Sonographically measured hyoid bone displacement during swallow in preschool children: a preliminary study

PURPOSE

This study explored normative parameters regarding maximum displacement of hyoid bone movement during spontaneous swallows using ultrasound (US) in a sample of healthy preschool children. We hypothesized that consistency and bolus size would influence hyoid movement, but gender would not be a factor.

METHODS

Parental questionnaire responses and sensorimotor examinations were utilized to determine subject eligibility. Subjects were presented randomized bolus volumes of thin liquids/puree via a spoon while the US probe was placed submentally in the midsagittal plane. Maximum hyoid bone displacement was determined following a frame-by-frame analysis of the US recording during spontaneous swallowing of discrete bolus sizes.

RESULTS

Twenty-nine subjects produced 346 swallows that were subsequently analyzed. Significant findings (p < 0.05) included a gender effect with the smallest bolus of liquids presented. Bootstrap estimates based on our sample revealed that 99% of preschool children would present with hyoid bone displacement within 0.3 cm of our sample.

CONCLUSIONS

Based on our early experience, we were able to observe and measure changes in hyoid bone position during swallowing in preschoolers, which may be gender related. More studies are needed to corroborate our findings. In addition, comparisons of maximum hyoid displacement are warranted in subjects that present with feeding delays.

Clinical implications of design characteristics, flow rates, and suction pressure attributes in commercially available training cups

OBJECTIVE

Transitioning from a bottle to open cup drinking can be a lengthy process in typical development. Children are often introduced to training cups during this period. Due to a lack of standardization in commercially available training cups, differences in design and performance characteristics may potentially create medical complications in developmentally delayed individuals. Our purpose is to report commercially available training cup design characteristics, residual fluid, flow rates, and suction pressures and discuss the potential clinical implications.

DESIGN

A testing apparatus was developed to determine suction pressure and flow rate. Nine commercially available training cups were tested by two independent research teams. Experimental data were filtered and then fit with a linear approximation determined by a least squares method.

RESULTS

Commercially available cups exhibited extensive variability in design parameters, suction pressure, rate of flow, and residual fluid.

CONCLUSION

The extensive variability of design and function within current commercially available cups has clinical implications for children with development delays such as the ingestion of air and aspiration. Studying the variability of existing training cup performance identifies characteristics that impact cup function which can influence future cup design.

Hypothetical anatomical model to describe the aberrant gag reflex observed in a clinical population of orally deprived children

In this 'clinical conundrum', we propose a hypothetical anatomical model to explain the abnormal gag reflex that is consistently observed in a clinical population of children experiencing feeding delays. This model is based on the presence of 'transient' connections formed during the normal development of autonomic brainstem circuitry involving the nucleus tractus solitarius (NTS). We propose that, as a result of normal feeding and swallowing, the activity of these transient fibers typically diminishes shortly after birth. In children who are orally deprived during infancy, these transient connections persist and the aberrant gag reflex is maintained into childhood. The most critical feature of the proposed model is the idea that swallowing during feeding initiates the retraction of the tactile 'transient' input to NTS. In the NICU feeding clinics, it has been suggested that triggering the gag reflex in neonates by tactile stimulation of non-oral body areas and anterior portions of the mouth directly or indirectly may contribute to oral feeding delays. To the contrary, we propose an anatomical model to suggest that oral feeding delays and lack of swallowing food, when experienced by neonates, actually contribute to the development of the aberrant gag reflex observed in later developmental stages.