This study compared the effects of oral stimulation with those of oral support on non-nutritive sucking and feeding parameters in preterm infants. Preterm infants (23 males, 20 females) born between 29 and less than 34 weeks' gestational age (GA; mean GA 31.2wks [standard error of mean{SEM} 0.39]; mean birthweight 1580g [SEM 120]) were allocated to one of three experimental groups: (Stimulation+support [five males, four females]; Stimulation [four males, seven females]; and Support [seven males, five females]) or a control group. Non-nutritive sucking pressure and sucking activity were quantified in the gavage and transition periods. Oral support minimizes fluid loss, stabilizes the jaw, and organizes deglutition. The time of transition, the quantity of milk ingested per day, and the number of bottle feeds per day were recorded. Variables were analyzed by repeated-measures analysis of variance, with birthweight as covariate (ANCOVA). Transition time was reduced (p<0.0001) for the Stimulation+support and Support groups. ANCOVA computed during gavage showed increased nonnutritive sucking pressure and sucking activity (p<0.001) for the Stimulation and Stimulation+support groups. ANCOVA computed during transition revealed increases in non-nutritive sucking pressure and daily bottle feeds (p<0.001) for the three experimental groups and in daily milk ingested (p=0.002) for the Stimulation+support and Support groups. We demonstrated that oral support is the result of both the action of chin and cheek support, and the aid to deglutition. An analysis of the organization of sucking patterns should be undertaken to provide better understanding of the mechanisms involved in oral support.

The aim of this study was to identify the origin of swallowing sound components by using modern techniques that can provide numeric, synchronized acoustic-radiologic data. We enrolled 15 volunteer subjects (10 men and 5 women, average age = 29.5 +/- 8 years) and used an X-ray camera connected to a video acquisition card to obtain synchronized acoustic-radiologic data (25 images/s). The subjects were asked to swallow 10 ml of a barium suspension. Each sound component was associated with a specific position of the bolus and the anatomic structure that was moving. The average duration of the pharyngeal sound was 690 +/- 162 ms. The durations of the laryngeal ascension sound and the laryngeal release sound were significantly different (72 +/- 38 ms and 106 +/- 47 ms, p < 0.001). The upper-sphincter opening sound was present in 100% of the recordings. Its duration was 185 +/- 103 ms and was significantly different from the two other sounds. The duration of the first interval was 108 +/- 44 ms and the duration of the second was 236 +/- 139 ms. This study allowed us to determine the origin of the three main sound components of the pharyngeal swallowing sound with respect to movements in anatomic structures and the different bolus positions.

Cervical auscultation is a noninvasive technique for studying swallowing that was first used in the 1960s. The aim of our study was to use the numeric acoustic recording technique for analyzing swallowing sound signals in healthy subjects while they ingested a defined volume and consistency of a specific substance. Twenty males and ten females were included in the study and given 10 ml of a barium suspension to swallow. A microphone was placed on the skin overlying the lateral border of the trachea, directly under the inferior border of the cricoid, and connected to a computer. For each sound recording, the total duration of the sound (td), the number (n) of sound components (SC), the duration of each SC (c1, c2, c3,...), and the intervals (i1, i2,...) between the SCs were measured. For all the recordings, the mean durations of acoustic parameters (TDm, C1m, C2m, C3m, I1m, I2m) were calculated and compared by using Student's t test. In the 20 male subjects, the mean acoustic parameters were calculated (MTDm, MC1m, MC2m, MC3m, MI1m, MI2m) and compared with the mean acoustic parameters (FTDm, FC1m, FC2m, FC3m, FI1m, FI2m) in the ten females by using a Wilcoxon nonparametric statistical test. We were able to interpret 80% of the recordings. The TDm was 710 +/- 28 ms. Three main SCs were detected: C1m = 100 +/- 56, C2m = 150 +/- 90, C3m = 80 +/- 54 ms; I1m = 100 +/- 66, I2m = 190 +/- 120 ms. No significant difference in these parameters was observed with respect to gender. This study enabled us to decompose the swallowing sounds into three main SCs and to quantify their normal durations. These results should prove useful for the assessment of sound variations in pathologic conditions.

The aims of this study were to analyze the following by audiorecording of swallows: (1) the influence on the volume and consistency of ingested substances on the audiosignal recorded during separate swallows; and (2) the characteristics of successive swallows during ingestion of 100 ml of the same substances to define deglutitive behaviors. Volunteers followed two protocols. Protocol (P) 1 comprised ingestion of 100 ml of water or yoghurt in successive swallows and Protocol 2 comprised separate swallows of different volumes of the same substances. Audiosignal recordings were made with a dynamic microphone. The following parameters were measured in P1: total time of ingestion (TT), number of swallows necessary for ingestion (N), and spontaneous swallowing intervals (SI). In P2 the duration (d) of each signal was measured according to consistency and volume. Mean (m) values were then calculated (TTm, Nm, SIm, and dm). During P1, TTm for yoghurt was significantly longer than for water (23.1 vs. 6.5 sec (men) and 21.8 vs. 7.8 sec (women). Nm was also greater for yoghurt (10.1 vs. 4.3 (men) and 10.0 vs. 4.8 (women). Three types of swallowing behavior were defined according to SI: swallowing at regular intervals (Reg) with increasing intervals during ingestion (Prog) and swallowing at variable intervals (Irreg). These patterns did not differ significantly according to sex. In P2 the increase in volume swallowed increased the duration (dm) of the signal for water (600 msec for 5 ml and 960 msec for 15 ml). The dm for yoghurt was significantly less than for water (580 msec for 5 ml and 920 msec for 15 ml). Our technique of recording sounds of pharyngeal swallowing is simple, reproducible, and not expensive. It permitted the analysis of each swallow according to volume and consistency and the determination of three swallowing patterns (Reg, Prog, and Irreg), taking into account the spontaneous swallowing interval. Ingestion by successive swallows could be used to characterize certain pharyngoesophageal motor dysfunctioning in relation to this reference population and to integrate this into a deglutition rehabilitation program.

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