Speech perception outcomes following auditory brainstem implantation in both tumour and non-tumour patients: A review

Objective: A broad variation in speech perception results has been observed in patients who have received electrical stimulation of the cochlear nucleus complex from auditory brainstem implants (ABIs). This study aims to investigate the factors following implantation that influence speech perception outcomes in both tumour (T) and non-tumour (NT) patient groups by reviewing the current literature and also help explain the reasons behind the broad variation in speech perception outcomes reported. Study design: A search strategy was devised and applied to databases including PubMed, Medline, Google Scholar, CINAHL, and the Cochrane review library to identify relevant cohort studies available. Relevant citations from current publications were also followed up. Papers investigating speech perception outcomes post ABI implantation were sought. Results: Six longitudinal studies were identified that assessed speech perception outcomes in ABI recipients. Meta-analysis was not possible due to variations in methodologies and outcome measures. Qualitative analysis was completed and suggests that speech perception improves for at least the first year post implantation. Conclusions: There is currently limited evidence for the factors post implantation that effect speech perception outcomes, although current literature would suggest that speech perception improves for at least the first year after implantation. Current research also implies that the choice of speech processing strategy may also affect outcomes although further research in this area is required.