[Paramedian thalamo-mesencephalic infarct con triphasic waves]. / Infarto talamomesencefálico paramediano con ondas trifásicas.

Triphasic waves are usually associated with metabolic encephalopathies but have been reported in patients with other etiologies. The pathophysiology of this EEG pattern remains poorly understood, although they have been attributed to lesion in the connections between the thalamus and cortex. We report a case of top-of-the-basilar artery occlusion with selective paramedian thalamic-mesencephalic infarct in which triphasic waves were evident on the EEG during clinical hypersomnia. To our knowledge this is the first reported case of triphasic waves with selective paramedian thalamomesencephalic infarct. We conclude that triphasic waves are a nonspecific manifestation of diencephalic dysfunction, probably of the paramedian thalamomesencephalic reticular system.