Validation of the optimal site in the neck region for detecting swallowing sounds

Recently, the swallowing sound has been used to detect swallowing events non‐invasively. A previous study, using an accelerometer, showed that the site over the lateral border of the trachea immediately inferior to the cricoid cartilage was the optimal site for detecting swallowing sounds. However, the optimal site for detection of the swallowing sound using a microphone remains undetermined. To validate the optimal site in the neck region for detecting swallowing sounds. Fourteen healthy subjects (mean age, 27·6 ± 2·2 years; seven male and seven female) participated in this study. Twenty condenser microphones were attached to 20 sites on the left neck surface to detect swallowing sounds. Participants were instructed to swallow five different stimuli three times as follows: Resting saliva, 1 and 5 mL of Japanese tea, and 1 and 5 mL of yoghurt. Mean relative peak intensity was used to indicate the magnitude of the swallowing sound. Sound spectrograms were used to illustrate differences in the properties of swallowing sounds. Mean relative peak intensity number was highest in sites at the inferior border of the mandible just above the sternocleidomastoid muscle (site 11) and sites over the lateral border of the trachea immediately inferior to the cricoid cartilage (site 8). Comparison of spectrograms showed a greater density distribution of higher frequency components at site 11 compared with site 8. These results indicate that the inferior border of the mandible just above the sternocleidomastoid muscle is the optimal site for the detection of swallowing sounds.     

Differences in Left Ventricular Twist Related to Age: Speckle Tracking Echocardiographic Data for Healthy Volunteers from Neonate to Age 70 Years

Objective: To determine normal left ventricular (LV) twist characteristics in different age groups and assess changes between neonates and the elderly. Methods: Short‐axis left ventricle images at basal and apical levels were acquired in 274 healthy volunteers (aged 15 days to 72 years) by two‐dimensional echocardiography, and were analyzed off‐line using Speckle tracking echocardiography (STE) software to obtain LV twist measurements. The peak apical rotation (PAr), peak basal rotation (PBr), peak LV twist (Ptw), peak LV twist normalized by LV length (Ptw N ), peak untwisting velocity (PutwV), and isovolumic untwisting% (Iutw%) were measured. Results: LV twist values vary with age. Ptw was higher in older volunteers. PtwN varied inconsistently with age. PutwV and Iutw% were lower in the young and old with a peak in mid–age ranges. Conclusions: STE is an effective noninvasive method to assess LV twist. Age‐related differences in LV twist may reflect maturation and adaptive modulation of LV torsional biomechanics from neonate to the elderly. (Echocardiography 2010;27:1205‐1210)