Conversion disorder and fMRI

Conversion reactions can involve many neurologic functions ranging from movement and somatic sensation to the special senses and cognitive intellectual abilities. The diagnosis is made at the bedside and is usually straightforward. However, up to 15% of diagnosed conversion reactions subsequently prove to be due to missed neurologic conditions.¹

The sooner new methods define the neurobiological mechanisms that underlie conversion reactions as well as subtle presentations of organic disease capable of mimicking them, the better for both patient and neurologist. The report in this issue of Neurology by Ghaffar et al. on noninvasive observations made by functional MRI (fMRI) in three patients with unilateral psychogenic sensory disturbance is a useful step in that direction.² We also believe that further effort in this area can advance general understanding of how the nervous system works.

The essential feature of a conversion reaction is that the complaints and findings do not follow known neurologic damage patterns.¹ There is no recognized location within the motor, sensory, special sensory, or cognitive intellectual pathways where organic injury or malfunction will produce the reported symptoms or observed signs. The information that fMRI can obtain about what the nervous system is doing while …