A Systematic Review of Speech and Language Therapy Interventions for Presbyphonia Using the Rehabilitation Treatment Specification System

BACKGROUND: The prevalence of voice disorders in the elderly is 4× higher than for the population at large. The most common cause of dysphonia in this group is presbyphonia, the preferred first-line treatment for which is voice therapy with a speech and language therapist. This systematic review seeks to identify how voice therapy affects multidimensional voice outcomes in people with presbyphonia.

METHODS: A systematic search of CINAHL, Embase, Emcare, MEDLINE and Google Scholar was carried out in March 2023. No limitations were placed on date or language of publication. Subgroup analysis was used to compare studies based on participant demographics, intervention duration, study design and intervention content. Interventions were specified using the Rehabilitation Treatment Specification System (RTSS) employing a consensus methodology among the reviewers. Results were synthesized utilizing metanalysis when outcomes were adequately specified, and narrative analysis when they were not.

RESULTS: 23 studies were included in this review with a total of 1,050 subjects (mean age: 72.5 ± 8.6; 51% female). The most reported intervention was Vocal Function Exercises. Per the RTSS, 14 reported interventions employed a predominantly Organ Functions approach and 14 remaining interventions employed a Skills & Habits approach. Metanalysis confirmed post-therapy improvement in patient-related outcome measures (PROMs) of 0.93 standard mean difference (p<0.001, 95% CI: 0.70-1.17); studies with predominantly men and with longer treatment periods were associated with larger improvements, whilst RCTs reported more modest improvements. Metanalysis also identified a mean post-therapy increase in maximum phonation time (MPT) of 5.37 s (p<0.01, 95% CI: 3.52-7.22). Treatments with an Organ Functions focus resulted in greater gains in MPT than those with a Skills & Habits focus (7.52 s vs. 2.90 s). Finally, metanalysis identified reductions in acoustic perturbation measures (jitter: 0.62%, p<0.001, 95% CI: 0.26-0.97%; shimmer 1.05%, p<0.00001, 95% CI: 0.67-1.44%). Narrative synthesis further identified improvement in auditory-perceptual voice quality in all active treatment groups as well as improved glottal function in the majority of studies which reported this.

CONCLUSIONS: Despite the uncertainty around internal validity introduced by the inclusion of a wide range of study designs, there is convincing evidence that voice therapy for presbyphonia results in significant improvement in patient-reported, aerodynamic, acoustic, and expert-rated voice outcomes. Treatments with an Organ Functions focus may better address the underlying physiological deficits of presbyphonia, although future comparative studies are warranted.