Conversion refers to an alteration in voluntary motor or sensory function that mimics an organic neurological disorder but lacks a detectable organic cause. It manifests involuntarily and is typically considered a symbolic expression of psychological conflict or stress. Conversion symptoms are hallmark features of conversion disorder (functional neurological symptom disorder) and may involve motor, sensory, or mixed presentations.

Pathophysiology

The exact mechanism of conversion is not fully understood but involves psychogenic disruption of normal neurological function:

• Psychodynamic perspective: Repression of emotional conflict manifests as physical symptoms.

• Neurobiological hypotheses: Altered connectivity between the limbic system, prefrontal cortex, and motor/sensory pathways may suppress voluntary control while preserving involuntary reflexes.

• Stress response: Acute or chronic psychological stress can precipitate functional motor or sensory deficits.

• Symbolic expression: Symptoms may symbolically represent internal conflicts, fears, or desires.

Examination Technique

Patient Observation

• Observe involuntary movements, gait abnormalities, or sensory deficits during routine interaction.

• Note inconsistencies: symptoms may improve with distraction or are incongruent with anatomical pathways.

Structured Assessment

• Motor conversion: Weakness, paralysis, tremors, dystonia, abnormal gait.

• Sensory conversion: Numbness, blindness, deafness, anesthesia.

• Positive signs: Hoover’s sign for functional leg weakness, tremor entrainment test, or co-contraction patterns inconsistent with organic disease.

Clinical features

Differential Diagnosis

Pediatric considerations

• Conversion symptoms may occur in school-aged children and adolescents.

• Often precipitated by emotional stress, academic pressure, or family conflict.

• Presentation may include non-epileptic seizures, functional weakness, or mutism.

Geriatric considerations

• Less common but may present as functional weakness or gait disorders.

• Important to differentiate from neurodegenerative diseases and acute cerebrovascular events.

Limitations

• Conversion diagnosis is one of exclusion; organic causes must be carefully ruled out.

• Symptoms can coexist with true neurological disorders.

• Requires careful, empathetic evaluation to avoid stigmatization.

Patient counseling

• Explain that the symptoms are real and involuntary, even without structural disease.

• Emphasize the role of stress and psychological factors in symptom manifestation.

• Encourage psychotherapy (e.g., cognitive-behavioral therapy) and gradual functional rehabilitation.

• Reassure patients and families about prognosis, which is generally favorable with early recognition and treatment.

Conclusion

Conversion is a functional neurological syndrome where psychological conflict manifests as involuntary motor or sensory dysfunction. Early recognition, thorough evaluation to exclude organic disease, and targeted psychological and rehabilitative interventions are essential for recovery and functional restoration.

References

1. American Psychiatric Association. DSM-5: Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Arlington, VA: APA; 2013.

2. Stone J, et al. Functional neurological disorders: Diagnosis and management. BMJ. 2010;341:c6826.

3. Voon V, et al. The neurobiology of functional (conversion) disorders. J Neurol Neurosurg Psychiatry. 2016;87(2):130–137.

4. Kanaan RA, et al. Neurology of functional disorders. Handb Clin Neurol. 2016;139:3–13.

5. Feinstein A. Conversion disorder: Advances in neuroimaging and clinical management. Curr Psychiatry Rep. 2011;13(4):326–331.