Underline importance of isolated sudden cognitive and memory changes as presenting feature of left thalamic lacunar strokes.

Post stroke or multi infarct ‘vascular’ dementia is well known. While the commonest lacunar syndromes are sensorimotor stroke, pure motor hemiplegia, and ataxic hemiparesis, less well known is the syndrome of Anterior Thalamic strokes presenting with sudden isolated cognitive and memory change without weakness, apraxia, sensory or vision disturbances.

We present three patients with sudden change in cognition and memory loss. None of them had significant weakness, aphasia, sensory loss, or visual field loss. None of them had any alteration of sensorium. MRI brain showed left anterior thalamic infarcts in all the three patients. Detailed neuropsychological tests revealed impairments in verbal learning and memory, apathy, executive dysfunction.

Anatomically and functionally the thalamus comprises of four regions, anterior, medial, lateral and posterior.  While complex, the predominant blood supply of the thalamus is from the vertebrobasilar posterior circulation via penetrating branches of the posterior cerebral arteries. The anterior part gets blood supply from the tuberothalamic artery that is a branch of the posterior communicating artery. Anterior Thalamic nuclei are part of the Papez circuit which are probably disrupted due infarction in this anterior location.