The respiratory control of carbon dioxide in children and adolescents referred for treatment of psychogenic non-epileptic seizures.
Psychogenic non-epileptic seizures (PNES) are a common problem in paediatric neurology and psychiatry that can best be understood as atypical responses to threat. Threats activate the body for action by mediating increases in arousal, respiration, and motor readiness. In previous studies, a range of cardiac, endocrine, brain-based, attention-bias, and behavioral measures have been used to demonstrate increases in arousal, vigilance, and motor readiness in patients with PNES. The current study uses respiratory measures to assess both the motor readiness of the respiratory system and the respiratory regulation of CO2. Baseline respiratory rates during clinical assessment and arterial CO2levels during the hyperventilation component of routine video electroencephalogram were documented in 60 children and adolescents referred for treatment of PNES and in 50 controls. Patients showed elevated baseline respiratory rates [t(78) = 3.34, p = .001], with 36/52 (69%) of patients [vs. 11/28 (39%) controls] falling above the 75th percentile (χ2= 6.7343; df = 1; p = .009). Twenty-eight (47%) of patients [vs. 4/50 (8%) controls] showed a skewed hyperventilation-challenge profile-baseline PCO2<36 mmHg, a trough PCO2≤ 20 mmHg, or a final PCO2<36 mmHg after 15 min of recovery-signaling difficulties with CO2regulation (χ2= 19.77; df = 1; p < .001). Children and adolescents with PNES present in a state of readiness-for-action characterized by high arousal coupled with activation of the respiratory motor system, increases in ventilation, and a hyperventilation-challenge profile shifted downward from homeostatic range. Breathing interventions that target arousal, decrease respiratory rate, and normalize ventilation and arterial CO2may help patients shift brain-body state and avert PNES episodes.
Psychological Medicine, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW, 2145, Australia. Kkoz6421@uni.sydney.edu.au.|Brain Dynamics Centre, Westmead Institute for Medical Research, Westmead, NSW, Australia. Kkoz6421@uni.sydney.edu.au.|University of Sydney Medical School, Sydney, NSW, Australia. Kkoz6421@uni.sydney.edu.au.
Kasia
http://orcid.org/0000-0002-9578-0753
K
Kozlowska
Psychological Medicine, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW, 2145, Australia.|University of Sydney Medical School, Sydney, NSW, Australia.
Reena
R
Rampersad
Psychological Medicine, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW, 2145, Australia.
Catherine
C
Cruz
Psychological Medicine, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW, 2145, Australia.|University of Sydney Medical School, Sydney, NSW, Australia.|Lady Cilento Children's Hospital, Brisbane, QLD, Australia.
Ubaid
U
Shah
Psychological Medicine, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW, 2145, Australia.|University of Sydney Medical School, Sydney, NSW, Australia.
Catherine
C
Chudleigh
Psychological Medicine, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW, 2145, Australia.|University of Sydney Medical School, Sydney, NSW, Australia.
Samantha
S
Soe
Psychological Medicine, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW, 2145, Australia.|University of Sydney Medical School, Sydney, NSW, Australia.
Deepak
D
Gill
University of Sydney Medical School, Sydney, NSW, Australia.|Department of Psychiatry, Harvard Medical School, Boston, MA, USA.|McLean Hospital, Belmont, MA, USA.
Stephen
S
Scher
Department of Anatomy, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
Pascal
P
Carrive
D000293:Adolescent; D001921:Brain / Q000473:pathology*; D002245:Carbon Dioxide / Q000494:pharmacology / Q000627:therapeutic use*; D002648:Child; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D012640:Seizures / Q000188:drug therapy* / Q000473:pathology / Q000523:psychology*
D002245:Carbon Dioxide
Conversion disorder; Dissociative convulsions; Functional neurological symptom disorder; Hyperventilation; Non-epileptic seizures