Sex Differences in Pitch Range and Speech Fundamental Frequency After Arytenoid Adduction and Thyroplasty

The purpose of this study was to clarify the sex differences in pitch range (PR) and speech fundamental frequency (SFF) after arytenoid adduction (AA) combined with type 1 thyroplasty (TP1) in patients with unilateral vocal fold paralysis (UVFP) and to assess the cause of these differences.

This is a retrospective review of clinical records.

The records of 50 patients with UVFP for whom PR, SFF, and maximum phonation time (MPT) had been evaluated before and 1 year after AA combined with TP1 were analyzed. Patients consisted of 36 men and 14 women. In particular, in the 37 patients (24 men and 13 women) who had ≥2 semitones (STs) in preoperative PR (pre-PR), the differences and correlations between the pre-PR and the postoperative PR (post-PR), SFF, and MPT were compared between the sexes. We also discussed cases of post-PR deterioration and abnormal SFF.

The characteristics of PR in men are narrow pre-PR (14.7 ± 11.5 STs) and significant extension of post-PR (22.6 ± 6.3 STs). MPT extended from 4.6 ± 2.5 seconds to 14.8 ± 7.2 seconds. In contrast, women had a wide pre-PR (18.1 ± 7.2 STs) and showed no significant post-PR extension (21.7 ± 7.8 STs). MPT extended from 5.1 ± 1.9 seconds to 16.8 ± 7.2 seconds. Although there were no significant changes in average SFF, as well as the highest and lowest pitch after the operation, the variance of the pre-SFF tended to converge into the physiological range in the post-SFF (P = 0.08). Compared with the SFF data of normal adult controls, post-SFF in the normal range was 46.0% (23/50). In patients who showed a >20% improvement in PR, normal post-SFF appeared in 68.8% of the patients (11/16). Particularly in those women, 83.3% (5/6) showed a normal post-SFF. Men showed greater difficulty in recovery of normal PR, SFF, and MPT; however, there were fewer patients (4.2%; 1/24) with a PR deterioration of >20%. Regarding women, although some patients showed a parallel recovery in PR and SFF to the normal range, there was a high rate of patients showing PR deterioration (30.8%; 4/13).

AA combined with TP1 resulted in the recovery of not only MPT but also PR and SFF. In addition, sex differences in operative effects were suggested. In men, although MPT is difficult to be fully recovered, PR deterioration was mild. In women, although MPT was more easily extended, PR deterioration occurred more readily because of operative effects such as hypermedialization of their smaller larynx. The post-PR variation appeared to be associated with SFF. Our results indicate the necessity to assess patients' PR and SFF even if their MPTs recover, particularly in patients with postoperative voice insufficiency.