John Libbey Eurotext

A multimodal diagnostic approach for lateralised rhythmic delta activity in the ictal-interictal continuum Volume 22, issue 3, June 2020

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Authors
1 SOD Neurofisopatologia, Dipartimento Neuromuscoloscheletrico e Organi di Senso, AOU Careggi,
2 SOD Stroke Unit, Dipartimento DEA, AOU Careggi,
3 SOD Neuroradiologia, Dipartimento dei Servizi, AOU Careggi,
4 IRCCS Fondazione Don Carlo Gnocchi, Florence, Italy
* Correspondence: Maddalena Spalletti SOD Neurofisiopatologia, Azienda Ospedaliero-Universitaria Careggi, Largo Brambilla 3, 50134, Florence, Italy

The ictal-interictal continuum represents a diagnostic challenge even for expert neurrophysiologists, often requiring an additional multimodal diagnostic workup to understand its clinical significance. Lateralised rhythmic delta activity (LRDA) is an ictal-interictal continuum pattern that has only recently been investigated and recognised as potentially ictogenic or sometimes even ictal.

We describe a patient who presented with acute-onset aphasia, initially suspected of having a stroke; advanced brain imaging with CT-perfusion showed features suggesting regional left temporo-parietal hyperperfusion and an EEG revealed LRDA with fluctuations and intermixed sharp waves in the same areas. Treatment with lacosamide caused both clinical and EEG improvement after a few hours, supporting the hypothesis that the EEG pattern represented an ictal/interictal phenomenon.

In the literature, a correlation between metabolic/perfusion imaging and ictal-interictal continuum patterns is described regarding lateralised periodic discharges but less studied for LRDA.

In this case, we adopted a multimodal approach, integrating advanced imaging, EEG, clinical features, and response to therapy, to consider the overall clinical presentation as focal NCSE.