Feature Article

Facial movement and expression disorders: Part 1. Facial weakness

Jason Warren, Christopher Kneebone



The extraordinary expressive range of the human face is taken for granted in daily life. We invest our faces and those of our loved ones with powerful emotional overtones, and diseases which produce facial disfigurement are uniquely distressing to patients. In Part 1 of this article, key features and underlying causes of facial weakness are outlined.

Key Points

  • Bell’s palsy should not be diagnosed if deafness, a reduced corneal reflex or ptosis is present. However, altered taste or hyperacusis is an important pointer to this diagnosis.
  • A viral prodrome is present in 60% of cases of Bell’s palsy. The strongest association is with herpes simplex.
  • Unusual or sinister causes should be suspected in all cases of bilateral facial weakness.
  • Pathological affect should be distinguished from other situations in which emotional lability and euphoria result from diffuse brain pathology or pathological emotions of psychosis or drug intoxications.