Results and Discussion

Vocal Fold Stimulation 

Vocal Cord Adduction Vocal Cord Abduction 

According to the ANOVA test, no significant interactions between Electrode_Positioning, Pulse_Rate, and Pulse_Width for Δ_Abduction_Angle (p>0.05) are observed. However, Pulse_Rate is the main effect significant (p<0.05), indicating a relationship with Δ_Abduction_Angle. The results may not generalize and unmeasured factors could influence Δ_Abduction_Angle, so further trials on a broader population is needed.

Discussion

Our exploration into the application of transcutaneous stimulation to influence vocal fold adduction has produced promising results. Analyzing the outcomes of our tests, we found that the vocal fold adduction angles widened to varying degrees after stimulation. Remarkably, we achieved an approximate 22.61 degrees opening while the subject held their breath, using two large leads placed vertically on the trachea, a pulse rate of 60 Hz, and a pulse width of 100 μs. Interestingly, the same lead positioning with a pulse width of 50 μs resulted in the second-largest degree of adduction.

These findings, achieved using a vertical cricothyroid electrode orientation, suggest that this might be an optimal approach for breaking laryngospasms. The parameters employed during the experiment were a 90 mA current, frequencies of 30 and 60 Hz, and pulse widths of 50, 100, and 200 μs. Notably, we did not register any significant change in the adduction angle with alterations in stimulation frequency.

Despite these promising results, our study had certain limitations, mainly time constraints, that prevented comprehensive testing on various electrode positions. Instead, we concentrated on a select range of positions we deemed most likely to deliver the required outcomes. There is also a need for more trials involving different types of electrodes and leads. Our restricted timeline also led to a limited number of test subjects (n=2), questioning the broader applicability of our findings.

Furthermore, conducting all tests within one session could potentially have led to muscle fatigue, thus decreasing reactivity to electrical stimulation and complicating our results. The limitation of pain during the tests also prevented us from maximizing intensities.

Consequently, we believe further extensive testing and trials, ideally utilizing pig models, will be crucial in evaluating this transcutaneous stimulation method's efficacy for breaking laryngospasms. However, our initial trials and data suggest that this approach offers significant potential for inhibiting laryngospasms.