Perceptual changes in place of stimulation with long cochlear implant electrode arrays

Landsberger, David M.; Mertens, Griet; Punte, Andrea Kleine; Heyning, Paul Van de

doi:10.1121/1.4862875

Cited by 34 publications

(32 citation statements)

References 16 publications

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“…If so, apical stimulation would be less precise than stimulation in the middle and basal regions, reducing the need for an accurate frequency place match. This possibility is supported by the findings that with 31 mm electrodes, some users are able to get good pitch information from all electrodes while others have difficulty discriminating the most apical electrodes (Baumann and Nobbe, 2006; Hamzavi and Arnoldner, 2006; Gani et al, 2007; Landsberger et al, 2014). Alternatively, an accurate frequency place match might require a current focused stimulation mode (e.g.…”

Section: Discussionmentioning

confidence: 77%

The Relationship Between Insertion Angles, Default Frequency Allocations, and Spiral Ganglion Place Pitch in Cochlear Implants

et al. 2015

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Objectives Commercially available cochlear implant systems attempt to deliver frequency information going down to a few hundred Hz, but the electrode arrays are not designed to reach the most apical regions of the cochlea which correspond to these low frequencies. This may cause a mismatch between the frequencies presented by a cochlear implant electrode array and the frequencies represented at the corresponding location in a normal hearing cochlea. In the following study, the mismatch between the frequency presented at a given cochlear angle and the frequency expected by an acoustic hearing ear at the corresponding angle is examined for the cochlear implant systems that are most commonly used in the United States. Design The angular insertion of each of the electrodes on four different electrode arrays (MED-EL Standard, MED-EL Flex28, Advanced Bionics HiFocus 1J, and Cochlear Contour Advance) was estimated from x-rays. For the angular location of each electrode on each electrode array, the predicted spiral ganglion frequency was estimated. The predicted spiral ganglion frequency was compared with the center frequency provided by the corresponding electrode using the manufacturer’s default frequency-to-electrode allocation. Results Differences across devices were observed for the place of stimulation for frequencies below 650 Hz. Longer electrode arrays (i.e. the MED-EL Standard and Flex28) demonstrated smaller deviations from the spiral ganglion map than the other electrode arrays. For insertion angles up to approximately 270°, the frequencies presented at a given location were typically approximately an octave below what would be expected by a spiral ganglion frequency map, while the deviations were larger for angles deeper than 270°. For frequencies above 650 Hz, the frequency to angle relationship was consistent across all four electrode models. Conclusions A mismatch was observed between the predicted frequency and default frequency provided by every electrode on all electrode arrays. The mismatch can be reduced by changing the default frequency allocations, inserting electrodes deeper into the cochlea, or allowing cochlear implant users to adapt to the mismatch. Further studies are required to fully assess the clinical significance of the frequency mismatch.

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Section: Discussionmentioning

confidence: 77%

The Relationship Between Insertion Angles, Default Frequency Allocations, and Spiral Ganglion Place Pitch in Cochlear Implants

et al. 2015

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“…The amplitudes of each stimulus were adjusted to ensure that all stimuli were equally loud at a most comfortably loud level using a method similar to Landsberger et al (2014). Four stimuli were presented with a 300 ms inter-stimulus-interval (ISI) at amplitudes corresponding to what had been previously described as the most comfortable loudness.…”

Section: Methodsmentioning

confidence: 99%

“…Similarly, using a multi-dimensional scaling technique, Vermeire et al (2013) demonstrated that a change in acoustic frequency can be represented by the same perceptual dimension as a change in electrode. However, it is worth noting that while a change in place of stimulation produces a change in place pitch for all electrode locations on even long (31 mm) electrode arrays (Landsberger et al, 2014), the changes in pitch corresponding to the most apical electrodes on these arrays are relatively small (e.g. Baumann and Nobbe, 2004; 2006; Dorman et al, 2007; Landsberger et al 2014).…”

Section: Introductionmentioning

confidence: 99%

“…However, it is worth noting that while a change in place of stimulation produces a change in place pitch for all electrode locations on even long (31 mm) electrode arrays (Landsberger et al, 2014), the changes in pitch corresponding to the most apical electrodes on these arrays are relatively small (e.g. Baumann and Nobbe, 2004; 2006; Dorman et al, 2007; Landsberger et al 2014). The corresponding pitch from high rate stimulation on the most apical electrodes of long electrode arrays typically asymptotes down to approximately 300 Hz (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Qualities of Single Electrode Stimulation as a Function of Rate and Place of Stimulation with a Cochlear Implant

et al. 2016

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Objectives Although it has been previously shown that changes in temporal coding produce changes in pitch in all cochlear regions, research has suggested that temporal coding might be best encoded in relatively apical locations. We hypothesized that although temporal coding may provide useable information at any cochlear location, low rates of stimulation might provide better sound quality in apical regions that are more likely to encode temporal information in the normal ear. In the present study, sound qualities of single electrode pulse trains were scaled to provide insight into the combined effects of cochlear location and stimulation rate on sound quality. Design Ten long term users of MED-EL cochlear implants with 31 mm electrode arrays (Standard or FLEXSOFT) were asked to scale the sound quality of single electrode pulse trains in terms of how “Clean”, “Noisy”, “High”, and “Annoying” they sounded. Pulse trains were presented on most electrodes between 1 and 12 representing the entire range of the long electrode array at stimulation rates of 100, 150, 200, 400, or 1500 pulses per second. Results While high rates of stimulation are scaled as having a “Clean” sound quality across the entire array, only the most apical electrodes (typically 1 through 3) were considered “Clean” at low rates. Low rates on electrodes 6 through 12 were not rated as “Clean” while the low rate quality of electrodes 4 and 5 were typically in between. Scaling of “Noisy” responses provided an approximately inverse pattern as “Clean” responses. “High” responses show the trade-off between rate and place of stimulation on pitch. Because “High” responses did not correlate with “Clean” responses, subjects were not rating sound quality based on pitch. Conclusions If explicit temporal coding is to be provided in a cochlear implant, it is likely to sound better when provided apically. Additionally, the finding that low rates sound clean only at apical places of stimulation is consistent with previous findings that a change in rate of stimulation corresponds to an equivalent change in perceived pitch at apical locations. Collectively, the data strongly suggests that temporal coding with a cochlear implant is optimally provided by electrodes placed well into the second cochlear turn.

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“…It was shown in earlier studies that deeply inserted electrode arrays result in increased intracochlear trauma and the loss of residual hearing , limited stimulation of the basal frequencies [Finley and Skinner, 2008] and confusion of the apical pitch due to neural interaction of the more densely located neural fibers in the apical regions in the cochlea [Gani et al, 2007]. On the other hand, other studies show that stimulation of the lower frequencies in the apical region of the cochlea are related to better speech perception outcomes [Hochmair et al, 2003;Yukawa et al, 2004], increased range of place pitches by stimulating a larger number of neural fibers [Landsberger et al, 2014], or reduced mismatch between the predicted and default frequencies by a further approximation of the normal frequency to place function of the cochlea [Landsberger et al, 2015]. Another study also showed that deeper inserted electrode arrays are not associated with scalar translocations [Wanna et al, 2014].…”

Section: Introductionmentioning

confidence: 93%

Comparison of the HiFocus Mid-Scala and HiFocus 1J Electrode Array: Angular Insertion Depths and Speech Perception Outcomes

Jagt¹,

Briaire²,

Verbist³

et al. 2016

Audiol Neurotol

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The HiFocus Mid-Scala (MS) electrode array has recently been introduced onto the market. This precurved design with a targeted mid-scalar intracochlear position pursues an atraumatic insertion and optimal distance for neural stimulation. In this study we prospectively examined the angular insertion depth achieved and speech perception outcomes resulting from the HiFocus MS electrode array for 6 months after implantation, and retrospectively compared these with the HiFocus 1J lateral wall electrode array. The mean angular insertion depth within the MS population (n = 96) was found at 470°. This was 50° shallower but more consistent than the 1J electrode array (n = 110). Audiological evaluation within a subgroup, including only postlingual, unilaterally implanted, adult cochlear implant recipients who were matched on preoperative speech perception scores and the duration of deafness (MS = 32, 1J = 32), showed no difference in speech perception outcomes between the MS and 1J groups. Furthermore, speech perception outcome was not affected by the angular insertion depth or frequency mismatch.

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Perceptual changes in place of stimulation with long cochlear implant electrode arrays

Cited by 34 publications

References 16 publications

The Relationship Between Insertion Angles, Default Frequency Allocations, and Spiral Ganglion Place Pitch in Cochlear Implants

The Relationship Between Insertion Angles, Default Frequency Allocations, and Spiral Ganglion Place Pitch in Cochlear Implants

Qualities of Single Electrode Stimulation as a Function of Rate and Place of Stimulation with a Cochlear Implant

Comparison of the HiFocus Mid-Scala and HiFocus 1J Electrode Array: Angular Insertion Depths and Speech Perception Outcomes

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