A 37-year-old man was evaluated for recurrent episodes of impaired awareness since childhood. EEG showed right temporal focal dyshormia (Figure 1). MRI revealed a right temporal mass (Figure 2).

Niedermeyer coined the term “dyshormia” to define epileptiform discharges that occur in conjunction with K-complexes on arousal from sleep¹1. Niedermeyer E. Epileptiform K complexes. Am J Electroneurodiagnostic Technol. 2008 Mar;48(1):48-51.. Although dyshormia was originally described in generalized epilepsies¹1. Niedermeyer E. Epileptiform K complexes. Am J Electroneurodiagnostic Technol. 2008 Mar;48(1):48-51., unilateral, focal dyshormia is occasionally seen in focal epilepsies²2. Geyer JD, Carney PR, Gilliam F. Focal epileptiform spikes in conjuction with K-complexes. J Clin Neurophysiol. 2006 Oct;23(5):436-9. https://doi.org/10.1097/01.wnp.0000228499.92313.d6
https://doi.org/10.1097/01.wnp.000022849... .

In focal epilepsies, epileptiform discharges associated with K-complexes are typically ipsilateral to the epileptogenic zone, and are more common in frontal than in temporal lobe epilepsies²2. Geyer JD, Carney PR, Gilliam F. Focal epileptiform spikes in conjuction with K-complexes. J Clin Neurophysiol. 2006 Oct;23(5):436-9. https://doi.org/10.1097/01.wnp.0000228499.92313.d6
https://doi.org/10.1097/01.wnp.000022849... . Their presence can assist in localization of epileptogenic regions.

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