Activating Effect of Nasal and Oral Hyperventilation on Epileptic Electrographic Phenomena: Reflex Mechanisms of Nasal Origin

Abstract

In experiments on animals, airflow through the nasal cavity elicits rhythmic synchronized activity that can trigger and/or elicit epileptic electrographic activities in the limbic structures of the brain. This could be demonstrated in studies of lower vertebrates (frogs and turtles). In the turtle the elicited paroxysmal activity often had the shape of regular high-voltage activity in the theta-frequency range (average frequency, 4.1 Hz). It was further proven in clinical experiments that nasal deep breathing with a closed mouth effectively activates epileptic electrographic phenomena of a temporal (limbic) origin. The activating effect was more pronounced on the side ipsilateral to the ventilated nasal meatus. It could also be evoked by air insufflation into the nasal cavity. This effect was suppressed by anesthesia of the mucous membrane in the upper nasal meatus. Possible mechanisms of this, probably reflex, phenomenon are discussed.

Hyperventilation Revisited: Physiological Effects and Efficacy on Focal Seizure Activation in the Era of Video‐EEG Monitoring

“…Conversely, local anesthesia of the mucosal membrane of the superior nasal meatus led to temporary suppression of the activation in 91.3% of the patients. All this evidence associated with the very short latency (30–60 s after the start of deep breathing) for the activating effect to take place favors the possibility of reflex mechanisms triggered by mechanical stimulation of the olfactory epithelium in opposition to the metabolic hypothesis in the group of TLE (25).…”

Nasal Airflow in Health and Disease

“…There is much supporting evidence from the scientific and clinical literature that airflow through the nose can influence cerebral activity. Deep nasal breathing has been shown to have an activating effect on the electroencephelogram (EEG) in humans to such an extent that it can trigger epileptic abnormalities in susceptible persons (101,102). This arousal effect of nasal airflow was not caused by any change in blood gases due to hyperventilation as passive airflow through the nose had similar effects to hyperventilation and the activating effect of nasal airflow was suppressed by local anaesthesia of the nasal mucosa.…”

Hyperventilation induces sympathetic overactivation in mesial temporal epilepsy

“…Conversely, local anaesthesia of the mucosal membrane of the superior nasal meatus led to temporary suppression of this activation (Servit and Strejckovà, 1976;Servit et al, 1977). This evidence, together with the very short latency for the activating effect to take place (30-60 s after the start of deep breathing), facilitates the possibility of a reflex mesial-temporal cortical activation triggered by mechanical stimulation of the olfactory epithelium through HV in MTLE (Servit et al, 1981). Servit and colleagues also demonstrated that this mechanical activation is mediated by the stimulation of subcortical limbic structure, as hippocampus and amygdale, which can, in turn, influence the autonomic visceral balance and, in particular, the heart rate (Oppenheimer et al, 1992).…”