feelings, memories, and identity is altered, as is the integration of somatic experiences and functions, and patients lose functioning of motor control or sensory awareness

• Dissociation may occur due to fatigue, panic attacks, physical injuries, recognisable diseases, iatrogenic triggers such as anaesthesia, or drug side effects

• In this model, the symptoms of paralysis or abnormal movement arise during the dissociated state when the patient is personalised

• Attention is paid asymmetrically to this experience, combined with fear of what the symptom might represent e.g. stroke

Neurobiologic model

• May result in abnormalities in the neural network of grey matter brain regions rather than a disturbance in one specific structure.

• These networks are thought to include frontal and subcortical structures that may be activated by emotional stress

Psychodynamic models

• Unconscious conflict that is converted into somatic symptoms

• This symptom serves as a defence again anxiety and distress

• In this model, a new conflict or traumatic event leads to the recurrence of previous patterns of abnormal behaviour and the development of physical symptoms

• The physical symptoms are regarded as a coping response secondary to emotional dysregulation

Prognosis

Generally poor

One study over 14 years

• 20% remitted

• 30% improved

• 25% persisted

• 25% worsened

Sensory symptoms may have a better prognosis than weakness, dystonia, tremor

Factors associated with a positive outcome included:

• Onset in childhood or adolescence

• Early diagnosis

• Good response to initial treatment

• Comorbid anxiety or depression

• A subsequent change in marital status

• Good therapeutic alliance with the clinician

Factors associated with a poor outcome included:

• Multiple physical symptoms

• Longer duration of symptoms

• Poor physical functioning

• Comorbid personality disorder

• Beliefs that symptoms are irreversible and caused by a disease with a known pathological basis

• Illness-related financial benefits

Clinical Features

General principles — Conversion disorder can present with:

• Nonepileptic seizures

• Weakness and paralysis

• Movement disorders

• Speech disturbances

• Globus sensation

• Sensory complaints

• Visual symptoms

• Cognitive symptoms

Symptoms may be episodic, sustained, acute or chronic.

Assessment

• Medical history

• Physical examination

• Lab tests

• Psych history

• MSE

• Prior records can help to provide information about previous symptoms or problems that patients may have forgotten or not recognised as a functional disorder

• Essential to look for neurologic and other medical conditions, particularly early-stage diseases

• Comorbid psych disorders are common

History

Current symptoms

• Make a list of all symptoms

• Ask about fatigue, pain, dizziness, sleep disturbance, impaired memory and concentration

• Multiple current neuro symptoms are often found

• The mean number of symptoms was 2.5

Circumstances at onset

• Common clinical features at onset are

  • Panic attacks

  • Migraines

  • Pain

  • Physical injury (occurred in 37%)

• Onset usually sudden

  • Functional weakness with sudden onset (<6 hours to maximal onset) while awake occurred in 46%, or upon waking from sleep or general anaesthesia in 15%

Dissociation

• Patients may describe dissociative symptoms as feeling “outside of myself,” “spaced out,” “far away,” or “unreal.”

Disability

• Disability and distress in patients with conversion disorder is comparable to recognisable neurological disease

Ideas, Concerns, Expectations

• Asking patients what they think may be causing their symptoms and what should be done to treat them

• Patients are frequently dissatisfied with exclusively psychologic explanations

Family history

• Illnesses in parents, siblings, and children are common

• General medical disorders in first-degree relatives were more common in patients with conversion disorder (80% vs 40%)

Course of illness

• Asking “When did you last feel well” is a useful way of determining when the onset of conversion symptoms occurred

• Previous functional disorders such as IBS or fibromyalgia can be helpful as evidence of a patient’s vulnerability to conversion

Prior clinical experiences

• Patients may have iatrogenic harm from a misdiagnosis of a recognised neurological disease

Recent psychological stressors

• Common but not always obvious

Symptoms of Comorbdit psychiatric disorders

• Ask about anxiety and depression at the end of the consult

Physical and sexual abuse

• More common in conversion patients

• Ask at the end of the consult

• Allow patients time to volunteer information if they feel comfortable

Exam

Useful for looking for

• Inconsistency at different points (e.g. no ankle reflexes but able to stand on tiptoes, gait changes walking in versus walking out, what happens when distracted)

• The incongruity between symptoms and recognised disease (i.e. symptoms do not conform to known anatomical pathways)

Subtypes of conversion disorder

Nonepileptic seizures

• This condition is marked by apparent impaired or loss of consciousness with abnormal generalized limb shaking or sudden motionless unresponsiveness, and the lack of paroxysmal activity on electroencephalograms

• An example of a positive sign of conversion disorder with seizures is closed eyes with resistance to opening

Weakness and Paralysis

• Weakness is common in 30% of patients

• History of dropping things or dragging or buckling of the affected leg

• Common that affect limb doesn’t feel part of them or belong to them

• The key finding in conversion disorder is that the weakness or paralysis is inconsistent at different times in the exam

• Hoover sign – The test is based upon the principle that the hip is extended when the contralateral hip is flexed against resistance

• Co-contraction sign – Co-contraction is the simultaneous contraction of agonist and antagonist muscles. During muscle strength testing of the agonist (eg, the biceps) in patients with conversion disorder, the clinician may be able to detect the contraction of the antagonist (eg, the triceps)

• Give-way or collapsing weakness – The patient is asked to exert force in a particular direction, and as the examiner lightly exerts force in the opposite direction, the examiner feels an abrupt decrease in resistance as the patient’s extremity gives way suddenly

• A delayed, slow, or jerky descent when the clinician positions the outstretched arm in front of the patient and then releases it.

• A global or inverted pyramidal pattern of weakness in the legs (eg, extensors weaker than flexors)

• Drift without pronation sign – If patients with functional upper limb weakness are asked to hold their arms in the air with their palms facing upwards, fingers adducted, and eyes closed, the affected arm may drift downwards but without accompanying pronation commonly seen in patients with upper motor neuron lesions

• Sternocleidomastoid test – Patients are asked to rotate their head against resistance. In functional weakness, patients exhibit difficulty rotating to the affected side, whereas patients with recognizable neurologic disease less commonly manifest weakness.

Abnormal movement 

Conversion disorder with motor symptoms or deficits can manifest as movement disorders. There are several functional movement disorder syndromes that are based upon the presenting symptoms, including:

• Functional tremor

• Functional dystonia

• Functional gait disorder

• Functional myoclonus

• Functional Parkinsonism

Speech symptoms 

• The most common conversion speech symptom is functional dysphonia, which usually presents as whispering or hoarseness, often after an episode of viral laryngitis has remitted

• Clues that the speech impairment is related to a functional disorder include the presence of a normal cough or singing voice

Globus sensation

• Globus sensation (also called globus pharyngeus) describes the conversion symptom of a “lump” or “ball” in the throat

Sensory symptoms 

• Sensory disturbance (eg, anaesthesia or sensory loss) is common in conversion disorder; a randomized trial with 127 patients found that paresthesias occurred in 50 per cent and numbness in 41 per cent

• In addition, patients often report a feeling of being “cut in half” (midline splitting) or that one side or part of their body “doesn’t belong” to them, and may report a mixture of pain, sensory disturbance, and weakness

• Sensory symptoms in conversion disorder may be incongruent with known nerve pathways. As an example, patients may describe sensory loss in the entire arm with a circumferential cut off at the shoulder, or the whole leg with a circumferential cut off at the groin, which is incompatible with dermatomal or cortical sensory loss

• Signs of conversion disorder

  • Altered vibration sense across the forehead or sternum (which generally should not occur in recognizable disease because these are single bones)

  • Midline splitting, sensory loss should be 1-2 cm from the midline due to overlapping

Visual symptoms 

Functional visual disturbance is common; a randomized trial with 127 patients found that functional visual symptoms occurred in 16 percent. Conversion visual symptoms include intermittent blurred vision, double vision (due to spasm of convergent eye movements), nystagmus, visual field defects, and complete blindness

• Complete blindness, as with complete paralysis, is associated with an increased probability that the symptom is factitious.

• Fingertip test, which is performed by asking the patient to touch the tips of their index fingers together. Whereas blind people can readily do so using proprioception, patients with conversion disorder tend to have difficulty bringing their fingers together.

• Signature test, which is a nonvisual task that blind people can perform. Patients with conversion disorder may have difficulty writing their signature.

• Menace reflex, which involves presenting a visual threat (eg, a rapidly approaching hand) to the eye. Flinching or blinking is generally observed in conversion disorder. This test does not exclude a cortical visual problem.

Cognitive symptoms 

Cognitive symptoms are not usually described as part of conversion disorder. Nevertheless, a functional cognitive disorder can be diagnosed if there are positive clinical findings that demonstrate either inconsistency at different points in the examination, or incongruity between the symptoms and recognized disease. Cognitive symptoms that are commonly encountered in patients with conversion disorder include

• Poor concentration and memory

• Impaired fluency

• Jumbling of words when speaking

• Word finding difficulty

• Variability in speed of response

Investigations

Laboratory, radiologic, and neurophysiologic tests are generally required to seek neurologic/general medical disorders that either explain the presenting symptoms or are comorbid

Investigations should be performed as quickly as possible; protracted testing may encourage diagnostic uncertainty in patients, who then focus upon finding a disease rather than rehabilitation

Comorbid Conditions

Comorbid psychiatric disorders may occur in up to 90 percent or more of patients with conversion disorder

• Unipolar major depression – 32 versus 7 percent

• Generalized anxiety disorder – 21 versus 2 percent

• Panic disorder – 36 versus 13 percent

Compared with patients who have defined neurologic disease, patients with conversion disorder are more likely to have personality disorders, especially:

• Borderline personality disorder

• Histrionic personality disorder

• Narcissistic personality disorder

Treatment

• Education about the illness

• Motor symptoms is physical therapy +/- CBT

• Symptoms other than motor = CBT

First line treatment = Education

• Ask the patient what they think is wrong and whether the problem is caused by damage to their body

• State the symptoms are real and taken seriously

• Provide a diagnosis

• Discuss how the diagnosis was made

• Emphasise the mechanism underlying the symptoms rather than the cause

• Causes are complex and uncertain, despite this we still diagnose and try to treat

• Similarly, we don’t understand how epilepsy or migraines work

• Enlist family members to help

Second line treatment

• Physical therapy

  • Essential for treating functional motor disorders

  • Biopsychosocial model

  • Education

  • Eliciting normal movements

  • Movement retraining by diverting attention

• Cognitive Behavioural Therapy

Third line treatment

• Pharmacotherapy

  • SSRI

• Hypnosis

• Brief psychodynamic psychotherapy

• Multidisciplinary inpatient treatment

• Family therapy

• Group therapy