Modulation of EEG spectral edge frequency during patterned pneumatic oral stimulation in preterm infants.

BACKGROUND: Stimulation of the nervous system plays a central role in brain development and neurodevelopmental outcomes. Thalamocortical and corticocortical development is diminished in premature infants and correlated to electroencephalography (EEG) progression. The purpose of this study was to determine the effects of orocutaneous stimulation on the modulation of spectral edge frequency fc = 90% (SEF-90), which is derived from EEG recordings in preterm infants. METHODS: A total of 22 preterm infants were randomized to experimental and control conditions. Pulsed orocutaneous stimulation was presented during gavage feedings begun at ~32 wk postmenstrual age. The SEF-90 was derived from two-channel EEG recordings. RESULTS: Compared with the control condition, the pulsed orocutaneous stimulation produced a significant reorganization of SEF-90 in the left (P = 0.005) and right (P < 0.0001) hemispheres. Notably, the left and right hemispheres showed a reversal in the polarity of frequency shift, demonstrating hemispheric asymmetry in the frequency domain. Pulsed orocutaneous stimulation also produced a significant pattern of short-term cortical adaptation and a long-term neural adaptation manifested as a 0.5 Hz elevation in SEF-90 after repeated stimulation sessions. CONCLUSION: This is the first study to demonstrate the modulating effects of a servo-controlled oral somatosensory input on the spectral features of EEG activity in preterm infants.

Effects of Oral Stimulus Frequency Spectra on the Development of Non-nutritive Suck in Preterm Infants with Respiratory Distress Syndrome or Chronic Lung Disease, and Preterm Infants of Diabetic Mothers.

The precocial nature of orofacial sensorimotor control underscores the biological importance of establishing ororythmic activity in human infants. The purpose of this study was to assess the effects of comparable doses of three forms of orosensory experience, including a low-velocity spectrally reduced orocutaneous stimulus (NT1), a high-velocity broad spectrum orocutaneous stimulus (NT2), and a SHAM stimulus consisting of a blind pacifier. Each orosensory experience condition was paired with gavage feedings 3x/day for 10 days in the neonatal intensive care unit (NICU). Four groups of preterm infants (N=214), including those with respiratory distress syndrome (RDS), chronic lung disease (CLD), infants of diabetic mothers (IDM), and healthy controls (HI) were randomized to the type of orosensory condition. Mixed modeling, adjusted for gender, gestational age, postmenstrual age, and birth weight, demonstrated the most significant gains in non-nutritive suck (NNS) development among CLD infants who were treated with the NT2 stimulus, with smaller gains realized among RDS and IDM infants. The broader spectrum of the NT2 stimulus maps closely to known response properties of mechanoreceptors in lip, tongue, and oral mucosa and is more effective in promoting NNS development among preterm infants with impaired oromotor function compared to the low-velocity, spectrally reduced NT1 orosensory stimulus.

Short-Term Effects of Pacifier Texture on NNS in Neurotypical Infants.

The dense representation of trigeminal mechanosensitive afferents in the lip vermilion, anterior tongue, intraoral mucosa, and temporomandibular joint allows the infant's orofacial system to encode a wide range of somatosensory experiences during the critical period associated with feed development. Our understanding of how this complex sensorium processes texture is very limited in adults, and the putative role of texture encoding in the infant is unknown. The purpose of this study was to examine the short-term effects of a novel textured pacifier experience in healthy term infants (N = 28). Nonnutritive suck (NNS) compression pressure waveforms were digitized in real time using a variety of custom-molded textured pacifiers varying in spatial array density of touch domes. MANCOVA, adjusted for postmenstrual age at test and sex, revealed that infants exhibited an increase in NNS burst attempts at the expense of a degraded suck burst structure with the textured pacifiers, suggesting that the suck central pattern generator (sCPG) is significantly disrupted and reorganized by this novel orocutaneous experience. The current findings provide new insight into oromotor control as a function of the oral somatosensory environment in neurotypically developing infants.