Cortical arousal in children and adolescents with functional neurological symptoms during the auditory oddball task

Abstract

ObjectiveStress, pain, injury, and psychological trauma all induce arousal-mediated changes in brain network organization. The associated, high level of arousal may disrupt motor-sensory processing and result in aberrant patterns of motor function, including functional neurological symptoms. We used the auditory oddball paradigm to assess cortical arousal in children and adolescents with functional neurological symptom disorder.MethodElectroencephalogram (EEG) data was collected in fifty-seven children and adolescents (41 girls; 16 boys, aged 8.5–18 years) with acute functional neurological symptoms and age- sex- matched controls during a conventional auditory oddball task. The high-resolution fragmentary decomposition technique was used to analyse the amplitude of event-related potentials (ERPs) to target tones at midline sites (Fz, Cz, and Pz).ResultsCompared to age- and sex-matched controls, and across all three midline sites, children and adolescents with functional neurological symptoms showed increased amplitude of all ERP components (P50, N100, P200, N200, and P300) (t-value range 2.28–8.20; p value-range 0.023 to < 0.001) to the emotionally-neutral auditory stimulus.ConclusionsOur findings add to a growing literature indicating that a baseline state of high arousal may be a precondition for generating functional neurological symptoms, a finding that helps explain why a range of psychological and physiological stressors can trigger functional neurological symptoms in some patients. Interventions that target cortical arousal may be central to the treatment of paediatric patients with functional neurological symptom disorder.

The respiratory control of carbon dioxide in children and adolescents referred for treatment of psychogenic non-epileptic seizures

“…First, because of the close coupling between respiration and sympathetic arousal, HV-induced increases in cortical arousal could trigger PNES by disrupting cortical executive control over the motor cortex and cortico–basal ganglia–thalamocortical loops. Since children/adolescents with PNES show increased baseline autonomic and cortical arousal [ 10 , 13 , 15 ], even minor elevations in arousal mediated by HV could disrupt cortical control and serve to disrupt cortical integration [ 60 – 62 ] and trigger PNES. Second, if HV continues beyond the excitatory stage into the hypoxic stage, then hypoxia-related impairments in the cortex and basal ganglia [ 63 ] will likewise contribute to dysfunction in top–down control mechanisms within the motor system and to disruptions in the brain’s vertical integration.…”

“…A growing number of studies have examined the neurophysiological characteristics of patients with PNES. Key findings include: (1) increased baseline arousal indexed by elevated cortisol, elevated heart rate (HR), decreased heart rate variability (HRV) [ 8 – 10 ] 1 ; (2) exaggerated neurophysiological responses—lower HRV recovery, increased cortisol release, and increased amplitudes of event-related potentials (ERPs)—to psychological or physiological stress stimuli [ 8 , 14 , 15 ]; (3) increased vigilance, and motor readiness to respond, to emotional signals [ 8 , 11 ]; (4) changes in connectivity in resting-state brain networks, with alterations in brain circuits mediating emotion regulation and arousal, cognitive control, self-referential processing, and motor planning and coordination [ 5 ]; (5) changes in EEG synchrony, both within cortical brain systems and between cortical and subcortical brain systems [ 16 – 19 ]; (6) arousal-related impairments in prefrontal cortex function [ 12 , 14 ]; and (7) increased avoidance tendencies to social-threat cues [ 20 ]. Taken together, these findings suggest that PNES may emerge in the context of an upregulated stress system and extreme reactivity to psychological or physiological threat stimuli.…”

“… 1 In the earlier studies by Kozlowska et al, children/adolescents with PNES made up 51% ( n = 29/57) of the samples [ 10 – 12 ]. In the most recent study of cortical arousal, children/adolescents with PNES made up 56% ( n = 32/57) of the sample [ 13 ]. …”

Psychogenic non-epileptic seizures in children and adolescents: Part II – explanations to families, treatment, and group outcomes

“…In the eyes-open, resting-state condition, our patients showed increased heart rate (reflecting increased sympathetic arousal) and lower heart rate variability (reflecting decreased vagal or restorative-parasympathetic tone) ( Kozlowska et al, 2015 ). Under task conditions, they showed an increased cortical response to an auditory stimulus (suggesting activation of brain arousal systems) ( Kozlowska, Melkonian, Spooner, Scher, & Meares, 2017 ) and increased motor readiness to emotion faces (suggesting activation of the motor system) ( Kozlowska, Brown, Palmer, & Williams, 2013 ). In the current cohort of 60 children/adolescents with PNES, in the baseline eyes-open, resting state-condition, we also found that our patients (vs controls) showed increased heart rates and increased respiratory rates ( Kozlowska, Rampersad, et al, 2017 ), consistent with the coupling between sympathetic arousal (which innervates the cardiac motor system) and the respiratory motor system.…”

Processing of Emotion in Functional Neurological Disorder

“…PNES patients also showed increased avoidance tendencies to social threat cues ( 47 ) but other study showed that avoidance learning is impaired in heterogenous FND group ( 38 ). In a pediatric FND patients, Kozlowska et al ( 37 ) found increased cortical arousal during an auditory oddball task and the same research group also demonstrated high autonomic arousal at baseline and in response to emotional faces in children with FND ( 49 ).…”