'No-No' head movement as a true epileptic phenomenon - A case series with SEEG and signal processing evaluation

Horizontal side-to-side head shaking, often referred to as 'No-No' Head Movement (NNHM), has traditionally been considered a hallmark of Functional Dissociative Seizures (FDS). Its significance in epileptic seizures remains largely unexplored. We present a case series of patients who displayed NNHM as part of their epileptic semiology.

Six patients with ictal NNHM were identified between 2023 and 2025. Epileptic NNHM was confirmed through multimodal analysis. This semiology was also recorded in two patients undergoing stereo-electroencephalography (SEEG). Signal processing was applied to selected NNHM seizures using an in-house MATLAB-based pipeline. Band-specific filtering and event-related desynchronization/synchronization (ERDS) analysis were applied to video-annotated peri-onset epochs to map the associated network and its dominant spectral profile. Quantitative ERDS, patient-specific imaging-based anatomical localization, regional clustering, null-control comparison, and false discovery rate correction were used to define semiology-associated networks.

All six patients were confirmed to have NNHM movements as part of their habitual epileptic seizures. The signal processing framework identified a distributed network centered on the anterior cingulate, mesial premotor, and insula-opercular regions, characterized mainly by delta activity with lesser theta/alpha contribution.

NNHM, when included within a broader manifestation of clinical features and also as part of a multimodal assessment integrating neuroimaging and electrophysiological data, may suggest involvement of widespread cortical epileptic networks rather than non-epileptic behaviour.

Recognizing that this semiology may also be epileptic can help prevent misdiagnosis and mislabeling of patients, guide appropriate electrode implantation in pre-surgical evaluations, and contribute to a deeper understanding of motor network organization in focal epilepsy.