Development and First Evaluation of a Spatial Auditory Training Program for SSD Cochlear Implant Users

Cochlear implants (CIs) allow single-sided deafness (SSD) patients to regain hearing on both sides. However, current rehabilitation programs primarily focus on speech perception, leaving a significant gap in spatial hearing abilities compared with normal-hearing individuals. In this study, we developed and evaluated a novel method for training spatial hearing abilities in SSD CI users.

Twelve SSD CI patients underwent a 4-week training program. Twice a week, subjects completed training sessions of approximately 30 minutes, each involving 50 stimuli presented by 7 loudspeakers arranged from -90 to +90 degrees in the horizontal plane. Spatial hearing was evaluated before and after training using the root mean square error (RMSE), the mean absolute error (MAE), and the bias of source location angles, and by the Speech, Spatial and Quality of Hearing Scale (SSQ) questionnaire.

Localization abilities assessed by MAE and by RMSE were better with CI than without ( p < 0.001), but further significantly improved after spatial auditory training (both p < 0.05), especially for signals presented from the frontal direction. Furthermore, subjective spatial hearing abilities measured by the SSQ also improved after training ( p < 0.01). Subjects with a larger pretraining bias showed a greater reduction in bias after training.

A 4-week lasting spatial auditory training led to significant improvements both in subjective and in objective spatial hearing outcomes in adult SSD CI subjects. Therefore, the inclusion of such training programs in the postoperative rehabilitation setting of SSD CI patients and its evaluation in larger studies is a worthwhile next step.