Imaging repressed memories in motor conversion disorder

Abstract

Objectives: Conversion disorders comprise neurologically unexplained symptoms with a presumed psychiatric cause, though a neuroscientific basis for this is lacking. The standard psychiatric model of conversion holds that events and processes that might explain the symptoms are, by hypothesis, either repressed or subconscious. This makes assessments based on subjective reports unreliable. We circumvent this by using a standardized method to quantify stressful life events and by assessing objectively the neural correlates of emotion processing.

Methods: Single case study of a 37-year-old woman with clinically repressed recall and unexplained right-sided paralysis. We describe the application of the Life Events and Difficulties Schedule (LEDS) to her history, and a novel functional magnetic resonance imaging (fMRI) procedure exploring emotion processing of traumatic and control memories.

Results: While in the scanner, cued recall of the clinically repressed event was associated with regional brain activations characteristic of emotional arousal, including the amygdala and right inferior frontal lobe, when compared with an equally severe event from the patient's past, as rated by the LEDS. Such recall was also associated with decreased motor activity in the area corresponding to the subjectively paralyzed limb.

Conclusion: This case study provides neuroimaging evidence for a connection between traumatic events and ongoing neurological symptoms.