Sound localization in patients with unilateral cochlear implants

Abstract

Spontaneous development of sound localization ability in totally deaf patients with unilateral cochlear implants is proportional to the time interval between implantation and initial testing. Improvement appears to be influenced by training, and to be greater in postlingual than in prelingual implantees.

Effect of Audiovisual Training on Monaural Spatial Hearing in Horizontal Plane

“…However, while these cues can account for some performances in monaural sound localization, not all unilateral deaf patients present satisfactory performances [3]. Such impairment is especially accentuated in unilaterally cochlear implanted deaf patients [6], [7]. In this case, patients probably use the information provided by the other sensory modalities (cross-modal compensation), especially the visual channel because visuo-auditory interactions can improve sound localization [8].…”

Spatial hearing with a single cochlear implant in late-implanted adults

“…Nonetheless, some localisation abilities have been documented when frequency cues were preserved (Grantham et al, 2008; see also Noble et al, 2008) or when monaural CI recipients were trained using pure tones of fixed intensity (Luntz et al, 2002(Luntz et al, , 2005. In addition, the study by Luntz et al (2005) suggests that the longer the experience with the CI, the better the monaural localisation abilities, regardless of deafness onset. Remarkably, all of the previous studies on monaural localisation abilities with a single CI have been conducted on recipients who acquired deafness postlingually.…”

“…This suggests that there may be a close relationship between years of implant use and the development of monaural localisation abilities in CI recipients. The only previous report of monaural localisation abilities in a group of 4 prelingual CI users was conducted by Luntz et al (2005) and documented chance performance in this population. However, it should be emphasised that the duration of implant use in their study was relatively short (range 1 and 7 months), whereas our prelingual recipients had an experience with their monaural implant that ranged between 2 and 12 years.…”

“…However, it should be emphasised that the duration of implant use in their study was relatively short (range 1 and 7 months), whereas our prelingual recipients had an experience with their monaural implant that ranged between 2 and 12 years. Furthermore, the study by Luntz et al (2005) tested children of considerably different age (8, 10, 12 and 14 years old). Our findings expand the current knowledge on monaural spatial abilities of prelingual CI recipients, by testing for the first time a sample of adult prelingual CI users and by showing a relationship between years of implant use and acquired monaural abilities.…”

“…Given these considerations, the most informative context for assessing sound localisation abilities with a single CI are the recipients who are only implanted unilaterally, or the sequentially implanted recipients tested before activation of the second implant. Remarkably, only a minority of studies has conducted such investigations in CI recipients fitted with a single device (Luntz et al, 2002(Luntz et al, , 2005Buhagiar et al, 2004;Tyler et al, 2006Tyler et al, , 2007Dunn et al, 2008;Grantham et al, 2008;Noble et al, 2008). Furthermore, the majority of these investigation focused primarily on postlingually deaf CI recipients.…”