Stroke in supplementary motor area mimicking functional disorder: a case report

Supplementary motor area, the posterior third of the medial aspect of superior frontal gyrus, is known to be a heterogeneous area in function. It is involved in self-initiated motor movements, planning and sequencing the motor action, response inhibition, and bimanual movements. Blood supply for supplementary motor area is mostly by callosomarginal branch of anterior cerebral artery. Stroke in anterior cerebral artery territory is relatively uncommon, moreover, isolated supplementary motor area stroke is a rare entity. Supplementary motor area stroke, as a syndrome, has variable symptoms consisting of impairment of volitional movements, hemineglect, dyspraxia of contralateral limbs, impaired muscle tone, mutism and contralateral weakness. As symptoms are sometimes ambivalent, patients may be misdiagnosed as functional disorder and lose the chance for immediate adequate treatments such as thrombolysis. We report a 59-year-old man with previous history for myocardial infarction, referred to emergency room with an acute dense right-side hemiplegia, positive Hoover sign, asymmetrical Babinski responses and intermittent ability to move his arm in some specific reflex actions despite plegia. Since brain computed tomography scan was unremarkable we could not be sure whether his symptoms were organic or functional until a diffusion weighted imaging of magnetic resonance imaging elucidated the situation. To our knowledge, there is only one case report in the literature prior to ours, presenting a supplementary motor area stroke patient, mimicking functional disorder. Therefore, we may claim our report to be the second reported case.