Abstracts

Rationale: In humans, yawning is a physiologic, stereotypical, involuntary response that is known to be primarily controlled by paraventricular nucleus of the hypothalamus, the locus coeruleus and reticular activating system. Excessive yawning has been described in some neurological conditions and rarely as an ictal phenomenon. Only a few case reports have described it as a peri-ictal or a part of ictal manifestation especially of temporal lobe epilepsy. Here, we report the first case of controllable yawning as a primary seizure semiology with dominant frontal lobe involvement. Methods: A 20-year-old right-handed young man, presented with brief episodes of strange symptoms with yawning noted since age 18 years. He described these as brief episodes of yawning lasting a few seconds, with associated lightheadedness, at times with muscle spasms over his hands/arms or neck without loss of awareness. These occurred usually upon waking up in the morning or when sitting at a computer, also when tired or sleep deprived. He added that he could restrain his urge to yawn. To characterize his spells, 8 hour video EEG (VEEG) monitoring was performed with a repeat study after 6 months for follow up. Magnetoencephalography (MEG) was also completed with 148 channels Neuromagnetometer system with 32 channels of simultaneous digital EEG. Overall functional brain connectivity was imaged with Coherence Source Imaging (MEG-CSI). Results were encoded as a color spectrum for values between 1 (entirely coherent) and 0 (no coherence) and overlaid on the patient's MRI with the solutions restricted to the gray matter. Results: Initial 8-hour VEEG did not show any interictal epileptiform activity, however 8 typical yawning episodes were recorded that at times were accompanied with right arm movement and showed semi-rhythmic diffuse delta/theta range activity with left hemispheric predominance lasting for up to 7 seconds on EEG. A follow up study was performed after 6 months that recorded episodes when he restrained his yawn with no ictal correlates on EEG. Stronger yawning episodes showed similar ictal patterns as recorded in the previous study. No interictal epileptiform activity was present in the MEG for dipole analysis. MEG-CSI exclusively lateralized high coherence to the left hemisphere, results were consistent with persistent neuronal networks reported in localization-related epilepsies, and were most reliably present in the left inferior frontal gyrus. Conclusions: Controllable yawning could be a primary seizure semiology in dominant frontal lobe epilepsy as seen in our patient diagnosed with VEEG and MEG. In such cases, it is possible that epileptogenic areas could also be intricate with widespread networks involving the frontal lobe symptomatogenic areas. Funding: None