Unexplained Nerve Symptoms Linked to Brain Scan Changes
Contralateral somatosensory region does not activate after stimulation
THURSDAY, Dec. 14 (HealthDay News) -- Patients with unexplained numbness or tingling who are diagnosed with sensory conversion disorder have defects in the activation of the contralateral somatosensory region of the brain after stimulation, according to the results of a functional magnetic resonance imaging study published in the Dec. 12 issue of Neurology.
Anthony Feinstein, M.D., of the University of Toronto in Canada, and colleagues describe the cases of three individuals with unexplained sensory loss in a foot or hand, who met the criteria for conversion disorder. The subjects and six healthy controls were examined by brain functional magnetic resonance imaging during unilateral and bilateral vibrotactile stimulation.
The researchers found that unilateral stimulation did not activate the contralateral primary somatosensory region in the three cases, in contrast to controls. Bilateral stimulation activated the left and right primary somatosensory regions in both subjects and controls.
"The principal finding is that stimulation of the numb body part did not activate the somatosensory region of the brain, while stimulating both limbs did," said co-author Omar Ghaffar, M.D., M.Sc., of Sunnybrook Health Sciences Centre in Toronto, in a statement. "To our knowledge, this represents a novel result that may help explain the differing results in the few studied articles devoted to this topic."