An 84 year old woman with history of moderate Alzheimer's disease, depression, and an anxiety disorder presented to our emergency room at Victoria Hospital, London, Ontario in an 'unresponsive' state. The patient was akinetic with mutism, and clonic perseveration induced in the upper limbs was evident while she was examined. Heart attack, massive stroke, or intracranial bleed were ruled out, and an electroencephalogram showed no epileptiform activity. Despite a normal CT, a magnetic resonance scan was ordered and showed bilateral acute paramedian thalamogeniculate infarction arising from occlusion of the artery of Percheron. Bilateral thalamic infarcts can cause sudden onset of akinetic mutism with clonic perseveration, which may be confused with coma and seizures due to life threatening conditions such as a massive stroke. Thorough clinical assessment and early use of MRI scanning will assist physicians with a more accurate diagnosis of older adults with this kind of presentation.