The aim of this double-blind, randomized, controlled, three-period cross-over study was to evaluate the effectiveness of an adjuvant therapy (CoQ10 in its water-soluble form (QTer) and vitamin A) in supporting voice rehabilitation in a large group of patients with muscle tension dysphonia (MTD).

To do so, 50 patients with MTD were randomly assigned to two counter-balanced arms. Group A (ADJ-PLA) patients were administered QTer 300 mg (equal to CoQ10 30 mg) and Vit A acetate 500.000 Ul/g 1 mg twice daily for a 4-week intervention period, followed by a 4-week period of wash-out, and then were submitted to a last 4-week period of placebo. Patients in Group B (PLB-ADJ) were given the treatment period in reverse order.

Results showed a trend toward recovery of vocal function regardless of group assignment. A significant time by group effect was found on Dysphonia Severity Index (DSI) (p = 0.03), the highest possible frequency (F0-high) (p = 0.008) and Shimmer (acoustic analysis of relative amplitude disturbance) (p = 0.048), under CoQ10 and Vit A treatment, with a small effect size. There was no significant time by group effect on the other study measures, namely Maximum Phonation Time (MPT), the lowest intensity, Voice Handicap Index (VHI). Authors concluded that even if a recovery in vocal function was observed in all patients (voice rehabilitation), the improvement of DSI was greater under CoQ10 and Vitamin treatment, indicating a more pronounced improvement of vocal quality under adjuvant therapy

Ruoppolo G, Longo L, Pescerelli P, Mango C, Nicastri M, Flaccadoro F, Mancini P, Greco A, De Vincentiis M. CoQ10 and Vitamin A Supplementation Support Voice Rehabilitation. A Double-Blind, Randomized, Controlled, Three-Period Cross-Over Pilot Study. Front Pharmacol. 2019 Sep 10;10:939.