Definition of voice rest

There is no internationally accepted definition of what is meant by ‘relative voice rest’ nor is there a standardised protocol for the parameters of relative voice rest. Most of these definitions and parameters depend on the choice of the operating surgeon or are based on institution preference. In this study, the term ‘relative voice rest’ was defined as being “along with the generalised voice hygiene instructions mentioned in the pamphlet given to each patient, the patient can use the voice for 5–10 minutes per hour with 45–50 minutes of voice rest and not more than 1–2 minutes at a stretch.”

Because there is no standardised definition of what is meant by relative voice rest, it has been described differently by different authors. Whitling et al.^{Reference Whitling, Lyberg-Åhlander and Rydell4} allowed the relative voice-rest group to use voice for 7 days post-operative in a gentle, comfortable way and to avoid whispering and shouting. Kaneko et al.^{Reference Kaneko, Shiromoto, Fujiu-Kurachi, Kishimoto, Tateya and Hirano2} described relative voice rest as 3 days voice-rest period and compared the results to a complete 7 days voice-rest group and Kiagiadaki et al.^{Reference Kiagiadaki, Remacle, Lawson, Bachy and Van der Vorst5} described relative voice rest as 5 days of voice rest.

Another survey done by Coombs et al.^{Reference Coombs, Carswell and Tierney6} revealed that ‘complete voice rest’ meant no voice production as per 86.5 per cent of respondents, while there was no consistent response as to how respondents described ‘relative voice rest’, and eight physicians were not aware of the term or had not put it to use in their clinical practice. There was a general agreement that a ‘relative voice-rest’ group should be given general instructions of no shouting, no singing, or whispering; however, several respondents also mentioned that they had their own ‘relative voice-rest’ regimes.

Comparison of voice parameters between the two groups

Our study evaluated jitter changes from pre-op values to one-week post-surgical and one-month post-surgical periods in both of the groups (absolute and relative). There was a significant difference in one-week post-op period values in case and control subjects (p = 0.035), but there was no such significant difference in one-month post-op values between the case and control subjects (p = 0.512).

Raju et al.^{Reference Raju, Sargunaraj, Thejesh, Paul, Albert and Mathews7} conducted a prospective randomised control trial which was single-blinded involving 35 patients and categorised the patients into five- and two-day voice-rest groups. They found no statistically significant difference between the two groups, with the exception of jitter, where the five-day voice-rest group showed a statistically significant improvement over the two-day voice-rest group and found compliance was 43 per cent in the absolute voice-rest group of patients.^{Reference Raju, Sargunaraj, Thejesh, Paul, Albert and Mathews7}

A systematic review and meta-analysis done by Chi et al.^{Reference Chi, Cho, Yang, Chen and Chen8} compared four randomised control trials of 112 patients. Chi et al.^{Reference Chi, Cho, Yang, Chen and Chen8} reported comparable voice handicap index and acoustic variables in the form of jitter, shimmer and maximum phonation time in shorter- and longer-term voice-rest groups and unfavourable outcomes on QoL and compliance in the longer-term voice-rest group. In contrast, Cohen et al.^{Reference Cohen, Fridman, Trushin, Benyamini, Duek and Shinnawi9} reported results on 167 patients (a cohort study done both prospectively and retrospectively in a combined way and approximately equally divided into two groups of standard and no voice-rest groups). They noted that voice handicap index scores and acoustic variables showed no difference between the voice-rest and no-voice-rest groups in shimmer (p = 0.9590), jitter (p = 0.5692) or harmonic-to-noise ratio (p = 0.1871) which was statistically significant, and concluded that quality of voice and healing of wound post-operatively were similar in both groups and that ‘no voice rest’ gave equally good results.^{Reference Cohen, Fridman, Trushin, Benyamini, Duek and Shinnawi9}

A prospective study of 55 patients by Singh et al.^{Reference Singh, Upadhyay, Shrivastava and Mundra10} concluded that histopathologically the most common lesions were vocal fold cyst (20) vocal fold polyps (17), papilloma (6) and vocal nodules (7) in 40 per cent of the patients 30–40 years of age and 34 per cent 40–50 years of age and. We found most of our study population to be 40–50 years of age and vocal fold polyps (28) to be the most common histopathology diagnosis. The mean voice handicap index score pre-surgically was 88.15, which reduced to 26.5 after 3 months post-surgically, showing a statistically significant (< 0.001) improvement.^{Reference Singh, Upadhyay, Shrivastava and Mundra10} This is similar to our study in which statistically significant differences were found between the voice handicap index scores of various sessions in absolute and relative groups separately (p < 0.001).

Dhaliwal et al.^{Reference Dhaliwal, Doyle, Failla, Hawkins and Fung11} conducted a randomised controlled trial with 30 patients (15 in each group) and found that post-operative voice handicap index scores and secondary outcomes were not significantly different in the two groups. They ultimately argued that there is no advantage of voice rest on post-operative voice measurements and parameters as determined by patient self-perception, acoustic variables, and auditory-perceptual analysis. In contrast, we found statistically significant differences in the absolute voice-rest and relative voice-rest groups when it came to certain primary outcomes (shimmer, jitter) and secondary outcomes (voice handicap index and compliance), which makes relative voice rest a preferred prescription.

Owing to the fact that some amount of mechanical stimulation in the early stages helps in functional recovery of the vocal folds, 31 patients were recruited and were divided into two groups of three-day and seven-day voice rest in a randomised controlled trial done by Kaneko et al.^{Reference Kaneko, Shiromoto, Fujiu-Kurachi, Kishimoto, Tateya and Hirano2} They found that voice-analysis parameters (jitter, shimmer, and voice handicap index) were significantly better in the three-day group at one month post-surgical intervention. The data suggest that subjects who were in the relative voice-rest category (three days of voice rest followed by voice therapy) did better in terms of wound healing of the vocal fold and had generally better post-operative outcomes as compared to patients put on seven days of absolute voice-rest therapy.

Out of the 43 patients analysed in the retrospective study done by King et al.,^{Reference King, Novaleski and Rousseau12} 13 patients were put in the seven-day absolute voice-rest group, 15 were put in the less than seven-day voice-rest group, with voice handicap index scores noted during the pre-operative period once and twice in the post-operative phase. King et al.,^{Reference King, Novaleski and Rousseau12} found improvement in voice handicap index scores post-operatively amongst all patients and voice handicap index outcome did not change with the difference in the voice-rest recommendation in the different groups. Our study had similar results in which voice handicap index improvement was observed in all cases post-operatively in both the groups. In addition, significant differences in voice handicap index scores were noted from pre-op to one-week post-surgical and one-month post-surgical values in absolute voice-rest and relative voice-rest groups, with statistically significant difference between the two groups (p values 0.005 and < 0.001, respectively).