Pitch and loudness estimation for single and multiple pulse per period electric pulse rates by cochlear implant patients

Abstract

Numerical estimates of loudness and pitch for electric pulse rates were obtained from 14 patients using the 22 electrode cochlear implant manufactured by Cochlear Limited. Six patients were postlinguistically deafened adults, and eight patients were adults and children who became deaf very early in life. Comparisons were made between two types of pulse rate patterns. The SPP pulse pattern presented a single pulse every period, the inverse of the pulse rate. The MPP pulse pattern presented multiple pulses in the first half of the period, using a rate of 1000 pulses/s, with no stimulation in the second half of the period. The pulse rates used for the SPP and MPP pulse patterns were 71.4-500 pulses/s, which corresponded to periods of 14-2 ms. For the SPP pulse pattern, the total number of pulses over the duration of the stimulus increased with increases in pulse rate, while for the MPP pulse pattern, the total number of pulses remained constant. Pitch and loudness estimates were obtained from the postlinguistically deafened patients for the SPP and MPP pulse patterns, and from the early-deafened patients for the MPP pulse pattern. Loudness estimates for the SPP pulse pattern increased with increases in pulse rate for all postlinguistically deafened patients. Loudness estimates for the MPP pulse pattern decreased with increases in pulse rate for three of the six postlinguistically deafened patients and for six of the eight early-deafened patients. For the other patients (three postlinguistically deafened and two early-deafened), loudness estimates marginally increased with increases in pulse rate. Pitch estimates for the SPP and MPP pulse patterns increased with increases in pulse rate for the six postlinguistically deafened patients. For the early-deafened patients, pitch estimates for the MPP pulse patterns increased with increases in pulse rate for only five of the eight patients. For the other three early-deafened patients, pitch estimates were similar to the loudness estimates and decreased with increases in pulse rate.

Acoustic to Electric Pitch Comparisons in Cochlear Implant Subjects with Residual Hearing

“…Increasing the rate of stimulation from 100 pps up to about 600 pps produces increasingly higher pitch sensations, and this effect tends to asymptote at higher rates (Simmons et al 1979;Eddington 1980;Tong et al 1983;Townshend et al 1987;Busby and Clark 1997). In this study, stimulation rates were always higher than 700 pps and were held constant during the experiments.…”

“…Pitch sensations produced by multichannel cochlear implants have been extensively investigated in bilaterally deaf subjects using pitch-ranking experiments (Simmons et al 1979;Shannon 1983;Townshend et al 1987;Dorman et al 1990;Busby et al 1994;Nelson et al 1995;Collins et al 1997;Collins and Throckmorton, 2000) or pitch-estimation experiments (Eddington 1980;Tong et al 1983;Tong and Clark 1985;Shannon 1993;Busby et al 1994;Cohen et al 1996a;Busby and Clark 1997;Collins et al 1997). These studies demonstrated that electric stimulation of the ear produced complex auditory sensations, one component of which was similar to pitch.…”

Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling

“…For example, CIs have up to 22 electrodes, but clinical and psychophysical studies show that users do not receive functional benefit on all channels (Busby and Clark 1997;Chatterjee and Shannon 1998;Collins et al 1997;Shannon et al 2004). Additionally, tissue-electrode interactions cause fibrosis with deleterious effects (Bas et al 2012).…”

“…However, challenges remain in the design of these and other neuroprosthetic devices, given the drawbacks of conventional electrical stimulation (Grill et al 2009). Tissue-electrode electrochemical interactions induce fibrosis with deleterious effects (Bas et al 2012), and electrical current spread can lead to interference among channels (Busby and Clark 1997;Chatterjee and Shannon 1998;Collins et al 1997). In CI patients, the loss of perceptual channels results in a poor performance for music perception and word recognition in noisy environments (Drennan and Rubinstein 2008;McDermott 2004;Spahr et al 2008).…”

Modulation Frequency Discrimination with Modulated and Unmodulated Interference in Normal Hearing and in Cochlear-Implant Users

“…Some pitch information is conveyed to CI users via periodicity in the temporal envelope of the pulse trains or, in the case of low pulse rates (less than about 300 Hz), by the pulse rate itself (e.g., Busby and Clark 1997;Kong et al 2009). Carlyon and colleagues have shown that CI users are often sensitive to changes in pulse rates in ways that resemble the sensitivity shown by normal-hearing (NH) listeners when presented with acoustic pulse trains that are high-pass filtered to remove potentially resolved spectral components (e.g., Carlyon et al 2002Carlyon et al , 2008.…”