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

Objective: 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. Methods: 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. Results: 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. Conclusion: 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. Significance: 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.