Biomedical subjects

Eric W Reynolds

Publications and source records attributed to Eric W Reynolds.

3 recordsLinked to original sources

PubMed2003

Integration of suck and swallow rhythms during feeding in preterm infants with and without bronchopulmonary dysplasia.

The aim of this study was to define quantitative measures for assessing the integration and maturation of suck and swallow rhythms in preterm infants as they relate to each other. Fourteen preterm infants (eight males, six females; gestational age range 26 to 32 weeks) with bronchopulmonary dysplasia (BPD) and an age-matched cohort of 20 infants (10 males, 10 females; gestational age range 26 to 33 weeks) without BPD were studied weekly from time of initiation of oral feeding using simultaneous recordings of nipple and pharyngeal pressure. The integration of suck and swallow rhythms was quantified by using the coefficient of variation (COV) of the suck-swallow dyad interval. Infants without BPD had a significant correlation between increasing postmenstrual age (PMA) and decreasing COV of the dyadic interval (increasing stabilization; r=0.45; p=0.008). In the non-BPD cohort 35 weeks or less PMA, the mean dyadic COV was 0.42 (SD 0.12) versus 0.34 (SD 0.09) in those more than 35 weeks PMA (p=0.039). In contrast, dyadic stability in infants with BPD was not correlated with PMA. Infants with BPD of more than 35 weeks PMA had less dyadic stability (0.45, SD 0.10) than did age-matched controls (p<0.001). Dyadic stability was also correlated with feeding efficiency in the non-BPD group (r=0.46;p=0.007) but not in the BPD cohort. Therefore, ontogeny of rhythmic suckle feeding can be described quantitatively in preterm infants, allowing comparison with at-risk populations. Infants with BPD do not follow predicted maturational patterns of suck-swallow rhythmic integration.

Analysis of Variance↗

PubMed2003

Cervical accelerometry in preterm infants with and without bronchopulmonary dysplasia.

Cervical accelerometry with digital signal processing (DSP) can identify signals that are consistently associated with swallowing during feeding of infants. It is shown that these signals, called initial discrete sounds (IDSs), become more uniform with advancing postmenstrual age (PMA) in healthy preterm infants. The objectives of this study were to determine if cervical accelerometry and DSP at a higher sample rate than previously used (22 kHz versus 16 kHz), in conjunction with a DSP software package that allows manipulation of the sound files, would improve the accuracy of the previously developed variance index (VI) method of analyzing accelerometric information. The modified VI method was then used to measure developmental differences in the IDS morphology of infants with and without bronchopulmonary dysplasia (BPD). VIs were calculated for 24 feeding studies of infants of between 32 and 39 weeks PMA: 12 studies on healthy preterm infants (n = 10: three males, seven females; mean gestational age [GA] 28.6 weeks, SD 0.4; mean birthweight [BW] 1080 g, SD 82; PMA mean 35.2 weeks, SD 0.6) and 12 studies on infants with BPD (n = 7: five males, two females; GA 27.1 weeks, SD 0.4; BW 911 g, SD 71; PMA 36.2 weeks, SD 0.6). There was a significant inverse correlation between VI and PMA for the healthy preterm group (r = 0.66, m = -2.31/week,p = 0.02). There was no significant correlation between VI and PMA for the BPD cohort. The VI of infants with BPD was significantly different from that of infants without BPD (p < 0.007, multiple regression analysis, interaction PMA x Group). Additionally, using our modified VI technique, 100% of swallows were found to have the expected IDS signals.

Analysis of Variance↗

PubMed2002

Cervical accelerometry in preterm infants.

The objective of this study was to develop a method to use digital signal processing (DSP) technology to describe quantitatively and statistically swallow-associated sounds in preterm infants and to use this method to analyze changes as infants mature. Twelve recordings of accelerometric and physiological data on bottle-feeding preterm infants between 32 and 39 weeks' postmenstrual age (PMA) were analyzed. Cervical auscultation was performed using an accelerometer attached over the larynx. Acoustic data were recorded and graphically displayed using DSP software. Initial discrete sounds (IDSs) were identified and used to construct an average waveform from which a 'variance index' (VI) was calculated for each infant. The shape of the IDS waveforms became progressively more uniform with advancing PMA, as indicated by a significant inverse correlation between VI and PMA (r=0.739; p=0.006). DSP technology facilitated the development of a new method to quantitatively analyze feeding in preterm infants. This method provides an elegant tool to track maturation of infant feeding and assessing feeding readiness. This technique makes the interpretation of cervical auscultation data less subjective by replacing the verbal description of the sounds of feeding with quantitative numeric values. It is anticipated that this method can be automated to facilitate further the analysis of cervical accelerometry data.

Acoustics↗