History and exam

Key diagnostic factors

common

unconventional behavior during history

Presentation of patients with somatic symptom disorder may be vague, dramatic, or odd.[63]

emotional processing problems

Typical in both disorders, either due to an inability to be aware of emotions or tendency to suppress and avoid emotions, or due to high neuroticism and emotional reactivity. Evidence suggests links between somatization and alexithymia (difficulty identifying and describing feelings); somatization and deficits in affective theory of mind (the ability to know the emotional contents of someone else's mind); and somatization and neuroticism (lifelong tendencies to experience negative affect and distress).​[60][61][62][89]

recent psychological or physical stressors

Acutely stressful life events may precede onset of both disorders and include family/relationship problems and health problems.​[32][65]​ In some patients, symptoms of functional neurologic disorder are triggered by physical injury, surgery, or another neurologic disorder such as migraine.[31] Note that patients may present without identifiable stressors.[30]

remote life stressors

Typical risk factors for both disorders, and sometimes are precipitating factors. Examples include history of sexual/physical abuse, and history of unstable childhood (witnessing domestic violence, exposure to verbal aggression, family dysfunction).[30][54][55][56][57][58][59]​​ Note that patients may present without identifiable stressors.[30]

multiple illness behaviors

Patients exhibit behavior in response to feeling ill that is intended to relieve the illness symptoms and results in focusing attention on the illness (e.g., going to the doctor or emergency department, avoiding perceived environmental triggers for the illness, adjusting lifestyle to anticipate the illness).

unusual neurologic deficits

Distribution of motor or sensory deficits that do not conform to any nerve, root, truncal, or central distribution (e.g., sharp demarcation at the shoulder or groin, "splitting the midline") can suggest functional neurologic disorder.

give-way weakness

When testing motor strength, sudden collapse after several seconds of full resistance can suggest functional neurologic disorder.

inconsistent examination findings

For example, severe leg weakness on strength testing in patients who are ambulatory; patients claiming to be blind who are able to avoid obstacles when walking. Can suggest functional neurologic disorder. Weakness that varies from moment to moment, particularly when spontaneous activity is better than that performed during exam, can suggest functional neurologic disorder.

paradoxical sensory findings

Some present as anesthesia, paresthesia, blindness, tunnel vision, diplopia, triplopia, olfactory distortions, deafness, midline sensory split, and lateralization of the tuning fork. Can suggest functional neurologic disorder.

distractible symptoms

Symptoms that abate during the examination when attention is drawn elsewhere (e.g., a tremor that stops when the patient is asked to walk or perform a cognitive task) can suggest functional neurologic disorder.

generalized seizure-like motor movements without loss of awareness

Features most suggestive of functional seizures include prolonged duration (>5 minutes), eyes tightly closed, tearfulness, hyperventilation, and side-to-side head shaking.[73] Functional seizures can be asynchronous with stop/start quality, and may involve back arching, pelvic thrusting, stuttering, flailing motor movements, and speaking in a whisper or baby voice.[75] There is often an emotional or pain trigger and paradoxical worsening with anticonvulsant medications. Events may be either never witnessed or occur only in the presence of an audience.

gait disorders

Diagnosis of functional gait disorders is challenging as no single walking pattern is pathognomonic, and there is considerable overlap with other causes of gait disorders.[90] Astasia-abasia (paradoxical ability to use the legs normally except when standing or walking), collapsing gait, and noneconomical gait can suggest functional neurologic disorder. Other suggestive features may include an antalgic, buckling, or waddling gait.[90]

functional movement disorders

Apparent fixed dystonias that have variability in amplitude and frequency of movements; inconsistent movements; variable direction and pattern to the movements; suggestibility; distractibility; suppressibility; and active resistance to passive movement. Tremors and tics are also suggestive of functional neurologic disorder.[72]

Other diagnostic factors

common

cognitive complaints

Many patients with somatic symptom or functional neurologic disorder also commonly forget whole conversations, unintentionally use the wrong words, forget how to do basic activities or tasks that they should know, lose the ability to multitask, and experience short-term memory problems.[67][68][69]

Hoover sign

Involuntary extension of the seemingly weak leg when the unaffected leg is flexing against resistance can suggest functional neurologic disorder.

speech disturbance

Aphonia, dysphonia, stuttering, and foreign accent syndrome can suggest functional neurologic disorder.[91]

swallowing disturbance

People with functional neurologic disorder may have globus pharyngeus or globus sensation (a painless sensation of fullness in the neck or difficulty swallowing).[92]​

uncommon

pseudoclonus

Irregular, erratic flexion and extension at the ankle, unlike typical clonus, can suggest functional neurologic disorder.

convergence spasm

Intermittent or excessive convergence of the eyes when patients are asked to stare at an object can suggest functional neurologic disorder.

Risk factors

strong

history of sexual or physical abuse

Frequently reported for both functional neurologic disorder and somatic symptom disorder (50% to 75% of patients), often occurring in childhood.[7][54][55][56]

adverse childhood events

Childhood traumatization has been associated with somatic symptom and functional neurologic disorders.[30][55][56][57]​​ Witnessing domestic violence can be developmentally deleterious to later mental health stability, and exposure to verbal aggression may even be associated with abnormalities in white matter tract integrity.[58][59]​ Evidence from one study also suggests that, among functional neurologic disorder patients, greater cognitive and somatic dissociative symptoms are associated with maternal (but not paternal) dysfunction.[55]

history of trauma-related disorders

Post-traumatic stress disorder, dissociative disorder, and acute stress disorder are associated with functional neurologic disorder and somatic symptom disorder.

female sex

For both somatic symptom disorder and functional neurologic disorder, a strong female predominance (about 75%) is consistently observed.[5][12][13][14]

alexithymia

Evidence suggests a link between somatization and difficulty identifying and describing feelings.[60][61]

neuroticism

Evidence suggests a link between somatization and a lifelong tendency to experience negative affect and distress.[7][62]

weak

previously poor doctor-patient relationships

Physicians who show lack of empathy or understanding by being overly dismissive, or, on the other hand, contribute to alarm over symptoms by overinterpreting test results or suggesting new symptoms, can perpetuate or increase symptoms.[63]

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