Altered responsiveness during hyperventilation-induced EEG slowing: a non-epileptic phenomenon in normal children

Area of Science:

• Pediatric Neurology
• Neurophysiology

Background:

• The relationship between hyperventilation (HV)-induced high-amplitude rhythmical slowing (HIHARS) and altered responsiveness in non-epileptic individuals is not well understood.
• It remains unclear if impaired responsiveness during HIHARS is a sign of generalized epilepsy or a physiological response.

Purpose of the Study:

• To investigate whether altered responsiveness during HIHARS is a nonspecific physiological response.
• To differentiate this response from symptoms indicative of generalized epilepsy.

Main Methods:

• Assessed verbal recall and motor response testing in 12 healthy children (mean age 9.6 years).
• Tests were conducted at baseline, during HV before EEG slowing, and during HIHARS.

Main Results:

• Verbal recall and motor responsiveness were unchanged at baseline and during HV before HIHARS onset.
• During HIHARS, all children showed impaired verbal recall (p < 0.005).
• 8 out of 12 children failed to respond to auditory stimuli during HIHARS (p < 0.005).

Conclusions:

• Altered responsiveness, including impaired verbal recall and motor response, can occur in healthy children during hyperventilation-induced high-amplitude rhythmical slowing.
• These findings suggest that impaired responsiveness during HIHARS in a normal setting is a physiological effect.