Objective
To investigate and compare proprioception characteristics in healthy adults using different measurement methods.
Methods
Participants engaged in three tasks using a device developed to assess elbow joint proprioception: the ipsilateral matching task (IMT), contralateral matching task (CMT), and pointing task (PT). Each task was performed three times at different angles (30°, 50°, and 70°) in a randomised order for nine trials and tested for both the right and left arms. Activity level was measured using the International Physical Activity Questionnaire-Short Form.
Results
Twenty healthy adults (10 males, mean age: 39.80±12.19 years) were enrolled. The absolute error of the IMT was significantly lower than that of the CMT and PT (Bonferroni [Bonf.] p=0.029 and 0.016, respectively). PT showed a higher variable error than that of IMT and CMT (Bonf. p<0.001, and 0.040, respectively). There were no significant differences in errors across tasks based on sex or age. The total International Physical Activity Questionnaire- Short Form score showed statistically significant correlations with the absolute error (r=-.460, p=0.041) and constant error (r=-.469, p=0.037) of the CMT and variable error of the PT (r=-.478, p=0.033).
Conclusion
This study demonstrated that different proprioceptive tasks can assess the unique characteristics of proprioceptive function. The IMT produced lower error values than those of the CMT and PT, with the PT exhibiting higher variability. These differences may stem from distinct mechanisms that depend on the nature of each task and warrant further investigation.

Objective
To explore the effects of tactile stimulation using air pressure at the auricular branch of the vagus nerve on autonomic activity in healthy individuals.
Methods
Three types of tactile stimulation were used in this study: continuous low-amplitude, continuous high-amplitude, and pulsed airflow. The tactile stimulations were provided to the cymba concha to investigate autonomic activity in 22 healthy participants. The mean heart rate (HR) and parameters of HR variability, including the standard deviation of R-R intervals (SDNN) and root mean square of successive R-R interval differences (RMSSD) were compared at baseline, stimulation, and recovery periods.
Results
Two-way repeated measures ANOVA indicated a significant main effect of time on HR (p=0.001), SDNN (p=0.003), and RMSSD (p<0.001). These parameters showed significant differences between baseline and stimulation periods and baseline and recovery periods in the post-hoc analyses. There were no significant differences in the changes induced by stimulation type and the interaction between time and stimulation type for all parameters. One-way repeated measures ANOVA showed that HR, SDNN, and RMSSD did not differ significantly among the three time periods during sham stimulation.
Conclusion
Parasympathetic activity can be enhanced by auricular tactile stimulation using air pressure, targeting the cymba concha. Further studies are warranted to investigate the optimal stimulation parameters for potential clinical significance.

Citations

• Effects of tactile auricular vagus nerve stimulation using heated and humidified airflow on cardiac autonomic activity: a pilot experimental study
  Soohyun Wi, Sungwoo Park, Byung-Mo Oh, Han Gil Seo, Yae Lim Lee, Woo Hyung Lee
  Clinical Autonomic Research.2025; 35(3): 519.     CrossRef
• Auricular neuromodulation may act through interoception modulation
  Frédéric Canini, Damien Claverie, Florence Weill, Christine Pailler, Béatrice Paquier, Mireille Michel-Cherqui, Sonia Pellissier, Marion Trousselard, Emmanuel Sagui
  Brain Research.2025; 1863: 149736.     CrossRef
• Stroking Stimuli to the Ear to Enhance Pleasant and Non-arousing Feelings while Listening to Sounds
  Yuta GOTO, Shogo OKAMOTO
  International Journal of Affective Engineering.2024; 23(3): 251.     CrossRef
• Relaxation Effects of Auricular Vibration Stimuli Synchronized with Music
  Yuta GOTO, Shogo OKAMOTO
  International Symposium on Affective Science and Engineering.2024; ISASE2024: 1.     CrossRef