Articulatory-kinematic changes in speech following surgical treatment for oral or oropharyngeal cancer: A systematic review

Background: Treatment for oral or oropharyngeal squamous cell carcinoma (O&OSCC) often leads to problems with speech articulation. Articulatory-kinematic data may be especially informative in designing new therapeutic approaches for individuals treated for these tumours.

Aims: To provide a systematic review of the literature assessing the articulatory-kinematic consequences of oral and oropharyngeal cancer treatment.

Methods & procedures: Five databases (PubMed, Embase, Scopus, Web of Science and PsycInfo) were used to identify studies that used kinematic methods to characterize the speech of individuals treated for O&OSCC. Risk of bias was assessed using the critical appraisal checklist from the Joanna Briggs Institute. Data were synthesized using the Synthesis Without Meta-Analysis guidelines.

Outcomes & results: In total, 29 studies with a total of 197 individuals treated for O&OSCC were included. In most studies the risk of bias was moderate to high and certainty of evidence was very low to low. Results showed both global changes (i.e., reduced movement and increased asymmetry of the tongue) as well as more local changes (i.e., reduced palatal contact and more centralized productions of consonants) following treatment for O&OSCC. Generally, reported changes were related to tumour size and location. Smaller tumours resulted in better or more typical articulatory-kinematic speech outcomes. Articulatory movements were most reduced in the affected region of the tongue as compared with neighbouring parts. Study findings were limited to small sample sizes with generally minimal descriptions of patient characteristics. No study assessed the influence of primary radiation treatment or adjuvant radiation therapy on kinematic speech outcomes.

Conclusions & implications: Based on the literature to date, surgical treatment for O&OSCC seems to reduce articulatory-kinematics of speech, and post-treatment outcomes may be partially explained by tumour size and location. The absence of studies assessing the effect of primary or adjuvant radiation therapy on articulatory-kinematics limits our knowledge of how these interventions influence post-treatment kinematic speech outcomes. Future studies should provide detailed patient descriptions and develop standardized speech assessment tools in order to further our knowledge regarding articulatory-kinematic speech changes following treatment, and to move towards the development of active rehabilitation strategies for those with O&OSCC.

What this paper adds: What is already known on this subject Treatment for O&OSCC can result in problems with speech articulation. Speech outcomes for O&OSCC are highly variable. What this paper adds to the existing knowledge We systematically reviewed and synthesized the literature on articulatory-kinematic changes following O&OSCC treatment and identified 29 related studies. Treatment for O&OSCC resulted in global (i.e., more asymmetrical or reduced movement patterns) and local (i.e., reduced palatal contact) articulatory-kinematic changes. In general, smaller tumours resulted in better or more typical articulatory-kinematic speech outcomes as compared with larger tumours. Articulatory movements were most reduced in the affected region of the tongue as compared with neighbouring parts. What are the potential or actual clinical implications of this work? Understanding articulatory-kinematic impacts of surgical intervention for O&OSCC can guide (the development of) tailored speech rehabilitation.