# Wearable Voice Dosimetry System
## 2 Related Work
### Voice Dosimetry Studies  
Voice dosimetry studies predominantly focus on professions where vocal demands are significant, such as teaching. These studies help understand the vocal strain associated with these professions and explore potential mitigations.  
1. **Teachers and Vocal Load**: [PERSON] and [PERSON] noted that teachers with frequent vocal fatigue complaints exhibited a higher fundamental frequency (F0) and intensity (I) at the day's end and week's end, indicating significant vocal strain [7]. In contrast, [PERSON] and [PERSON] found that teachers' vocal usage during work was substantially higher in duration, intensity, and pitch compared to non-working periods. They documented that speaking constituted 29.9% of work hours compared to 12% during rest, with a higher pitch and intensity of about 2.5 dBSPL [45; 46];
2. **Mitigation Strategies**: The use of audio amplification systems has been shown to effectively reduce the vocal load by lowering the need for vocal intensity [8; 47; 48]. Additionally, classroom acoustics play a crucial role; poor acoustics often lead teachers to increase their voice intensity, further straining their voices [49]. Similarly, a noisy environment forces an increase in voice intensity [50; 51];
3. **Voice Monitoring and Feedback Systems**: [PERSON] et al. successfully used a voice response/feedback system in children to achieve and maintain lower intensity levels during speech activities [28]. However, [PERSON] et al. noted that without the continuous use of such devices, the learned behaviours were not maintained, indicating the need for regular use [52]. These systems have also been applied to study vocal pauses and their effects on vocal health [53; 54];
4. **Clinical Applications**: [PERSON] et al. reported the use of a voice response dosimetry system that helped avoid surgeries by aiding in the recovery of vocal fold pathologies, such as polyps and nodules, through regular monitoring [24]. Similarly, [PERSON] and [PERSON] observed that short-term oortracheal intubation increased shimmer and jitter in sustained vowels, affecting vocal quality [55];
5. **Post-Surgery Voice Rest Monitoring**: After laryngeal surgeries, voice rest is crucial. [PERSON] et al. demonstrated that voice dosimetry devices could effectively monitor and enforce voice rest, showing significant reductions in phonation time and intensity [56];
6. **Innovative Measurement Techniques**: Apart from acoustic signal analysis, other methods like using accelerometers to measure skin vibrations at the larynx provide a non-invasive and privacy-respecting way to assess vocal cord activity during phonation. These measurements can be crucial for diagnosing and prognosticating voice disorders [55; 57].  
These studies underscore the importance of monitoring and managing vocal load, particularly in vocally demanding professions, to prevent long-term damage and improve vocal health outcomes.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Voice Parameter** & **APM** & **VoxLog** & **VocalLog** & **Voice-Care** \\ \hline Intensity (dBspl) & X & X & X & X \\ Intensity warning & X & X & X & \\ Fundamental frequency (Hz) & X & X & & X \\ Frequency warning & X & X & & \\ Phonation time (hh:mm:ss) & X & X & X & X \\ Ambient noise (dBSPL) & & X & & \\ Number of Cycles & X & & & \\ Distance travelled by the vocal & & X & & \\ folds (meters) & & & & \\ Intensity calibration & Daily & Not necessary & Once & Once \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparison of commercial devices [20; 38].