Subtraction brain SPECT imaging in a patient with paroxysmal exercise-induced dystonia: Role of the primary somatosensory cortex

Background: Paroxysmal exercise-induced dystonia is a rare hyperkinetic disease characterized by episodic dystonic attacks after prolonged exercise. However, its pathophysiological and anatomical basis are poorly understood. Objective: To explore the exact anatomical location responsible for paroxysmal exercise-induced dystonia by conducting ictal-interictal single-photon emission computed tomography subtraction, which was coregistered to the patient's own magnetic resonance image. Design: This is a case report of a 16-year-old boy who developed a right foot dystonic attack following prolonged exercise. Result: Subtraction single-photon emission computed tomographic imaging showed significantly increased cerebral perfusion in the medial aspect of the postcentral gyrus and mildly increased perfusion in the primary motor area and cerebellum during an attack of foot dystonia. Conclusions: The primary somatosensory cortex may be a relevant structure in paroxysmal exercise-induced dystonia. Paroxysmal exercise-induced dystonia may result from defective processing of sensory information.