scholarly journals Correlation of Electrically Evoked Compound Action Potential Amplitude Growth Function Slope and Anamnestic Parameters in Cochlear Implant Patients—Identification of Predictors for the Neuronal Health Status

Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 203
Author(s):  
Lutz Gärtner ◽  
Katharina Klötzer ◽  
Thomas Lenarz ◽  
Verena Scheper
Keyword(s):  
Hearing Loss ◽  
Health Status ◽  
Cochlear Implantation ◽  
Electrode Array ◽  
Compound Action Potential ◽  
Growth Function ◽  
Evoked Compound Action Potential ◽  
The Mean ◽  
Amplitude Growth ◽  
Compound Action

Cochlear implants (CI) are the treatment of choice in profoundly deaf patients. Measuring the electrically evoked compound action potential (ECAP) has become an important tool for verifying the function of the spiral ganglion neurons (SGN), which are the target cells of the CI stimulation. ECAP measurement is only possible after electrode insertion. No information about the neuronal health status is available before cochlear implantation. We investigated possible correlations between the ECAP amplitude growth function (AGF) slope and anamnestic parameters to identify possible predictors for SGN health status and therefore for CI outcome. The study included patients being implanted with various electrode array lengths. Correlation analysis was performed for the mean AGF slope of the whole array, for separate electrodes as well as for grouped electrodes of the apical, medial, and basal region, with duration of deafness, age at implantation, residual hearing (grouped for electrode length), and etiology. The mean ECAP AGF slopes decreased from apical to basal. They were not correlated to the length of the electrode array or any etiology. For the mean of the full array or when grouped for the apical, middle, and basal part, the ECAP AGF slope was negatively correlated to the duration of hearing loss and the age at implantation. Since a significant negative correlation of the ECAP AGF slope and age at cochlear implantation and duration of deafness was observed, this study supports the statement that early implantation of a CI is recommended for sensorineural hearing loss. Additional factors such as the cochlear coverage and insertion angle influence the ECAP AGF slope and performance of the patient and should be included in future multifactorial analysis to study predictive parameters for the CI outcome.

Preliminary results on correlation between neural response imaging and ‘most comfortable levels' in cochlear implantation

2006 ◽  
Vol 120 (4) ◽  
pp. 261-265 ◽  
Author(s):  
I Akin ◽  
G Kuran ◽  
C Saka ◽  
M Vural
Keyword(s):  
Cochlear Implantation ◽  
Average Duration ◽  
Compound Action Potential ◽  
Neural Response ◽  
Evoked Compound Action Potential ◽  
The Mean ◽  
The One ◽  
Bilateral Deafness ◽  
Implanted Device ◽  
Compound Action

During cochlear implantation, precise placement of the cochlear electrodes against the cochlear nerve is one of the most important steps, necessary to enable the patient to be aware of the stimulus from the implanted device. Neural response imaging (NRI) is a new tool which measures the evoked compound action potential generated as a result of electrical stimulation of the cochlea by properly placed electrodes during surgery.The aim of this study was to examine the correlation between intra-operative NRI recordings and ‘most comfortable levels’ (M levels) measured during standard fitting with the SoundWave fitting software, in cochlear implantation patients. Seven adult subjects were included in the study. The average duration of profound bilateral deafness was seven years (range = 19 years) and the mean age at implantation was 24 years (range = 17–34 years). All subjects underwent implantation and reached the one-month fitting session; one patient reached the two-month fitting session. The intra-operative NRI threshold (tNRI) was observed to be much higher than the first fitting M levels. The tNRI was 203 per cent of the sequential M value and 246 per cent of the paired M value. All but one intra-operative tNRI values were greater than 150 clinical units (CU), and all first fitting M levels were on average below 100 CU. No obvious correlation was found between individual intra-operative tNRI and first fitting M levels. The M levels at one month were much higher than the first fitting M levels, with much more dispersion.

scholarly journals Effect of Chronological Age on Pulse Rate Discrimination in Adult Cochlear-Implant Users

2021 ◽  
Vol 25 ◽  
pp. 233121652110073
Author(s):  
Kelly C. Johnson ◽  
Zilong Xie ◽  
Maureen J. Shader ◽  
Paul G. Mayo ◽  
Matthew J. Goupell
Keyword(s):  
Pulse Rate ◽  
Compound Action Potential ◽  
Action Potential Amplitude ◽  
Growth Functions ◽  
Evoked Compound Action Potential ◽  
Rate Discrimination ◽  
Amplitude Growth ◽  
Temporal Pulse ◽  
Compound Action Potential Amplitude ◽  
Compound Action

Cochlear-implant (CI) users rely heavily on temporal envelope cues to understand speech. Temporal processing abilities may decline with advancing age in adult CI users. This study investigated the effect of age on the ability to discriminate changes in pulse rate. Twenty CI users aged 23 to 80 years participated in a rate discrimination task. They attempted to discriminate a 35% rate increase from baseline rates of 100, 200, 300, 400, or 500 pulses per second. The stimuli were electrical pulse trains delivered to a single electrode via direct stimulation to an apical (Electrode 20), a middle (Electrode 12), or a basal location (Electrode 4). Electrically evoked compound action potential amplitude growth functions were recorded at each of those electrodes as an estimate of peripheral neural survival. Results showed that temporal pulse rate discrimination performance declined with advancing age at higher stimulation rates (e.g., 500 pulses per second) when compared with lower rates. The age-related changes in temporal pulse rate discrimination at higher stimulation rates persisted after statistical analysis to account for the estimated peripheral contributions from electrically evoked compound action potential amplitude growth functions. These results indicate the potential contributions of central factors to the limitations in temporal pulse rate discrimination ability associated with aging in CI users.

scholarly journals Impedance and Electrically Evoked Compound Action Potential (ECAP) Drop within 24 Hours after Cochlear Implantation

PLoS ONE ◽  
2013 ◽  
Vol 8 (8) ◽  
pp. e71929 ◽  
Author(s):  
Joshua Kuang-Chao Chen ◽  
Ann Yi-Chiun Chuang ◽  
Georg Mathias Sprinzl ◽  
Tao-Hsin Tung ◽  
Lieber Po-Hung Li
Keyword(s):  
Action Potential ◽  
Cochlear Implantation ◽  
Compound Action Potential ◽  
Evoked Compound Action Potential ◽  
Compound Action
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