La belle indifference, apparent lack of concern about the nature or implications of a symptom, entered neurology as a supposed hallmark of hysteria, but systematic review found it in approximately 21 percent of patients with conversion symptoms and 29 percent of patients with organic disease, with wide variation in how it was defined and rated. It therefore has no diagnostic value and should not be used to support or refute a functional diagnosis. It was removed from the diagnostic criteria for this reason.
The apparent indifference has several innocent explanations: stoicism, a wish not to appear to complain, cultural differences in emotional display, relief that a serious disease has been excluded, or simply the observer misreading a smile. Conversely, many patients with functional weakness are highly distressed and disabled, with levels of disability equal to those of patients with comparable weakness from neurological disease. The diagnosis must be based on positive physical signs of internal inconsistency, such as the give-way quality and a positive Hoover sign, not on the patient demeanour.
Recognizing which historical signs have been retired is solid PGY-3 and PGY-4 knowledge, placing this item at the Intermediate level of RITE content. The same caution applies to a history of childhood abuse, multiple unexplained symptoms and secondary gain, all of which shift probability only weakly and none of which should override the examination.
Incorrect Answers
- B. La belle indifference is neither sensitive nor specific and is no longer part of any diagnostic criteria for functional neurological symptom disorder.
- C. A frontal abulic syndrome would produce reduced spontaneous speech, apathy across all domains, grasp reflexes and executive impairment, not isolated arm weakness.
- D. Alexithymia refers to difficulty identifying and describing emotions and has not been shown to determine physiotherapy outcome in functional weakness.
- E. Malingering requires demonstrable deliberate deception for an identifiable external reward and cannot be inferred from affect during a consultation.
Testing Pearls
- La belle indifference occurs about as often in organic disease as in conversion symptoms.
- The sign has been removed from diagnostic criteria and should not influence diagnosis.
- Patients with functional weakness are as disabled as patients with comparable organic weakness.
- Diagnosis depends on positive physical signs, not on demeanour or psychosocial history.
- History of abuse and secondary gain are weak, non-diagnostic probability shifters.
References
- Jankovic J, Mazziotta JC, Newman NJ, Pomeroy SL, editors. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022. p. 2078-2079.
- Stone J, Smyth R, Carson A, Warlow C, Sharpe M. La belle indifference in conversion symptoms and hysteria: systematic review. Br J Psychiatry. 2006;188:204-209.
- Stone J, Warlow C, Sharpe M. The symptom of functional weakness: a controlled study of 107 patients. Brain. 2010;133(Pt 5):1537-1551.
