| dc.description.abstract | The vestibular system of the fetus is responsive to accelerations in utero by 25 weeks gestational age (Hooker, 1969). However, the restrictive environment of the crib/isolette in the neonatal intensive care unit (NICU) and decreased positional changes limits vestibular experience and associated neural activity among preterm infants. This project was developed to test a set of hypotheses concerning the role of vestibular inputs on respiratory and oromotor systems during suck and early feeding development in preterm infants. Linear acceleration of the vestibular otoliths was achieved using a customized glider chair, the VestibuGlide System, developed in the Communication Neuroscience Laboratories at the University of Kansas. The VestibuGlide system features an integrated position-servo motor and a digital controller to generate physiologically appropriate sinusoidal displacements of the glider chair in the horizontal plane at specified rates (.5, .65, .8, .95 Hz) and accelerations (.21, .36, and .51 m/s2). It was hypothesized that providing this type of input to the vestibular apparatus will modify the central patterning of chest wall motion, and secondarily may alter suck and feed development during a critical period of brain development. Twelve preterm infants (7F/5M, birth GA 32; 6, BW 1927g) were recruited from the NICU at Stormont-Vail Regional Hospital in Topeka. Each infant received the 15 minute gliding protocol starting at 32 wks PMA, 3x/day before a scheduled feed for 10 days. Infants were fitted with two soft cloth Respitrace¢â inductance bands around the rib cage and abdomen to measure respiratory rate. The gliding protocol alternates between baseline and stimulus conditions every minute. During baseline conditions, the glider chair was stationary. Respiration, suck dynamics, and pulse-oximetry were recorded and monitored throughout the study. On average, infants received 24 VestibuGlide sessions. Stimulus condition had a significant effect for the in rib cage [F (7, 77) = 25.53, p < 0.01] and abdominal [F (7, 77) = 23.60, p < 0.01] breaths per minute (BPM). In general, infants increased their respiratory rate in response to the VestibuGlide stimulus. Stimulus number 7 provided the highest acceleration to the infant and induced significantly higher BPM than stimuli 1, 4, and 5 for the rib cage and stimuli 1 and 4 for the abdomen. It is clear that acceleration has the largest influence over the respiratory central pattern generator (rCPG) and is capable of inducing significant changes in chest wall kinematics. In spite of the increases in BPM during vestibular stimulation, infants maintained stable oxygen saturation (SpO2) and pulse rate throughout the VestibuGlide study. In fact, stimulus condition had a significant effect on SpO2, F (7, 77) = 2.57, p <.05. Infants had higher SpO2 during stimulus conditions 3, 4, and 6 compared to baseline conditions; however, after a Bonferroni-correction these differences could not reach statistical significance. Infants are able to modify their respiratory rate in response to vestibular stimulus while maintaining their SpO2and pulse. All infants were offered a Soothie¢â pacifier during each VestibuGlide session. Vestibular stimulation had no effect on NNS development. Oral feeds were measured in days to achieve ¡Ã90% oral feed for two consecutive days. A daily oral feed percentage was calculated across the eight daily feeds for all infants in the study and was compared to a cohort of 12 untreated preterm infants matched for birth GA (n=12, 7F/5M, GA 33; 2, BW 1950g) from an ongoing NIH trial underway in the mentor¡¯s laboratory (NIH R01 DC003311, Barlow-PI) recruited from Stormont-Vail Healthcare NICU in Topeka, KS and Overland Park Regional Medical Center NICU in Overland Park, KS. ANOVA revealed no difference in the oral feed growth slopes between the VestibuGlide treated infants and the control infants: F (1, 22) = .25, p =.625. On average, VestibuGlide infants advanced their oral feeds at 8.17% per day; whereas, control infants advanced their oral feeds at 9.47% per day. The length of stay in the NICU was measured from the admission date (birth date) to the discharge date for all infants in the VestibuGlide study and 15 untreated preterm control infants matched for birth GA (n=15 8F/7M, GA 32; 5, BW 1888g). ANOVA revealed a significant difference between the two groups F (1, 26) = 4.82, p=.03. The VestibuGlide group discharged from the hospital 9 days sooner than the control infants resulting in a substantial reduction in hospitalization costs (~$31,500/infant). Overall, vestibular stimulation delivered to the preterm infant between 32 and 34 weeks PMA effectively modulates respiratory rate and resets the rCPG. | |
