Exploding Head Syndrome in the Epilepsy Monitoring Unit: Case Report and Literature Review

Exploding Head Syndrome: A Systematic Scoping Review

Exploding head syndrome (EHS) has historically been viewed as a disorder predominantly affecting older people and being more common in females. Through a comprehensive review of data since 2005, this scoping review provides updated evidence from 4082 participants reporting EHS across a variety of study designs on: how EHS presents; key information on comorbidity and correlates of EHS; how EHS is experienced in terms of symptoms and beliefs; causal theories arising from the research reviewed; and evidence-based information on how research has reported on the management of EHS. Since 2005, EHS has attracted increasing research interest; however, there are significant gaps in the research that are hindering a better understanding of EHS that might be helpful for clinicians.

Co-activation of rhythms during alpha band oscillations as an interictal biomarker of exploding head syndrome

Background

Exploding head syndrome is a rarely reported benign sensory parasomnia that may nonetheless have significant impact on patients’ quality of life and their perceived well-being. To date, the mechanisms underlying attacks, characterised by a painless perception of abrupt, loud noises at transitional sleep-wake or wake-sleep states, are by and large unclear.

Methods and results

In order to address the current gap in the knowledge of potential underlying pathophysiology, a retrospective case-control study of polysomnographic recordings of patients presenting to a tertiary sleep disorders clinic with exploding head syndrome was conducted. Interictal (non-attack associated) electroencephalographic biomarkers were investigated by performing macrostructural and event-related dynamic spectral analyses of the whole-night EEG. In patients with exploding head syndrome, additional oscillatory activity was recorded during wakefulness and at sleep/wake periods. This activity differed in its frequency, topography and source from the alpha rhythm that it accompanied.

Conclusion

Based on these preliminary findings, we hypothesise that at times of sleep-wake transition in patients with exploding head syndrome, aberrant attentional processing may lead to amplification and modulation of external sensory stimuli.