The impact of low rate stimulation on speech understanding and sound perception using the ACE strategy
23 April 2019 (online)
Low rate stimulation in cochlear implant (CI) subjects has gained interest recently, as the development of smaller speech processors is increasingly challenging. Due to the transcutaneous wireless signal and power transmission, the power consumption of CI systems is inherently high. Subsequently, the relatively large battery occupies a significant amount of space inside the external speech processor. With lower stimulation rates, a significant reduction of the systems' power consumption could be achieved. However, former studies on performance at lower stimulation rates were not yet conclusive, so a new study investigating the effect of stimulation rate on speech understanding as well as frequency discrimination at lower rates was initiated.
The study consisted of an active and a passive branch. Subjects with the latest generation of Cochlear devices using the ACE strategy were selected. In the active part rates of 1200 Hz and 500 Hz have been compared with regard to frequency discrimination and modulation detection below 500 Hz. In the chronic part, rates of 900 Hz and 500 Hz were compared to each other. Speech tests (Monosyllables and Oldenburg Sentence Test) as well as frequency discrimination have been examined at 900 Hz first. Subsequently, subjects have been sent home with a 500 Hz stimulation rate for accommodation and the test battery was repeated at 500 Hz three weeks later.
The results show equal hearing performance at the different stimulation rates.
Lower stimulation rates in the range of 500 Hz are applicable without limitations in the clinical routine.